i

The closed circle of empathy: mirror neuron system activation and anterior EEG

asymmetries in response to outgroup members.

by

Jennifer N. Gutsell

Master’s thesis submitted in conformity with the requirements

for the Masters of Arts and Science

Department of Psychology,

University of Toronto, 2009

© Copyright by Jennifer Nadine Gutsell (2009)

ii

The closed circle of empathy: mirror neuron system activation and anterior EEG asymmetries

in response to outgroup members. - Jennifer N. Gutsell, Department of Psychology,

University of Toronto, 2009

Abstract

Empathy varies with similarity and familiarity of the other. Since outgroups are seen as

dissimilar to the self, empathy might be restricted to the ingroup. We looked at two neural

correlates of empathy: mirror neuron system activation as indicated by

electroencephalographic mu suppression and prefrontal alpha asymmetry. Non black

participants watched videos of ingroup and outgroup members acting and expressing

emotions, and then acted and experienced emotions themselves. Due to methodological

problems, mirror neuron system activation was not obtained. However, anterior asymmetries

indicated avoidance motivation during the experience of sadness and the mere observation of

sad ingroup members while participants did not show anterior asymmetry when observing the

black outgroup. These findings suggest that empathy is bounded to a closed circle of similar

others.

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Table of Contents

Abstract… ..........................................................................................................ii

Table of contents… .......................................................................................... .iii

List of Tables… ................................................................................................ .iv

List of figures… ................................................................................................. .v

Introduction….. .................................................................................................. 1

Theoretical Background .................................................................................... 2

Empathy – a definition… ..................................................................................... 2

How do we empathize? – The Perception Action Model of empathy .................... 4

The stages of empathy .......................................................................................... 5

The limits of empathy – moderators for empathic responses ................................. 8

The mirror neuron system – a neural account for vicarious emotions and the

basis of empathy – moderators for empathic responses ...................................... 10

Prejudice and the distinction between “us” and “them” ....................................... 14

Perceiving others as different ............................................................................. 15

Social neuroscientific methods to measure empathy ........................................... 16

Measuring Mirror Neuron System activation ........................................... .16

Measuring vicarious prefrontal alpha asymmetries .................................... 18

Overview ........................................................................................................... 20

Method .............................................................................................................. 21

Participants ........................................................................................................ 21

Procedure ........................................................................................................... 21

Stimulus Materials ............................................................................................. 22

Measures ............................................................................................................ 24

Measures of ingroup favouritism .............................................................. 24

Measures of empathy ................................................................................ 25

EEG data acquisition and processing .................................................................. 35

Results ............................................................................................................... 26

Mu suppression .................................................................................................. 26

Anterior Alpha Asymmetry ................................................................................ 27

Behavioural measures ......................................................................................... 30

Correlation with empathy………………………………………………….30

Correlation with ingroup favouritism – IAT, MRS and IOS……………...31

Discussion ......................................................................................................... 31

Limitations and further directions ....................................................................... 34

Conclusions ........................................................................................................ 35

References ......................................................................................................... 37

iv

List of Tables

Table 1 Correlations between anterior alpha asymmetry scores and the measures

of ingroup favouritism and empathy………………………………………….…5

v

List of Figures

Figure 1 The human MNS and its main visual input in action understanding and

imitation...….. ..................................................................................................... 5

Figure 2 Anterior alpha asymmetry scores during the two emotion conditions

(Sad, Happy) for ingroup, self and black. ............................................................. 5

1

I am a Jew. Hath not a Jew eyes? Hath not a Jew hands, organs, dimensions, senses,

affections?

--From The Merchant of Venice (III, i, 60-63)

In the quote above, the character of Shylock pleads for empathy and equal treatment

noting that Jews bleed when pricked, laugh when tickled, and killed when poisoned. Given

our shared humanity, then, why does prejudice seem so inevitable? To answer this question,

the current study looks at the basic processes involved in prejudice by taking a closer look at

brain activity. I propose that the neural systems involved in empathy and action understanding

are less responsive to outgroup members than ingroup members, leading people to ignore the

shared humanity of others.

Empathy is the capacity to recognize and understand other people’s experiences, needs,

and goals, and thus facilitates social understanding and cooperation. Empathy is bounded,

however: it varies as a function of similarity and familiarity of other people (Preston & de

Waal, 2002). According to self-categorization theory (Turner, 1987), ingroup favouritism and

prejudice result from the intersection between one’s self and one’s ingroup. Once one

identifies with a group, the self and the group merge to become interchangeable. The self,

importantly, overlaps with the ingroup, but not with the outgroup. This overlap facilitates

perspective taking and empathic reactions. On the other hand we might be less sensitive to the

feelings of outgroup members and less likely to take their perspective. If people do not feel

other people’s pain, the door for discrimination is wide open. The aim of the current study is,

first, to investigate whether empathy is bounded to ingroup members and, thus, excludes

outgroup member and, second, to find a neural account for why empathy is bounded. To

achieve these goals, this study draws on neuroscientific research on empathy and perspective

taking.

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In what follows, I will first review research on empathy and which factors promote and

prevent empathy. Second, I will present a neuroscientific view on empathy and discuss its

potential origins in our evolutionary history. Third I will discuss prejudice and its causes. I

will further describe the concept of self-other overlap and dehumanization of outgroups, and

connect them to prejudice. I propose that the perceived distance between groups impairs

empathy towards these groups and that this is reflected in the neural processes underlying

empathy. I will, then, discuss two neural correlates and potential measures of empathy –

mirror neuron system activity measured by EEG mu rhythm suppression and asymmetries in

the activity of the prefrontal cortex measured by anterior alpha asymmetries. Third, based on

this theoretical background, I will develop an appropriate research method for examining the

role of the mirror neuron system in prejudice. I will then describe the research design and the

empirical and analytical methods. Finally I will present the results and discuss their

implications.

Theoretical Background

Empathy - a definition

Empathy is generally referred to as the ability to feel with others (Batson et al., 1997).

Usually, when we see others in pain, we suffer along with them and this is one of the building

blocks of human and animal societies (McDougall, 1923). In addition to this fundamental

function, empathy is the basis for numerous important social processes (Carr, Iacoboni,

Dubeau, Mazziotta & Lenzi, 2003). First, empathy functions as the driving force behind

helping behavior (Dovidio, Allen, & Schroeder, 1990; Batson et al., 1997) and other prosocial

behavior, such as cooperation, moral sense, altruism, and justice (Vignemont, & Singer,

2006). Second, in addition to its effects on prosocial behavior, empathy promotes

understanding and, therefore, influences people’s attitudes towards others (Batson et al.,

1997). Feeling empathy for someone elicits a concern about the welfare of the other person.

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This increase in concern persists even after empathy lessens (Batson, Turk, Shaw & Klein,

1995). Third, empathy helps one to predict others’ future behaviour and to understand their

motivational states and goals (Vignemont, et al., 2006). Therefore, empathy is a very effective

tool for social understanding and leads to smooth social interactions. Finally, empathy

facilitates social communication. When we empathize with others, we tend to imitate or

mirror their intonations, gestures, and postures. This imitation elicits fondness and affiliation

in others (Lakin & Chartrand 2003). Similarly, perceiving that others empathize with us

improves our opinion about them (Chartrand, Bargh, 1999).

Because of its importance people have researched empathy for many years (Batson,

Fultz, & Schoenrade, 1987, Cialdini, Brown, Lewis, Luce, & Neuberg, 1997, Hume 1888,

Lipps, 1903 (as cited in Preston, & de Waal, 2002). Despite this interest, researchers still

disagree about what constitutes empathy (Preston, & de Waal, 2002). Some define empathy as

an affective response more appropriate to another’s situation than one’s own (Hoffman,

2000), affect sharing (Preston, & de Waal, 2002), or the sensitivity to and understanding of

the mental states of others (Smith, 2006).

These relatively broad definitions subsume a whole array of related sub concepts that

can be separated into two categories: emotional empathy and cognitive empathy. Emotional

empathy highlights the aspect of feeling others emotions. It includes more basic processes

such as emotional contagion or personal distress (e.g. I feel sad because I see that you feel

sad) and higher order processes that go beyond the mere mirroring of others’ emotions. For

example, empathic concern (Batson, Fultz, & Schoenrade ,1987) results from further

processing based on the information obtained from vicarious emotions (e.g. I feel sorry for

you because you are sad). Cognitive empathy, on the other hand, is the understanding of the

other’s emotional state as opposed to simply vicariously feeling with the other. It includes

phenomena such as cognitive perspective taking (e.g. because I know you and your situation I

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infer that you are sad) and theory of mind. Sometimes a more restrictive definition of empathy

is necessary to allow precise hypotheses and predictions for research purposes (Batson et al.,

1987, Vignemont, & Singer (2006). However, following Preston and de Waal’s (2002)

approach, I see empathy as a concept that joins all phenomena that are based on the same

underling process – the vicarious experience of the emotions of another person. Such a

process based concept of empathy defines empathy in even broader terms than the definitions

discussed above. It includes all levels of empathy related phenomena starting from emotional

contagion to sympathy, guilt, cognitive empathy, and finally even helping behaviour. It also

links empathy to related behaviours such as imitation and priming. Hence, using a process

based definition of empathy enables us to look at the whole array of behaviours that constitute

much of our social nature and, at the same time, to focus on their joint evolutionary origins

and neural basis (Preston, & de Waal, 2002).

How do we empathize? The Perception Action Model of empathy

According to Preston and de Waal (2000) empathy is based on the same mechanism as

motor behaviour – the perception-action mechanism. Actions and the mere perception or

imagination of the same actions share common representations (Prinz, 1987). Through these

common representations, observing behaviour automatically activates and facilitates the same

behaviour in the observer. For example, hyenas are 70% more likely to drink when they see

co specifics drinking (Glickman et al. 1997). Further, Muesseler and Hommel (1997) found

that participants were unable to perceive a stimulus that represented a certain action (e.g. right

key press) while they performed that same action (e.g. pressing the right key), even though

they could easily perceive the stimulus when it did not correspond with the action (e.g. while

pressing the left key). These findings show that, because perception and action share the same

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representation perception and thus are incompatible with each other, perception is blocked

when the representation is used for acting (Chartrand, & Bargh, 1999).

Linking perception, imagination and action through a common representation is

evolutionary highly adaptive since it enables the organism to react quickly and appropriate to

its environment (Preston, & de Waal, 2002). Social animals and especially primates, who rely

heavily on their co specifics for survival, use the action perception link to navigate through

their complicated social systems (Preston, & de Waal, 2002). When someone (the subject)

observes another (the object), the subject has access to the object’s inner states, because the

mere observation activates the same neural and bodily representations in the subject. Through

this mechanism the subject feels with the object; it happens without intention or

consciousness, and that is what we call emotional contagion. Chartrand and Bargh (1999)

proposed that the action perception link consists of three steps. First, the subject observes the

targets facial expression and bodily postures, in a second step this observation activates the

subjects own representations. Finally, this activation increased the tendency for the subject to

behave in the same way as the object. As proposed in the facial feedback hypothesis (Izard,

1990, James, 1913, Laird, 1974), once the subject has adopted the object’s expressions and

posture, these elicit bottom-up processes that elicit the correspondent emotions. Therefore, by

enacting the object’s emotions, the subject experiences these emotions – the ground for

empathy is laid. This emotional contagion is the most basic process in empathy and seems to

be biologically hard wired (Atkinson, 2002). However, as soon as higher order cognitive

processes become involved more sophisticated forms of empathy evolve.

The stages of empathy

Empathy consists of three different stages: Emotional contagion, empathic concern and

empathic perspective taking (de Waal, 2008). Emotional contagion of negative emotions

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results in personal distress. This stage is not altruistic. Instead, it is self focused; since the

negative feelings, elicited by the other, cannot be distinguished from one’s own feelings. The

observer feels distressed but does not, or cannot, take the next step of distancing him- or

herself from these feelings. This self centered empathy leads to the selfish motivation to

alleviate one’s own pain. One can ease one’s pain by either reducing the distress of the other

through helping, or by leaving the distressing situation and turning one’s back to the sufferer

(Batson, Fultz, Schoenrade, 1987). This negative side of personal distress was shown by rats

who failed to press a button to save another rat that suffered from electric shock. Instead of

helping the other rat, they crunched fearfully in the furthest corner expressing high levels of

distress (Rice, 1962). For many species, emotional contagion is the only form of empathy and

it often proves to be useful, for instance, when a flock of birds flies away from a predator after

hearing the distress signals of a flock member, or when a rat mother comes to help one of its

pups squeaking in distress.

The next evolutionary step of empathy and the next step in child development is

empathic concern. Here, while the subject feels the emotions of the object, the process does

not stop. Instead, the subject is aware that the object is the source of its emotions and can

appreciate and comprehend the other’s situation (De Waal, 2008). This new distinction

between internally and externally generated emotions opens the door for more sophisticated

empathic emotions – emotions such as guilt, compassion, sorrow, but also spitefulness,

resentment and envy. Often, empathic concern evokes an other-oriented, altruistic motivation

to alleviate the other’s distress (Batson 1991).

However, at this stage, “real empathy”, or what the lay person would consider to be

empathy, is not yet achieved. We generally speak of empathy only when it involves

perspective-talking. Only when we feel with the other and consequently feel for the other, and

we understand the other and his situation, we say that someone truly empathizes with another

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(de Waal, 2008). Hence, top down processes are involved in empathy. The subject takes the

object’s perspective and imagines their mental state and situation to understand the emotions

the subject sensed from the object through emotional contagion. Thus, the third and last stage

of empathy is empathic perspective taking – the cognitive process of taking the other’s

perspective plus empathic concern. Empathic perspective taking can result in targeted

helping, which is helping adapted to the specific needs and goals of the other (de Waal, 2008).

This happens, for instance, when a mother hears her baby crying. Initially feeling distressed

herself; she quickly shifts perspectives and consequently feels compassion with the baby and

a strong motivation to alleviate the baby’s distress. She, then, assesses the baby’s situation,

taking into account what she knows about its preferences, goals, and behavioral patterns, to

infer what caused the distress and what can reduce it. She might then come to the conclusion

that the baby is hungry and will take steps to feed the baby. Without the initial vicarious

distress, however, the mother would lack the basis for all subsequent steps in her progress to

helping. Because she would not feel with the baby, she would see her babies’ distress signals,

but would not understand what they mean. Although she could try to infer what they mean by

top down processing, for example recollecting what she knows about babies and that their

crying indicates that they are in need of something. Nonetheless, she would still lack the

emotions necessary to fuel the motivation to help. Research on anti-social personality disorder

illustrates this point. Individuals diagnosed with this disorder are said to lack the ability to feel

with others. They are able to severely harm and sometimes kill others because they are

unresponsive to other’s distress signals (Blair, 1997). Despite their lack in empathic concern,

individuals with anti-social personality disorder have intact cognitive functions and are fully

capable of cognitive perspective taking (Blair, 2008). Thus, without the ability to feel with

and for others, all cognitive reasoning is useless. The experience of vicarious emotions is vital

for all subsequent stages of empathy. Recent findings, however, suggest, that this basic and

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automatic process is not as universal as one would expect. Empathy was shown to be biased

and restricted by certain factors and this might even start at its crucial basic process.

The limits of empathy – moderators for empathic responses.

Whether we empathize with someone or not depends on perceived similarity (Cialdini,

Brown, Lewis, Luce, & Neuberg, 1997), familiarity with the target (Cialdini, et al. 1997),

need for nurturance and protection of the target (Batson, et al., 2005), and affiliation with the

target (Vignemont & Singer, 2006). For example, in an experiment on the effects of similarity

on empathy, participants where led to believe that an ostensible second participant was similar

or dissimilar to them. They, then, saw the other participant getting electric shocks.

Participants showed heightened arousal and reported more empathic emotions when the other

was similar as compared to when he was different. Apes, also, empathize more with familiar

apes who received electric shocks then with unfamiliar apes (Miller, Murphy, & Mirky,

1959). Moreover, Cialini, et al. (1997) found that in humans, emphatic concern for others is

eliminated when one controls for “oneness” – the degree to which participants perceive

themselves in the other.

The reasons why similarity, familiarity and affiliation promote empathy lay in our

evolutionary history. According to the concept of inclusive fitness (Hamilton, 1964, as cited

in Cialdini, et al., 1997), individuals do not act to secure their own welfare but to secure the

welfare of their genes. Hence, from an evolutionary perspective, it is irrelevant whether one

survives or two of one’s siblings survive. In both cases, the contribution of one’s own genes

to the gene pool is the same. From the perspective of evolution, then, empathy and prosocial

behaviour should be determined by their contribution to reproductive success in ancestral

environments. Hence, one can preserve one’s genes by promoting the survival of those who

share one’s genetic make-up. Since people can promote their own evolutionary success by

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helping relatives (Sime, 1983), inclusive fitness can explain altruistic behaviour within

families. When a mother saves her children by risking her own death, according to inclusive

fitness, this is a smart thing to do. Following this strategy it is easy to determine who to help

and who not to help when dealing with relatives. When asked how they would respond to

various situations in which someone needed help, participants expressed more motivation to

help close relatives and especially younger and healthy ones (Burnstein, Crandall, &

Kitayama, 1994).

Relatives are not the only ones with whom we share genes. Our genetic makeup

overlaps with other people as well; sometimes even with strangers. At one point in our

evolutionary history we had a common ancestor with everyone. What counts is the degree of

genetic overlap we share with others. Since this degree of genetic overlap is impossible to

detect, we must rely on cues that usually come along with genetic similarity. The more similar

someone is to us, the more likely it is, that he or she shares at least some of our genes.

Therefore, similarity is an important factor leading to empathy and prosocial behaviour

(Krebs, 1991). Natural selection not only operates on individuals, it can operate on groups as

a whole. Humans can sometimes increase their reproductive success by protecting their

groups’ interests as opposed to the interests of other groups (Wilson & Sober 1998). This

could explain, at least in some part, why we empathize with and help others who are unrelated

but socially connected to us.

Knowing that similarity influences empathy, an important question is at which stage of

empathy does similarity moderate the empathic reaction? Most behavioural studies cannot

provide an answer to these questions since they investigate the result of the process through

empathic behaviour or self report and these approaches are insufficient to distinguish between

the different stages of empathy. However, research on the neural basis of empathy suggests

that the most basic processes in empathy are sensitive to similarity, familiarity and affiliation

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of the object. This research examines the mirror neuron system - a neural system said to be

the basis for the perception-action link and which can provide useful insight in the basic

mechanisms underlying empathy.

The mirror neuron system – a neural account for vicarious emotions and the basis of empathy

The idea of the perception-action mechanism had been around for several years before it

gained additional support from the neurosciences. While recording single cell activity in the

monkey premotor cortex, an area usually responsible to retrieve the appropriate motor act in

response to sensory stimuli, Rizzolatti, Fadiga, Fogassi, and Gallese (1996) discovered that

premotor neurons fire when the monkeys grasped food and when the monkeys simply

observed the experimenter doing so. Since, during observation, these cells “mirror” the

activation patterns that produce that same action, they have been called “mirror neurons”.

Further research on mirror neurons revealed that they only respond to biological, object-

directed actions (Rizzolatti, & Luppino, 2001). For example, mirror neurons are unresponsive

to the mere sight of an object and actions without an object being present. Further, an action

performed by a mechanical device is not effective either .These specific demands for the

subject, action and object suggests that mirror neurons represent goal-directed actions

(Rizzolatti & Arbib, 1998). These representations enable individuals to understand and imitate

others’ actions and goals (Rizzolatti, Craighero, 2004). After the discovery of the mirror

neuron system in monkeys, the research focus shifted to humans. Behavioural,

neuropsychological, and imaging studies with positron emission tomography (PET),

functional magnetic resonance imaging (fMRI) and electroencephalography (EEG)

established that humans, indeed, have a mirror neuron system (Buccino, Ferdinand, & Lucia,

2004; Rizzolatti, & Craighero, 2004). In humans the observation of actions activates a

complex network formed by occipital, temporal, and parietal visual areas. The core of the

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human mirror neuron system is the rostral part of the inferior parietal lobe and the lower part

of the precentral gyrus plus the posterior part of the inferior frontal gyrus (IFG) - brain

regions primarily specialized in motor functions, action planning and intentions (Rizzolatti &

Craighero, 2004) (Please see figure 1 for a depiction of the human mirror neuron system).

Similar to the monkey’s mirror neuron system, the human mirror neuron system reacts to the

sight of biological movements, the abstract and general representations of actions, and it is

especially receptive to intentional action (Rizzolatti, Fogassi, Gallese, 2001). With these

properties, the mirror neuron system seems to serve a mapping function (Fogassi et al., 2005).

Rizzolatti et al. (2001) propose that the mirror neuron system is the basis for the perception

action mechanism; we understand actions when we map the visual representation of the

observed action onto our motor representation of the same action.

Figure 1: The human MNS (in red) and its main visual input (yellow) in action understanding

and imitation. The MNS in the rostral inferior parietal lobule (IPL) is primarily concerned

with the motoric description of the action. The frontal MNS located in the Prefrontal Motor

Cortex (PMC) and Inferior frontal Gyrus (IFG) is more concerned with the goal of the action.

The yellow and red arrows represent the flow of information from visual to motor and

Iacoboni and Dapretto (2006)

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prefrontal areas. The black arrows represent an efferent copy send back from prefrontal

cortex to posterior Superior temporal sulcus (STS).

If we want to apply the perception action mechanism to emotions and empathy, things

become more complicated. The brain areas underlying the mirror neuron system are generally

not involved in emotions (Iacoboni & Lenzi, 2002). Then, how can the mirror neuron system

be the basis of empathy? The insula connects limbic areas, which generate emotions, with the

areas involved in the mirror neuron system and, as shown by fMRI studies, the insula is

heavily involved in affect generation during imitation tasks. Hence, the insula is the necessary

link between the action oriented mirror neuron system and emotional areas, providing a

possible pathway from observation of motor behaviour, such as expressions and body posture,

to empathy (Carr, et al., 2000, Iacoboni, Lenzi, 2002).

Several brain imaging studies further support the action-perception model of empathy. 2

In all of these studies, mirror neuron system activation appeared almost automatically;

whenever participants observed emotions, the mirror neuron system was active. But, are

mirror neurons really automatically triggered every single time we see someone’s emotions?

As we have seen, empathy is more selective. Is this true even at this most basic level of

empathy?

Recent studies suggest that some kind of moderation processes determine activation of

the mirror neuron system. In their research on mirror neuron system function, Oberman,

Pineda, & Ramachandran (2006) showed participants videos that differed in the degree of

social interaction. In the “no interaction”condition, participants saw three individuals standing

in a circle, each of them tossing a ball in the air and catching it. In the “medium interaction”

condition the three individuals tossed the ball to each other and in the “high interaction”

condition the three individuals tossed the ball to each other, but sometimes they tossed it off

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the screen, seemingly to the observer. Thus in the no interaction condition there was no

interaction between the three individuals nor was there any interaction with the observer. In

the medium interaction condition, the three individual interacted but they did not interact with

the observer. Finally, in the high interaction condition, the three individual interacted and they

also interacted with the observer. As measured with the EEG, mirror neuron system activation

was moderated by the degree of interaction. When the participants were included in the

interaction, their mirror neurons fired the most, followed by interaction without involvement

of the participant, and the least activation in the no interaction condition. Hence, mirror

neuron activation depends on the degree of social interaction and mirror neurons are

especially active when there is face-to-face interaction. These results show that the mirror

neuron system is reactive to variations in social content. Singer, et al. (2006) provided further

support for the mirror neuron system’s sensitivity for social content. They found evidence that

mirror neuron system activation is moderated by the affective link between individuals. To

manipulate liking versus disliking, they let their participants play an economic game with two

ostensible other participants, who were actually confederates. One of the two confederates

played unfair and the other played fair. Later, mirror neuron system activation was measured

with f MRI while participants watched the confederates receive seemingly painful stimuli

administered to their hands. Both, male and female participants exhibited mirror neuron

system activation in pain-related brain areas when they saw fair players feeling pain. Male

participants showed significantly reduced mirror neuron system activation towards the unfair

players, whereas female participants showed mirror neuron activity in response to both

players. At the same time only males showed increased activation in reward-related brain

areas and they later expressed the desire for revenge.

Taken together, research on the neural processes involved in empathy confirms the

perception action model of empathy– we know what others feel because we actually feel it,

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and we feel their emotions because we simulate them in our brains. Even these basic

mechanisms seem to be influenced by similarity, familiarity and affiliation, thus bounding

empathy to certain others. This bias towards similar, familiar and affiliated others suggests

that there is a fundamental difference in how our brain processes information about people to

whom we have different social relations and attitudes. This might have far reaching

consequences for interactions with individuals who cannot activate our mirror neuron system.

We might not be as responsive to these people’s needs, and less likely to understand their

intentions; we might be less likely to help them, and might communicate less effectively with

them. Usually our ingroup members are the ones who are similar to us, who we are familiar

and affiliated with. So what about outgroups? Is it possible that we empathize less with

outgroup members? Research on prejudice suggests that this might be the case.

Prejudice and the distinction between “us” and “them”

Prejudice can be defined as an unfair negative attitude toward a social group or a

member of that group (Dovidio, & Gaertner, 1999). People prefer their ingroup to an outgroup

(Perdue, Dovidio, Gurtman, & Tyler, 1990), they assign more positive attributes to the

ingroup than to the outgroup (Gaertner Mann, Murrell, & Dovidio, 1989), and they show less

helping behaviour towards outgroup members (Dovidio, et al., 1997, Frey, & Gaertner, 1986).

Interestingly, empathy seems to be an antidote for prejudice (Batson et al., 1997; Galinsky, &

Moskowitz, 2000). The determining factor for these biases might be similarity.

In social identity theory, Turner, Brown, and Tajfel (1979) introduced the concept of

self-categorization. People who identify with a group come to perceive themselves not as

unique personalities with individual differences, but as interchangeable parts of a group. As a

result, the self and the group merge and the group identity becomes an integral part of the self.

When people merge with their group, they tend to stress similarities with the ingroup and

15

differences with the outgroup. Thus the self and the ingroup become seemingly more similar,

whereas the gap between the self and the outgroup grows. Consequently, people perceive

outgroup members as radically different from their own group. This distinction can even lead

to the feeling that others lack typically human characteristics (Leyens, et al., 2000). As a

result, people sometimes consider outgroup members as less than human.

Perceiving others as different

Fiske, Cuddy, Glick and Zu (2002) addressed the question, why we sometimes ignore

the shared humanity of outgroup members, in their stereotype content model. According to

this model the extent to which we deny others their full humanity depends on their group

membership. We judge groups on two dimensions: warmth - the group intends to help and not

harm us - and competence - the group is capable of enacting those intentions. Groups who are

high in warmth and competence elicit respect and admiration. Mostly this is the case for one’s

ingroup. However, when we judge a certain group as low in warmth and low in competence,

the elicited emotions are disgust, disrespect, and dislike (Fiske, Cuddy, Glick, & Zu, 2002).

Such devalued groups are most likely to be seen as less than human and are often

dehumanized (Harris & Fiske, 2006). Dehumanization is the most extreme form of prejudice

and it applies for example to homeless people, drug addicts and sometimes, but to a lesser

degree, ethnic groups and in particular Arabs and Blacks.

Not all outgroups are dehumanized, and those who are, are not necessarily dehumanized

to the same extent by everybody at all times. Sometimes people devalue others only in certain

domains. For example, people judge outgroups as inferior especially in typically human

characteristics such as intelligence (Crocker, Major, & Steele, 1998), and social competence

(Glick & Fiske, 2003). Interestingly, Leyens and colleagues (2000) found that people deny

outgroup members of having certain, characteristically human emotions. These so-called

16

second order emotions, for example jealousy and contempt, differ from primary emotions

such as anger and curiosity in that they are more complex, internally caused, more invisible,

and more cognitive. They occur only later in age, are less intense, and more persistent.

Secondary emotions are not ascribed to animals (Leyens et al., 2000). For example, dogs can

be frightened, angry, or even surprised, but one would not say that a dog admires something

or feels disillusioned. The restriction of secondary emotions to be exclusive for ingroups

enlarges the gap between different groups and further fosters a sense of dissimilarity between

groups. If people do not feel related and affiliated with outgroup members and perceive them

as dissimilar, they might have a harder time to empathize with them. To investigate whether

we feel less empathy toward outgroup members and to specify what particular aspect of

empathy might be impaired, we attempt to look beyond the behavioural level of empathy and

to investigate by using the social neuroscientific approach.

Social neuroscientific methods to measure empathy

A recurrent problem in research on intergroup bias is how to measure it. People often

are unwilling to reveal their prejudice and often are not even aware of them (Guglielmi,

1999). Thus research participants might not be willing or able to report possible bias in

empathy towards outgroups. Moreover, conventional measures of empathy, such as self report

and helping behaviour, do not allow to distinguish between the different levels of empathy (de

Waal, 2008), which leaves researchers unable to make inferences about the specific

mechanisms that lead to a lack in empathy. To avoid these problems, the current study uses

the EEG to measure mirror neuron system activity, and to measure vicarious emotions

through prefrontal alpha asymmetries.

Measuring Mirror Neuron System activation.

Mirror neuron system activation has been measured using several methods, including

transcortical magnetic stimulation (TMS), fMRI and EEG. Because the EEG is a non-

17

invasive, inexpensive method to measure mirror neuron activity online, we chose EEG as the

main dependent measure of this study.

The EEG measures mirror neuron activity by comparing electrical signals from

sensorimotor neurons at rest and during the experimental conditions. At rest sensorimotor

neurons spontaneously fire in synchrony, leading to large amplitude EEG oscillations in the 8-

13HZ frequency band called mu band. When participants perform an action, these neurons

fire asynchronously, and therefore, the power of the mu oscillations weakens. The connection

between mu rhythms and mirror neuron activity was first suggested by Altschulter et al

(1997). According to Altschulter the mu rhythm reflects the downstream modulation of

sensorimotor neurons by cells in the premotor cortex, some of which are mirror neurons.

However, when people observe actions or emotions in others, then mu rhythm reflects mirror

neuron activity exclusively (Pineda, 2005). The relationship between mu rhythm and mirror

neuron activity is supported by several similarities in properties between the mu rhythm and

mirror neurons. First the mu rhythm is generated by activity in mirror neuron areas. Second

mu rhythm is suppressed during action, but also during the observation of action (Cochin,

Barthelemy, Lejeune, Roux, Martineau, 1998). Third, the mu rhythm reacts more strongly to

goal directed actions than to non goal directed actions, and when the action is object oriented

compared to non object oriented (Muthukumaraswamy, Johnson, McNair, 2004). Because of

this overlap in location and functional properties, researchers agree that mu suppression can

be used as a selective measure of mirror neuron system activity (Oberman, et al. 2006). As

discussed above, mirror neurons are said to be the very basis of emotional contagion (Gallese,

Ferrari, & Umilta, 2002), but the absence of mirror neuron activity does not necessarily equal

the absence of empathy. Similarity and familiarity could exert their influences to a higher

more cognitive level of empathy. Thus, we need a direct measure of the vicarious emotions

constituting empathy.

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Measuring vicarious prefrontal alpha asymmetries.

A potential measure of vicarious emotions is anterior frontal asymmetries as measured

by relative EEG alpha wave strength in the right vs. left prefrontal cortex. Although a

relatively broad measure of general motivation, it can distinguish between positive, approach

related, emotions (e.g. happiness) and negative, avoidance related emotions (e.g. sadness)

(Harmon-Jones, & Allen, 1998). The earliest finding on asymmetrical organization of the

prefrontal cortex comes from research on patients with brain damage to one hemisphere. For

example, patients showed symptoms of depression after damage to the left hemisphere of the

prefrontal cortex and mania after damage to the right hemisphere (Robinson, Kubos, Rao, &

Price, 1984). These discoveries fed an extended research line on EEG alpha asymmetries in

the prefrontal cortex (Fox et al., 2001, Harmon-Jones, & Allen, 1998, Jones, Field, &

Davalos, 2000, Sutton & Davidson, 1997). This research consistently showed that the left

prefrontal and the left anterior temporal cortex are involved in the experience and expression

of positive, approach related emotions and that the right prefrontal and the right anterior

temporal cortex is involved in the experience and expression of negative, avoidance related

emotions (Davidson, Ekman, Saron, Senulis, & Friesen, 1990). This functional asymmetry is

measured by comparing of EEG alpha band activity of both hemispheres either at rest or

during different experimental conditions. This method revealed, for example, that

asymmetries in alpha in the prefrontal cortex are associated with depression (Allen, Iacono,

Depue, & Arbisi, 1993), a general trait like emotional style (Wheeler, Davidson, & Tomarken,

1993) and with emotional responses elicited by negative vs. positive films (Davidson, et al.,

1990).

When we speak about findings gained from frontal alpha asymmetries we are mainly

talking about activity in the dorsolateral prefrontal cortex (Davidson, 2004). That is because

19

the dorsolateral prefrontal cortex is the brain structure most likely to be directly reflected in

the EEG (Davidson, 2004). The dorsolateral prefrontal cortex is involved in cognitive control,

and has strong connections with the orbital prefrontal cortex, a structure that assigns affective

value to stimuli. Thus, the dorsolateral prefrontal cortex is essential for processing of reward

and punishment. Along this line, neurophysiological research on primates suggests that

reward and punishment information is passed from orbitofrontal to dorsolateral prefrontal

cortex which then uses this information to guide behaviour (Wallis and Miller, 2003). Hence,

although it seems that positive and negative emotions are lateralized within the prefrontal

cortex, it really is the motivational component of these emotions. To distinguish the

motivational aspect from the valence of emotions, Harmon-Jones and Allen, (1998) looked at

anger, an emotion that has a negative valance but an approach motivational value. The

negative valance should lead to left-frontal activity, whereas the approach component should

lead to right-frontal activity. The researchers found that anger was associated with right-

anterior activity and, thus, the left dorsolateral cortex. Hence, emotions guide our behaviour

by means of approach and withdrawal motivation, motivating us to either move towards or

away from stimuli. Usually, positive emotions are associated with approach motivation, for

instance love leading us towards another person, while negative emotions are associated with

avoidance motivation, for instance fears driving us away from another person. This

motivational aspect of the experienced emotions is what we can investigate with frontal EEG

asymmetries. Hence, anterior alpha asymmetries, when measured in a social setting, provide

us with a measure of vicarious emotions. Moreover, since the prefrontal cortex seems to be

exclusively involved in the experience and expression of emotions and not the perception of

emotions (Davidson, 1994), Alpha asymmetries are a measure of vicarious emotions free of

any confounds from the mere perceptions of emotions.

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We used anterior alpha asymmetries as a measure for vicarious emotions, and to

investigate the neural process underlying these vicarious emotions, we used EEG mu rhythm

as an indicator of mirror neuron activity. We asked whether people process actions and

emotional reactions of ingroup members differently than those of outgroup members. Taking

together, evolutionary humans are equipped with an empathy system that allows them to

navigate their social system, by understanding the emotional and cognitive states of others.

However, this system evolved in a way that that makes us empathize more with similar

people. Similarity and familiarity seem to even influence our most basic emphatic processes –

the ability to feel with others by simply simulating their emotions. In this context research

findings on Prejudice, categorization and dehumanization are alarming: If we feel less similar

to outgroups than to ingroups, sometimes to the degree that we see them as less human, do we

even distinguish between them on a neural level? Is our mirror neuron system less sensitive to

outgroup members and is empathy bounded to our ingroup?

Overview

This study investigated the phenomenon of bounded empathy and aimed to establish the role

of the mirror neuron system in prejudice. We asked whether actions and emotional reactions

of ingroup members are processed differently than those of outgroup members. We measured

mirror neuron system activation and the experience of vicarious emotions with the EEG while

participants saw videos of ingroup and outgroup members performing actions and expressing

emotions. We predicted that the mirror neuron system would be more active when the

participants observe ingroup members than when they observe outgroup members, and

further, that they would feel more vicarious emotions for ingroup members than for outgroup

members. In addition we expected that ingroup favouritism would be negatively correlated

with, both, mirror neuron system activation and vicarious emotions in response to outgroup

21

members. Thus, this study suggested that the MNS is less responsive to outgroups, and that

this reduction of mirror MNS activation, and the resulting lack of empathy, are at least one of

the reasons for prejudice.

Method

Participants

The original sample consisted of 30 right handed (assessed through self report)

university students who were recruited from the University of Scarborough subject pool, and

who participated in the study for course credit. Two participants were excluded due to a

technical malfunction in the EEG system and another 7 participants had to be excluded due to

excessive movement artifacts that resulted in an inability to obtain sufficient EEG data. As a

result we included 21 participants in our final sample. Ten males and 11 females participated;

5 of them where white, 4 East Asian and 12 South Asian. The participants ranged in age from

18 to 23 Years (M= 18.86, SD= 1.23).

Procedure

Participants were told that the study’s purpose was to investigate the neural

underpinnings of actions and emotions. Participants read and signed an informed consent

sheet and were then fitted with and electrode cap for EEG recording. EEG was recorded while

the participants watched two sets of videos. The first set of videos showed a variety of

ingroup and outgroup members performing a simple action. The second set of videos showed

ingroup and outgroup members displaying basic emotions. After watching each set, the

participants were asked to perform the action or to display the emotions respectively. After

completion of this task, EEG recording stopped. To control for individual differences we,

then, administered several measures related to ingroup favouritism, self-other overlap, and

empathy. Finally the participants were thanked and debriefed.

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Stimulus Materials

The video sets of ingroup and outgroup members performing actions and expressing

emotions served as the independent variable. For the purpose of this study I defined ingroup

as people who share the participant’s ethnic identity, and outgroup as people who do not. The

first set’s content was action (action block), with participants seeing and performing specified

actions. Specifically, participants observed and performed the action of repeatedly grabbing a

glass of water, lifting it up, drinking a small amount of the water, and putting it down. The

second set (emotion block) was about emotions, with participants seeing and feeling sadness

and happiness.

Each set consisted of three experimental conditions - the ingroup-, the outgroup-, and

the self-condition. In the outgroup condition the participant saw four different actors for each

outgroup. Thus, for example, a white participant would see four different black actors each for

20 seconds followed by four different East Asian actors, and four different South Asian

actors. The videos showed the actors sitting on a table in front of a white wall, either

performing the action or expressing an emotion depending on set. In the ingroup condition,

participants saw four different ingroup member, each for 20 seconds, acting or expressing

sadness and happiness. To ensure that every participant indeed saw videos of ingroup

members I presented videos depicting people with a South Asian, East Asian, Caucasian, and

African ethnic background. The depicted persons were male students of the University of

Toronto and, therefore, had approximately the same age but not always the same sex as the

participants. Each person was displayed for twenty seconds. In order to ensure enough clean

EEG data for the mu rhythm analysis, in the action set, participants observed and acted twice.

Consequently we obtained 160 seconds of EEG data during the self action condition and the

ingroup action condition and a total of 480 seconds during the outgroup action condition with

160 seconds for each ethnic outgroup. In the emotion conditions we obtained 80 seconds of

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EEG data during the self conditions, 80 seconds during the ingroup conditions and 240

seconds of during the outgroup conditions with 80 seconds during each of the different ethnic

outgroups. All ingroup and outgroup videos alternated in random order.

Before participants saw the ingroup and outgroup videos, they saw 160 seconds of

white noise (white noise condition). The data collected during the white noise condition was

used as the baseline of mirror neuron system activation and anterior alpha asymmetry during

rest.

At the end of each of the video sets, the participants were asked to perform the action or

display the emotions themselves (self condition). During this condition participants repeatedly

grabbed the glass of water in front of them with their right hand, brought it to their mouth, and

took a little sip; then they put the glass back to its former place. To ensure correct execution,

they were asked to remember how the actors did the exact same action and to try to do it in

the same way and same pace. In the emotion conditions participants had to either feel sad feel

happy, depending on block. They were also asked to express the emotion as naturally as

possible. To facilitate the experience of the emotions, participants completed an emotion

induction exercise, which consisted of a series of instructions aimed to elicit vivid memories

of past sad and happy events, respectively. For example, participants saw the following

instruction: “Please think about a situation in you past, which made you feel very sad/happy.

Imagine the situation as vividly as you can“. After completion of the exercise participants

tried to feel the emotion for 80 seconds while they were looking at a blank computer screen.

The action block always proceeded the emotion block and in each block the self

conditions appeared at the end of the block so that the participants could model their

performance after the videos. To ensure that participants attended the video throughout the

whole session, they performed a control task during all conditions except during the white

noise and self conditions. In this task, the videos stopped between 2 and 5 times and the

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screen turned black for 1second. Participants were asked to count how many times the black

screen appeared and to indicate the number of such pauses at the end of the condition.

Measures

Measures of ingroup favouritism. After completion of the EEG measurement, we gave

the participants two measures of ingroup favouritism. First, we implicitly measured group

bias with the Black-White evaluative Implicit Association Test (IAT) (Greenwald, Ghee, &

Schwartz (1998) – a computer-administered reaction time test of implicit associations with

race. In this task, participants were instructed to categorize photographs of Black and White

faces and positive and negative concepts. During one block, participants were asked to press

the same button for Black faces and negative words and for White faces and positive word

(compatible block). During a second block White faces were allocated to the same button as

negative words, and Black faces to the same button as positive words (incompatible

condition). We chose the IAT because it is a widely used and reliable (Greenwald, Nosek&

Banaji, 2003) measure of implicit race bias.

Modern Racism Scale. In addition to implicit racism with the IAT we measured

explicit racism with the modern racism scale (MRS) (McConahay, Hardee, & Batts, 1981).

The MRS is a valid measure of modern racism (McConahay, 1983) a construct that describes

a subtitle form of racism that combines racist feelings with abstract values, such as justice and

order. Modern racists believe that discrimination no longer exists and that Blacks demand

more than they deserve (Henry & Sears, 2002).

Measure of self other overlap. In order to measure the degree of overlap of the

self and the different outgroups, the participants were asked to complete the Inclusion of

Others in the Self Scale (IOS) (Aron, Aron, & Smollan, 1992). In the IOS Scale, respondents

select the overlapping circles that best describes their relationship from a set of diagrams each

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representing different degrees of overlap of two circles. For every group, South Asian, East

Asian, Caucasian and Black, the participants had to choose one of seven such depictions that

best illustrates their relationship with the group.

Measures of Empathy. To measure individual trait differences in empathy, we

administered the Empathy Quotient (Baron-Cohen, & Wheelwright, 2004). This measure is a

questionnaire that taps cognitive empathy and emotional reactivity to others (Lamm, Batson,

Decety, 2007), and was shown to be a valid and reliable measure of empathy, both, in a

clinical sample of autistic patients and in healthy individuals (Lawrence, Shaw, Baker, Baron-

Cohen, & David, 2004). The capacity for emotional perspective taking was assessed with the

Mind in the Eyes Test (Baron-Cohen, Jolliffe, Mortimore, & Roberston, 1997). In this test,

the participant is presented pictures of the eye-region of different people. They then have to

choose which of four one word descriptions of psychological states best describes what the

person on the picture is thinking or feeling. Performance on this task is an indicator of the

participant’s social sensitivity and is said to be an advanced test of theory of mind (Baron-

Cohen, et al., 1997)

EEG data acquisition and processing. To measure mu rhythm, we recorded the EEG

from 64 Ag/AgCl sintered electrodes embedded in a stretch-lycra cap with a high-density

amplifier and a sampling frequency of 512 Hz. The electrodes where positioned according to

the five percent (10 – 5) electrode system, which is an extension of the 10-20 system to

accommodate larger numbers of electrodes (Oostenveld & Praamstra, 2001). The EEG was

digitized at 512 Hz using ASA acquisition hardware (Advanced Neuro Technology,

Enschede, the Netherlands) with an average earlobe reference. Vertical eye movements

(VEOG) were monitored using a supra-to sub-orbital bipolar montage and the EEG was later

corrected for VEOG with the SOBI procedure (Belouchrani, Meraim, Cardoso, & Moulines,

1997). During recording, the impedances were kept below 10 Kohm to ensure a clear and

26

strong EEG signal. Since the mu frequency band overlaps with the posterior alpha band –

oscillations in the same frequency band as mu due to effects of attention – it is possible that

recordings from posterior central areas might be contaminated by these alpha waves

(Oberman, et al., 2007). To avoid this, we removed the first and last 10 seconds from each

EEG data block. Following we created 75% overlapping epochs of 2 seconds (using a

Hamming window) throughout the conditions and applied fast Fourier transforms in the 8-13,

8-11, 11-13, and 13-15 band passes to these epochs.

Results

The objective of our study was to investigate the possibility of bounded empathy: That

empathy relates to feelings for the ingroup, but not the outgroup. We examined the mirror

neuron system’s role in prejudice and tested whether the mirror neuron system is less active in

response to outgroup members than ingroup members, and whether this is reflected in

differences in vicarious emotions as measured by anterior frontal asymmetries. We therefore

induced empathy by having our participants observe in- and outgroup members acting and

feeling emotions and measured correspondent EEG activity.

Mu suppression

To measure mu suppression we calculated the ratio of the mu power (EEG

bands 8-13, 8-11, 11-13, 13-15 and 15-18) during the self, ingroup and outgroup condition

relative to the white noise control condition. By looking at ratio scores, we could control for

individual differences in scalp thickness (Oberman, et al., 2007). We log transformed the ratio

scores in order to normalize the data. As a result we obtained positive and negative values,

where positive means enhancement of mu rhythm – less mirror neuron activity- and negative

means suppression of mu rhythm – more mirror neuron activity. Although we obtained data

27

from multiple electrodes across the scalp, we only looked at C3, Cz, and C4 since mu rhythm

is normally measured over the sensorimotor cortex (Oberman, et al.,2007).

None of these electrodes showed significant mu suppression during neither of the

experimental conditions. However, we found a significant decline in mirror neuron activity in

the 13-15 band during the self condition relative to the white noise control condition (t (C3) =

3.433, p = .003; t (C4) = 1.765, p = ns; t (CZ) = 2815, p = .011). Mu basically represents

sensory motor neurons being a rest and, thus, an increase in mu, as represented in our data,

indicates, that sensory motor neurons were less active when participants acted then when they

sat still. Since actions cannot be performed without activity of the respective neurons, the

obtained mu rhythm data are puzzling and cannot be interpreted.

Anterior alpha asymmetry

To assess approach and avoidance related emotions we obtained the alpha band power

at a left (F8) and a right (F7) frontal electrode site for each condition. Because the alpha

power values are usually positively skewed (Allen, Coan, & Nazarian, 2004), we log

transformed them to normalize the distributions. Following, to control for individual

differences in overall alpha power, we computed a log difference score for each of the

conditions (log right alpha power minus log left alpha power). Alpha power is highest when

the underlying neurons are at rest, thus we took alpha power as an index of the inverse of

cortical activity. A lower alpha power in the right hemisphere signals positive, approach

related emotions, and lower alpha power in the left hemisphere signals negative, avoidance

related emotions. Consequently, when creating the difference score lower scores indicate

relatively greater left fontal activity, or more negative emotions.

To investigate the specific effects of the experimental conditions on relative alpha

power, we ran several t-tests. In the self conditions, participants showed marginally

28

significantly lower scores, (t (20) = 1.91, p = .07), when they experienced sadness (M= -0.05,

SD= 0.16) than when they experienced happiness (M= -0.01, SD=0.15), indicating that the

manipulation induced the intended emotions. Moreover, asymmetry during the experience of

sadness was marginally significantly different from zero, (t (20) = -1.9, p = .07).

To test for vicarious emotions, we compared participants’ relative alpha power in the

ingroup and outgroup condition with their relative alpha power during the self condition. We,

also, looked at a specific case of the outgroup condition – the black condition. When looking

at frontal asymmetry related to sadness, asymmetry scores for the self (M=-0.07 SD=0.17)

and the ingroup condition (M=-0.03 SD=0.11) where not significantly different from each

other (t (20) = 1.4, p = .17), nor were Asymmetry scores for the self (M=-0.07 SD=0.17) and

the outgroup condition (M=-0.03 SD=0.15). Thus participants showed the same reaction when

feeling sadness and when observing ingroup and outgroup members expressing sadness.

However, this was not true for the black outgroup. Participants showed significantly higher

scores when they saw Blacks expressing sadness (-0.01, SD=0.16) then when feeling sad

themselves (M=-0.07 SD=0.17) (t (20) = 2.106, p = .048). There were no significant

differences between the ingroup and outgroup condition, the ingroup and black condition and

the outgroup and black condition. A trend analysis on asymmetry difference scores for the

self, ingroup, outgroup and black conditions revealed that participants showed a linear trend

(F=5.184, p = .03) with the strongest left frontal asymmetry during the self condition,

followed by the outgroup and ingroup condition and finally the black condition (Please see

figure 2 for a depiction of these results). Thus participants seem to feel saddest when acting

and experiencing sadness themselves, they feel less sad when they observe an ingroup

member or an outgroup member expressing sadness but they do feel a certain degree of

vicarious sadness. Contrary, they do not seem to feel vicarious sadness towards Blacks. Since

alpha power is relatively consistent within individual participants and sites (Allen, et al.,

29

2004) an expected, relative alpha power for all conditions correlate highly with each other (all

correlations higher than .62with p<0.09). The same analysis conducted at posterior sites P3

and P4 revealed the opposite pattern. We found significant differences between the ingroup

condition and the self condition and the ingroup condition and the outgroup condition, but no

difference between the black condition and the self condition. However, relative alpha power

of the posterior sites did not correlate with each other. This lack of congruence, and the fact

that posterior alpha activity is generally seen as related more to attention than emotions,

questions the relevance of these findings. The mismatch between the posterior and anterior

data, illustrates the topographical specificity of the effects for anterior cortical activity.

Contrary to the data with sadness, anterior alpha asymmetry was not significant in any

of the happy conditions. Neither was anterior alpha asymmetry significantly different from

zero during the experience of self-happiness nor did it reveal any experience of vicarious

emotions in the ingroup and outgroup condition.

Figure 2: Anterior alpha asymmetry cores during the two emotion conditions (Sad, Happy)

for ingroup, self and black. Participants showed significantly lower anterior alpha asymmetry

scores during the self condition than during the Black condition. This indicates relatively

more negative, avoidance related emotions during the experience of sadness than when

observing the black outgroup. The ingroup condition did not significantly differ from the self

condition.

30

Behavioural measures

Correlation with empathy. The hypothesis of bounded empathy is further supported by

the pattern of correlations observed between alpha power and empathy. Anterior alpha

asymmetry in response to sad ingroup members correlated negatively with participants’ scores

on the Empathy Quotient Scale. Thus the more empathy the participant was capable to

experience in general, the more vicarious sadness he or she felt towards ingroup members (r =

-.414, p<.062). This was not true, however, when the participants observed Blacks – there was

no correlation between frontal asymmetry in response to sad Blacks and trait empathy (r =

0.068, ns) (See table 1). These findings suggest that empathy is generally extensible in that

people can become experts in empathy. However, this expertise does not extend to outgroup

members.

Table 1: Correlations between anterior alpha asymmetry scores and the measures of ingroup

favouritism and empathy. Alpha asymmetry scores during the sad condition correlated

marginally significantly negatively with trait empathy (EQ) (p<.65, correlation bolded in

table) for the observation of sad ingroup members but not sad outgroup members.

Correlation with ingroup favouritism - IAT, MRS and IOS. The acquired IAT reaction

times where treated according to Greenwald et al. (2003), thus a single d- score was computed

Measures

Condition IAT MRS EQ RME Ingroup

Sad -0.215 0.203 -0.414 0.354

Happy 0.09 0.309 -0.221 0.249

Black

Sad 0.257 0.345 0.068 0.216

Happy -0.243 0.097 -0.361 0.191

Outgroup

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for each participant. A positive d-score indicates that the participant has stronger associations

between Blacks and negative words. The mean d-score was .1615 (SD= 0.213). D-scores

were significantly different from zero (t= 3.470, p = .002.) This replicates the general finding

that non-black participants have a stronger association between Blacks and negative words

and Whites and positive words a finding that indicates implicit bias against Blacks

(Greenwald, et al., 1998).

Contrary to our expectations, IAT scores did not correlate significantly with either of

our main measures of brain activity. In addition, none of our other measures of intergroup bias

correlated significantly with anterior alpha asymmetry. Hence, our hypotheses on the

relationship between vicarious emotions towards outgroups and prejudice were not confirmed.

Since the IOS, the MRS and the IAT are reliable measures of ingroup favouritism and

perceived similarity (Aron, Aron, & Smollan, 1992, Greenwald, Nosek& Banaji, 2003,

McConahay, 1983) this suggests that individual differences in prejudice and the subjective

closeness to outgroup do not influence the experience of vicarious emotions towards these

groups.

Discussion

Findings and implications

The aim of this study was to investigate bounded empathy as one of the underlying factors for

prejudice. First, we expected that the mirror neuron system would be less active in response to

outgroup members than ingroup members, and that this lack in mirror neuron system

activation will result in the experience of weaker vicarious emotions. Further we explored

how mirror neuron activity and the experience of vicarious emotions are influenced by

individual differences in trait empathy and level of prejudice.

32

Our findings support these hypotheses to some extent. However, methodological

problems left us unable to measure mu-rhythm suppression and, thus, we could not

investigate our hypotheses about mirror neuron activity. The analysis of the mu-band data

revealed no significant mu suppression in any condition. This lack in mu suppression suggests

that the motor neurons were inactive while participants moved their arms, hands and mouth.

There can be no movement without motor neuron activity. Still, our results show that the

participants moved without their motor neurons being active; hence, there must be a

measurement error. Unfortunately, our inability to replicate the basic relationship between mu

suppression and action makes it impossible to investigate mirror neuron activity.

Using anterior frontal asymmetry as a measure of vicarious emotions, we found that

participants felt weaker or less vicarious sadness in response to sad, black outgroup members.

When participants were confronted with sad ingroup members their frontal alpha patterns

where similar to when they experienced sadness themselves. According to the perception

action hypothesis of empathy, this was the case because the mere observation of sadness in

ingroup members activated the same brain structures involved in the experience of sadness.

Since anterior alpha power patterns in response to sad Blacks differed from the ones observed

during the experience of sadness, participants did not feel as strong vicarious sadness for

Blacks as for their ingroup. These findings suggest that empathy is bounded to ingroup

members, and to certain outgroups, but excludes the black outgroup. Since the finding of

bounded empathy only applied to the black outgroup and not to outgroups in general (i.e.

Whites, South Asians and East Asians), the question of why specifically Blacks do not elicit

an empathic reaction to other groups remains. Similarity could be an important factor that

distinguishes Blacks from the other groups. Recall that, according to Fiske’s et al. (2002)

Stereotype Content Model, each group can be defined by two dimensions: warmth and

competence. Groups that score low on both dimensions such as homeless and drug addicts are

33

perceived as extremely dissimilar to oneself and even as less than human. Blacks score lower

on both, warmth and competence then our other three groups (Fiske, et al., 2002), thus they

are likely perceived as being less similar to the participants. This perceived dissimilarity

might make Blacks an extreme outgroup leaving participants unable to empathize with them.

When looking at the happy conditions, anterior alpha asymmetry was not

significant in any of the conditions. This lack could result from an inadequate

operationalization of happiness. In the happy self condition, participants had to remember a

happy situation from their own experiences and try to re-experience the emotions they felt

during this event. Research on frontal asymmetries suggests that this manipulation might fail

because it is focussed on memory and thus elicits emotions that are past oriented. However,

because anterior alpha asymmetries are sensitive to approach related emotions they tend to be

sensitive to future oriented positive emotions during anticipation of positive outcomes

(Davidson, 2004, Gable, & Harmon-Jones, 2008). Therefore, future studies should investigate

alpha asymmetry while participants anticipate and see others anticipating a positive event.

Our second hypothesis predicted that individual differences in empathy and prejudice

would have an impact on the experience of vicarious emotion towards outgroups. This was

only confirmed for empathy. Participants with higher levels of trait empathy showed more left

anterior alpha activity in response to sad ingroup members. However, higher levels of trait

empathy had no effects on anterior alpha activity in response to sad Blacks. Thus participants

did not experience vicarious sadness for Blacks even when they generally were extremely

receptive to other’s emotions. It seems as if the ability to empathize is expandable but this

stops when it comes to Blacks.

Our findings indicate that people generally empathize less with Blacks and this might

lead to prejudice because it creates a barrier that blocks understanding and smooth

communication. As noted above, enhancing empathy towards an outgroup reduces prejudice

34

levels (Galinsky, & Moskowitz, 2000) thus a reduction of empathy might be a risk factor for

prejudice. This risk factor enhances the probability for prejudice, but people might be able to

compensate for the lack of empathy through cognitive perspective taking, which is a top down

process and does not rely on bottom up information from vicarious emotions (Preston, &

deWaal, 2002). In our society, in which expressing prejudice is socially undesirable (Devine,

Montheith, Zuwerink, & Elliot, 1991), people will be motivated to do so. Our sample

consisted of university students in one of North America’s most diverse cities studying at a

very diverse campus. Hence, it is likely that these students adopted strategies to compensate

for reduced empathy towards outgroup members. Additional research is necessary to

conclusively determine the relationship between empathy towards outgroups and prejudice

conclusively.

Limitations and Future Directions

We obtained two measures of trait empathy: the Mind in the Eyes task and the empathy

quotient, and one measure of state empathy: anterior alpha asymmetry. Although, anterior

alpha asymmetry has been shown to correlate with subjective self reported emotions

(Davidson, 2004), we did not include a self report measure of vicarious emotions, state

empathy or mood. Future research should include such measures to allow a comparison

between the subjective experience and anterior alpha asymmetries and to capture potential

differences between these two measures. Moreover, since anterior alpha asymmetries cannot

inform us on the specific nature of the approach or avoidance motivation, self report measures

could provide interesting additional information. For example, since there are different stages

in empathy we cannot tell whether we measured the initial vicarious emotions (i.e. sadness in

response to the observation of sadness) or the result of higher cognitive processing (i.e. the

motivation to avoid the stimulus in order to reduce personal distress).

35

Another important extension to our research would be to investigate the possible

positive effects of empathy enhancing factors such as fostering fondness, perceived

familiarity and similarity. Theoretically these factors should make the target a more likely

object of empathy, and should thus enhance the experience of vicarious emotions. This

extension would also enable researchers to disentangle the different reasons for why blacks

are perceived differently than other outgroups. Do they fail to elicit empathy due to their

dissimilarity, unfamiliarity or because they are disliked more?

Conclusions

To our knowledge, this study is the first that directly demonstrates reduced empathy towards

an outgroup. Although, others did show a connection between empathy and prejudice by

showing that empathy reduces prejudice (Galinsky, & Moskowitz, 2000) and that people

show less helping behavior towards outgroups (Dovidio, et al., 1997), these studies lack a

direct measure of empathy. By applying an objective measure of empathy based on neural

signals – anterior alpha asymmetries – this study could directly measure empathy towards

outgroups. Thus, we could establish that empathy is bounded to ingroup members and that at

least extreme outgroups, such as blacks, are excluded from our circle of empathy.

The fact that neither general ability to empathize nor individual differences in intergroup bias

had an effect on empathy towards Blacks further suggest that the bounds of empathy are

relatively fixed.

Given the positive effect of empathy such as the facilitation of social understanding and

prosocial behaviour, helping behaviour, and the inhibition of aggression and antisocial

behaviour, the lack of vicarious emotions towards blacks draws a rather dark picture.

However, taking into account the current findings, promoting perspective taking is a

promising candidate for a possible remediation. Instead of trying to equal our reactions

36

towards outgroups to those towards ingroups – a distinction that might be unchangeable - this

strategy aims to include outgroup members into our ingroup. This could create feeling of

common humanness and could help us remember Shylock’s words that all of us bleed, laugh

and die, no matter our colour, race, or religion.

37

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