Subliminal influencing in advertising: does it...

Subliminal influencing in advertising: does it work?

Eva Van den Bussche, Gigliola Brintazzoli, Natacha Deroost & Eric Soetens

Colloquium 16-06-2011

6/23/2011 1Herhaling titel van presentatie

Overview

• Can subliminal information influence our behavior…

• …in an experimental context? (PART I)

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• …in an experimental context? (PART I)

• …in a more real-life/advertising context? (PART II)

16-06-2011 2Colloquium Utrecht

Part I

Can subliminal information influence our behavior in an experimental context?

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experimental context?


Overview Part I

• Early demonstrations

• Masked priming paradigm

• Prime awareness

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• Prime awareness

• Meta-analysis

• Conclusion


Early demonstrations

• Can subliminally presented information influence our behaviour?- Controversial

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- Controversial

- Long history

- Subliminal = ideas below the “limen” or threshold for consciousness (Herbart, 1776-1841)



• First empirical studies:

1. Peirce & Jastrow (1884):

�Conclusion: even when claiming to be Wich Wich

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�Conclusion: even when claiming to be unaware of any difference (score=0), subjects could still discriminate the two pressures above chance level!


Pressure 1 Pressure 2Wich

pressurewas the strongest?

Wichpressurewas the strongest?

0 1 2 3 P1 P2

“No preference, nonsensical answer”forced-choice discrimination

task


2. Sidis (1898):

5 S Digit orletter?

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�Conclusion: even when claiming seeing only a dim, blurred spot, subjects could discriminate letters and digits AND identify them above chance level!


5 S letter?

Masked priming paradigm

• Can subliminally presented information influence our behaviour?- Subliminal perception = a stimulus is

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- Subliminal perception = a stimulus is demonstrated to be invisible while still influencing thoughts, feelings, actions, learning or memory (Kouider & Dehaene, 2007)

- How do we measure subliminal perception today?


9


�Masked priming paradigm (Marcel, 1983)

17ms ##

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Larger than 5Smaller than 5

17ms

33ms

480ms

##

6

##


Congruent

condition

Incongruent

condition

Prime 6 1


Prime 6 1

Target 9 9

Both > 5

Faster RTs

One <, one > 5

Slower RTs

Difference (RT_I - RT_C) = priming effect


• 1983: Masked priming paradigm (Marcel)

• 1986: Criticism (Holender) � are we really

measuring subliminal/unconsciousperception? Inadequate measures of prime

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perception? Inadequate measures of prime awareness!


Prime awareness

• Prime awareness assessment:

1. Subjective threshold � self-report (e.g.:

“Were you aware of the prime”)

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2. Objective threshold � discriminative abilities � post-hoc post-test– Identification: identify the prime

– Forced choice absent/present: was there a prime?

– Forced choice categorization: classify the prime


Prime awareness

• How “fast” will a method conclude that the primes were unconscious?1. Subjective report

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2. Prime identification

3. Forced choice absent/present, forced choice categorization


Preferred! If a priming effect is observed AND the primes could not be perceived above chance, most strict evidence of truly unconscious/subliminal priming!

Meta-analysis (Van den Bussche et al., 2009, Psych Bull)

• Mid-1990s: methodological improvements (Dehaene, Greenwald) � more reliable

masked priming paradigms

• From then on: numerous experimental

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• From then on: numerous experimental studies using the masked priming paradigm

�Statistically combine published and unpublished data using meta-analytic techniques



• Search criteria: Published between 1983 – 2006 inEnglish, Dutch, French or German

• Search string: (SEMANTIC OR ASSOCIATIVE) AND (PRIMING OR PRIME) AND (MASKED OR

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(PRIMING OR PRIME) AND (MASKED OR SUBLIMINAL OR UNCONSCIOUS OR AUTOMATIC)

• Four databases were searched (WoS, ScienceDirect, PubMed, PsycInfo)

• Cross-references, reviews, experts

• 749 published articles were selected

• Two reviewers coded these articles using 7 criteria



• Inclusion criteria: 1. Prime-target relation of a semantic nature in the visual domain (e.g. cat - dog)

2. Primes had to be presented subliminally

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3. Semantic categorization, lexical decision or naming task

4. Standard priming procedure

5. Centrally presented single word or symbol primes

6. Healthy sample and N>1

7. Sufficient statistical information to compute an effect size



• 46 published and 8 unpublished studies containing 156 separate conditions

• Effect sizes were computed:

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• Effect sizes were computed:

RT (unrelated trials) – RT (related trials)

ES =

SD

– ES = 0: no effect

– ES > 0: positive ES (~ priming effect)



• Effect sizes: Overall mean ES = 0.80 (CI: 0.60-1.00)

3,5


-1,5

-0,5

0,5

1,5

2,5

Effect Sizes

Conclusion Part I

• Strong and robust subliminal priming effects across the experimental literature

• Subliminal information can influence

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• Subliminal information can influence our behavior… in an experimentalcontext!


Part II

Can subliminal information influence our behavior in an real-life/advertising context?

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real-life/advertising context?


Overview Part II

• Early demonstration

• People’s perception

• Time-course of subliminal priming

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• Time-course of subliminal priming

• Subliminal priming applied

• Our approach

• Conclusions



• Vicary (1957): subliminal messages “drink coca-cola”, “eat popcorn” �

increased product sales

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increased product sales

• Enormous impact on public opinion:



• Subliminal advertising was banned in many countries

• Vicary had falsified data

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• Vicary had falsified data

• Impact on public remained

• Subliminal advertising is still being used today � McDonald’s


People’s perception

• Consumers:- are familiar with subliminal advertising (74-81%)

- believe it is being used (68-81%)

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- believe it is being used (68-81%)

- believe it “works” (72%)

• Significant positive correlation with education

Zanot et al., 1983; Synodinos, 1988; Rogers & Smith, 1993



• Our study (in prep):

- N=99, psychology students, mean age = 18.7, 89% female

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- Participants received definition of experimental subliminal perception

- 6 questions assessing their perception on these kinds of effects in a daily life and advertising situation



• Our study (in prep):1. Unconscious influencing (UI) is present in daily life: 99%

2. People in general are susceptible to UI in daily life: 92%

3. I am susceptible to UI in daily life: 91%

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3. I am susceptible to UI in daily life: 91%

4. UI is is being used in advertising: 95%

5. People in general are susceptible to UI in advertising: 82%

6. I am susceptible to UI in advertising: 68%

� Difference between men (27%) and women (73%)

(p= .002)!



• Actual application of unconscious advertising:

- Rogers & Seiler (1994) questioned 256

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- Rogers & Seiler (1994) questioned 256 American advertising companies about whether they had ever used UI

- 91% NO, 8% did not understand the concept of UI correctly, only 1 firm had used it “as a prank”



• Conclusion:

• People are familiar with subliminal advertising, they believe it is being

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advertising, they believe it is being used and they believe it works

• BUT: companies are not using it

� Discrepancy between the perception

of people and the actual use!


Time-course of subliminal priming

• Still the question remains: does it work?

• Generalizing findings made in an exp

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• Generalizing findings made in an exp context to a more real-life situation is problematic � time-course of

subliminal priming


9


�Masked priming paradigm

17ms ## SOA = 50ms


Larger than 5Smaller than 5

17ms

33ms

480ms

##

6

##

50ms


• Exp context: subliminal info (prime) and behavior undergoing the influence of it (response to target) follow each other very closely in time

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closely in time

� prime exerts its influence almost

immediately

• Meta-analysis: average SOA = 128ms (max = 784ms)



• Subliminal priming is short-lived!

• Priming drops to a non-significant value within a few hundreds of milliseconds (Forster & Davis, 1984; Greenwald et al., 1996; Ferrand, 1996)

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Davis, 1984; Greenwald et al., 1996; Ferrand, 1996)

�Casts serious doubt on its effectiveness in everyday life and advertising

�Subliminal info (an ad) and the behavior undergoing the influence of this info (buying the product) are much farther apart




Pratkanis, 1992

Trappey, 1996

Subliminal priming applied

• Still, some studies have successfully applied subliminal priming in more real-life contexts

• Karremans et al. (2006):

- Subliminally primed with “Lipton Ice” or “Npeic

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- Subliminally primed with “Lipton Ice” or “NpeicTol” (23ms + masked)

- Questions:- If you were offered a drink now, what would you prefer (Lipton Ice or Spa Rood)

- If you would sit on a terrace now, how likely is it that you would order Lipton Ice/Coca Cola/Spa Rood (scale 1-7)

- I would like to drink Lipton Ice/Coca Cola/Spa Rood at this moment (scale 1-7)



• Karremans et al. (2006):

- Increased choice for, and intention to, drink Lipton Ice, but only for thirsty participants

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- See also Strahan et al., 2002; Bermeitinger et al., 2009



• Consumer choices can be influenced by subliminal primes that could help fulfill a need, but only if the consumer is already deprived!

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deprived!

- Veltkamp et al. (2011): even when no deprivation is present, subliminal conditioning can motivate consumers as if they were deprived

- Verwijmeren et al. (in press): subliminally priming an habitual brand has no effect, and a primed brand can lead to increased choice even at the expense of an habitual brand



• Can we conclude that subliminal influencing in a real-life/advertising situation works?

• Let’s not jump to conclusions just yet…

• Methodological issues:

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• Methodological issues:

- Prime awareness assessment

- Time-course: prime and target still very close in time, laboratory context


Our approach

• Aim: examine whether subliminal influencing can be effectively and reliably implemented in more everyday life and advertising situations, using strict methodology

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situations, using strict methodology

• New studies:1. A replication of Karremans et al. (2006)

2. A brand study


1. A replication

• First aim: replicate Karremans et al.’s (2006) study

• Method: Identical replication, except: - We assessed level of thirst at t0 and t1

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- We assessed level of thirst at t0 and t1

- We used a more strict prime awareness assessment (i.e. categorize subliminal primes as word or non-word)

- Same subjects participated in actual experiment AND post-hoc prime awareness test

- N = 28


1. A replication

• Results:

- Prime awareness: 43% � subliminal!

- No differences between “Lipton Ice” group and control group with regards to choice for and

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control group with regards to choice for and intention to, drink Lipton Ice

- No differences between thirsty and non-thirsty subjects

- BUT: “Lipton Ice” group showed a significant increase in thirst (p = .007), compared to the control group (p = .11)


1. A replication

• Why were we unable to replicate Karremanset al. (2006)?

- Power?

- Difference in prime visibility?

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- Difference in prime visibility?

- Role of habits: 50% of our participants indicated Lipton Ice as their favorite brand (cf. Verwijmeren et al.)

- Can subliminal priming induce a deprivation?

� Requires further investigation!


2. A brand study (Brintazzoli et al., in prep)

• Idea = back to basics!

• Design an experiment very similar to a typical masked priming study

BUT: with more real-life stimulus

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• BUT: with more real-life stimulus material



• Stimuli• Typical masked priming experiment

• Primes = 10 very familiar brand logos �

selected in a pilot study

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selected in a pilot study

• Targets = letter strings

• Task: decide as fast as possible whether the target is a word (or brand name) or a nonsensical non-word

• 2 versions: conscious (17ms) or unconscious (13ms)



• 5 conditionsa) related brand: - MCDONALD’S

b) unrelated brand: - LACOSTE

c) related non-brand: - HAMBURGER

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c) related non-brand: - HAMBURGER

d) unrelated non-brand: - CAR

e) non-word: - NOOLWEF

� 400 trials (50% word and 50% non-word)

� Only 200 word trials were analyzed


Design:

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• Prime visibility• Objective forced choice categorization test

• Conscious version (N=29):

- Subjects correctly categorized 75% of the primes

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- d’ =1.56, t(38)= 9.43, p< .001

• Unconscious version (N=19):


- d’ = 0.19, t(18)= 2.28, p= .035, no correlation with priming



• Results

530

540

550

**

**


480

490

500

510

520

brand non-brand brand non-brand

conscious unconscious

RT (ms)

related

unrelated

**


• Discussion

• Brand logos possess the power to prime their brand names and, remarkably, words associated to the brand

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associated to the brand

• primes “McDonald's”, but also “hamburger”!

• However, this only occurred when they were presented above the consciousness threshold!


Conclusion Part II

• Real-life primes only elicited priming when they were presented consciously

• BUT: what do we define as “conscious” and “subliminal”???

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• Exp context: strict methodology to assure prime invisibility required!

• Is there a consensus in this more applied field? Is it the same as in the exp field? Should it be?

• What are we studying? What do we want to study?


Conclusion Part II

• Future studies:1. More laboratory/experimental studies:

- Focus on strict design: compare “conscious” versus “unconscious”

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versus “unconscious”

- Different stimulus material, tasks,…

- Influence on decision-making, choice behavior

- Still only short-lived effects � longevity of

subliminal priming?

2. What about field studies?


Conclusion

• Can subliminal information influence our behavior…

• …in an experimental context? YES!

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• …in an experimental context? YES!

• …in a more real-life/advertising context? ???


Contact

Eva Van den Bussche

Vrije Universiteit Brussel

Department of Psychology

Pleinlaan 2

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Pleinlaan 2

1050 Brussels

Belgium

[email protected]

http://homepages.vub.ac.be/~evdbussc//

16-06-2011 52SCAN Utrecht

Subliminal influencing in advertising: does it...

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