Nature-Nurture Debate
NATURE NURTURE
Classic Ethologists Comparative Psychologists
Konrad LorenzWatson
Behavioral Development
Genes
(Innate/Nature)
Environment
(Learned/Nurture)
DNA is both inherited and environmentally responsive
The ability to learn is influenced by genes
Environmental differences lead to behavioral variation
• Phenotypic plasticity: multiple alternative phenotypes within a species whose differences are induced by key differences in the environments experienced by members of this species
• Reaction norm– Reaction norms provide graphical representations of
phenotypic plasticity—the ability of a genotype to produce different phenotypes across an environmental gradient
Phenotypic plasticity is favored when conditions are ____________
a) variable/unpredictable
b) constant/predictable
Resolution of the Nature vs. Nurture Debate
• Contemporary view– No behavioral trait is ‘genetically determined’ nor
‘environmentally determined’– Rather, behavioral development is an interactive process
between genes and the environment– differences in phenotype may be due to genetic and/or
environmental differences among individuals
Both genes and environment are 100% important in the development of all behavior. (Donald Hebb)
Overall Success
YesNo
Exp
lora
tion
Div
ersi
ty
Successful hyenas display a wider array of behaviors in 1st trial
Logistic regression results:
*= p < 0.05
Exploration diversity: # of exploratory behaviors used Digging, investigating, biting, flipping or dragging the box
Individual variation in exploration diversity
Likelihood ratio test:
Hyena ID: P < 0.0001
Generalized linear mixed model:
Success: P < 0.0001
Least Diverse Most Diverse
Mea
n ex
plor
atio
n di
vers
ity s
core
per
indi
vidu
al 4
3
2
1
0
Hyena ID
Personality Differences/Behavioral Syndromes
Consistent long-term behavioral differences among individuals across time and context•may be heritable•may be affected by individual and social learning-especially when learning occurs early in development
Behavioral syndrome: a suite of correlated behaviors reflecting between-individual consistency in behavior across multiple situations. Within the syndrome, individuals have a behavioral type (i.e. less aggressive or more aggressive) - Sih et al. 2004
Behavioral consistency, both within and between individuals
Behavioral Syndromes
Aggression in contests
Aggression in feeding
Aggression in mating
Parental care behavior
Boldness with predators present
Good territory
High feeding rates
Sexual coercion
Poor parenting
DEATH
Personality Is Often Heritable
• A recent review of temperament and personality in nonhumans found evidence for heritability in twenty species (Reale et al 2007, 2010).
Boldness and Shyness
• Psychologists have long proposed that where a person falls on the continuum from very shy to very bold behavior is one of the most stable personality variables studied.
• Boldness = the tendency to take risks in both familiar and unfamiliar situations
• Shyness = the reluctance to take risks, or even a reluctance to engage in unfamiliar activity at all.
Barnacle geese - consistent leaders (bold risk takers) and consistent followers (Kurvers et al. 2009; 2011)
• costs to leaders
- increased predation/injury
• benefits to leaders- first access to
food
Q: Why do some guppies exhibit high predator inspection behavior?
H1: Guppies inspect predators to protect vulnerable offspring
P1: Only guppies with an active nest nearby should exhibit high predator inspection behavior
H1: Guppies inspect predators to protect vulnerable offspring
Level of Analysis?
A. Phylogeny
B. Mechanism
C. Function
D. Ontogeny
Q: Why do some guppies exhibit high predator inspection behavior?
H1: Guppies exhibit high predator inspection behavior due to activational effects of testosterone, which causes guppies to be more aggressive and more willing to take risks
P1: Guppies that exhibit high predator inspection behavior have higher circulating testosterone levels than guppies that exhibit low predator inspection behavior
Level of Analysis?
A. Phylogeny
B. Mechanism
C. Function
D. Ontogeny
H1: Guppies exhibit high predator inspection behavior due to activational effects of testosterone, which causes guppies to be more aggressive and more willing to take risks
Q: Why do some guppies exhibit high predator inspection behavior?
H1: Predator levels during development trigger predator inspection behavior in adult guppies.
P1: Guppies that develop in environments with a high concentration of predators will exhibit higher predator inspection behavior than guppies developed in environments where predators were absent
Level of Analysis?
A. Phylogeny
B. Mechanism
C. Function
D. Ontogeny
H1: Predator levels during development trigger predator inspection behavior in adult guppies.
• Also tested the ability of males guppies to learn an association
• Treatment 1: males evaluated on boldness and then given a learning task
• Treatment 2: males given a learning task and then evaluated on boldness
• Results: Bolder guppies in treatment 1 learn more quickly than behaviorally inhibited guppies.
• This result did not hold for treatment 2. Predator inspection may prime bold fish to learn better, or it may have a negative effect on learning in behaviorally inhibited fish. This may be due to higher levels of stress hormones in the behaviorally inhibited fish after seeing a predator.
Predator Inspection in Guppies
What behavioral observation method did
Sih et al. use?
a. ad libitum sampling
b. scan sampling
c. focal animal sampling
d. critical incident sampling
Personality in Great Tits
Photo by K. van Oers
• Slow birds take longer to explore an environment
• spend more time learning about each aspect of a new environment
• and vary their foraging routine often
Personality in Great Tits
Photo by K. van Oers
• Fast birds take less time to explore an environment
• spend only a short time in any particular area
• but are unlikely to change established foraging patterns
Photo by K. van Oers
• Used marked birds in a natural population in the Netherlands.
• measured the reproductive success of slow and fast birds in different types of environments
• found that reproductive success was greatest when pairs of bird had similar personalities
• slow-slow and fast-fast pairings led to the production of the healthiest chicks
Does personality affect fitness?
Does personality affect fitness?
Photo by K. van Oers
• Found that females paired with males that had a personality type similar to their own had the highest rates of extrapair matings
• increase behavioral variation among offspring?
slow-slow and fast-fast pairings led to the production of the healthiest chicks• In small groups, come up with two hypotheses
to explain this result. Why do these pairings result in the healthiest chicks?
• Each hypothesis has to be at a different level of analysis
• State the level of analysis for each hypothesis, and give a very brief (one sentence) explanation for your answer
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