personality. announcements first exam on thursday remember the review session tonight! bs 218 at 7pm

Personality

Announcements

• First exam on Thursday

• Remember the review session tonight!

• BS 218 at 7pm

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

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

2 forms of tiger salamanders

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)

Personality

Individual Variation is Important

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

Predator Inspection in Guppies

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


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


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

Octopus Personalities

What behavioral observation method did

Sih et al. use?

a. ad libitum sampling

b. scan sampling

c. focal animal sampling

d. critical incident sampling

Bold and shy sunfish

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



• 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


• 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?


• 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

personality. announcements first exam on thursday remember the review session tonight! bs 218 at 7pm

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