Introduction to PsychologySuzy Scherf

Lecture 6: How Do We Act?

Learning and the Role of Experience

Psychology without Evolution

Behaviorists -

Nativists -

Psychology without Evolution

Behaviorists and Nativists came up with same conclusion:

Since learning results from an individual’s experience:

Psychology without Evolution

1. Nature vs. Nurture -

2. Genetic Fallacy -

3. Instincts control animal behavior -

Nature vs. Nurture - False Dichotomy

Genetic Fallacy

The idea that traits with a genetic basis are automatically fixed and inflexible.

Instincts vs. Learning

What do we mean by “instincts”

Instincts vs. Learning

Even animal behaviors that appear to be completely “instinctual” require learning:

Instincts vs. Learning

What do we mean by “learning”

Instincts vs. Learning

Even animal behaviors that appear to be completely “learned” are influenced by the genotype:

Psychology with Evolution

1.

2.

3.

4.

Genes Differ in Responsiveness to the Environment

1. Obligate Effects -

Why Design an Obligate Adaptation?

• When a single solution works best across a wide range of environments

• Obligate traits ‘expect’ a certain range of environments

Experience Still Matters:

Genes Differ in Responsiveness to the Environment

2. Facultative Effects -

Why Design a Facultative Adaptation?

1. When the environment is variable within the lifetimes of individuals.

2. When the fittest alternative varies from one environment to the next

Norm of Reaction for a Facultative Trait:

Level of UVb Radiation

Low HighLow

High

(Environment)

(Phe

noty

pe)

Lev

el o

f M

elan

in S

ynth

esis

Reaction Range for an Obligate Trait: Discontinuous

(Range of Normal Environment)

(Ran

ge o

f N

orm

al

Phe

noty

pe)

Abnormal

Abnormal

Selection will prefer facultative or obligate traits depending on -

What Kind of Learning?

• Learning involves -

• Learning mechanisms are -

• Facultative adaptations are -

What Kind of Learning?

1. Birds learning “star compass” -

2. Ants navigation home in most efficient way using “dead reckoning”

3. Human infants learning language -

4. Monkeys showing “insight” in food foraging

What Kind of Learning?

5. Dogs being classically conditioned -

6. Cats being operantly conditioned -

7. Human’s learning to play a game of weather forecasting using -

8. Monkeys learning to do -

Concepts Relevant to Learning

1. Ecological Context - -

• EEA (Environment of Evolutionary Adaptedness):

Concepts Relevant to Learning

2. Critical Period Learning -

• Specialized to happen once -

• Indigo Buntings -

• Human’s -

Concepts Relevant to Learning

2. Critical Period Learning -

• Requires specialized experiences to develop

• Time window -

• Traits vary in their sensitivity to critical periods

Concepts Relevant to Learning

2. Critical Period Learning -

• Deprivation and excessive enrichment experiences -

• Related to plasticity

• Different brain systems -

Concepts Relevant to Learning

3. Preparedness -

• Over-prepared -

Concepts Relevant to Learning

3. Preparedness -

• Under-prepared -

Are there any General-Purpose Learning Mechanisms?

• Can we think of any general problems that animals face?

• Problems that would be solved with a single learning mechanism?

Classical Conditioning

• Learning that some external thing can elicit a reaction from your body

• Forming an association (noticing a pairing) between -

Classical Conditioning is Still notGeneral-Purpose

Operant Conditioning:Learning Associations between Behaviors and Consequences

Operant Conditioning

Reinforcers and Punishers affect behavior

Reinforcers -

Punishers -

Operant Conditioning

Still not general-purpose

Limitations of Conditioning

1.

2.

3.

4.

Problem-Solving Using Insight or Trial-and-Error

Problem-Solving Using Insight or Trial-and-Error