Responding appropriately to the environment: Instincts, learning, and the physiology of "filtered" signal detection and response

Our ultimate goal is to understand the expression of particular behaviors under specific conditions.

We have seen that environmental inputs, genetic coding, and development are all fundamental to the production of behaviors

Given that a complex system of specialized cells is assembled (the organism), where do behaviors come from?

"Innate" vs. "Learned" behaviors:

"Innate" behavior (or instinct) requires no prior experience to be performed in the correct context

"Learning" is the adaptive modification of the animal's behavior as a result of experience

The Nature vs. Nurture argument

Konrad Lorenz: focus on the source of required information that produces an adaptive behavior.

Crucial information can be encoded in the genes (expressed during or after development) or obtained through experience in the environment (learning), or both.

 

Revisiting "instinctive" behaviors

Typically stereotyped/uniform among all individuals

Typically released by simple stimuli

These observations initiated the field of "Ethology" as biologists began to ask: What elicits these responses?

Definitions:

Sign Stimulus

Fixed Action Patterns (FAP)

Some discussions of "learned" behaviors

Non-associative learning

Does not involve a temporal connection between multiple stimuli or events.

Experience with one stimulus modifies future behavior.

Examples: Habituation and dishabituation

Habituation: the waning of a behavioral response as a result of the repeated presentation (or continued presence) of the stimulus. Not due to sensory adaptation or motor fatigue; a learned change in the responsiveness.

Dishabituation: Enhanced responsiveness of a previously habituated response.

Associative learning requires learning about the temporal relationship between two or more events.

Pavlov, his dog, and classical conditioning.

Classical conditioning: When an association is formed between two temporally correlated stimuli; i.e., one stimulus comes to predict the impending occurrence of the other.

Formally, classical conditioning is produced when:

1. A stimulus (the Unconditioned Stimulus, US) that elicits a response called the Unconditioned Response (UR);

2. is preceded by another stimulus, the Conditioned Stimulus (CS).

3. When the interval between CS and US is short (usually no more than a few seconds) and the CS is a good predictor of the US, then the CS will come to elicit the UR which is then called a Conditioned Response (CR)

 

Operant or "Instrumental" Conditioning: Learning an association between the production and the consequences of a behavior

Learning to obtain a particular reward (or to avoid a punishment) by performing a specific behavior.

So, why are some behaviors more "instinctual" while others are more "learned"?

Both have shortcomings

Learning requires mistakes, so carries some cost

Innate responses are unable to respond to complex or varied environmental contexts

Whether a trait is derived more from instinct or learning ultimately depends on:

The likelihood that the environmental context that elicits a response is predictable

The costs of making a mistake

Once this complex system of specialized cells is in place (the organism), where do behaviors come from?

 

The expression of innate vs "learned" behaviors reflects a level of predictability about the environment and the costs of making mistakes (See table 4.1 in Principles of Animal Behavior reading - page 131)

Remember, to behave adaptively, an animal should be able to:

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