Instinct and learning 1

Question 1

Instinct behaviours

Answer 1

*innate behaviours - “hardwired”
–reliably develops in most individuals
–Initiated by a releaser or sign stimulus the 1st time stimulus encountered

For example: Fixed action pattern (FAP):
–innate, stereotyped response
–triggered by well defined simple stimulus,
–once activated response performed fully

Question 2

Instinctive behaviour FAP example: Egg rolling behaviour in European Greylag Goose

Answer 2

*activated by simple sensory stimulus (sign stimulus)
*continues to completion regardless of sensory feedback.
*little flexibility.
* Fixed Action Pattern - mother goose continues the rolling pattern even when Tinbergen takes away the egg showing it is a FAP behaviour

Question 3

Instinctive behaviour example 2: Herring gull chicks pecking the red spot on parents bill for food regurgitation

Answer 3

Chicks perform this behaviour as soon as they hatch from the egg

–2 stimuli:
*general appearance of bill
*movements of bill
(Supernormal stimuli)

Question 4

instinctive behaviour example 3: male-male aggression in sticklebacks triggered by red colouration of other males

Answer 4

aggression towards model initiated by big red belly

Question 5

Instinctive behaviours can be influenced by learning

Answer 5

Closed Instinct:
–environmental cue X -> response ‘A’ (not influenced by life experience/environment)

Open Instinct:
– environmental cue X occurs -> response ‘A’
– but any feedback from consequences is stored for later modification = An element of ‘learning’

Most instincts appear to be open instincts - Therefore FAP is rarely used now (variations, modifications) – substituted by ‘behaviour patterns’ or ‘behavioural acts’

Question 6

Instinct vs learned response

Answer 6

Instinct: results from evolutionary changes during history of the spp.

Learning: shapes behaviour during the life of the individual to improve effectiveness and efficiency

Question 7

What do we mean by ‘learning’?

Answer 7

*individual learning cf. social learning (e.g. ‘cultural transmission’)
*“a change in behaviour as a result of experience.”

–But, for example, hunger affects behaviour, changing motivation – hunger is not learning, but it is necessary to learn how to find food better – so linked to learning.

–NB: NOT including changes due to aging & condition (exhaustion, illness etc).

*learning can be defined as “a relatively permanent change in behaviour as a result of experience” (Shettleworth, 1998).

–But - how long = “relatively permanent.”?

*Learning is persistent “adaptive changes in individual behaviour as a result of experience” (Thorpe, 1963)

Question 8

Learning and phenotypic plasticity

Answer 8

*Learning = a type of phenotypic plasticity
*but not all phenotypic plasticity involves learning.

e.g. an organism becomes more spiny in a response to grazing by nudibranch - this is not learning

Question 9

How animals learn: mechanisms of learning:
non associative/ associative

Answer 9

*Non-associative
–Habituation & Sensitisation

*Associative
–Imprinting
–Classical conditioning
–Operant conditioning
–Learning from Experience
–Insight learning
–Imitation
–Play

*Latent learning

Question 10

Non-associative: Habituation and sensitisation

Answer 10

habituation example: introducing a blue stick in to a rats enclosure can initially cause fear until the rat becomes habituated to it and no longer sees it as a threat

*One of simplest kinds of learning.

Habituation & Sensitisation are non-associative forms of learning

Hard to measure without following the lives of specific organisms for example at Donna Nook the seals may not have been habituated to humans but instead under some kind of artificial selection

involves:
*stimulus-induced responses that show decrement versus increment with stimulus repetition.
*changes in response probability, magnitude, latency of onset, or duration.
*changes in response associated only with stimulus repetition,
*Does not involve reward or punishment, therefore = non-associative learning processes.

Habituation example 2: Seagulls lose fear response under repeated exposure to humans to steal food
Although this could be active learning lead by bold individuals risk taking behaviour

Question 11

Non-associative sensitisation

Answer 11

*Opposite of habituation.

*Enhanced response to a repeated significant stimulus. E.g. spraying Aplysias gills with water causing them to retract.
*Lowers threshold for the elicitation of appropriate behaviour
result:
-> subsequent presentations of the stimulus, not normally capable of eliciting the behaviour, now do so.

Question 12

Example of non-associative sensitisation: siphon withdrawal response to gentle touch in Aplysia

Answer 12

Aplysia punctata (aka Spotted Sea Hare) is native to the british isles
if preceded by electric shock to tail a gentle touch to siphon elicits a longer period of withdrawal.

Question 13

habituation: guppy example

Answer 13

When a predator in an adjacent tank is visible to guppies, bold individuals are more likely to approach.
As these prey fish learn that the predator cannot reach them more fish may approach the predator in the next door tank.

Question 14

Issues with studies using domesticated species

Answer 14

Problem for ethological expt.
(Huntingford 1984, Rowland & Sevenster 1985).
Experiments using human bred organisms may be skewed due to the domestication effect
(Conservation biology – captive releases (Bauer, 2005))

Individuals raised in captivity may not fear humans enough when released in the wild

Question 15

Associative learning (associating stimulus with reward/risk)

Answer 15

*An action or stimulus of previously little significance becomes important.
*Occurs if consequences reliably flow from the action or stimulus
*Leads to a long-term association – i.e. conditioned

Question 16

Imprinting (filial)

Answer 16

*Type of social learning based on early experience.

*Occurs during a critical sensitive period usually within a few hours or days after birth (or hatching).

*genetically determined (‘innate’)

Filial Imprinting: Young Animals → Parents
- Visual imprinting: individual learns to respond to a particular animal or object
-Imprinting by sound: young chicks recognise their mothers voice whilst still in the egg
- Imprinting by scent: particularly in mammals

Question 17

Sexual imprinting

Answer 17

Offspring imprint on members of own spp (normally)

& when mature, they prefer their own spp. for sexual imprinting

Evidence: ‘counter experience’ experiments

Fostering individuals with another species results in chicks imprinting on the form of their foster parent

Question 18

Associative learning (classical or operant)

Answer 18

*Classical or Pavlovian conditioning (conditioned response Type I)
–animal learns to associate an external event with a change in its internal state or its behaviour.

*Operant or instrument conditioning (conditioned response Type II)
–animal learns to associate an act that it performs with some kind of reward.

Question 19

Classical conditioning

Answer 19

Pavlovs dog experiment - dogs learn to associate the ringing of a bell with food and this new stimuli becomes conditioned as a releaser of saliva.
A canula in the cheek of the dog collects saliva and the quantity is recorded to confirm effect

Question 20

Pavlov’s terminology:

Answer 20

*unconditioned stimulus (US) = the physiologically meaningful stimulus (food)
→ Unconditioned response (UR) = normal response. (salivation)

*conditioned stimulus (CS) = normally irrelevant stimulus (bell) that becomes a substitute for the US.
→ Conditioned response – the learned response.

Question 21

Classical conditioning second example:
rats and prey response

Answer 21

rat is habituated to the blue stick, then the researcher combines the blue stick with a new unconditioned stimulus (cat urine) - soon the presence of the blue stick is associated with the smell causing the rat to hide

*second-order conditioning
*once a CR learned (US -> CS1)
*new stimulus is presented before CS1

stimulus CS1 is a blue stick, CS2 is a light. then the rat associates the light with a predator

Question 22

Types of stimuli in classical conditioning

Answer 22

*appetitive stimuli: +ve stimulus (e.g. food, presence of potential mate, safe haven)

*aversive stimuli: -ve (shock, noxious odours)

*positive vs negative relationships:

–If CS predicts US: +ve relation between events -> excitatory conditioning
–if CS predicts US will not occur: -ve relationship -> inhibitory conditioning.

for example: blue stick followed by not feeding the rat

Question 23

Operant conditioning

Answer 23

*Typical lab. Experiment: The ‘Skinner’ Box:
Skinner box contains various levers and buttons the animal can trigger for an outcome e.g. +ve release of a food pellet or –ve an electric shock – then the animal associates their action between the behaviour performance and outcome.

*random actions of rat result in pressing the bar -> food
= positive reinforcement for pressing the bar.
*rat learns association & presses bar to obtain food

Question 24

Operant compared to Classical conditioning

Answer 24

*Classical Conditioning: individual performs some behaviour in response to a stimulus.

Compared to:

*Operant conditioning: motivationally significant event occurs after individual performs some behaviour.

–learns to associate a voluntary action with consequences
–Learning based on ‘trial and error’
–Action (operant) alters in likelihood of occurring if reinforced

*gain a reward (positive reinforcement)
*avoid ‘costs’/’punishment’ (negative reinforcement).

Question 25

Operant conditioning: behaviour reinforcement

Answer 25

A reinforcer is any event (outcome/stimulus) following the performance of a behaviour that increases the likelihood that the behaviour it follows will recur in future.

positive: a desirable stimulus is added that makes the act it follows more likely to recur
e.g. a behaviour that leads to a food reward

negative: an undesirable stimulus is removed that makes the act it follows more likely to re-occur
e.g. a behaviour that avoids a painful outcome

Question 26

Operant conditioning: Reinforcement compared to punishment

Answer 26

*Reinforcement leads to an increase in the performance of a behaviour,
*Punishment leads to a decrease in the performance a behaviour

Punishment can also be positive or negative

For example:
positive: A behaviour that leads to a painful outcome will reduce the likelihood of that behaviour recurring
negative: A behaviour that leads to the removal of a desirable outcome (e.g. food) will reduce the likelihood of that behaviour recurring (removing a reward)

Question 27

operant conditioning example: tank dogs and dolphins

Answer 27

Tank dogs taught to run under tanks to get food, then a saddlebag of explosives is strapped on their back and when they run under the tank the trigger on their back detonates exploding the tank – worked for a while until German army learnt to shoot dogs on sight.

Dolphins have been trained to rescue divers and find mines

Question 28

operant conditioning examples from nature

Answer 28

-squirrels cracking nuts
- chimps using tools

Operant conditioning is probably the way animals learn to perform & perfect complex tasks.

Question 29

Operant conditioning: examples from nature:
Herring gull chicks pecking red spot on parents beak for food

Answer 29

Operant conditioning has a role in the development of some behaviours that appear innate:

Such as the pecking behaviour in herring gull chicks to get parent to regurgitate food:

Precision of pecking improves a few days after hatching showing a learnt element

*1st attempts inaccurate but sufficiently functional to get food,
*gets better with practice.

So behaviour that might appear wholly genetic (innate) is improved with learning

Question 30

Learning from experience

Answer 30

*Learning abilities are biased:
–information most important to survival is most easily learned
E.g. Rats associate poison with negative outcome

Question 31

quick learning in response to unpleasant experiences forms basis of warning colourations & impersonators

Answer 31

Aposematic colouration: bright contrasting colouration warns predators of toxic species

*Batesian mimicry: harmless species mimicking this colouration

*Mullerian mimicry: a form of mimicry in which two or more harmful or unpalatable animals develop similar appearances as a shared protective device e.g. bee and wasp colouration