Learning and Behaviour Learning Enduring change in behaviour

Learning and Behaviour • Learning – Enduring change in behaviour – Due to experience – How something is done • Behaviour – Procedures and actions performed – Learning – Non-learning – What is done

Types of Learning • • Habituation/sensitization Classical conditioning Operant conditioning Observational/vicarious

Adaptation • Changing conditions • Time scales • Learning only one type of adaptation

Innate Behaviours

Innate Behaviours • Evolved • Environmental change • Re: Learning – Roots in innate behaviours – Parallels • Homeostasis, reflexes, tropisms, modal (fixed) action patterns

Evolutionary Theory • Voyage of the Beagle (1831 -1836) • On the Origin of Species (1859) • Artificial, natural, and sexual selection • Adaptation to environment

Natural Selection • • • Variation, inheritance, selection Differential reproductive success No intelligent design Level of the individual Change over generations

Examples: Physical Evolution • Skull • Bipedalism Australopithecus afarensis (400 cc), Homo erectus (1200 cc), Homo sapiens (1400 cc)

Examples: Behavioural Evolution • Cooperation (e. g. , food sharing, child rearing) • Pair bonding • Altruism

Homeostasis • Internal balance of the body • Drives • Regulatory drives

Control System • • Comparator Reference input Actual input Action system Output Feedback system (closed-loop system) Response lag

Blood Salinity Comparator Reference input Output Actual input Action System Eat more peanuts! Drink water! peanuts!

Reflexes • Stereotypic movement patterns • Reliably elicited by appropriate stimulus • Survival benefit

Example: Grasping in Infants • Humans, other primates

Example: Eyeblink • Stimulus (e. g. , airpuff) • Eyelid closes

Example: Limb Retraction • Sharp rock, hot surface, etc. • Fast muscle contraction • Pulls limb away

Reflexes • Rapid response • Simple neural pathways • Sensory neuron, interneuron, motor neuron

Reflex Arc sensory neuron interneuron muscle motor neuron ?

Tropisms • Movement, or change in direction, of the entire animal • Jacque Loeb – Geotropism

Geotropism

Types of Tropisms • Kinesis – Movement random with respect to stimulus • Taxis – Non-random (directed) movement with respect to stimulus

Kinesis • Movement in a random direction testing arena hot slow cool medium fast heat source

Taxis • Movement that bears some relationship to the location of a stimulus testing arena hot cool heat source

The Models • Kinesis – Random turn – Set move length – No more than 180° turn – Movement speed variable (fast, medium, slow) • Taxis – Turn so as to move away from heat – Set move length – No more than 180° turn – Movement speed fixed

Modal (Fixed) Action Patterns • Originally “fixed”; variable to some degree • Species specific, often state dependent • Sign stimulus (“releaser”) activates a dedicated neural system • To completion in sequence

Graylag Goose • Rolls displaced egg near its nest back with beak • Sign stimulus: displaced egg • Remove egg during sequence • http: //www. youtube. com/ watch? v=v. UNZv-By. Pk. U www. cerebromente. org. br/n 09/fastfacts/comportold_I. htm

Stickleback Bruno Cavignaux / Biosphoto www. arkive. org/three-spined-stickleback/ gasterosteus-aculeatus/image-A 23078. html http: //www. mylot. com/w/image/1967361. aspx

Supernormal Stimuli • Extreme version of sign stimulus • Size, colouration, etc. • Preference sometimes detrimental

Beetles on the Bottle • Gwynne & Rentz (1983) • Male Jewel beetles (Julodimorpha bakewelli) • Colour and reflection of bumps on bottle as supernormal stimuli for female beetle

General Behaviour Traits • Behavioural traits strongly influenced by genes • Not the same as Modal Action Patterns – GBTs more plastic than MAPs – No single sign stimulus • e. g. , Species Specific Defense Reactions – Freeze, flee, fight – Mouse vs. bear

Environmental Interaction • Not strictly genetically controlled • Susceptible to conditioning • e. g. , twin studies

Behavioural Influence • • • Selective breeding studies Artificial or natural selection e. g. , morphine addiction in rats e. g. , Silver foxes http: //www. youtube. com/watch? v=ot 2 www 2 CF 3 Y

Habituation and Sensitization Simplest form of Learning

Habituation and Sensitization • Changes reflex response • Learning without new axons/synapses • Temporary effect at existing synapse – E. g. , less neurotransmitter released from axon terminal

Habituation • Decease in a response following repeated stimulus presentation • Note: note everything that results in a decrease in response is habituation Sensitization • Increase in a response following repeated stimulus presentation

Example: Banana Slug Habituation • Eyestalk retraction • Touch back • Record time until eyestalks are fully reextended

Results – – – Trial 1: 23 sec Trial 2: 12 sec Trial 3: 10 sec Trial 4: 7 sec Trial 5: 3 sec Trial 6: 1 sec re 25 Time (sec. ) • Slug eyestalk -extension times 12. 5 1 2 3 Trial 4 5 6

Example: Rat Sensitization • 1. Gentle touch, no response • 2. Painful shock, flinch • 3. Gentle touch, flinch

Habituation and Sensitization Generalization Habituation Less Sensitization More Length of effect Longer Shorter Rate of relearning Quicker than initially • Generalization: treat other stimuli like learned stimuli • Discrimination: distinguish other stimuli from learned stimuli

Spontaneous Recovery • Post habituation or sensitization • Return to original level of responding • Due to passage of time

Limits of Natural Selection • Adaptation relatively slow • Generally not helpful during a lifetime • Select best adapted individuals from each generation • Evolutionary time lag • Variation within species

Learning: Evolved Modifiability • Selective pressure • Learning – Going beyond innate behaviour patterns • All animals • Evolutionarily selected for • Allows individuals to adapt to rapid environmental change

Nature and Nurture • • • Long debate British Empiricists vs. Nativists Not “either/or, ” but “both” Genes and environment constantly interact Biology and experience both shape an organism’s behaviour patterns

The Ability to Learn • A by-product of both heredity and experience • e. g. , rats reared in complex environments • e. g. , educational aids for infants