Chapter 12The Limitations of Learning

LimitsPhysical CharacteristicsNon-heritability

Heredity of learning abilityNeurological DamageCritical PeriodsPreparedness

Instinctual DriftBiological PreparednessSign Tracking

Physical CharacteristicsPhysiological structure of the speciesLimitations on behaviours

e.g. teaching chimps to talk vs. teaching sign language

Nonheritability of Learned BehaviourLearned behaviours are not inheritedLamarckian evolution: passing acquired

characteristics to offspringShort neck giraffe needs to stretch to reach

foodNeck gets longerPasses on long neck to offspring

McDougall’s ratsTrained rats to run on avoidance taskTrained those rats offspring on avoidance

taskTrained those rats offspring on avoidance

task, etc.Each generation should learn faster (inherit

skill of parents, and ancestors)

BUT, no control group…

Agar (1954)Replicated McDougall’s design, but added a

control groupControl: every second generation was

untrainedFound same pattern of results with control

groupi.e. successive generation also learned faster

than previous generationsBut also many fluctuations within both groups

Suggests that training of parents has no effect on offspring

Non-inheritanceInheritance of learning could limit

adaptabilityAdvances/changes in ways of thinking

e.g. sun revolves around the earth?Traditional male/female roles?

Heredity and Learning AbilityDon’t inherit learned behaviours BUT…Genetic influences on ability to learnTryon (1940): rats learn maze, breed

“smartest” together and “dumbest” together for 18 generations‘Smart’ rats had ‘smart’ rat pupsNot inheriting a learned behaviour, but ability

to learn quicklyIdentical twins reared apartNature and nurture

Neurological DamageNeurotoxinsPrenatal damage to CNS (e.g., fetal alcohol

syndrome, crack cocaine)Envrionmental toxins (e.g., lead)Physical damage (e.g., concussions)

Critical PeriodsStage for

optimum learning

Puppy dogsKonrad Lorenz

& Imprinting

Harlow & HarlowMonkeys & terry cloth

mothers“Pit of despair”Critical period for

development of social skills

Preparedness & LearningSeligman’s ‘Continuum of Preparedness

PreparedUnpreparedContraprepare

AutoshapingPigeons peck at key light CS even though

unnecessary for arrival of US (food)‘Prepared’ for learning to peck key-lightautoshaping

Instinctive DriftBreland & Breland

(1961)“miserly” raccoonContrapreparedInnate tendencies

(GBTs, FAPs) interfere with learning

Biological PreparednessRemember ‘bright-noisy water’?Prepared for ‘flavour’ taste aversion,

unprepared for ‘noise’ taste aversion

Pre-cond Post-cond Pre-cond Post-cond

X-ray Shock

Flavoured water “Bright-noisy” water

Learning & EvolutionLike evolution, learning has no specific goalNot all learning is good

Learned helplessnessVicarious learning of aggressionDrug conditioning