animal studies Flashcards
lorenz
divided goslings eggs into 2 groups - one left with natural mother and other eggs were placed in incubator.
when incubator eggs hatched, first living thing they saw was lorenz - they soon started following him around. to test effect of imprinting he marked the two groups to distinguish them and placed them together - they’d become imprinted on him
goslings quickly divided themselves up, one following natural mother and other group following lorenz and showed no recognition of natural mother
lorenz findings
process of imprinting restricted to critical period of young animal’s life
noted imprinting on humans doesn’t occur in all animals
process of imprinting is irreversible and long lasting.
early imprinting had effect on later mate preferences - sexual imprinting - animals choose to mate with same kind of object they imprinted on
harlow
created two wire mothers with different heads - one additionally wrapped in soft cloth. 8 infant rhesus monkeys studied for 165 days - for 4 monkeys milk bottle was on cloth covered mother and on plain wire mother for other 4. time measurements made of amount of time each infant spent with different mothers, observations also made of monkey’s responses
harlow findings
all 8 monkeys spent most time with cloth covered mother, monkeys who fed from wire monkey spend short amount of time getting milk and then returned to cloth covered mother. when frightened, all monkeys clung to cloth covered mother and when playing with new objects monkeys often kept one foot on cloth covered mother for reassurance
infants don’t attempt attachment to person who feeds them but to person offering contact comfort
continued to study monkeys as they grew up - motherless monkeys, even those who had contact comfort, developed abnormally - sexually abnormal - didn’t show normal mating behaviour and didn’t cradle their babies.
critical period - if motherless monkeys spent time with other monkeys they seemed to recover but only if this happened before they were three months old. more than 6 months with only wire mother - unable to recover from it
lorenz evaluation - research support for imprinting
guiton - demonstrated that leghorn chickens exposed to yellow rubber gloves while being fed during first few weeks became imprinted on the gloves - supports view that young animals not born with predisposition to imprint on specific type of object but probably on any moving thing present during critical period, also found that male chickens later tried to mate with the gloves - early imprinting is linked to later reproductive behaviour
lorenz evaluation - criticism of imprinting
imprinting not irreversible
guiton - found he could reverse imprinting in chickens on gloves - after spending time with their own species they were able to engage in normal sexual behaviour with other chickens - imprinting may not be different from other kinds of learning - learning can also take place rapidly with little conscious effort and is reversible
harlow evaluation - confounding variables
stimulus objects varied in more ways that being cloth covered or not - heads were also different which acted as confounding variable as it varied systematically with independent variable - possible that monkeys preferred one mother to the other because it had a more attractive head - lacks internal validity
harlow evaluation - generalising animal studies to human behaviour
while animal studies act as useful pointers in understanding human behaviour, we should always seek confirmation by looking at research with humans:
number of studies found that observations made of animal attachment behaviour are mirrored in studies of humans - harlow’s research is supported by schaffer and emerson’s findings that infants aren’t most attached to person who fed them
