case study 7

Context and aims: nature vs nurture debate/is behaviour innate/is behaviour learnt/60's behaviourist movemet=nuture psychology/was depth perception learnt or innate/depth perception=the ability to make sense of sensory information on depth/nativists believed we are born with the capacity to perceive depth/empiricists believed we learn to perceive depth through experience/interactionists believed depth perception involved botch learning pathways/aims to investigate weather we learn the ability to perceive depth of weather a child is born with this ability/if it is innate babies will show good depth perception as soon as they are mobile/if depth perception is learnt throught experience they will show less refined depth perception/hoped to demonstrate that the ability of depth perception is innate.

Procedures:Cornell uni/USA laboratory/36 human babies 6-14 month old/had to be able to crawl independantly/cliff 30 cm off ground covered with perspecx drops away half way to demonstrate a cliff/mothers stood at either side of the table and beckoned for 2 minutes/baby used size/spacing of pattern and motion paralax to tell depth/made tiles on the floor bigger to test only one depth cue at a time/also used newborn animals;chicks,lambs,turtles,rats and kittens/however animals were placed on the deep side and then shallow and their behaviour was observed/some animals were reared in the dark so no depth perception was formed while they developed independant mobility

FIndings and conclusions:human babies 27 crawled to the shallow side/3 crawled to the deep side/when in deep side crawled away from mothers and cried when told to go to the deep side/chicks and lambs all went to the shallow side none went to the deep side/even at one day old avoided the deep side and lambs froze if placed ontop/rats 95% went to the shallow side/alot of them went to the deep side/if couldn't whisker glass avoided deep side/kittens prefered shallow side and froze on the deep side/those reared in the dark went to the shallow side and deep side equally/turtles 76& went to shallow side/preferred shallow side/concluded nature approach was supported as babies were able to discriminate shallow and deep as soon as they were mobile/supports evolution idea that depth perception is learnt due to survival/animals perceived in dark did not respond to different depths/however within one week of the animals living in light had developed full depth perception

Alternative evidence:Campos(1970) tested 1-9 months on visual cliff/held over shallow and deep sides and HR was monitored/1 month old showed no reaction to depth/2 months old showed decrease in HR and stopped crying/6-9 months old showed an increase in HR and crying when held over deep side/adds support to D.P being innate but as younger babies showed no fear supports nature.

Radar & ashley(1983):harnessed babies/new crawlers/7-10 months old/removed glas from deep side/5/12 babies fell off deep side/appear to contradict conclusions that D.P is innate but also contradicts idea that it is learnt via crawling/however babies that feel were the youngest which suggests something is being learnt.

Sorce(1985):repeated visual cliff but mothers had to look fearful or happy/when mum appeared happy baby was more likely to cross to deep side/shows the importance of non-verbal cues

Methodology:was a experiment making results quantative/good as it is scientific and is more likley to be valide and easy to replicate/Conducted in a lab allowed for good level of control over variables/conditions for each baby remained constant/may lack ecological validity as babies not encouraged to climb over cliffs every day/babies were safe but as they didnt follow their mothers orders they became distressed which is wrong/also if babies did crawl to deep sides and thoguht it was safe they might gte hurt in the real world/Baby animals being reared in the dark is wrong as it would probably cause distress and anxiety.