Outline and evaluate research into the effect of day care on children's social behaviour (aggression and peer relations). [12marks] Many psychologists have researched into the effect of day care on both aggression and peer relations in children/toddlers. One of those psychologists was Shea (1981) who studied 3-4 year olds who spent a certain amount of days a week in day care for 10 weeks. He discovered that day care does not increase aggression in children as they became more sociable and aggression towards one another decreased. He also observed that day care improves peer relations, the children became more sociable with one another but drifted further away from the staff/caregiver. Children who spent 5 days a week in day care showed greater changes than those that spent 2 days a week in day care. This study could be criticised as it is not specified the number of children observed; this will affect the reliability of the findings as a larger sample would be preferred, this is because the more children that are observed the easier it is to pin point a trend in behaviour. On the other hand a strength of this study could be the fact that Shea went to a day care centre and did not set up an artificial play room as this could have caused abnormal behaviour due to the new environment. NICHD (National Institute of Child Health and Human Development) study (1991) studied over 1000 American children; the findings were that the longer the child was left in day care the more aggressive he/she became. The study also stated that the child was 3 times more likely to: show behavioural problems, argue, have tantrums, lie and hit. The fact that over 1000 children were studied makes this study very reliable because it is a significant amount of data collected, therefore a trend is more likely to be spotted. However the study was only carried out on American children which could be weakness for this study because methods to bringing up children, cultures and traditions will differ widely across the world so the results from the NICHD study would be bias towards the American method to bring up children and the American culture and tradition. In 2000 Campbell et al examined toddlers aged between 18 months and 3 1/2 years old who spent time in day care on a regular basis when parents/primary caregivers went to work. Campbell et al concluded that spending time in day care would affect peer relations positively or negatively depending on their age. However overall Campbell et al found that the longer a child spent in day care the less sociable he/she became as they got more tired; this study also stated that the impact of early day care directly affected later social abilities. This implies that this study followed children from attending day care to observing their social abilities later in life. To conclude there have been studies carried out on both sides of the argument which and there are certain characteristics in all the studies that make them strong but also some characteristics that make the studies weak.