<p>This thesis examines whether childhood family configuration influences performance on cognitive functions and health in adulthood and old age. All studies examined participants in the Betula Prospective Cohort Study aged 35 to 85 years (Nilsson et al., 1997). Study Ι established whether there are reliable effects of sibship size and birth order in a large sample of participants in adulthood and old age. The results showed that the effects previously demonstrated in children and adolescents (e.g., Belmont & Marolla, 1973; Mercy & Steelman, 1982) have a long-lasting effect and can be demonstrated in an adult sample. These studies concluded that intelligence and executive functioning decreased as the sibship size increased. Birth order, in contrast, had only influenced executive functions and working memory: earlier born siblings performed at a higher level than later born siblings. Study ΙΙ examined whether the effects of sibship size and birth order can be replicated and extended to episodic memory and whether the effects of family configuration are stable over a five-year interval. The results showed that early born siblings and siblings belonging to a smaller sibship size performed at a higher level and that these effects on both recall and recognition were stable over a five-year interval. Study ΙΙΙ explored whether childhood family configuration influences chronic adult diseases (myocardial infarction and circulatory disorders, stroke, and hypertension). The overall results showed that being born in a large sibship is a risk factor for stroke, myocardial infarction /circulatory disorders, and hypertension in old age. The results also suggest that being born early in a sibship is a predictor of stroke.</p>

This thesis examines whether childhood family configuration influences performance on cognitive functions and health in adulthood and old age. All studies examined participants in the Betula Prospective Cohort Study aged 35 to 85 years (Nilsson et al., 1997). Study Ι established whether there are reliable effects of sibship size and birth order in a large sample of participants in adulthood and old age. The results showed that the effects previously demonstrated in children and adolescents (e.g., Belmont &amp; Marolla, 1973; Mercy &amp; Steelman, 1982) have a long-lasting effect and can be demonstrated in an adult sample. These studies concluded that intelligence and executive functioning decreased as the sibship size increased. Birth order, in contrast, had only influenced executive functions and working memory: earlier born siblings performed at a higher level than later born siblings. Study ΙΙ examined whether the effects of sibship size and birth order can be replicated and extended to episodic memory and whether the effects of family configuration are stable over a five-year interval. The results showed that early born siblings and siblings belonging to a smaller sibship size performed at a higher level and that these effects on both recall and recognition were stable over a five-year interval. Study ΙΙΙ explored whether childhood family configuration influences chronic adult diseases (myocardial infarction and circulatory disorders, stroke, and hypertension). The overall results showed that being born in a large sibship is a risk factor for stroke, myocardial infarction /circulatory disorders, and hypertension in old age. The results also suggest that being born early in a sibship is a predictor of stroke.

The aim of this study was to investigate whether there is a correlation between birth order, academic performance and need for achievement. 166 students from Alvesta Gymnasium/ High school and Växjö Fria Gymnasium/ High school participated in the study. The result showed a significant correlation between birth order and study result, but unlike previous studies this study showed that it was the youngest siblings that had the best academic performance. Furthermore, a significant correlation between academic performance and need for achievement was found, also that higher need for achievement results in higher academic performance. The study also showed that there is a significant correlation between birth order and need for achievement, and it is the youngest children that have the highest need for achievement. Finally the study shows, in resemblance with previous studies, that sibship size has a negative effect on study results. Most prominent in this current study was that the number of brothers has a significant negative correlation with study result. / Syftet med denna föreliggande studie är att undersöka huruvida det finns samband mellan syskonplacering, studieresultat och prestationsbehov. 166 elever från Alvesta Gymnasium och Växjö Fria Gymnasium deltog i studien. Resultatet visade ett signifikant samband mellan syskonplacering och studieresultat, men i motsats till tidigare studier visar resultatet av föreliggande studie att yngstabarnen har högst studieresultat. Dessutom påvisades ett signifikant samband mellan studieresultat och prestationsbehov, där högre prestationsbehov leder till högre studieresultat. Slutligen visar studien, i likhet med tidigare forskning, att en stor syskonskara påverkar studieresultaten negativt. Mest framträdande i föreliggande studie är att antal bröder visar sig ha ett signifikant negativt samband med studieresultat.

<p>The aim of this study was to investigate whether there is a correlation between birth order, academic performance and need for achievement. 166 students from Alvesta Gymnasium/ High school and Växjö Fria Gymnasium/ High school participated in the study. The result showed a significant correlation between birth order and study result, but unlike previous studies this study showed that it was the youngest siblings that had the best academic performance. Furthermore, a significant correlation between academic performance and need for achievement was found, also that higher need for achievement results in higher academic performance. The study also showed that there is a significant correlation between birth order and need for achievement, and it is the youngest children that have the highest need for achievement. Finally the study shows, in resemblance with previous studies, that sibship size has a negative effect on study results. Most prominent in this current study was that the number of brothers has a significant negative correlation with study result.</p> / <p>Syftet med denna föreliggande studie är att undersöka huruvida det finns samband mellan syskonplacering, studieresultat och prestationsbehov. 166 elever från Alvesta Gymnasium och Växjö Fria Gymnasium deltog i studien. Resultatet visade ett signifikant samband mellan syskonplacering och studieresultat, men i motsats till tidigare studier visar resultatet av föreliggande studie att yngstabarnen har högst studieresultat. Dessutom påvisades ett signifikant samband mellan studieresultat och prestationsbehov, där högre prestationsbehov leder till högre studieresultat. Slutligen visar studien, i likhet med tidigare forskning, att en stor syskonskara påverkar studieresultaten negativt. Mest framträdande i föreliggande studie är att antal bröder visar sig ha ett signifikant negativt samband med studieresultat.</p>