imate of the family decreases. Zajonc and Markus put the data from the Belmont and Marolla study into a table that provided information about the number of children and the average intellectual score for the children. They noticed that in larger families there is somewhat of a leveling off or even an increase in scores for the extreme later-born children. The reason for this increase is because the other siblings start to leave the family and contribute towards the average intellectual climate. Zajonc and Markus also found that twins and triplets performed lower on tests of intelligence than non-twin siblings. Zajonc and Markus didn't try to claim that the only determinates of intellectual ability were family size and birth order. There were other factors such as genetic heritage and prenatal care that also contribute to intellectual development. After reading about this research, I feel that it was very well done. It seems to be ethical and Zajonc and Markus had a large sample to evaluate. I personally agree with what was found in the study. I am the youngest of three children in my family. My brother is the oldest and he always took the hardest classes and got straight A's. My sister was the second oldest. She was a lot like my brother but she always went to my brother for help with her school work. Then it comes down to me. I had pretty good grades through school; mostly B's and a few A's. It just seems like the order of intelligence in my family goes down from my brother to me. One of the things that Zajonc and Markus couldn't evaluate was how motivated people are. The older sibling might be more intelligent but that doesn't mean they are a harder worker or more motivated that the last-born sibling....
