Suppose you learn that two children, a 10-year boy and a 10-year old girl, have brains of quite different sizes, with the boy's brain being about 40% larger than that girl's brain. Which of the following conclusions would be the best to draw from this data?
A) The girl most likely has something wrong with her brain, because it should be at least 10% larger than the boy's brain.
B) The girl's brain most likely has something wrong with it, because it should be very close to the same size as the boy's brain at this age.
C) The girl most likely was malnourished in early childhood, giving rise to a smaller-than-average brain.
D) There is no reason for concern, since children's brain sizes can vary by as much as 50% without any appreciable difference in cognitive skills.

Question

Quizplus · Accepted Answer

Although male brains are on average about 10% larger than female brains throughout childhood and adulthood, brain volumes vary considerably among healthy individuals. A volume difference of 50%, while it seems large and significant, is not generally accompanied by different levels of cognitive abilities. Therefore, a size difference of 30% is within the normal range of brain size differentials.

Suppose You Learn That Two Children, a 10-Year Boy and a 10-Year