Differences between males and females can be based on (a) actual gender differences (i.e., men and women are actually different in some abilities), (b) gender roles (i.e., differences in how men and women are supposed to act), or (c) gender stereotypes (i.e., differences in how we think men and women are). Sometimes gender stereotypes and gender roles reflect actual gender differences, but sometimes they do not.
In terms of language and language skills, girls develop language skills earlier and know more words than boys; however this does not translate into long-term differences. Girls are also more likely than boys to offer praise, to agree with the person they’re talking to, and to elaborate on the other person’s comments. Boys, in contrast, are more likely than girls to assert their opinion and offer criticisms (Leaper & Smith, 2004). In terms of temperament, boys are slightly less able to suppress inappropriate responses and slightly more likely to blurt things out than girls (Else-Quest, Hyde, Goldsmith, & Van Hulle, 2006).
With respect to aggression, boys exhibit higher rates of unprovoked physical aggression than girls, but no difference in provoked aggression (Hyde, 2005). Some of the biggest differences involve the play styles of children. Boys frequently play organized rough-and-tumble games in large groups, while girls often play fewer physical activities in much smaller groups (Maccoby, 1998). There are also differences in the rates of depression, with girls much more likely than boys to be depressed after puberty. After puberty, girls are also more likely to be unhappy with their bodies than boys.
There is considerable variability between individual males and females. Also, even when there are average group differences, the actual size of most of these differences is quite small. This means, knowing someone’s gender does not help much in predicting his or her actual traits.