In the 1970s, some people took this to mean boys and girls were born entirely the same, and only behaved differently because sexist parents and a sexist society taught them to. Now, however, it's accepted that society and biology both create the difference.
Since parenting plays a part, maybe there's room for improvement.
Research in the workplace shows men's careers are hurt when men are too blunt, and some women achieve less because they're too nice.
When we tried our lemonade test on adults, the results were remarkably similar.
Georgetown Professor Deborah Tannen, who's written best sellers about gender differences, says each sex would benefit by adopting some of the opposite sex's traits. "For the men," Tannen said, "it might mean backing off, toning down or just saying a few words to show that you're cognizant of the other person's feelings," and women, she said, could work on being "more explicit in what they think and what they want and what they expect of the other person."
Reinforce Confident, Not Aggressive, Behavior
Can parents teach that? How could we teach the girls to be more assertive, and teach the boys to pick up on the girls' people skills?
Some families from our experiments let us put cameras in their homes, and we showed the tapes to Witt.
Witt offered a few tips for parents of girls: Don't help them so much. Research shows parents tend to help girls more than boys. This can make girls feel helpless and less confident. In addition, it's good to encourage girls to make choices.
In our tests, 9-year-old Patty didn't hesitate to tell us what she thought. And sure enough, our videotapes showed that in Patty's house, her parents prompt her to make choices about what to eat and drink, and what clothes she would like to wear.
"The girl who knows how to make a decision or starts making decisions when she's little," Witt said, "is going to be one of those girls who's better able to make decisions and assert herself as she gets older."
In the case of the boys who were maybe too honest in our test, we saw that their parents gave them a lot of freedom to act out. Maybe too much, says Witt.
For example, one boy shouted to his mother that he wanted something to drink. Moms should discourage kids who scream out demands, Witt said, perhaps by walking out of the room. Conversely, they should reward polite requests with a hug or kind words.
Finally, a caution about generalizing about gender. The differences between individuals are frequently bigger than differences between sexes. In our experiments, some girls did speak their mind, and some boys were very polite.