U of M News Service
“Women are more likely to rely on enumeration,” said Brown, a visiting research scientist at the University of Michigan Institute for Social Research. “They tend to say, ‘I just know,’ and if you ask them to explain how they know, they say, ‘Well, there was John, Tom, etc.’ This is a strategy that typically leads to underestimation.
“Men are twice as likely to use rough approximation to answer the question. And rough approximation is a strategy known to produce over-estimation.”
男は多めに、女は少なめに答える傾向。これは男の見栄とかじゃなく、女は「太郎さんでしょ、一郎さんでしょ」と個別に積み上げるから少なめになってしまい、男は「まあ５人か」とざっと答えるから多めになってしまうんだと。バレンタインネタだね。