Most prestigious prizes in science that are not set aside for women go primarily or only to men. The eight male 2010 Kavli prizewinners in astrophysics, nanoscience and neuroscience are the most recent examples (see http://go.nature.com/5xh17n).

The Kavli winners are accomplished and deserve their honours. But the frequency of all-male line-ups, and the number of meritorious women, indicates that women as a group are disproportionately overlooked. Why?

Gender schemas — cognitive structures that summarize our beliefs about the sexes — portray women primarily as nurturing and communal, and men as capable of independent action and work-oriented (V. Valian Why So Slow? The Advancement of Women; MIT Press, 1998). Such schemas mean that women's names are unlikely to come to nominators' minds; if women are considered, they are less likely than men to be perceived as prizeworthy (see also Nature 469, 472; 2011).

Prizes matter in part because young women with scientific abilities and interests are more likely to aim high if they see examples of women receiving top awards. Why stay in a field where you have little chance of recognition? We are squandering the abilities of half the human race.

Prize committees need to learn where, how and why our perceptions give men an edge. Committees also need actively to solicit nominations of women and members of under-represented groups. Few guidelines, including those for the Kavli prize, include such encouragements. It is time to stop this cycle of neglect of outstanding women in science.