But there was a twist. When Professor Dahl’s team examined the data more closely, the changes in pay depended on the gender of the child that the chief executives fathered. They reduced wages after having a son, but not after having a daughter.

Daughters apparently soften fathers and evoke more caretaking tendencies. The speculation is that as we brush our daughters’ hair and take them to dance classes, we become gentler, more empathetic and more other-oriented.

There are even studies showing that American legislators with daughters vote more liberally; this is also true of British male voters who have daughters, especially in terms of referendum and policy choices about reproductive rights. “A father takes on some of the preferences of his female offspring,” argue the researchers Andrew Oswald at the University of Warwick and Nattavudh Powdthavee, then at the University of York. For male chief executives, this daughter-driven empathy spike may account for more generous impulses toward employees that temper the temptation toward wage cuts.

Is it possible that proximity to infant girls prompts greater generosity? Additional studies, in a variety of fields, suggest this is the case — and that it might extend beyond daughters. Consider, for example, the series of studies led by the psychologist Paul Van Lange at the Free University in Amsterdam. To figure out what motivates people to act generously, Professor Van Lange and three colleagues set up a game in which more than 600 people made choices about sharing resources with someone they didn’t know and would never meet again. The participants chose between these basic options:

(a) You get $25 and your partner gets $10.

(b) You get $20 and your partner gets $30.

The first option is the selfish one; you’re claiming most of the resources for yourself. The latter option is more generous as it involves sacrificing a small amount ($5) to increase your partner’s gains by a much larger amount ($20).

The players expressed consistent preferences in each of the nine rounds they played on Professor Van Lange’s watch. The data showed that players who made the more generous choices had more siblings. The givers averaged two siblings; the others averaged one and a half siblings. More siblings means more sharing, which seems to predispose people toward giving.