Participants' offers (in percent) in the ultimatum game and the dictator game in the pilot studies.

<p>Participants' offers (in percent) in the ultimatum game and the dictator game in the pilot studies.</p

Mean offers (in %) for the ultimatum game (UG) and dictator game (DG) and minimal accepted offer for the ultimatum games.

<p><b>(The error bar is +/−1 standard error of mean.)</b></p

Participants'minimal accepted offer (in % of 100 yuan) by cohorts.

<p>Participants'minimal accepted offer (in % of 100 yuan) by cohorts.</p

Participants' offers (in % of 100 yuan) in the ultimatum game and the dictator game by cohorts.

<p>Participants' offers (in % of 100 yuan) in the ultimatum game and the dictator game by cohorts.</p

Correlations between age and offer (or minimum accepted offer) for the ultimatum game (UG) and the dictator game (DG).

<p>Correlations between age and offer (or minimum accepted offer) for the ultimatum game (UG) and the dictator game (DG).</p