Activated brain areas revealed by the human minus computer contrast in the first GLM.

<p>Consistent with previous studies, activations were found in the mentalizing networks, including the mPFC, bilateral TPJ, right STS, and precuneus. For display purposes, the statistical threshold was set at p < 0.001 (uncorrected) and cluster p < 0.05 (corrected) with no anatomical mask.</p

Areas in the striatum and midbrain positively correlated with the winning rate (obtained from the parametric analyses in the first GLM).

<p>Activities in the striatum (Left; caudate nucleus and putamen) and midbrain (Right) were significantly correlated with the winning rate in each block. Within the striatal ROIs, the statistical threshold was set at p < 0.005 (uncorrected) and cluster p < 0.05 (corrected).</p

(a) Bilateral anterior insula activity positively correlated with behavioral entropy (obtained from the parametric analyses in the first GLM).

<p>Within the insula ROIs, the statistical threshold was set at p < 0.005 (uncorrected) and cluster p < 0.05 (corrected). (<b>b</b>) The mean of the left anterior insula activities (beta-values) obtained from the second GLM by each entropy degree and opponent. Beta-values were extracted from the peak voxel identified by the first GLM.</p

(a) Experimental task.

<p>In each block, subjects played 20 trials of a matching pennies game with what they believed was either a human or computer opponent (subjects were informed of their opponent type at the beginning of each block). In each trial (2 s), subjects were asked to choice one of two decision by pressing a button (left or right) as soon as possible (within 1 s; decision period). After the decision period, an outcome of a decision was presented as two allow directions (1s; outcome). The arrow on topside indicates subjects’ chose direction, and the arrow on the bottom side indicates the opponent’s chose direction. If the players’ choices are the same, the subject wins the game. If they do not match, the opponent wins. The winning player scores 100 points, and the losing player loses 100 points in every trial. Total outcomes of both players were visually presented as the box’s heights beside the opponent’s picture during playing the game (if a current total outcome was positive for a subject, the box’s color was blue and if not, its color was red). After 20trials game, the total points that a subject got (or lost) in the session was displayed for 2 s. (b) Left: an example picture of displayed human opponents, Right: the displayed picture of computer opponent. These pictures were always presented on the top side of the screen during the game.</p

Summary of oxytocin measurements.

<p>unit: µU/ml per creatinin g/L.</p

Brain areas positively correlated with behavioral entropy.

<p>BA, Brodmann area; aINS, anterior insula</p><p>Brain areas positively correlated with behavioral entropy.</p

Distribution of demographics, oxytocin, and social capital variables by gender.

<p>Distribution of demographics, oxytocin, and social capital variables by gender.</p

Brain areas activated by the human vs. computer contrast.

<p>BA, Brodmann area; MPFC, medial prefrontal cortex; aINS, anterior insula; DLPFC, dorsolateral prefrontal cortex; PCC, posterior cingulate cortex; STS, superior temporal sulcus; OFC, orbitofrontal cortex; TPJ, temporoparietal junction.</p><p>Brain areas activated by the human vs. computer contrast.</p

Brain areas positively correlated with the actual winning rate.

<p>Brain areas positively correlated with the actual winning rate.</p

Association between urine oxytocin and social capital indicators by gender.

*<p>Adjusted for age, number of children, self-rated health, and education.</p