Experimental Design and Behavioral Performance.

(A) Visual analogues illustrating each avatar’s social values. Height of the left bars signals values on competence dimension, while height of the right bars signals trustworthiness. Labels for each of the two bars are omitted for illustration purpose. (B) Corresponding layout of the social value map and example trajectory in recall task. Scattered dots indicate the actual sets of positions generated for participants. (C) Positions of the avatars indicated by participants at the end of the whole experiment. (D) Trial timeline of the recall task. Participants first watched the bars morphing for one second according to a predefined competence-trustworthiness ratio (i.e., the first half of a trajectory in Figure 1B). After the bars stopped morphing, they were instructed to imagine the bars continue to morph according to the same ratio, at the same speed and for the same amount of time. (i.e., the second half of a trajectory in Figure 1B) (E) Color-coded trajectory map of the explore task during learning and review session. Color indicated the percentage of time spent in each pixel of the social value map during the explore task in the learning (left panel) and review (right panel) session. A pattern emerged that participants spent more time at avatars and less time at edge during review. (F) Memory test performance of the collect and recall task in learning, review and scan-day session. (G) The distance effect in comparison task across the review and scan-day session. Colored dots indicated the estimates of distance effect regressor while error bars indicated standard error of the estimates. (H) Ratings became predictable from the avatars’ social value after experiment. Icons of avatars are for illustration and retrieved from https://pixabay.com/vectors/avatar-flat-modern-minimal-5261900/, https://pixabay.com/vectors/avatar-flat-modern-minimal-5261896/.

Neural representation of Euclidian distance on the social value map.

(A) Activity in the bilateral Precuneus positively correlated with travelled Euclidian distance. (B) Activity in bilateral Fusiform and the right middle occipital gyrus negatively correlated with travelled Euclidian distance. Display threshold: cluster-defining threshold p < 0.001.

Evidence of grid-like activity aligned to putative grid orientation in the right orbitofrontal cortex and the right posterior-medial entorhinal cortex

(A) Theoretical prediction of grid-like activity (B-C) ROIs for deriving putative grid orientations: (B) right FP ROI from quadrature filter analysis showing sensitivity to hexagonal modulation. A 5-mm sphere was defined around the peak coordinate to compute grid angle. Display threshold: voxel-level p < 0.001, cluster-level p < 0.05 FWE-corrected. (C) Anatomically defined right pmEC ROI used to compute grid angle. (D-G) Grid like activity aligned to putative grid orientations in the right FP ROI (D-E) and right pmEC (F-G) ROI respectively. Left panels: clusters from whole-brain hexagonal consistency analysis. Color indicates T statistics as shown in the colorbar in B. Display threshold: voxel-level p < 0.005, cluster-level p < 0.05 FWE-corrected. Middle panels: hexagonal consistency effects plotted as contrast estimates of the 12 trial-bin regressors extracted from corresponding cluster in the left panel; To illustrate effect in EC in E, estimates were extracted from the intersection of the suprathreshold cluster and anatomical mask of EC. Right panels: such effects were specific to six-fold. Notes: n.s., p>0.05, * p<0.05, ** p<0.01, *** p<0.001. Abbreviations: FP, frontal pole; pmEC, posterior-medial entorhinal cortex; vmPFC, ventral medial prefrontal cortex; STP, superior temporal pole.

Behavioral relevance of hexagonal consistency effect.

(A-B) Higher hexagonal consistency in temporal lobe aligned to grid orientation of (A) right FP ROI and (B) right pmEC significantly correlated with stronger distance effect in compare task when choosing preferred partners for cooperation. Display threshold: voxel-level p < 0.005, cluster-level p < 0.05 FWE-corrected. (C) Hexagonal consistency effect in left Precuneus aligned to grid orientation of right FP ROI significantly correlated with social avoidance score. Display threshold: voxel-level p < 0.001, cluster-level p < 0.05 FWE-corrected. Notes: n.s., p>0.05, *p<0.05, **p<0.01, ***p<0.001. Abbreviations: FP, frontal pole; pmEC, posterior-medial entorhinal cortex; MTG, middle temporal gyrus; LING, lingual gyrus.