Sematic diagram of a typical trial during the blind choice task.

<p>Participants were required to press a key to initiate a trial (A), followed by a presentation of fixation for 1 s (B). Next, two identical dummy faces were presented for 10 ms (C) and followed by masking stimuli presented for 1 s (D). After the dummy faces were presented, participants were asked to respond in accordance with an instruction (e.g., “CHOOSE” represents to choose a preferred face). Once completed the response, target faces were presented (F). Note that participants were instructed that target faces were presented two times within a trial, one in C and another in F.</p

Post-choice change in preference in Experiment 4.

<p>Change in preference ratings for chosen and unchosen facial stimuli after blind choice between two equally preferred faces in the Experiment 4 (choice of a preferred face between two alternatives). Note that participants rated their preference for faces after they explicitly knew that their choices had been actually random. Bars indicate differences in mean-corrected ratings between the pre- and post-choice rating tasks. Error bars represent standard errors (SE) of the mean.</p

Post-choice change in preference in Experiment 3.

<p>Change in preference ratings for chosen and unchosen facial stimuli after a blind choice between two equally preferred faces in the ‘preference judgment’ trials (choice of a preferred face between two alternatives) and the ‘roundness judgment’ task (choice of a rounder face between two alternatives) in Experiment 3. Bars indicate differences in mean-corrected ratings between the pre- and post-choice rating tasks. Error bars represent standard errors (SE) of the mean.</p

Post-choice change in preference in Experiments 1 and 2.

<p>Change in preference ratings for chosen and unchosen facial stimuli after a blind choice between two equally preferred faces in Experiment 1 (choice of a preferred face between two alternatives) and Experiment 2 (choice of an unpreferred face between two alternatives). Bars indicate differences in mean-corrected ratings between the pre- and post-choice rating tasks. Error bars represent standard errors (SE) of the mean.</p

The histogram of Yes responses for the genuineness judgment of happiness (upper part) and anger (lower part).

The histogram of Yes responses for the genuineness judgment of happiness (upper part) and anger (lower part).</p

Heatmap of each component’s loadings for facial expressions of anger (upper part) and visual representations (lower part). Value colors represent each facial movement’s contribution to component scores.

Heatmap of each component’s loadings for facial expressions of anger (upper part) and visual representations (lower part). Value colors represent each facial movement’s contribution to component scores.</p

Heatmap of each component’s loadings for facial expressions of happiness (upper part) and visual representations (lower part). Value colors represent each facial movement’s contribution to component scores.

Heatmap of each component’s loadings for facial expressions of happiness (upper part) and visual representations (lower part). Value colors represent each facial movement’s contribution to component scores.</p

Time-series patterns for the magnitude of difference between the perceived-as-genuine and perceived-as-deliberate expressions of happiness.

The y-axis represents the extent of the “δ” parameters for each component. Solid lines indicate the expected a posteriori. Positive values refer to a relatively large spatial component of (left: perceived-as-genuine, center: deliberate, right: genuine), while negative values indicate a relatively large spatial component of (left and center: perceived-as-ambiguous, right: deliberate). The ribbons represent 99% credible intervals.</p

Results for the magnitude of difference between the perceived-as-genuine and perceived-as-posed expressions of happiness compared to ambiguous expressions.

(XLSX)</p

Results for the magnitude of difference between the perceived-as-genuine and perceived-as-posed expressions of anger compared to ambiguous expressions.

(XLSX)</p