Figure 1.
On the left side, the participant's face (eye brows, eyes, nose mouth) is shown that has been pasted into the shape of the stimulus person's face. On the right side, an example for a stimulus face is shown. In the center, the face morph is shown (morph ratio = 40:60). Both faces are used for illustration purposes only (i.e., because of copyright restrictions, the faces do not correspond to faces actually used in the present study). Written consent (as outlined in the PLoS consent form) was obtained from both individuals before publishing these photos.
Figure 2.
Mean ratings for mismatching and matching parent-child face pairs (taken from the KinFace database) and participant-morph face pairs. Upper panel: Mean facial resemblance ratings on a scale ranging from 1 (“very dissimilar”) to 6 (“very similar”). Lower panel: Mean ratings of the perceived degree of kinship on a scale ranging from 1 (“not related”) to 6 (“closely related”). The error bars represent the standard errors of the means.
Figure 3.
Screenshot of the social-cooperation game.
On the left side, the participant is represented by a black silhouette. On the right side, a self-resembling or other-resembling face is shown representing the interactant. The number in the upper arrows refer to the investments. In this example, the interactant is cooperative and invests the same amount of money as the participant (30 cents). In the center of the screen, the sum of the investments and the bonus are shown. The numbers in the lower arrows refer to the participant's and the interactant's share of the total sum.
Figure 4.
Cooperation-game investments, likability ratings, and the amount of benevolent guessing in the source memory test as a function of facial likability in Bell et al. 's (in press) Experiment 1 (for comparison only) and as a function of facial self-resemblance in the present experiment.
Upper panel: Mean investments into the cooperation game. Participants could choose to invest 15 or 30 cents. Middle panel: Mean test phase likability ratings on a scale ranging from 1 (“not likable at all”) to 6 (“extremely likable”. Lower panel: Probability estimate of parameter g, which represents guessing that a face (of which the behavior was not known) belonged to a cooperative person. Thus, a high g probability estimate represents a tendency towards guessing that the face belonged to a cooperator, whereas a low g probability estimate represents a tendency towards guessing that a face belonged to a cheater. The error bars represent the standard errors of the means.
Figure 5.
Mean cooperation-game investments for self- and other-resembling interactants in each of the 20 trials of the cooperation game.
Figure 6.
The source memory model adapted from Bayen et al. [53].
The rounded rectangles on the left side represent the stimulus category (cooperative, cheating, new). The rectangles on the right side represent the participants' responses to the faces in the source memory test. The letters along the links represent the probabilities with which certain cognitive states occur (D = probability of correctly recognizing a face as old or new; d = probability of correctly identifying the source of a face as cheating or cooperative; g = probability of guessing that a face belonged to a cooperative interactant; b = probability of guessing that a face was old).