Fig 1.
a) The apparatus hanging on the wire mesh with the neutral start symbol on the touchscreen. b) A chimpanzee touching the neutral start stimulus to initiate video playback during a trial. c) Examples of how the touch screen program displays social (top) and control (bottom) videos. Note: All testing was done in the indoor dens; however, pictures A and B were taken outdoors in order to get a clear view of the screen in use.
Fig 2.
The cumulative number of times the chimpanzees (a) touched to initiate playback of social and control videos and (b) the number of times they watched social and control videos. Bars represent the average across subjects, error bars indicate std. error. *** p < 0.001; ** p < 0.01; * p < 0.05.
Fig 3.
The number of touches (mean ± std. error) during video (a & b) and picture (c & d) experiments as a function of session order (ABBA / BAAB) and condition (social or control). Gray bars represent average number of touches across sessions within each condition.
Table 1.