Taken last, selected first: The sampling bias is also present in the haptic domain

Takashi Mitsuda, Yuichi Yoshioka

When people are presented with a pair of images and asked to identify which one is more attractive, their eye gaze shifts gradually toward the image that they eventually choose. This study examined whether this sampling bias also occurs in other sensory modalities by observing participants' behavior in a haptic preference task. The results indicated that the participants tended to sample the chosen item just prior to making their decision when they were instructed to identify their most preferred item (i.e., the "like" task), but not when they were instructed to identify their least preferred item (i.e., the "dislike" task). This indicates that the sampling bias is a general phenomenon regardless of sensory modality. In addition, the sampling bias in the like task was larger when the difference in preference ratings between the paired items was smaller. However, the sampling bias decreased when the two items were given equal preference ratings, despite there being a longer decision time on those trials. This suggests that the sampling bias is not simply related to task difficulty, but is also related to preference formation and/or selective encoding of task-relevant information.