Oculomotor guidance and capture by irrelevant faces

Abstract

Even though it is generally agreed that face stimuli constitute a special class of stimuli, which are treated preferentially by our visual system, it remains unclear whether faces can capture attention in a stimulus-driven manner. Moreover, there is a long-standing debate regarding the mechanism underlying the preferential bias of selecting faces. Some claim that faces constitute a set of special low-level features to which our visual system is tuned; others claim that the visual system is capable of extracting the meaning of faces very rapidly, driving attentional selection. Those debates continue because many studies contain methodological peculiarities and manipulations that prevent a definitive conclusion. Here, we present a new visual search task in which observers had to make a saccade to a uniquely colored circle while completely irrelevant objects were also present in the visual field. The results indicate that faces capture and guide the eyes more than other animated objects and that our visual system is not only tuned to the low-level features that make up a face but also to its meaning.

Figure 1. Illustration of a display used in the present study.

Participants were instructed to make a saccade to a unique colored target circle and ignore the pictures of objects. Here, an upright face is presented as critical object and its spatial location mismatches that of the target (orange circle).

Figure 2. Influence of the Critical object type during mismatch trials.

Mean percentage of oculomotor capture (A) and mean fixation durations following oculomotor capture (B). Error bars represent 95% confidence intervals (CI; see [29]).

Figure 3. Oculomotor guidance and interference by the different Critical objects.

Results of the search task in terms of mean latency (A), mean accuracy (B), mean search time (C) and mean number of saccades to reach the target (D), as a function of the critical object type included in the display and as a function of the location of the critical object matching or not that of the target. Error bars represent CI.