The upper visual field advantage for face-processing: A product of endogenous attentional bias?

• ¹ Macquarie University, Department of Cognitive Science, Australia
• ² ARC Centre of Excellence in Cognition and its Disorders, Macquarie University Research Node, Australia

There is mounting evidence to suggest that face-processing may be more robust in the upper visual field (UVF) than in the lower visual field (LVF) (cf. Quek & Finkbeiner, in press). We asked whether this UVF advantage for face-processing could be due to an endogenous attentional bias towards the upper hemifield. Participants made reaching movements to classify the sex of a target face which appeared either immediately above or below fixation. The target was preceded by a masked prime face of either the same or opposite sex (i.e. congruent or incongruent). Our index of face-processing was the extent to which prime-target congruency modulated the sex-categorisation response (i.e. the masked congruence effect, or MCE). We manipulated participants' endogenous attention to the vertical hemifields by varying the predictability of the target's location across days, using a UVF:LVF ratio of 50:50 on day 1 and 20:80 on day 2. We expected participants would respond to the increased probability of LVF targets on day 2 by covertly attending to this hemifield. We found that when target location was unpredictable (day 1), the prime influenced the sex-categorisation response sooner when the faces appeared in the UVF compared to the LVF. This UVF advantage was inverted on day 2, however, when targets were more likely to appear below-fixation and participants could deploy attention appropriately in response. Here the MCE arose much earlier for LVF targets than for UVF targets, suggesting that the allocation of endogenous attention facilitated prime processing. Critically however, encouraging participants to covertly attend to the LVF had no effect on face-processing in the UVF. The MCE emerged at exactly the same stage of stimulus processing (around 165ms) even when participants covertly attended to the opposite hemifield. We conclude that the UVF advantage for face-processing is unlikely to be driven by an endogenous attentional bias towards the upper hemifield.