Face Inversion Disproportionately Disrupts Sensitivity to Vertical Over Horizontal Changes in Eye Position

Presenting a face inverted (upside down) disrupts perceptual sensitivity to the spacing between the features. Recently, it has been shown that this disruption is greater for vertical than horizontal changes in eye position. One explanation for this effect proposed that inversion disrupts the processing of long-range (e.g., eye-to-mouth distance) more than local (e.g., interocular distance) spatial relations. Here we investigated the spacing inversion effect for horizontal and vertical changes that could involve long- and short-range spatial relations. Our results replicated the finding of larger inversion effects for vertical than for horizontal changes, and found it was observed regardless of the spatial distance. These results argue against a long-range versus short-range spatial relations explanation of the horizontal versus vertical difference in the size of the spacing inversion effect for eye position. We support the view that inversion effects are relatively small when spacing changes occur within the eye region, but are larger when they occur outside of this region in the absence of focal attention.