Feature–location effects in the Thatcher illusion

Abstract

Face perception is impaired for inverted images, and a prominent example of this is the Thatcher illusion: "Thatcherized" (i.e., rotated) eyes and mouths make a face look grotesque, but only if the whole face is seen upright rather than inverted. Inversion effects are often interpreted as evidence for configural face processing. However, recent findings have led to the alternative proposal that the Thatcher illusion rests on orientation sensitivity for isolated facial regions. Here, we tested whether the Thatcher effect depends not only on the orientation of facial regions but also on their visual-field location. Using a match-to-sample task with isolated eye and mouth regions we found a significant Feature × Location interaction. Observers were better at discriminating Thatcherized from normal eyes in the upper compared to the lower visual field, and vice versa for mouths. These results show that inversion effects can at least partly be driven by nonconfigural factors and that one of these factors is a match between facial features and their typical visual-field location. This echoes recent results showing feature-location effects in face individuation. We discuss the role of these findings for the hypothesis that spatial and feature tuning in the ventral stream are linked.

Individual differences in visual salience vary along semantic dimensions

“…Different types of objects tend to appear at different parts of the visual field and recent findings suggest that observers are attuned to these contingencies [30][31][32] . The most prominent spatial bias in the scene stimuli we used was a strong tendency for faces to appear in the upper visual field Supplementary Fig.…”

Eye movements and retinotopic tuning in developmental prosopagnosia

“…Computational models show that the theoretically optimal alignment occurs when fixation is directed toward a region between the eyes and the nose tip (Or et al, 2015;Peterson & Eckstein, 2012Tsank & Eckstein, 2017). NT individuals preferentially fixate this region, and both recognition performance (de Haas & Schwarzkopf, 2018;Or et al, 2015;Peterson & Eckstein, 2012Peterson et al, 2016) and the response of face-selective cortical regions (de Haas et al, 2016;Zerouali, Lina, & Jemel, 2013;Stacchi, Ramon, Lao, & Caldara, 2019) are maximized when fixating near the theoretical optimum location. The Poor Information Hypothesis holds that individuals with DP fixate outside the optimal region, directly impairing face recognition accuracy through a reduction in the quality of information entering cortex.…”

How to Enhance the Power to Detect Brain–Behavior Correlations With Limited Resources

“…For example, de Haas et al (2016) and de Haas and Schwarzkopf (2018a) recently argued that face inversion effects are driven by retinotopic tuning biases. A potential way of testing this hypothesis would be to probe a correlation between the corresponding neural and behavioral effects across observers.…”

“…However, these authors did not use this type of strategy, because their measures did not reliably capture individual differences. Figure 1A shows the individual magnitude of the Thatcher illusion ( Thompson, 1980 ) for 36 observers in de Haas and Schwarzkopf (2018a) . The illusion was highly robust – every observer showed the effect for both, odd and even trials (all data are in the upper right quadrant).…”

“… Measurement relibaility. (A) Shows individual data for the magnitude of the Thatcher illusion in odd and even trials from ( de Haas and Schwarzkopf, 2018a ). The effect is highly robust on the group level (all data are in the top right quadrant, i.e., every participant shows the effect in both, odd and even trials).…”