Global processing of Navon stimuli primes the general (face) congruency effect but not the standard composite face effect
16.542, Friday, May 10, 5:30 - 8:00 pm, Vista Ballroom
Bruno Rossion1, Zaifeng Gao2, Anastasia Flevaris3, Lynn Robertson4, Shlomo Bentin5; 1Face categorization lab, University of Louvain, 2Department of Psychology, Zhejiang University, 3Department of Psychology, University of Washington, 4Veterans Administration, Martinez, CA and Department of Psychology, University of CA, Berkeley, 5Department of Psychology and Interdisciplinary Center for Neural Computation, Hebrew University
Navon hierarchical letter stimuli are often used to measure interference between global and local visual information, with global-to-local interference effects being usually interpreted as evidence for perceptual grouping (e.g., Behrmann & Kimchi, 2003). The relationship between this measure and holistic/configural face perception, namely the encoding of the multiple features of a face as a whole representation, remains elusive. In a recent study, Gao and colleagues (2011) showed that global processing of Navon stimuli increased the sensitivity to incongruence between the upper and the lower halves of a composite face and concluded that global processing of Navon stimuli augments holistic face processing. However, rather than using a standard composite face matching paradigm, the authors used a congruency paradigm with composite faces (e.g., Richler et al., 2008), namely a paradigm that has a built-in decisional confound and includes responses on different trials likely reflecting part-based judgments (Rossion, in press). Here we reanalyzed Gao et al. (2011)s data by examining only the same trials, as in a standard composite face measure, and found that global processing of Navon stimuli did not increase the composite face effect, neither in accuracy rates nor in correct RTs. The effect initially described is due only to a priming of the different composite face trials, reflecting part-based judgments. These findings reinforce the view that the congruency paradigm with composite faces measures general processes that should not be mistaken with face-specific holistic/configural perceptual processes measured in the standard composite face paradigm. More generally and importantly, they support the view that processing global aspects of hierarchical Navon stimuli is functionally distinct than holistic/configural perception of individual faces (Busigny & Rossion, 2011) and suggest that correlations between the two measures across individuals or impairments at the Navon task in cases of congenital prosopagnosia (Behrmann et al., 2005) essentially reflects general visual processes.