General recognition theory with individual differences: a new method for examining perceptual and decisional interactions with an application to face perception

Abstract

A common question in perceptual science is to what extent different stimulus dimensions are processed independently. General recognition theory (GRT) offers a formal framework via which different notions of independence can be defined and tested rigorously, while also dissociating perceptual from decisional factors. This article presents a new GRT model that overcomes several shortcomings with previous approaches, including a clearer separation between perceptual and decisional processes and a more complete description of such processes. The model assumes that different individuals share similar perceptual representations, but vary in their attention to dimensions and in the decisional strategies they use. We apply the model to the analysis of interactions between identity and emotional expression during face recognition. The results of previous research aimed at this problem have been disparate. Participants identified four faces, which resulted from the combination of two identities and two expressions. An analysis using the new GRT model showed a complex pattern of dimensional interactions. The perception of emotional expression was not affected by changes in identity, but the perception of identity was affected by changes in emotional expression. There were violations of decisional separability of expression from identity and of identity from expression, with the former being more consistent across participants than the latter. One explanation for the disparate results in the literature is that decisional strategies may have varied across studies and influenced the results of tests of perceptual interactions, as previous studies lacked the ability to dissociate between perceptual and decisional interactions.

Double Jeopardy in Inferring Cognitive Processes

“…A review of current research trends reveals a number of researchers who are ready to switch from the subject aggregating procedures, and instead consider using individual subject analysis, if they are not already en route to developing and using such methods (e.g., Myung et al, 2000;Brown and Heathcote, 2003;Estes and Maddox, 2005;Soto et al, 2014). The main challenge in using individual subject data is to provide an integral assessment of such data that can enable clear communication between researchers.…”

Connecting Crossmodal Perception and Garner's Integrality: An Investigation into Crossmodal Correspondences using General Recognition Theory

“…Outlier detection was done with the individual differences measures from the GRT-wIND analysis (GRT-with Individual Differences, a type of GRT analysis that estimates several individual difference parameters, including a pair of decision bounds for each participant; Soto et al, 2015). When individual decision bound parameters were estimated for each participant, some participants showed a clear deviation from the rest of the sample (Figure 1 is a plot of the decision bound slopes for the loudness dimension using the unfiltered data).…”

“…An experimental session consisted of 12 blocks of 50 trials each (following the example of Soto et al, 2015). On each trial, one of the four stimulus categories was selected and a pair of stimulus values were generated to create a new compound stimulus.…”

“…Perceptual integrality, as defined by GRT, describes a situation where two stimulus dimensions interact in such a way that the mean perceived value of a stimulus dimension, or the variability of this value over repeated presentations, changes as a function of the other stimulus dimension (Ashby & Townsend, 1986;Soto, Vucovich, Musgrave, & Ashby, 2015). Perceptual independence describes the relationship between stimulus noise across the two dimensions; like SDT, GRT assumes that perception is inherently noisy, and that there will always be some degree of perceptual noise associated with the process (Ashby & Soto, 2014;Ashby & Townsend, 1986;Green & Swets, 1966).…”

“…For example, if decisional separability does not hold for brightness, a participant may be more willing to make a "bright" response when the auditory component is loud rather than soft, or vice versa. It is important to note is that while perceptual separability and independence are considered to be enduring traits, decisional separability reflects the strategy employed for the task at hand, and so there is no expectation that it would generalize to other contexts (De Gelder & Bertelson, 2003;Soto et al, 2015; for those who are interested, a more thorough explanation of the methods and analyses of GRT is given in the Appendix).…”