Robin D. Thomas

Perceptual interactions of facial dimensions in speeded classification and identification

The representation underlying the identification and classification of semirealistic line drawings taken from a computer model of the face was investigated by using a speeded classification task and an identification task. These data were analyzed by using a multidimensional extension of signal detection theory, within which varieties of perceptual interactions between dimensions within and across stimuli can be characterized. The dimensions of interest here were eye separation, nose length, and mouth width. The response time and accuracy data from the speeded classification task suggest that processing of a given feature did depend on whether other features were present or absent, but given that other features were present, the results strongly support separability (a macrolevel, across-stimulus form of invariance) for all pairs of facial dimensions used. This separability was confirmed by the subsequent identification task. Owing to its greater resolution, the identification task can reveal interactions that might exist at more microlevels of processing. In fact, the identification data did indicate the presence of perceptual dependence between facial dimensionswithin a stimulus when the dimensions that were varied were close in spatial proximity (i.e., eye separation and nose length). Within the theoretical framework, perceptual dependence can be interpreted as correlated noise between otherwise separate channels (and hence, is logically distinct from separability). This dependence was greatly reduced for dimensions that were more distant (eyes and mouth). The relation between these results and the configural effects that have been observed with faces as stimuli in other studies is discussed.

Decisional separability, model identification, and statistical inference in the general recognition theory framework.

Recent work in the general recognition theory (GRT) framework indicates that there are serious problems with some of the inferential machinery designed to detect perceptual and decisional interactions in multidimensional identification and categorization (Mack, Richler, Gauthier, & Palmeri, 2011). These problems are more extensive than previously recognized, as we show through new analytic and simulation-based results indicating that failure of decisional separability is not identifiable in the Gaussian GRT model with either of two common response selection models. We also describe previously unnoticed formal implicational relationships between seemingly distinct tests of perceptual and decisional interactions. Augmenting these formal results with further simulations, we show that tests based on marginal signal detection parameters produce unacceptably high rates of incorrect statistical significance. We conclude by discussing the scope of the implications of these results, and we offer a brief sketch of a new set of recommendations for testing relationships between dimensions in perception and response selection in the full-factorial identification paradigm.

Evidence for Criterion Shifts in Visual Perceptual Learning: Data and Implications

Work on visual perceptual learning for contrast detection has shown that reliable decreases in detection thresholds are accompanied by reliable increases in false alarm rates (Wenger & Rasche, 2006). The present study assesses the robustness and replicability of these changes, demonstrating that they are independent of a variety of task demands (i.e., the specific method used for perceptual practice and threshold estimation) and the presence or absence of trial-by-trial feedback and that the source of the increases can be found in shifts in changes in sensitivity and in bias for detection, identification, or both. Although the increase in false alarm rates suggests a strategic shift in response criteria for detection, we demonstrate that there are multiple potential explanations, including explanations that do not require strategic shifts on the part of the observer. The empirical evidence and analysis of alternative explanations reinforce the inference that visual perceptual learning may involve more than changes in perceptual sensitivity and that cortical circuits beyond the primary visual areas may be involved.

On the Need for A General Quantitative Theory of Pattern Similarity

Abstract The concept of similarity evokes different meanings for different people. However similarity is conceived, it certainly plays an important role in the modeling of pattern perception. The contrasting approaches toward psychological similarity taken by the measurement theorists, the psychometricians of multidimensional scaling, and the process model oriented cognitive psychologists should be reconciled if a full account of the role of similarity in perception is to be adequately developed. This essay attempts to initiate a preliminary synthesis of these approaches while introducing some important philosophical questions concerning the application of multidimensional scaling ( MDS ) models of similarity. These questions arise from a deeper analytical investigation of the foundations of modeling perception. Along the way, the reader is introduced to mathematical concepts from topology and geometry that underlie the use of MDS . It is hoped that the discussion will provide some tutorial benefits as well as open the door to a more unified treatment of similarity and its role in psychological representation.

Who do you look like? Evidence of facial stereotypes for male names

The present research provides evidence that people use facial prototypes when they encounter different names. In Experiment 1, participants created face exemplars for fifteen common male names, subsets of which were endorsed as good examples by a second set of participants. These most typical faces were morphed to create face-name prototypes. In Experiment 2, participants matched one of the names to each of the prototype faces from Experiment 1. Participants’ matching choices showed convergence in naming the prototypes for many of the names. Experiment 3 utilized these same prototypes in a learning task designed to investigate if the face-name associations revealed in Experiment 2 impacted the learnability of the names. Participants learned face-name pairings that had a higher association (based on frequencies from Experiment 2) faster than pairings with a low association. Results suggest a more direct relationship between faces and names than has been previously proposed.

Technical clarification to Silbert and Thomas (2013): “Decisional separability, model identification, and statistical inference in the general recognition theory framework”

We offer a minor technical correction to the published proof of part (ii) of the main theorem in Silbert and Thomas (Psychonomic Bulletin & Review, 20, 1–20, 2013) that somewhat limits the scope of the equivalence observed in that work. Specifically, in order for a mean shift integrality with decisional separability to be mimicked by a perceptually separable but nondecisionally separable configuration, one needs to assume stimulus invariance. This holds when all of the covariance matrices in the stimulus configuration are equal to each other. We note that part (i) of the theorem is unaffected by this modification; an empirical finding of perceptual separability and the failure of decisional separability can be mimicked by a perceptually nonseparable, decisionally separable configuration without restricting the covariance matrices to be equal. We also note that stimulus invariance is often assumed in simple designs (e.g., Macmillan & Ornstein in Journal of the Acoustical Society of America, 97, 1261–1285, 1998), due to the implausibility of different perceptual correlations being present within stimuli perched very closely in perceptual space.

Physio-behavioral Coupling as an Index of Team Processes and Performance: Overview, Measurement, and Empirical Application

Research shows that teammates often exhibit similarity in their physiological and behavioral responses during cooperative task performance, a phenomenon referred to here as physio-behavioral coupling (PBC). Goals of this manuscript are to provide an overview of research examining the utility of PBC as an index of team processes (e.g., coordination) and performance, discuss applied and theoretical issues in PBC measurement, and present findings from a study using linear and nonlinear statistics to assess PBC.

ERP Responses of Elementary-Age Children to Video Game Simulations of Two Stimuli Types: Study 1 and 2 Comparisons

ABSTRACT The hypothesis that brain activity may differ during varied types of video game play was investigated in two studies of event-related potentials exhibited by children age 7 to 12 when processing game-based stimuli requiring correct/incorrect responses or choices between two imaginative alternative responses. The first study had 22 children of families from the university community and the second (replication) study had 22 children from a diverse group of community families. These participants also were interviewed regarding the children’s video game habits. In Study 1, mean amplitude of P300 in the two conditions showed significant differences at P100 and N200 locations. Study 2 results showed greater N200 and P300 positive amplitude in the choice condition at Pz. Both studies found significant frontal lobe interaction for younger children in mixed conditions, suggesting they put more attention resources into the mixed task. Implications of video game play effects on brain development during the elementary years are discussed.