Social psychophysics: Using psychophysics to answer “social” questions with PsychoPro

OTTO H. MACLIN 0 M. KIMBERLY MACLIN 0 DWIGHT PETERSON 0 OSMAN CHOWDHRY 0 PRIYANKA JOSHI 0 0 University of Northern Iowa , Cedar Falls, Iowa Complex social stimuli (like faces) can be studied using a methodology typically reserved for studying lights, tones, and colors: psychophysics. Given that psychophysics examines how humans detect and respond to stimuli in their environment, we can extend that to the study of how humans detect social stimuli in the environment. Using psychophysical methodology to answer social questions provides another dimension of experimental manipulation and control to the diverse array of methodologies already used by social psychologists. In this article, we review psychophysical methodology, provide a rationale for social psychophysics, describe an easy-touse software program called PsychoPro, for collecting psychophysical data, and present data collected using this program to examine racial thresholds that provide evidence for a cognitive gating mechanism for racial information that impacts face processing (MacLin & MacLin, 2007, in press; MacLin, MacLin, & Peterson, 2008). - This article provides a rationale for social psychophysics, reviews psychophysical methodology, describes an easy-to-use computerized system in Visual Basic (VB) 2005 for collecting psychophysical data, and presents data examining racial thresholds that provide evidence for a mechanism for gating racial information (MacLin & MacLin, 2007, in press; MacLin, MacLin, & Peterson, 2008). Furthermore, we discuss how the long tradition of psychophysics can be extremely useful in exploring current research questions in areas beyond perception that include complex stimuli relevant to social psychology. We use the term social psychophysics to describe research that uses psychophysical methods to study social questions. Using psychophysics methodology to answer social questions is not a new practice, but it is underutilized. It adds another dimension of experimental manipulation and control to the diverse array of methodologies already used by social psychologists. As psychophysics has been used in areas such as perception and color vision to unravel the underlying perceptual mechanisms, so too can psychophysics be used to help unravel complex socialcognitive phenomena. In particular, we present data supporting a theory that racial classification has evolved to facilitate the identification of persons belonging to out-groups as well as to in-groups, allowing for different cognitive processing depending on the outcome of the racial classification. Using psychophysical methods, we have been able to further explore the cognitive processes involved in, and social effects of, racial categorization. Psychophysical Methods Psychophysics examines the relationship between the physical world and our perception of it. Early emphasis of psychophysics was on determining sensory thresholds the point where a stimulus or change in stimulus is detected 50% of the time (Fechner, 1860/1966; Snodgrass, 1975). Thresholds can be the point at which a weak stimulus is detected (absolute threshold ) or the point at which a strong stimulus is no longer detected (terminal threshold ). Being able to detect signals in the environment allows for exploring whether a sensory stimulus is changing on a continuum or in discrete steps (Gescheider, 1997). Psychophysicists have developed several experimental methods to establish thresholds and evaluate signal detection. A simple example of measuring thresholds would be for luminance intensity. At what point can a light be detected? At what point can a light no longer be detected? Psychophysical methods are used to answer these perceptual questions and can be used to answer other social questions, such as Is this person Caucasian? or Is this person African American? Social Psychophysics Social psychologists have long been methodologically creative in their study of complex social phenomena. Social psychologists have borrowed methodologies from other content areas in psychology when their use will assist in uncovering new aspects of social thought or behavior. Contributions from cognitive psychology and neuroscience in particular have led to the areas of social cognition and social neuroscience, respectively. Another area that can be useful for social psychologists is psychophysics. Given that psychophysics is the study of how humans detect events and stimuli in their environment, social psychophysics is the study of how humans detect social events and stimuli in the environment (Geincreasing the possibility for misidentification and subsequent false conviction (Innocence Project, 2008). Early attempts to explain the cross-race effect focused on social circumstances, such as negative racial attitudes and a lack of contact with members of other races (Malpass & Kravitz, 1969). More recent attempts at explaining the cross-race effect posit a deficit model wherein other-race faces are poorly encoded (...truncated)