Within-category discrimination of musical chords: Perceptual magnet or anchor?

Abstract

Recent speech research has begun to evaluate the internal structure of categories. In one such study, Kuhl (1991) found that discrimination was poorer for vowel stimuli that were more representative of the category (prototype, or P, set) than it was for less representative stimuli (nonprototype, or Np, set). This finding was interpreted as indicating that a category prototype may function as a "perceptual magnet," effectively decreasing perceptual distance, and thus discriminability, between stimuli. The present study examines the function of prototypes in a musical category-another natural, but nonspeech category. Paralleling the Kuhl study, representative (P) and less representative (NP) sets of major triad stimuli were constructed, based on equal temperament. Musically experienced subjects rated the stimuli in each set for goodness as a major triad, with the highest rated stimulus serving as a prototype standard for a subsequent discrimination task. Results from the discrimination task demonstrated better performance in the P context than in the NP context. The current nonspeech results indicate that a prototype functions as an anchor rather than a magnet. In addition to providing a natural, nonspeech standard for comparison with speech findings, the results provide some important insights into the nature of musical categories.Although it has long been conjectured that speech categorization may be based on the use of prototypes or exemplars, most speech perception research has tended to focus on the location of category boundaries. This focus on category boundaries is probably a carryover from the notions of categorical perception which posited absolute recoding of perception in terms of discrete phonetic categories, and which dismissed any within-category perceptual variation as being due to stimulus artifacts (StuddertKennedy, Liberman, Harris, & Cooper, 1970). As a result, little attention has been given to differences in perceptual quality or goodness, which, in theory, should exist within categories that are based on the use of prototypes or exemplars. In contrast to this long tradition ofcategorization studies based on labeling tasks, some recent research has begun to examine the internal structure of speech categories (e.g., Kuhl, 1991;Li & Pastore, 1992;Samuel, 1982; Volatis & Miller, 1992). In general, these studies have found category membership to be qualitatively graded, with Kuhl (1991) providing evidence that quality ofmembership in a vowel category is reflected in a distinct pattern of discriminability between stimuli. Patterns of qualitative grading and related patterns of discrimination This research was supported by Grants F496209310033 and F490693I 0327 from the Air Force Office of Scientific Research to the second author. The opinions expressed are those of the authors and do not necessarily represent those of the granting agency. We would like to thank Cynthia Connine for several helpful suggestions concerning the discrimination models. Correspondence should be addressed to B. Acker, Psyc...

Categorical Perception of Control

“…This phenomenon is consistent with previous studies of categorical perception that examined within-category changes. Once a subjective category has been formed, changes in toward the prototype of the category are less detectable than changes toward the boundaries ( Etcoff and Magee, 1992 ; Acker et al, 1995 ). Further, a recent study on the sense of control also reported that initial exploration of control greatly influences the detection sensitivity of changes in the subsequent sensing of control ( Wen et al, 2020 ).…”

What good is goodness? The effects of reference points on discrimination and categorization of shapes.

“…The suggested attraction effect is in line with the assimilation to prototypes or perceptual magnet hypothesis , which states that reference points shrink the psychological distance around them, which implies decreased sensitivity around reference points (Feldman et al, 2009; Hellström, 2007; Kuhl, 1991; Samuel, 1982). In contrast, the perceptual anchor hypothesis suggests that reference points (i.e., anchors) cause an increase in sensitivity in their vicinity (Acker et al, 1995; Quinn, 2000). Evidence has been found for both of these hypotheses, and task context seems to be a moderating factor (Quinn, 2000), whereas increased sensitivity around reference points (above threshold) has been found for tasks involving direct perceptual comparisons with plenty of perceptual evidence present and minimal memory demands, decreased sensitivity around reference points has been reported for tasks in which a currently available stimulus was compared to stimuli stored in memory (i.e., for which there was limited perceptual input).…”

Absolute Judgment of Musical Interval Width

“…A musical prototype can assimilate an area of approximately 25 cents in either direction (Vurma & Ross, 2006), i.e., musically trained listeners may perceive all stimuli within 25 cents of a prototype to be identical (Perlman & Krumhansl, 1996;Siegel & Siegel, 1977a). Alternatively, a prototype may show enhanced discrimination in its immediate vicinity compared to the same area surrounding a non-prototype (Acker, Pastore, & Hall, 1995;McFadden & Callaway, 1999). Neither of these effects must necessarily occur, even among trained listeners (Schellenberg, 2002); however, it may be that with increasing musical experience, a prototype gradually changes from magnet to anchor, as detecting fine mistunings becomes more important to professional performance (Barrett, 1999).…”