Influence of sensitivity on response bias in taste and audition

Abstract

A detection theoretic analysis was employed to examine sensitivity and response bias in two modalities. In Experiment 1, 6 tasters made same-different judgments about the concentration of either sucrose or quinine in pairs of tonic water samples. The beverages were colored, but color was not predictive of the concentration of the sweet or bitter ingredient. When same-different ratings were collapsed to approximate the outcome of a categorical decision, tasters with poorer sensitivity appear to have adopted more extreme response criteria than did tasters with greater sensitivity, irrespective of taste quality, color, or whether pairs ofsolutions comprised the same or different colors. In Experiment 2, 3 individuals discriminated pairs of lOoo-Hz sinusoids differing in amplitude. Six amplitude differences were tested. Rating-scale versions of two paradigms: The single-interval yes-no task and the twointerval same-different task were used to measure sensitivity and bias. There was a preponderance of "same" responses in the same-different task. Estimates of bias obtained from collapsed ratings in both tasks were unaffected by sensitivity, but a consideration of the range over which sets of criteria were spread suggested a general tendency toward more conservative response biases as sensitivity declined.The outstanding contribution of detection theory to psychophysical measurement is its ability to provide measures of sensitivity that are independent across manipulations of response bias, and vice versa. Thus, a number of recent papers evaluating both parametric and "nonparametric" indices of response bias agree on the-need to select an index displaying this property (Donaldson, 1992;Macmillan & Creelman, 1990See, Warm, Dember, & Howe, 1997;Snodgrass & Corwin, 1988). On occasion, however, researchers overlook the fact that statistical independence does not imply behavioral independence. For example, Snodgrass and Corwin (1988), who were scrupulous in their choice of bias measures, concluded that different dementias produced characteristic response biases. The recognition memory task in which bias was measured in their study was markedly more difficult for some groups than for others; thus, the conclusion presupposes the behavioral independence of bias and sensitivity. In a set of three experiments, See et al.The authors thank Michael Hautus for making available the computer program from which the d' estimates were obtained and Douglas Creelman, Sandy MacRae, and one anonymous reviewer for their valuable suggestions on an earlier version of this manuscript. Correspondence should be addressed to J. A. Stillman,

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“…The fact that, in this study, despite displaying different degrees of conservatism, observers displayed a tendency to choose unsure, probably different over unsure, probably same is contradictory to previous research in other modalities (Macmillan & Creelman, 2005;Stillman, Brown, & Troscianko, 2000). A possible reason for this may be that in the entire set of 510 trials, the probability of same pairs was relatively low.…”

On the Adaptive Nature of Anxiety: Toward an Integrative Signal Detection Approach to the Defensive Emotions

“…Thirdly, it may seem counterintuitive for more sensitive individuals to display more biased responding, especially since SDT posits sensitivity and response bias to be independent (Stanislaw & Todorov, 1999). Here, it is important to mark the distinction between statistical and behavioral independence (Stillman et al, 2000). Beyond mere preference for a given response category, response bias reflects the amount of information an individual requires to infer the presence of a signal.…”