Adaptive decision processes in perceptual comparisons: effects of changes in the global difficulty context

Dynamics of choice during estimation of subjective value

This study characterized preferential choice in binary trials and investigated intra-session variations in response time (RT). In Experiment 1, participants (N=77) were asked to choose the preferred of two images of body wash; all unique combinations of 19 images were presented. The results showed: (a) marked and consistent individual preferences for specific stimuli; (b) RT decreased monotonically with increasing exposure to each stimulus; (c) RT decreased exponentially as a function of relative preference ranking of the 2 images in a trial; and (d) a regression model efficiently predicted trial RT as a function of exposure and relative preference. Experiment 2 (N=112) explored the effect of amount of exposure on RT, and relative preference as a function of the type of choice task (a previously completed vs. a new choice task). The results showed that: (a) within a single choice task, amount of exposure and relative preference between the stimuli predicted the systematic changes in RT observed in Exp. 1; and (b) when the choice task changed, the effects of previous amount of exposure, and relative stimulus preference did not transfer to the new task.

Selective attention and subjective confidence calibration

In the present experiments, failures of selective visual attention were invoked using the B. A. Eriksen and C. W. Eriksen (1974) flanker task. On each trial, a three-letter stimulus array was flashed briefly, followed by a mask. The identity of the two flanking letters was response congruent, neutral, or incongruent with the identity of the middle target letter. On half of the trials, confidence ratings were obtained after each response. In the first three experiments, participants were highly overconfident in the accuracy of their responding to incongruent flanker stimulus arrays. In a final experiment, presenting a prestimulus target location cue greatly reduced both selective attention failure and overconfidence. The findings demonstrate that participants are often unaware of such selective attention failures and provide support for the notion that, in these cases, decisional processing is driven largely by the identities of the incongruent flankers. In addition, responding was invariably slower and sometimes more accurate when confidence was required than when it was not required, demonstrating that the need to provide posttrial confidence reports can affect decisional processing. Moreover, there was some evidence that the presence of neutral contextual flanking information can slow responding, suggesting that such nondiagnostic information can, indeed, contribute to decisional processing.

Confidence and accuracy in deductive reasoning

In two experiments, we investigated the relationship between confidence and accuracy in syllogistic reasoning. Participants judged the validity of conclusions and provided confidence ratings twice for each problem: once quickly and again after further deliberation. Correlations between confidence and accuracy were small or nonexistent. In addition, confidence and accuracy were mediated by different variables. Confidence judgments appeared to reflect external cues, so that confidence was greater when the participants were allowed additional time to think about the problem, as well as when the conclusion was either believable or unbelievable, rather than neutral. In contrast, accuracy changed little as a function of the amount of time available and did not differ for believable and neutral problems. These data support a model in which initial decisions are made quickly, on the basis of heuristic cues, and analytic processes are used to justify or rationalize the earlier decision.