Abstract not found

Research on people’s confidence in their general knowledge has to date produced two fairly stable effects, many inconsistent results, and no comprehensive theory. We propose such a comprehensive framework, the theory of probabilistic mental models (PMM theory). The theory (a) explains both the overconfidence effect (mean confidence is higher than percentage of answers correct) and the hard-easy effect (overconfidence increases with item difficulty) reported in the literature and (b) predicts conditions under which both effects appear, disappear, or invert. In addition, (c) it predicts a new phenomenon, the confidence-frequency effect, a systematic difference between a judgment of confidence in a single event (i.e., that any given answer is correct) and a judgment of the frequency of correct answers in the long run. Two experiments are reported that support PMM theory by confirming these predictions, and several apparent anomalies reported in the literature are explained and integrated into the present framework. Do people think they know more than they really do? In the last 15 years, cognitive psychologists have amassed a large and apparently damning body of experimental evidence on overconfidence in knowledge, evidence that is in turn part of an even larger and more damning literature on socalled cognitive biases. The cognitive bias research claims that people are naturally prone to making mistakes in reasoning and memory, including the mistake of overestimating their knowledge.

Emotions are universally recognized from facial expressions—or so it has been claimed. To support that claim, research has been carried out in various modern cultures and in cultures relatively isolated from Western influence. A review of the methods used in that research raises questions of its ecological, convergent, and internal validity. Forced-choice response format, within-subject design, preselected photographs of posed facial expressions, and other features of method are each problematic. When they are altered, less supportive or nonsupportive results occur. When they are combined, these method factors may help to shape the results. Facial expressions and emotion labels are probably associated, but the association may vary with culture and is loose enough to be consistent with various alternative accounts, 8 of which are discussed. "Everyone knows that grief involves a gloomy and joy a cheerful countenance.... There are characteristic facial expressions which are observed to accompany anger, fear, erotic excitement, and all the other passions " (Aristotle, nd/1913, pp. 805, 808). Aristotle was not proposing a new idea but was cataloging what was known on the topic of physiognomy. The theory was that a person's physical appearance, especially in the face, reveals deeper characteristics: Poor proportions reveal a rogue, soft hair a coward, and a smile a happy person.' Today, few psychologists share Aristotle's belief about the meaning of poor proportions or soft hair, but many share his beliefs about facial expression and emotion. Oatley and Jenkins (1992) observed, "By far the most extensive body of data in the field of human emotions is that on facial expressions of emotion" (p. 67). Recent reviews of those data (see Table 1) agree that the face reveals emotion in a way that is universally understood: Happiness, surprise, fear, anger, contempt, disgust, and sadness—these seven emotions, plus or minus two, are recognized from facial expressions by all human beings, regardless of their cultural background.

this article, we present a model of similarity comparison that makes specific time course predictions, which were tested in three experiments. Before turning to that model, we first outline the need for a consideration of similarity processes

this article should be addressed to R. Goldstone, Psychology Department, Indiana University, Bloomington, IN 47405 (e-mail: rgoldsto@ indiana.edu). Further information can be found at http://cognitrn.psych. indiana.edu/ Similarity in context ROBERT L. GOLDSTONE DOUGLAS L. MEDIN Northwestern University, Evanston, Illinois and JAMIN HALBERSTADT Similarity comparisons are highly sensitive to judgment context. Three experiments explore context effects that occur within a single comparison rather than across several trials. Experiment 1 shows reliable intransitivities in which a target is judged to be more similar to stimulus A than to stimulus B, more similar to B than to stimulus C, and more similar to C than to A. Experiment 2 explores the locus of Tversky's (1977) diagnosticity effect in which the relative similarity of two alternatives to a target is influenced by a third alternative. Experiment 3 demonstrates a new violation of choice independence which is explained by object dimensions' becoming foregrounded or backgrounded, depending upon the set of displayed objects. The observed violations of common assumptions to many models of similarity and choice can be accommodated in terms of a dynamic property-weighting process based on the variability and diagnosticity of dimensions

A memory-based scaling model—ANCHOR—is proposed and tested. The perceived magnitude of the target stimulus is compared with a set of anchors in memory. Anchor selection is probabilistic and sensitive to similarity, base-level strength, and recency. The winning anchor provides a reference point near the target and thereby converts the global scaling problem into a local comparison. An explicit correction strategy determines the final response. Two incremental learning mechanisms update the locations and base-level activations of the anchors. This gives rise to sequential, context, transfer, practice, and other dynamic effects. The scale unfolds as an adaptive map. A hierarchy of models is tested on a battery of quantitative measures from 2 experiments in absolute identification and category rating. Category rating is a widely used method of data collection in experimental psychology. Ratings come in a wide variety of guises: psychophysical scales, similarity judgments, typicality judgments, confidence ratings, attitude questionnaires, health selfreports, and many others. The participants in all these tasks are asked to rate things using an ordered set of categories such as 1,..., 7 or strongly agree,..., strongly disagree. Most people

The effects of previous stimuli on responses in an absolute judgment of loudnesses situation were investigated when feedback was and was not provided. Whether or not information feedback was provided, responses were assimilated to the value of the immediately previous stimulus in the series. The effects of stimuli more than one trial back in the sequence depend on the presence or absence of feedback. When the entire stimulus scale was shifted up or down to 5 db. from the level on the previous day, a substantial shift occurred in the constant error of judgment in the direction of the scale shift, providing evidence that a relatively long-term (24-hr.) memory process was being used in the judgment situation. None of the currently available models is adequate to account for both these results and those of earlier studies. The form of the sequential dependencies observed may depend at least partially on the presence or absence of an identification function from stimuli to responses. The effects of the previous sequence of stimuli on judgment in a psychophysical task have long been of special interest, and the nature of the effects discovered seems to be different in different experimental situations. Some investigators report an inverse relation (contrast) between the response and the preceding stimuli (Fernberger, 1920;

Three experiments investigated the loci of contextual effects in judgment, Experiment 1 demonstrated the effect of stimulus spacing on category ratings and magnitude estimations of the darkness of dot patterns. Variations in the stimulus spacing were shown to affect both category ratings and magnitude estimations in a similar fashion. Experiment 2 was designed to determine whether contextual effects due to stimulus spacing influence the scale values or the judgment function. Subjects judged "differences " and "ratios " of the subjective darkness of dot patterns. Differences in mean judgments of single stimuli from Experiment 1 did not predict the rank order of judged "differences " and "ratios " from Experiment 2. The estimated scale values of the stimuli appeared to be independent of stimulus spacing. These findings suggest that contextual effects due to the stimulus spacing occur in the judgment function for within-modality judgments. Experiment 3 examined contextual effects in cross-modality judgments. Stimulus spacing and stimulus range were manipulated for "difference " and "total " judgments. Unlike the within-modality results, the stimulus range and spacing influenced the scale values. A contextual theory of within- and cross-modality judgment is presented. It is now well established that judgments are relative. That is, the response to a stimulus depends not only on the stimulus to be judged, but also on other stimuli that form a context, or frame of reference for judgment

Category judgments of the average lengths of sets of lines were inconsistent with context-independent models of information integration: the effects of any particular line upon the judgment of average length varied inversely with the lengths of the other lines within the same set. This interaction, obtained in five separate experiments, was similar to that previously reported for auditory intensities. The judgments reflect two kinds of contextual effects: (a) withinset effects, in which the judgment of the set varies directly with the range of values within the set, and (b) between-set effects, in which the apparent interaction between the stimuli within a set depends upon the context provided by the different sets. A simple range model provides a method for separating the two types of contextual effects. The context between sets is postulated to affect only the response scale; when the responses are rescaled to allow for the between-set context, the integrated impression is dependent upon both the mean and the range of components within the set. The term "information integration"

This paper presents an unusual prediction made by the DUAL-based model of judgment JUDGEMAP and its verification. The model is shortly presented as well as the simulation data obtained with it. These data predict that people will use the information on an irrelevant dimension when judging another dimension. This prediction is then tested in a psychological experiment and confirmed.