Bonnie L. Angelone

The relationship between change detection and recognition of centrally attended objects in motion pictures.

Observers typically detect changes to central objects more readily than changes to marginal objects, but they sometimes miss changes to central, attended objects as well. However, even if observers do not report such changes, they may be able to recognize the changed object. In three experiments we explored change detection and recognition memory for several types of changes to central objects in motion pictures. Observers who failed to detect a change still performed at above chance levels on a recognition task in almost all conditions. In addition, observers who detected the change were no more accurate in their recognition than those who did not detect the change. Despite large differences in the detectability of changes across conditions, those observers who missed the change did not vary in their ability to recognize the changing object.

Categorical perception of race.

Traditionally, research demonstrating categorical perception (CP) has assumed that CP occurs only in cases where natural continua are divided categorically by long-term learning or innate perceptual programming. More recent research suggests that this may not be true, and that even novel continua between novel stimuli such as unfamiliar faces can show CP effects as well. Given this, we ask whether CP is dependent solely on the representation of individual stimuli, or whether stimulus categories themselves can also cause CP. Here, we test the hypothesis that continua between individual faces that cross the categorical boundary between races show an enhanced CP effect. We find that continua running from a black face to a white face do, indeed, show stronger CP effects than continua between two black faces or two white faces. This suggests that CP effects are enhanced when continua run between two distinctly represented individual stimuli, and are further enhanced when those individuals are, in turn, members of different stimulus categories.

The Roles of Encoding, Retrieval, and Awareness in Change Detection

In the experiment reported here, we examined the processes by which expected (probable) changes are detected more frequently than are unexpected (improbable) changes (the change probability effect; Beck, Angelone, & Levin, 2004). The change probability effect may be caused by a bias toward probable changes during encoding of the prechange aspect, during retrieval of the prechange aspect, or during activation of an explicit response to the change. Participants performed a change detection task for probable and improbable changes while their eye movements were tracked. Change detection performance was superior for probable changes, but long-term memory performance was equivalent for both probable and improbable changes. Therefore, although both probable and improbable prechange aspects were encoded, probable prechange aspects were more likely to be retrieved during change detection. Implicit change detection was also greater for probable changes than for improbable changes, suggesting that the change probability effect is the result of a bias during the retrieval and comparison stage of change detection. The stimuli used in the change detection task may be downloaded from www.psychonomic.org/archive.

Knowledge About the Probability of Change Affects Change Detection Performance

The visual system continually selects some information for processing while bypassing the processing of other information, and as a consequence, participants often fail to notice large changes to visual stimuli. In the present studies, the authors investigated whether knowledge about the probability of particular changes occurring over time increased the likelihood that changes that were likely to occur in the real world (probable changes) would be detected. The results of two experiments showed that participants were more likely to detect probable changes. This occurred whether or not they were processing the scene in a meaningful manner or actively searching the scene for changes. Furthermore, participants were unable to accurately predict change detection performance for probable and improbable changes.

The Visual Metacognition Questionnaire : A measure of intuitions about vision

Recent research has revealed a series of striking limits to visual perception. One important aspect of these demonstrations is the degree to which they conflict with intuition; people often believe that they will be able to see things that experiments demonstrate they cannot see. This metacognitive error has been explored with reference to a few specific visual limits, but no study has yet explored peoples intuitions about vision more generally. In this article we present the results of a broad survey of these intuitions. Results replicate previous overestimates and underestimates of visual performance and document new misestimates of performance in tasks that assess inattention blindness and visual knowledge. We also completed an initial exploratory factor analysis of the items and found that estimates of visual performance for well-structured information tend to covary. These results represent an important initial step in organizing the intuitions that may prove important in a variety of settings, including performance of complex visual tasks, evaluation of others peoples visual experience, and even the teaching of psychology.

Visual search for a socially defined feature: What causes the search asymmetry favoring cross-race faces?

Levin (1996, 2000) reported that white subjects search for black targets more quickly than they search for white targets, suggesting that black faces are perceived as having a feature that is lacking in white faces. Here we test one of the implications of this asymmetry by having subjects search for samerace (SR) and cross-race (CR) faces that are distorted to look less like each other (producing caricatures that enhance race-specifying features), or are distorted to look more like each other (a prototypical distortion expected to reduce the salience of race-specifying features). Experiments 1 and 2 show that caricaturing the feature-positive CR distractors speeds search for the SR face and that prototypical distortion slows this search. The same distortions in SR faces did not affect the search slopes. However, these distortions also eliminated the overall advantage for CR faces. Experiment 3 shows that trial-to-trial variation in the specific distractors in each display can eliminate the asymmetry and suggests that this asymmetry depends on the subjects’ ability to set a consistent a priori perceptual criterion when searching for a CR target, while the distortion effects emphasize the importance of distractorrejection processes in determining the form of a serial search asymmetry.

Implicit learning for probable changes in a visual change detection task.

Previous research demonstrates that implicitly learned probability information can guide visual attention. We examined whether the probability of an object changing can be implicitly learned and then used to improve change detection performance. In a series of six experiments, participants completed 120-130 training change detection trials. In four of the experiments the object that changed color was the same shape (trained shape) on every trial. Participants were not explicitly aware of this change probability manipulation and change detection performance was not improved for the trained shape versus untrained shapes. In two of the experiments, the object that changed color was always in the same general location (trained location). Although participants were not explicitly aware of the change probability, implicit knowledge of it did improve change detection performance in the trained location. These results indicate that improved change detection performance through implicitly learned change probability occurs for location but not shape.

Metacognitive errors in change detection: Lab and life converge

Abstract Smilek, Eastwood, Reynolds, and Kingstone (2007) suggests that the studies reported in Beck, M. R., Levin, D. T. and Angelone, B. A. (2007) (Change blindness blindness: Beliefs about the roles of intention and scene complexity in change detection. Consciousness and Cognition) are not ecologically valid. Here, we argue that not only are change blindness and change blindness blindness studies in general ecologically valid, but that the studies we reported in Beck, Levin, and Angelone, 2007 are as well. Specifically, we suggest that many of the changes used in our study could reasonably be expected to occur in the real world. Furthermore, the conclusion from Beck et al. (2007) that knowledge about the role of intention and scene complexity in change detection is not readily accessible applies not only to the laboratory studies we conducted but also to real world situations.