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The present studies examined the roles of identity and spatial working memory in change detection. Observers completed a spatial or identity working m emory task concurrently with a change detection task. In the change detection task, participants we re presented naturalistic scenes that contained eit her a color or location change to one object. Concurren tly, participants remembered either the colors or locations of four squares. There was specific disru ption of performance when the working memory task and the change detection task loaded the same subsystem of working memory. There was also evidence that spatial information is processed more readily than identity information. This suggests that although there are separate systems for identi ty and spatial working memory, these subsystems are not necessarily created equal in that processing in the spatial processing may have priority over identity processing. However, this priority can be overridden during change detection if spatial memory is already occupied.

In the typical visual search experiment, participants search for targets that are present on half of the trials and absent on the other half. However, many real-world tasks involve targets that are present only occasionally. Given this, it is important to know how people deal with the problem of finding targets they have little experience with. One possibility is that they develop an awareness of the degree to which they have effectively completed a search through complex target-absent scenes. To test this hypothesis, we had participants complete two relatively long search tasks in which only a minority of trials included targets. Stimuli were cluttered real-world scenes, and targets were defined by category. We examined participants' ability to terminate search on the target-absent scenes based on an accurate assessment of scene difficulty. Scene difficulty was estimated by computing the mean correct-trial response time (RT) for each of the target-absent scenes across all participants. These group RTs were then correlated with each participants' individual correct-trial RTs for the same stimuli to assess the degree to which a given participant's search-termination times were correlated with those of the group. These correlations successfully predicted participants' target-detection success in both experiments. These experiments suggest that an integral part of visual search is the need to calibrate search behaviour to scenes of varying levels of complexity even when no targets are present.

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.

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 people’s 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 people’s visual experience, and even the teaching of psychology.

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.

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.

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.

People often have difficulty detecting visual changes in scenes, a phenomenon referred to as 'change blindness'. Although change blindness is usually observed in pictures of objects that are not the focus of attention, it also occurs for attended objects in the real world. Here, we further explore the finding that many participants fail to detect the unexpected substitution of one conversation partner for another. We show that change blindness for a conversation partner occurs in a variety of situations. Furthermore, when tested with a photographic lineup following the change, participants who noticed the substitution showed better memory for both pre- and post-change experimenters than participants who did not detect the change. We conclude that change blindness in this case is associated with relatively ineffective or inaccessible representations of previously attended objects, and we contrast these results with others indicating that change blindness arises from a failure to compare the original and changed object.

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.

In the typical visual search experiment, participants search for targets that are present on half of the trials and absent on the other half. However, many real-world tasks involve targets that are present only occasionally. Given this, it is important to know how people deal with the problem of finding targets they have little experience with. One possibility is that they develop an awareness of the degree to which they have effectively completed a search through complex target-absent scenes. To test this hypothesis, we had participants complete two relatively long search tasks in which only a minority of trials included targets. Stimuli were cluttered real-world scenes, and targets were defined by category. We examined participants' ability to terminate search on the target-absent scenes based on an accurate assessment of scene difficulty. Scene difficulty was estimated by computing the mean correct-trial response time (RT) for each of the target-absent scenes across all participants. These group RTs were then correlated with each participants' individual correct-trial RTs for the same stimuli to assess the degree to which a given participant's search-termination times were correlated with those of the group. These correlations successfully predicted participants' target-detection success in both experiments. These experiments suggest that an integral part of visual search is the need to calibrate search behaviour to scenes of varying levels of complexity even when no targets are present.

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 people's 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 people's visual experience, and even the teaching of psychology.

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.

Observers have difficulty detecting visual changes. However, they are unaware of this inability, suggesting that people do not have an accurate understanding of visual processes. We explored whether this error is related to participants' beliefs about the roles of intention and scene complexity in detecting changes. In Experiment 1 participants had a higher failure rate for detecting changes in an incidental change detection task than an intentional change detection task. This effect of intention was greatest for complex scenes. However, participants predicted equal levels of change detection for both types of changes across scene complexity. In Experiment 2, emphasizing the differences between intentional and incidental tasks allowed participants to make predictions that were less inaccurate. In Experiment 3, using more sensitive measures and accounting for individual differences did not further improve predictions. These findings suggest that adults do not fully understand the role of intention and scene complexity in change detection.

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.

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 same-race (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 distractor-rejection processes in determining the form of a serial search asymmetry.