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ABSTRACT: 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.
Memory & Cognition 04/2012; 35(4):610-620. · 1.92 Impact Factor
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ABSTRACT: 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.
British Journal of Psychology 08/2011; 102(3):313-27. · 2.37 Impact Factor
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ABSTRACT: 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.
Consciousness and Cognition 09/2008; 17(4):1192-208. · 2.31 Impact Factor
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ABSTRACT: 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.
The American Journal of Psychology 02/2008; 121(3):451-72. · 1.09 Impact Factor
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[show abstract]
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ABSTRACT: 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.
Memory & Cognition 06/2007; 35(4):610-20. · 1.92 Impact Factor
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ABSTRACT: 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.
Journal of Experimental Psychology Human Perception & Performance 09/2004; 30(4):778-91. · 3.06 Impact Factor
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ABSTRACT: a review, see Simons & Levin, 1997). Although research has consistently revealed the visual system's impressive ability to analyse scenes, segregate #gures from backgrounds, and quickly categorize objects, #ndings of change blindness suggest strict limits on the amount of information that can be consciously retained and compared from view to view, even 289 British Journal of Psychology (2002), 93, 289--302 2002 The British Psychological Society www.bps.org.uk * Requests for reprints should be addressed to Daniel Levin, Department of Psychology, PO Box 5190, Kent State University, Kent, OH 44242-0001, USA (e-mail: dlevin@kent.edu) over short delays. These data justify the conclusion that successful change detection, whether in complex natural scenes or simple arrays of objects, requires attention to be focused on the changing object (Rensink, O'Regan, & Clark, 1997). However, even if attending to an object may be necessary for change detection, it is not suf#cient---even changes to
03/2003;
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ABSTRACT: 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.
Perception 02/2003; 32(8):947-62. · 1.31 Impact Factor
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ABSTRACT: 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.
British Journal of Psychology 09/2002; 93(Pt 3):289-302. · 2.37 Impact Factor
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ABSTRACT: 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.
Perception 02/2002; 31(5):567-78. · 1.31 Impact Factor
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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.
Consciousness and Cognition 16(1):58-62. · 2.31 Impact Factor
