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2004, South African Journal of Psychology
This study explored trends in change detection within the change blindness (CB) flicker paradigm. A sample comprising 92 university students was tested for speed in change detection. A number of alternating photographic scenes with and without changes in objects were shown in a computer laboratory. There were significant differences between males and females for central and marginal interest changes on different change types, which included changes in colour, presence and location of objects. The results were used to illustrate the methodological restrictions of previous studies and to expand on theoretical explanations for this phenomenon. This study also challenged the various notions pertaining to the nature of the representations one forms when perceiving visually. The application of connectionist principles revealed the ambiguity of representational-based explanations for change detection.
Abstract Change blindness is a person‟ s inability to notice changes in a visual scene that seem obvious when pointed out. Recent experiments using eye tracking techniques have suggested that even though participants do not detect a change they fixate on the changing area more. Two studies test whether this finding is present across different change blindness paradigms and whether it is detectable after fixation. In the first study we compare behavior in flicker and gradual change paradigms.
2003
2.. Attention and storage in working memory protects against change blindness AA crucial factor in change detection seems to be attention, a phenomenon discussed in BOX 1.. In the real world, changes almost always involve motion or luminance changes. This often evokess a visual transient that is unique, or very salient with respect to background noise, so that itt attracts attention (Phillips & Singer, 1974; Rensink, 2000b, 2002). Without a blank interval in thee change blindness paradigm, the unique transient makes the change easy to detect. With the
Vision and Attention, 2001
In the not-too-distant past, vision was often said to involve three levels of processing: a low level concerned with descriptions of the geometric and photometric properties of the image, a high level concerned with abstract knowledge of the physical and semantic properties of the world, and a middle level concerned with anything not handled by the other two. 1 The negative definition of mid-level vision contained in this description reflected a rather large gap in our understanding of visual processing: How could the here-and-now descriptions of the low levels combine with the enduring knowledge of the high levels to produce our perception of the surrounding world?
Encyclopedia of Cognitive Science
Communicative & Integrative Biology, 2009
A large body of literature has shown that observers often fail to notice significant changes in visual scenes, even when these changes happen right in front of their eyes. For instance, people often fail to notice if their conversation partner is switched to another person, or if large background objects suddenly disappear. 1,2 These 'change blindness' studies have led to the inference that the amount of information we remember about each item in a visual scene may be quite low. 1 However, in recent work we have demonstrated that long-term memory is capable of storing a massive number of visual objects with significant detail about each item. 3 In the present paper we attempt to reconcile these findings by demonstrating that observers do not experience 'change blindness' with the real world objects used in our previous experiment if they are given sufficient time to encode each item. The results reported here suggest that one of the major causes of change blindness for real-world objects is a lack of encoding time or attention to each object (see also refs. 4 and 5).
Visual Cognition 10(2):233-255, 2003
Change blindness is a failure to detect a change in an scene when the change occurs along with some visual disturbances. Disturbances are thought to play a delocalizing role that affects the saliency of the “target” transient signal coming from the change location, which would otherwise capture attention and render the change visible. For instance, it is hypothesized that the appearance of new objects in the “mudsplashes” paradigm generates transient signals that compete with the target object's transient signal for attracting attention. Thus, experiments using the mudsplashes paradigm do not rule out a possible role of object changes in capturing attention. Here, by reversing image contrast polarity, we develop a new paradigm to produce change blindness when a real global transient signal is the only visual event occurring, with no edges added or deleted except in the target object. The results show that transient signals, per se, are able to prevent change detection. However, abrupt transients are not necessary if object change occurs in the zero-contrast phase of a smoothly fading and reappearing image, leaving attention as the only common factor affecting all cases of change blindness.
Tissue Antigens, 2004
Partial report methods have shown that a large-capacity representation exists for a few hundred milliseconds after a picture has disappeared. However,change blindness studies indicate that very limited information remains available when a changed version of the image is presented subsequently. What happens to the large-capacity representation? New input after the first image may interfere, but this is likely to depend
Consciousness and Cognition, 2010
The goal of this study is to characterize observers' abilities to detect gradual changes and to explore putative dissociations between conscious experience of change and behavioral adaptation to a changing stimulus. We developed a new experimental paradigm in which, on each trial, participants were shown a dot pattern on the screen. Next, the pattern disappeared and participants had to reproduce it. In some conditions, the target pattern was incrementally rotated over successive trials and participants were either informed or not of this change. We analyzed both awareness of the changes and the dynamics of behavioral adaptation, in a way that makes it possible to assess both variability and accuracy as they change over time. Results indicate a dissociation between change awareness and behavioral adaptation to the changes, and support the notion that unconscious representations of visual stimuli are more precise and detailed than previously suggested. We discuss the implications of these results for theories of change detection. Crown steps of 1°of visual angle on each display, with each display separated from the next one by a brief blank screen (1500 ms). Participants were instructed to press a button if they had noticed the scene change. The results indicated that half of the participants remained unaware of the change up to a dramatic rotation of 48°. However, when a shift back to the original scene was produced after a cumulated rotation of 20°or 30°that had so far remained undetected, most subjects could then clearly see the change. Authors concluded that visual memory had been updated, albeit in the absence of awareness. Indeed, if visual memory had not been updated at all, participants would not have been able to detect the change when presented anew with the original display. These results clearly challenge the idea that change blindness arises from a failure to maintain relevant information in memory (see also, .
Current Directions in Psychological …, 2005
People often fail to notice large changes to visual scenes, a phenomenon now known as change blindness. The extent of change blindness in visual perception suggests limits on our capacity to encode, retain, and compare visual information from one glance to the next; our awareness of our visual surroundings is far more sparse than most people intuitively believe. These failures of awareness and the erroneous intuitions that often accompany them have both theoretical and practical ramifications. This article briefly summarizes the current state of research on change blindness and suggests future directions that promise to improve our understanding of scene perception and visual memory.
Developmental Science, 2006
Changes to a scene often go unnoticed if the objects of the change are unattended, making change detection an index of where attention is focused during scene perception. We measured change detection in school-age children and young adults by repeatedly alternating two versions of an image. To provide an age-fair assessment we used a bimanual choice rather than open-ended verbal responses. The difference in detection speed and accuracy between 50-ms versus 250-ms blank screens between views indexed change detection in short-term visual memory independent of sensory and response processes. Younger children were significantly less efficient than older participants, especially when an object changed color or had a part deleted. Changes in object orientation were detected more readily. These results point to important differences in the perceptual reality of younger and older children.
Psychonomic Bulletin & Review, 2001
This study examined the notion that visually fixating at a stimulus can help prevent change blindness from occurring and looks at change blindness blindness, a common metacognitive error shown by participants. 77 participants were randomly selected and assigned to different conditions. Experimental group had an extra task that they had to perform while attending to the video and the control group only had to watch the video. Participants in both conditions were required to fill out a questionnaire measuring their confidence levels to notice the change. Both conditions failed to detect changes with insignificant difference between the groups, even though the stimulus was visually fixated. Most participants overestimated their change detecting abilities, predicting in the questionnaire that they would notice the change, while in practice they did not. Thus an extra task in the experimental condition did not produce a cognitive overload leading to change blindness. Still participants failed to detect changes when the stimulus was fixated and failed to measure their change detecting abilities realistically.
Psychological Science, 1997
When looking at a scene, observers feel that they see its entire structure in great detail and can immediately notice any changes in it. However, when brief blank fields are placed between alternating displays of an original and a modified scene, a striking failure of perception is induced: identification of changes becomes extremely difficult, even when changes are large and made repeatedly. Identification is much faster when a verbal cue is provided, showing that poor visibility is not the cause of this difficulty. Identification is also faster for objects mentioned in brief verbal descriptions of the scene. These results support the idea that observers never form a complete, detailed representation of their surroundings. In addition, results also indicate that attention is required to perceive change, and that in the absence of localized motion signals it is guided on the basis of high-level interest.
Psychologia, 2008
An overview is presented of the ways that change blindness has been applied to the study of various issues in perception and cognition. Topics include mechanisms of change perception, allocation of attention, nonconscious perception, and cognitive beliefs. Recent work using change blindness to investigate these topics is surveyed, along with a brief discussion of some of the ways that these approaches may further develop over the next few years.
Annual Review of Psychology, 2002
Key Words change blindness, visual attention, scene perception, eye movements, visual memory s Abstract Five aspects of visual change detection are reviewed. The first concerns the concept of change itself, in particular the ways it differs from the related notions of motion and difference. The second involves the various methodological approaches that have been developed to study change detection; it is shown that under a variety of conditions observers are often unable to see large changes directly in their field of view. Next, it is argued that this "change blindness" indicates that focused attention is needed to detect change, and that this can help map out the nature of visual attention. The fourth aspect concerns how these results affect our understanding of visual perception-for example, the implication that a sparse, dynamic representation underlies much of our visual experience. Finally, a brief discussion is presented concerning the limits to our current understanding of change detection.
2001
Functional magnetic resonance imaging (fMRI) of subjects attempting to detect a visual change occurring during a screen flicker was used to distinguish the neural correlates of change detection from those of change blindness. Change detection resulted in enhanced activity in the parietal and right dorsolateral prefrontal cortex as well as category-selective regions of the extrastriate visual cortex (for example, fusiform gyrus for changing faces).
Trends in Cognitive Sciences, 2005
Change blindness is the striking failure to see large changes that normally would be noticed easily. Over the past decade this phenomenon has greatly contributed to our understanding of attention, perception, and even consciousness. The surprising extent of change blindness explains its broad appeal, but its counterintuitive nature has also engendered confusions about the kinds of inferences that legitimately follow from it. Here we discuss the legitimate and the erroneous inferences that have been drawn, and offer a set of requirements to help separate them. In doing so, we clarify the genuine contributions of change blindness research to our understanding of visual perception and awareness, and provide a glimpse of some ways in which change blindness might shape future research.
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