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. (shrink)

Change blindness experiments had demonstrated that detection of significant changes in natural images is extremely difficult when brief blank fields are placed between alternating displays of an original and a modified scene. On the other hand, research on the visual mismatch negativity component of the event-related potentials identified sensitivity to events different from the regularity of stimulus sequences, even if the deviant and standard events are non-attended. The present study sought to investigate the apparent controversy between the experience (...) under the change blindness paradigm and the ERP results. To this end, the stimulus of Rensink, O’Reagen, and Clark was adapted to a passive oddball ERP paradigm to investigate the underlying processing differences between the standard and deviant stimuli measured in 22 subjects. Posterior negativity within the 280–330 ms latency range emerged as the difference between ERPs elicited by standard and deviant stimuli, identified as visual mismatch negativity. These results raise the possibility that change blindness is not based on the lack of detailed visual representations or the deficiency of comparing two representations. However, effective discrimination of the two scene versions requires considerable frequency differences between them. (shrink)

Evidence from many different paradigms (e.g. change blindness, inattentional blindness, transsaccadic integration) indicate that observers are often very poor at reporting changes to their visual environment. Such evidence has been used to suggest that the spatio-temporal coherence needed to represent change can only occur in the presence of focused attention. In four experiments we use modified change blindness tasks to demonstrate (a) that sensitivity to change does occur in the absence of awareness, and (b) this sensitivity (...) does not rely on the redeploy- ment of attention. We discuss these results in relation to theories of scene percep- tion, and propose a reinterpretatio n of the role of attention in representing change. (shrink)

Studies of change detection suggest that people tend to overestimate their ability to detect visual changes. In a recent laboratory study of change detection and human intention, Beck et al., found that individuals have an inadequate understanding that intention can improve change detection performance and that its importance increases with scene complexity. We note that these findings may be specific to unfamiliar situations such as those generated routinely in studies of change detection. (...) In two questionnaire studies, we demonstrate that when participants consider real world scenarios such as driving, people are well aware that the intention to detect changes improves detection performance, especially in complex scenes. We suggest several reasons why change detection findings like Beck et al.’s do not generalize to real world situations. More broadly, we suggest a possible way to bridge the gap between lab and life. (shrink)

Smilek, Eastwood, Reynolds, and Kingstone suggests that the studies reported in Beck, M. R., Levin, D. T. and Angelone, B. A. 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. 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. (shrink)

Studies of change blindness indicate that more intentional monitoring of changes is necessary to successfully detect changes as scene complexity increases. However, there have been conflicting reports as to whether people are aware of this relation between intention and successful change detection as scene complexity increases. Here we continue our dialogue with [Beck, M. R., Levin, D. T., & Angelone, B. . Change blindness blindness: Beliefs about the roles of intention and scene complexity in change (...) detection. Consciousness and Cognition, 16, 31–51; Beck, M. R., Levin, D. T., & Angelone, B. . Metacognitive errors in change detection: Lab and life converge. Consciousness and Cognition, 16, 58–62] by reporting two experiments that show participants do in fact intuit that more intentional monitoring is needed to detect changes as scene complexity increases. We also discuss how this dialogue illustrates the need for psychological studies to be grounded in measurements taken from real world situations rather than laboratory experiments or questionnaires. (shrink)

In three experiments, we investigated the priming effects induced by an image change on a successive animate/inanimate decision task. We studied both perceptual and conceptual priming effects, under correct change detection and change blindness . Under correct change detection, we found larger positive priming effects on congruent trials for probes representing animate entities than for probes representing artifactual objects. Under CB, we found performance impairment relative to a “no-change” baseline condition. This inhibition effect (...) induced by CB was modulated by the semantic congruency between the changed item and the probe in the case of probe images, but not for probe words. We discuss our results in the context of the literature on the negative priming effect. (shrink)

We present four new change detection methods that create an automated change map from a probability map. In this case, the probability map was derived from a 3D model. The primary application of interest is aerial photographic applications, where the appearance, disappearance or change in position of small objects of a selectable class (e.g., cars) must be detected at a high success rate in spite of variations in magnification, lighting and background across the image. The methods (...) rely on an earlier derivation of a probability map. We describe the theory of the four methods, namely Bernoulli variables, Markov Random Fields, connected change, and relaxation-based segmentation, evaluate and compare their performance experimentally on a set probability maps derived from aerial photographs. (shrink)

Attentional scanning was studied in anxious and non-anxious participants, using a modified change detection paradigm. Participants detected changes in pairs of emotional scenes separated by two task irrelevant slides, which contained an emotionally valenced scene and a visual mask. In agreement with attentional control theory, change detection latencies were slower overall for anxious participants. Change detection in anxious, but not non-anxious, participants was influenced by the emotional valence and exposure duration of distractor scenes. When (...) negative distractor scenes were presented at subliminal exposure durations, anxious participants detected changes more rapidly than when supraliminal negative scenes or subliminal positive scenes were presented. We propose that for anxious participants, subliminal presentation of emotionally negative distractor scenes stimulated attention into a dynamic state in the absence of attentional engagement. Presentation of the same scenes at longer exposure times was accompanied by conscious awareness, attentional engagement, and slower change detection. (shrink)

According to the influential thesis of attentional transparency, in having or reflecting on an ordinary visual experience, we can attend only outwards, to qualities the experience represents, never to intrinsic qualities of the experience itself, i.e., to “mental paint.” According to the competing view, attentional semitransparency, although we usually attend outwards, to qualities the experience represents, we can also attend inwards, to mental paint. So far, philosophers have debated this topic in strictly armchair means, especially phenomenological reflection. My aim in (...) this paper is to show how to design an experiment, using the change detection paradigm for studying visual working memory that, if yielding positive results, would support AS. The structure of the argument is as follows. In standard change detection tasks, which involve attention to qualities the experience represents, there exists a known object integration effect (Luck and Vogel in Nature 390(6657):279–281, 1997). I formulate a hypothesis I call “the turn-off hypothesis,” according to which this effect does not exist in change detection tasks where subjects are instructed to attend to mental paint. I argue that, given AS, we have some reason to expect the turn-off hypothesis to be true, but given AT, we do not. Consequently, the truth of the turn-off hypothesis would support AS. I further argue that one can straightforwardly test the turn-off hypothesis, taking the standard change detection paradigm and instructing participants to attend inwards. (shrink)

Heart rate variability (HRV) is an indicator of the regulation of the heart, see Task Force (Circulation 93(5):1043–1065, 1996). This study compares the regulation of the heart in two cases of healthy subjects within real life situations: Marathon runners and shift workers. After an update on the state of the art on HRV processing, we specify our probabilistic model: We choose modeling heartbeat series by locally stationary Gaussian process (Dahlhaus in Ann Stat 25, 1997). HRV is then processed by the (...) combination of two statistical methods: (1) Continuous wavelet transform for calculating the spectral density energy in the high frequency (HF) and low frequency (LF) bands and (2) Change point analysis to detect changes of heart regulation. Next, we plot the variations of the HF and LF energy in extreme conditions for both populations. This puts in light, that physical activities (rest, moderate sport, marathon race) can be ordered in a logical continuum. This allows to define a new index based on HF and LF energy that is log HF + log LF which appears relevant to measure HR regulation. The results obtained are pertinent but have to be completed by further studies. (shrink)

The goal of this study is to characterize observers’ abilities to discriminate between endogenous and exogenous changes. To do so, we developed a new experimental paradigm. On each trial, participants were shown a dot pattern on the screen. Next, the pattern disappeared and participants were to reproduce it. Changes were surreptuously introduced in the stimulus, either by presenting participants anew with the dot pattern they had themselves produced on the previous trial or by presenting participants with a slightly different dot (...) pattern . We analyzed awareness of the changes and behavioral adaptation to them in a dynamical manner. We observe signal attenuation in the presence of endogenous change, dissociation between self-attribution reports and behavioral effect of agency. We discuss the source of this sensitive attenuation as well as the relation between a minimal or core self and an extended, narrative or autobiographical self. (shrink)

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. (shrink)

Having evolved to escape detection of deception completely, self-deception must respond to social conditions registering different probabilities of detection. To be adaptive, it must have a mechanism to keep truthful information temporarily from the self during deception and retrieve it after deception. The memory system may serve this mechanism and provides a paradigm in which to conduct research on self-deception.

People can maintain accurate representations of visual changes without necessarily being aware of them. Here, we investigate whether a similar phenomenon also exists in touch. In Experiments 1 and 2, participants detected the presence of a change between two consecutively-presented tactile displays. Tactile change blindness was observed, with participants failing to report the presence of tactile change. Critically, however, when participants had to make a forced choice response regarding the number of stimuli presented in the two displays, (...) their performance was significantly better than chance . Experiment 3 demonstrated that tactile change detection does not necessarily involve a shift of spatial attention toward the location of change, regardless of whether the change is explicitly detected. We conclude that tactile change detection likely results from comparing representations of the two displays, rather than by directing spatial attention to the location of the change. (shrink)

Change blindness, the surprising inability of people to detect significant changes between consecutively-presented visual displays, has recently been shown to affect tactile perception as well. Visual change blindness has been observed during saccades and eye blinks, conditions under which people’s awareness of visual information is temporarily suppressed. In the present study, we demonstrate change blindness for suprathreshold tactile stimuli resulting from the execution of a secondary task requiring bodily movement. In Experiment 1, the ability of participants to (...) detect changes between two sequentially-presented vibrotactile patterns delivered on their arms and legs was compared while they performed a secondary task consisting of either the execution of a movement with the right arm toward a visual target or the verbal identification of the target side. The results demonstrated that a motor response gave rise to the largest drop in perceptual sensitivity in detecting changes to the tactile display. In Experiment 2, we replicated these results under conditions in which the participants had to detect tactile changes while turning a steering wheel instead. These findings are discussed in terms of the role played by bodily movements, sensory suppression, and higher order information processing in modulating people’s awareness of tactile information across the body surface. (shrink)

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 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 . 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. (shrink)

Previous studies suggested that facial attractiveness perception can be increased with facial skin homogeneity improving; and human’s facial change detection increases along with facial skin homogeneity increases. However, it’s unknown whether a face can be perceived prettier than it did before while still being considered as physically the same. It is possible that these two kinds of cognitive-aesthetic processing may have separate mathematical functions in psychophysical studies. In other words, human’s facial attractiveness differentiation may be more sensitive than (...) facial change detection. In this current study, we explored the above questions. Using three types of psychophysical techniques to manipulate facial skin homogeneity, we measured how participants’ sensitivity to facial skin homogeneity and attractiveness change. Results showed a linear function curve for facial physical change detection and a logarithmic function curve was drawn in the forced-choice technique, which was the most sensitive one, indicating that participants can judge a face prettier than before without being aware of it has physically changed. Besides, two linear function curves were shown in the same/different technique and a rating technique. Taken together, this current study revealed that facial attractiveness can be enhanced and discriminated by improving facial skin homogeneity, without being realized by people with conscious awareness that the face has been changed. (shrink)

To investigate whether implicit detection occurs uniformly during change blindness with single or combination feature stimuli, and whether implicit detection is affected by exposure duration and delay, two one-shot change detection experiments are designed. The implicit detection effect is measured by comparing the reaction times of baseline trials, in which stimulus exhibits no change and participants report “same,” and change blindness trials, in which the stimulus exhibits a change but participants report (...) “same.” If the RTs of blindness trials are longer than those of baseline trials, implicit detection has occurred. The strength of the implicit detection effect was measured by the difference in RTs between the baseline and change blindness trials, where the larger the difference, the stronger the implicit detection effect. In both Experiments 1 and 2, the results showed that the RTs of change blindness trials were significantly longer than those of baseline trials. Whether under set size 4, 6, or 8, the RTs of the change blindness trials were significantly longer than those in the baseline trials. In Experiment 1, the difference between the baseline trials’ RTs and change blindness trials’ RTs of the single features was significantly larger than that of the combination features. However, in Experiment 2, the difference between the baseline trials’ RTs and the change blindness trials’ RTs of single features was significantly smaller than that of the combination features. In Experiment 1a, when the exposure duration was shorter, the difference between the baseline and change blindness trials’ RTs was smaller. In Experiment 2, when the delay was longer, the difference between the two trials’ RTs was larger. These results suggest that regardless of whether the change occurs in a single or a combination of features and whether there is a long exposure duration or delay, implicit detection occurs uniformly during the change blindness period. Moreover, longer exposure durations and delays strengthen the implicit detection effect. Set sizes had no significant impact on implicit detection. (shrink)

The near-interface region of an epitaxial Ba 0.3 Sr 0.7 TiO 3 thin film grown on LaAlO 3 was found to consist of a high density of stacking faults bounded by partial dislocations. The stacking faults can extend over large distances . Various possible atomic configurations of the faults were considered. The atomic structures of the faults were identified using high-resolution electron microscopy and simulation as well as energy-filtered imaging. The and faults were found to lie predominately on the {100} (...) and {110} planes. The faults on , or have never been observed before in perovskites. The stacking faults on {100} have a structure consisting of a double layer of edge-sharing TiO 6 octahedra. The excess of Ti was detected by energy-filtered imaging. The formation of the extended stacking faults is probably related to a small amount of excess Ti during the film deposition, which may originate from the non-stoichiometry of the ceramic targets BaTiO 3 and SrTiO 3 . It is also enhanced by the misfit-induced compressive strain in the early stages of the film growth. (shrink)