The effect of cueing on change blindness and same blindness

We used the change blindness paradigm of Landman, Spekreijse, and Lamme (2003) to measure the effect of cues on the ability to detect changes between two presentations of an array of eight rectangles separated by an interstimulus interval (ISI). Next, we measured the ability to detect sameness as the target rectangle remained the same when all of the others changed orientation. We were surprised to find no difference between change-detection and same-detection performance. These results (1) are consistent with the notion that some kind of internal representation was cued during the ISI, (2) mitigate against the recruitment of grouping strategies and/or forming a Gestalt, and (3) imply that under conditions facilitated by cues same-detection performance can be as good as change-detection performance.     

Culture and change blindness

Research on perception and cognition suggests that whereas East Asians view the world holistically, attending to the entire field and relations among objects, Westerners view the world analytically, focusing on the attributes of salient objects. These propositions were examined in the change-blindness paradigm. Research in that paradigm finds American participants to be more sensitive to changes in focal objects than to changes in the periphery or context. We anticipated that this would be less true for East Asians and that they would be more sensitive to context changes than would Americans. We presented participants with still photos and with animated vignettes having changes in focal object information and contextual information. Compared to Americans, East Asians were more sensitive to contextual changes than to focal object changes. These results suggest that there can be cultural variation in what may seem to be basic perceptual processes.     

The failure to detect tactile change: A tactile analogue of visual change blindness

A large body of empirical research now shows that people are surprisingly poor at detecting significant changes in visually presented scenes. This phenomenon is known aschange blindness in vision. A similar phenomenon occurs in audition, but to date no such effect has been documented in touch. In the present study, we explored the ability of people to detect changes introduced between two consecutively presented vibrotactile patterns presented over the body surface. The patterns consisted of two or three vibrotactile stimuli presented for 200 msec. The position of one of the vibrotactile stimuli composing the display was repeatedly changed (alternating between two different positions) on 50% of the trials, but the same pattern was presented repeatedly on the remaining trials. Three conditions were investigated: No interval between the patterns, an empty interval between the patterns, and a masked interval between the patterns. Change detection was near perfect in the no-interval block. Performance deteriorated somewhat in the empty-interval block, but by far the worst change detection performance occurred in the masked-interval block. These results demonstrate that “change blindness” can also affect tactile perception.     

The effects of scene inversion on change blindness

In two experiments, participants searched for a difference between two views of a scene. In Experiment 1, the authors extended the change-blindness findings from previous work by R. A. Rensink, J. K. O'Regan, and J. J. Clark (1997), which used an experimenter-induced global transient, to a less artificial situation in which participants searched for a difference in a pair of photographic images presented simultaneously. To examine the idea that meaning-driven endogenous orienting was responsible for the previously observed advantage for changes in center-of-interest items, the authors inverted half of the image pairs. The advantage for center-of-interest items was replicated with upright displays, but it was completely eliminated by inversion, strongly supporting the role of meaning-driven endogenous orienting in this task. With flickering displays (Experiment 2), the center-of-interest effect was completely unaffected by inversion. The authors suggest that when change blindness is induced via flicker, scene modifications are typically found by stimulus-driven rather than by meaning-driven processes.     

The role of figure-ground segregation in change blindness

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 on the characteristics of the new input. In our first experiment, we show that a display containing homogeneous image elements between changing images does not render the largecapacity representation unavailable. Interference occurs when these new elements define objects. On that basis we introduce a new method to produce change blindness: The second experiment shows that change blindness can be induced by redefining figure and background, without an interval between the displays. The local features (line segments) that defined figures and background were swapped, while the contours of the figures remained where they were. Normally, changes are easily detected when there is no interval. However, our paradigm results in massive change blindness. We propose that in a change blindness experiment, there is a large-capacity representation of the original image when it is followed by a homogeneous interval display, but that change blindness occurs whenever the changed image forces resegregation of figures from the background.     

Oscillatory motion induces change blindness

Change blindness is the relative inability of normally sighted observers to detect large changes in scenes when the low-level signals associated with those changes are either masked or of extremely low magnitude. Change detection can be inhibited by saccadic eye movements, artificial saccades or blinks, and 'mud splashes'. We now show that change detection is also inhibited by whole image motion in the form of sinusoidal oscillations. The degree of disruption depends upon the frequency of oscillation, which at 3 Hz is equivalent to that produced by artificial blinks. Image motion causes the retinal image to be blurred and this is known to affect object recognition. However, our results are inconsistent with good change detection followed by a delay due to poor recognition of the changing object. Oscillatory motion can induce eye movements that potentially mask or inhibit the low-level signals related to changes in the scene, but we show that eye movements promote rather than inhibit change detection when the image is moving.     

Priming effects under correct change detection and change blindness

In three experiments, we investigated the priming effects induced by an image change on a successive animate/inanimate decision task. We studied both perceptual (Experiments 1 and 2) and conceptual (Experiment 3) priming effects, under correct change detection and change blindness (CB). 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.     

Inhibition of return exaggerates change blindness

Peripheral cues trigger attention shifts, which facilitate perceptual processing and enhance visual awareness. However, this facilitation is superseded by an inhibition of return (IOR) effect, which biases attention away from the cued location. While the link between facilitatory effects of visual attention and awareness is well established, no study has reported negative effects of spatial cueing on visual awareness. This failure is puzzling, given the claim that attention is a necessary precondition for awareness. If attention is necessary for awareness, inhibiting attention should also inhibit awareness. This leads to a slightly counterintuitive prediction: Spatial cueing will inhibit awareness at long cue–target latencies. This study shows that subliminal peripheral cues exaggerate change blindness at long cue–change latencies, demonstrating that IOR can suppress visual awareness of changes and suggesting that IOR can directly affect the contents of consciousness.     

The development of change blindness: children's attentional priorities whilst viewing naturalistic scenes

Change blindness describes the surprising difficulty of detecting large changes in visual scenes when changes occur during a visual disruption. In order to study the developmental course of this phenomenon, a modified version of the flicker paradigm, based on Rensink, O’Regan & Clark (1997 ), was given to three groups of children aged 6–12 years and to a group of adults. This paradigm tested the ability to detect single colour, presence/absence and location changes of both high and low semantic importance in a complex scene. Semantically important changes were detected more quickly and accurately than less semantically important changes, by all age groups, indicating that children had the same attentional priorities as adults. Older children achieved more efficient and accurate detection of changes than younger children and reached almost adult level at 10–12 years old. These improvements parallel age‐related developments in attention and visual perception.     

Change blindness blindness: beliefs about the roles of intention and scene complexity in change detection

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.     

Changing scenes: memory for naturalistic events following change blindness

Research on scene perception indicates that viewers often fail to detect large changes to scene regions when these changes occur during a visual disruption such as a saccade or a movie cut. In two experiments, we examined whether this relative inability to detect changes would produce systematic biases in event memory. In Experiment 1, participants decided whether two successively presented images were the same or different, followed by a memory task, in which they recalled the content of the viewed scene. In Experiment 2, participants viewed a short video, in which an actor carried out a series of daily activities, and central scenes' attributes were changed during a movie cut. A high degree of change blindness was observed in both experiments, and these effects were related to scene complexity (Experiment 1) and level of retrieval support (Experiment 2). Most important, participants reported the changed, rather than the initial, event attributes following a failure in change detection. These findings suggest that attentional limitations during encoding contribute to biases in episodic memory.     

Drunk,but not blind: The effects of alcohol intoxication on change blindness

Alcohol use has long been assumed to alter cognition via attentional processes. To better understand the cognitive consequences of intoxication, the present study tested the effects of moderate intoxication (average BAC between .071 and .082) on attentional processing using complex working memory capacity (WMC) span tasks and a change blindness task. Intoxicated and sober participants were matched on baseline WMC performance, and intoxication significantly decreased performance on the complex span tasks. Surprisingly, intoxication improved performance on the change blindness task. The results are interpreted as evidence that intoxication decreases attentional control, causing either a shift towards more passive processing and/or a more diffuse attentional state. This may result in decreased performance on tasks where attentional control or focus are required, but may actually facilitate performance in some contexts.     

Perceptual conditions necessary to induce change blindness

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.     

Onset of illusory figures attenuates change blindness

We examined whether the onset of a new object defined by illusory contours is detected with greater frequency than offset when neither is associated with a unique sensory transient. Observers performed a “one-shot” change detection task in which offsetting or onsetting elements of high luminance contrast circles generated the appearance or disappearance of a Kanizsa figure. Presenting “illusory figures” via this “flicker” method ensures that (1) any unique luminance transients associated with the two types of change are eliminated, and (2) the objects themselves can only be represented at a relatively high level. Results showed that offsets were detected more frequently than onsets only when they generated the onset of a Kanizsa figure. We argue that object appearance dominates object disappearance via mechanisms that operate at the level at which objects are constructed.     

Evidence for preserved representations in change blindness

People often fail to detect large changes to scenes, provided that the changes occur during a visual disruption. This phenomenon, known as "change blindness," occurs both in the laboratory and in real-world situations in which changes occur unexpectedly. The pervasiveness of the inability to detect changes is consistent with the theoretical notion that we internally represent relatively little information from our visual world from one glance at a scene to the next. However, evidence for change blindness does not necessarily imply the absence of such a representation---people could also miss changes if they fail to compare an existing representation of the pre-change scene to the post-change scene. In three experiments, we show that people often do have a representation of some aspects of the pre-change scene even when they fail to report the change. And, in fact, they appear to "discover" this memory and can explicitly report details of a changed object in response to probing questions. The results of these real-world change detection studies are discussed in the context of broader claims about change blindness.     

Global transsaccadic change blindness during scene perception

Each time the eyes are spatially reoriented via a saccadic eye movement, the image falling on the retina changes. How visually specific are the representations that are functional across saccades during active scene perception? This question was investigated with a saccade-contingent display-change paradigm in which pictures of complex real-world scenes were globally changed in real time during eye movements. The global changes were effected by presenting each scene as an alternating set of scene strips and occluding gray bars, and by reversing the strips and bars during specific saccades. The results from two experiments demonstrated a global transsaccadic change-blindness effect, suggesting that point-by-point visual representations are not functional across saccades during complex scene perception.     

Shuffling your way out of change blindness

Change detection is typically discussed in the literature as a 2-state phenomenon. Small differences between otherwise identical images are easy to detect when the images are superimposed in space and alternated in time (“shuffled”). However, change blindness results from any disruption that prevents the critical change from generating the sole salient transient. Here we show that different presentation strategies produce different degrees of change blindness for the same change. Specifically, shuffling the images supports faster change detection than viewing the same 2 images side by side, even when the images contain a number of distracting differences. In Experiment 1, pairs of photographs having a 50 % chance of containing a difference were viewed either in alternation, in a “Shuffle” condition, or simultaneously, in a “Side-by-Side” condition. Change detection was about 6 seconds faster when the images were viewed in the “Shuffle” mode. In Experiment 2, we presented two images that were slightly laterally shifted relative to each other (0–48 pixels). The RT benefit for the Shuffle viewing mode was very strong when the relative shift was small, to insignificant when there was a large difference between the two images. However, at large shifts, Shuffle maintained an accuracy advantage. It seems that changes are easier to detect when comparing images in a Shuffle condition rather than Side-by-Side. This has important implications for real world tasks like radiology where detection of change is critical.     

Crossmodal change blindness between vision and touch

Change blindness is the name given to people's inability to detect changes introduced between two consecutively-presented scenes when they are separated by a distractor that masks the transients that are typically associated with change. Change blindness has been reported within vision, audition, and touch, but has never before been investigated when successive patterns are presented to different sensory modalities. In the study reported here, we investigated change detection performance when the two to-be-compared stimulus patterns were presented in the same sensory modality (i.e., both visual or both tactile) and when one stimulus pattern was tactile while the other was presented visually or vice versa. The two to-be-compared patterns were presented consecutively, separated by an empty interval, or else separated by a masked interval. In the latter case, the masked interval could either be tactile or visual. The first experiment investigated visual-tactile and tactile-visual change detection performance. The results showed that in the absence of masking, participants detected changes in position accurately, despite the fact that the two to-be-compared displays were presented in different sensory modalities. Furthermore, when a mask was presented between the two to-be-compared displays, crossmodal change blindness was elicited no matter whether the mask was visual or tactile. The results of two further experiments showed that performance was better overall in the unimodal (visual or tactile) conditions than in the crossmodal conditions. These results suggest that certain of the processes underlying change blindness are multisensory in nature. We discuss these findings in relation to recent claims regarding the crossmodal nature of spatial attention.     

Look at them and they will notice you: Distractor-independent attentional capture by direct gaze in change blindness

Humans have shown a detection advantage of direct vs. averted gaze stimuli in visual search tasks. However, instead of attentional capture by direct gaze, the detection advantage in visual search may depend on attention-grabbing potential of the distractor stimuli to which the target needs to be compared. We investigated attentional capture by direct gaze using the change blindness paradigm, in which successful detection does not require comparison between the target and the distractor items. Participants detected a masked gaze direction change in one of four simultaneously presented schematic faces. The distractor gaze directions were systematically varied across three experiments. Changes resulting in direct gaze were detected more efficiently than those resulting in averted gaze, independently of distractor gaze directions. This finding suggests that the detection advantage is specifically due to attentional capture by direct gaze, not properties of distractor items.