Disambiguating ambiguous figures by selective attention

The present study was designed to investigate the hypothesis that the formation of a given percept of an ambiguous figure results from focusing attention on a focal area that contains features significant for this percept but not for the alternative one. Two such focal areas were designated for the two competing interpretations of the bird/plane and duck/rabbit ambiguous figures. Detecting a letter following the figure was faster when the letter appeared in the focal area of the perceived interpretation than in the focal area of the alternative one. Furthermore, directing attention to a given focal area shortly before the presentation of the figure increased the likelihood of forming the corresponding interpretation rather than the alternative one. Results suggest that maintaining different interpretations of the same ambiguous figure is mediated by focusing attention on different parts of the figure.     

Children's understanding that ambiguous figures have multiple interpretations

In three experiments we compared 5- and 6-year-old children's understanding of multiple interpretations arising from an ambiguous figure (e.g., the duck/rabbit) and other ambiguous partial input. Children found it equally easy to switch between alternative interpretations of ambiguous figures and partial views (Experiment 1, N = 19) and more difficult to accept two characters' conflicting interpretations of ambiguous figures, than partial views (Experiment 2, N = 29). Children found it more difficult to accept explicitly that one stimulus could simultaneously give rise to two interpretations, than to switch between them (Experiment 3, N = 40). Children's handling of multiple interpretations was not primarily affected by the type of input, but results suggest that there are two distinct stages in children's handling of multiple interpretations.     

Seeing and liking: Biased perception of ambiguous figures consistent with the “inward bias” in aesthetic preferences

Aesthetic preferences are ubiquitous in visual experience. Indeed, it seems nearly impossible in many circumstances to perceive a scene without also liking or disliking it to some degree. Aesthetic factors are only occasionally studied in mainstream vision science, though, and even then they are often treated as functionally independent from other aspects of perception. In contrast, the present study explores the possibility that aesthetic preferences may interact with other types of visual processing. We were inspired, in particular, by the inward bias in aesthetic preferences: When an object with a salient “front” is placed near the border of a frame (say, in a photograph), observers tend to find the image more aesthetically pleasing if the object faces inward (toward the center) than if it faces outward (away from the center). We employed similar stimuli, except that observers viewed framed figures that were ambiguous in terms of the direction they appeared to be facing. The resulting percepts were influenced by the frames in a way that corresponded to the inward bias: When a figure was placed near a frame’s border, observers tended to see whichever interpretation was facing inward. This effect occurred for both abstract geometric figures (e.g., ambiguously-oriented triangles) and meaningful line drawings (e.g., left-facing ducks or right-facing rabbits). The match between this new influence on ambiguous figure perception and the previously studied aesthetic bias suggests new ways in which aesthetic factors may relate not only to what we like, but also to what we see in the first place.     

What an image depicts depends on what an image means.

Previous research has shown that subjects visually imaging the classical ambiguous figures have great difficulty in reconstruing these images. To explain this finding, we propose that subjects' construal of their image strongly influences what is depicted in the image, leading to the inclusion of some aspects of an imaged figure and the exclusion of others. Thus, images of (supposedly) ambiguous figures may literally omit information necessary for the reconstrual. To test this claim, we asked subjects to form an image of the duck/rabbit figure, and then to compare their image to drawings that departed slightly from the original figure. We hypothesized that subjects would have a clear image of the side of the figure they understood as the "face" (the left side if the image is understood as a duck, the right side for the rabbit). Conversely, subjects would have only a vague image of the "back" of the head. Consequently, in comparing their image to test stimuli, subjects should be able to detect variations in the contour of the "face," but not in the contour of the "back" of the animal's head. These predictions were confirmed, strongly suggesting that the construal of an image does dictate what is depicted within the image.     

How to keep a reversible figure from reversing: teasing out top-down and bottom-up processes

The nature of processes underlying our perception of reversible figures was examined through two experiments investigating the effects of prior exposure conditions on an observer's report of figural reversal. In experiment 1, observers were adapted over several minutes to an unambiguous version of a rotating Necker cube prior to the presentation of the standard ambiguous figure. Results indicated that adaptation produced an immediate bias to perceive the ambiguous figure in the opposite configuration (ie reverse bias) and to reduce reports of reversal over the test period. The introduction of a brief delay between the adaptation and test periods revealed that this bias is a highly transient effect and is only clearly evident when the adaptation and test figures are matched in size. In experiment 2, observers were primed with an unambiguous figure for a few seconds prior to the presentation of the standard ambiguous figure. In this case, the obtained bias strongly favored the observer's reporting the ambiguous figure to be in the same configuration as the adapting figure (ie positive bias); and neither introducing a delay period nor changing figure size had any effect. We conclude that these experiments reveal the distinct roles of transient, retinally localized neural processes as well as more stable, global processes under specifiable conditions.     

Children's understanding of ambiguous figures: Which cognitive developments are necessary to experience reversal?

In two experiments involving one hundred and thirty-eight 3- to 5-year-olds we examined the claim that a complex understanding of ambiguity is required to experience reversal of ambiguous stimuli [Gopnik, A., & Rosati, A. (2001). Duck or rabbit? Reversing ambiguous figures and understanding ambiguous representations. Developmental Science, 4, 175–183]. In Experiment 1 a novel Production task measured the ability to acknowledge both interpretations of ambiguous figures. This was as easy as and significantly correlated with a False Belief task, and easier than a Droodle task. We replicated this finding in Experiment 2, and also found that perceiving reversal of ambiguous figures was harder than either the False Belief or Production tasks. In contrast to previous findings, the Reversal and Droodle tasks were not specifically related. We conclude that children only attempt reversal once they can understand the representational relationship between the figure and its two interpretations. The process resulting in reversal however is hard, probably requiring additional developments in executive functioning and imagery abilities.     

Can People Creative in Imagery Interpret Ambiguous Figures Faster than People Less Creative in Imagery?

The purpose of the research study was to investigate whether people creative in imagery are better than people non‐creative in imagery at interpreting ambiguous figures. Creativity, in the imagery paradigm, is said to involve two processes: combinational play and discovery. Discovery plays a major role in creativity as it is the process of discerning, judging or interpreting the value of a mental construction. Furthermore, creative people have been said to be insightful thus supporting the proposition advanced here that people creative in imagery are faster at interpreting and finding alternative interpretations for ambiguous figures than people less creative in imagery. This study reports both latencies and discoveries in perception and mental imagery as measured on a figure combination task. The data support the conclusion that people creative in imagery are more capable in reinterpreting ambiguous figures and that they are quicker in their discoveries than people less creative in imagery. The analysis to the questions of how the subjects arrived at their discoveries may also illustrate the Gestalt literature on insight as a rapid pattern recognition.     

Ambiguous figure perception and theory of mind understanding in children with autistic spectrum disorders

Researchers in early social‐cognition have found that the ability to reverse an ambiguous figure is correlated with success on theory of mind tasks (e.g. Gopnik & Rosati, 2001 ). The present experiment examined children with autistic spectrum disorders (ASD) without mental delay to see whether a similar relationship existed. Ropar, Mitchell, and Ackroyd (2003) demonstrated that children with ASD with mental delay were impaired on theory of mind tasks, but were as likely as mentally delayed controls to generate both interpretations of an ambiguous figure when informed of its ambiguity. The present study replicated this finding on children with ASD without mental delay. However, overall perception of ambiguous figures was different. These children were less likely to spontaneously generate both interpretations of the figure, and more likely to perseverate on a single interpretation than the comparison children. Like Ropar et al., we found no correlation between theory of mind and informed reversals, but spontaneous reversals were correlated with performance on an advanced theory of mind task. These data suggest that reversals of ambiguous figures are linked to higher‐level representational abilities, which might also be involved in social functioning, and impaired in children with ASD.     

Self-generated visual imagery alters the mere exposure effect

To determine whether self-generated visual imagery alters liking ratings of merely exposed stimuli, 79 college students were repeatedly exposed to the ambiguous duck—rabbit figure. Half the participants were told to picture the image as a duck and half to picture it as a rabbit. When participants made liking ratings of both disambiguated versions of the figure, they rated the version consistent with earlier encoding more positively than the alternate version. Implications of these findings for theoretical models of the exposure effect are discussed.     

The relationship between bilingualism and selective attention in young adults: Evidence from an ambiguous figures task

Previous research has shown that bilinguals outperform monolinguals on a variety of tasks that have been described as involving executive functioning, but the precise mechanism for those effects or a clear definition for “executive function” is unknown. This uncertainty has led to a number of studies for which no performance difference between monolingual and bilingual adults has been detected. One approach to clarifying these issues comes from research with children showing that bilinguals were more able than their monolingual peers to perceive both interpretations of an ambiguous figure, an ability that is more tied to a conception of selective attention than to specific components of executive function. The present study extends this notion to adults by assessing their ability to see the alternative image in an ambiguous figure. Bilinguals performed this task more efficiently than monolinguals by requiring fewer cues to identify the second image. This finding has implications for the role of selective attention in performance differences between monolinguals and bilinguals.     

Perceiving depth in point-light actions

The present study investigates how observers assign depth in point-light figures, by manipulating spatiotemporal characteristics of the stimuli. Previous research on the perception of point-light walkers revealed bistability (i.e., that a point-light walker is perceived as either facing the viewer or facing away from the viewer) and the presence of a perceptual bias (i.e., a tendency to perceive the figure as facing the viewer). Here, we study the generality of these phenomena by having observers indicate the global depth orientation of different ambiguous point-light actions. Results demonstrate bistability for all actions, but the presence of a preferred interpretation depends strongly on the performed action, showing that the process of depth assignment takes into account the movements the point-light figure performs. Two additional experiments, using unfamiliar movement patterns without strong semantic correlates, show that purely kinematic aspects of a naction also strongly affect d epth assignment. Together, the results reveal the perception of depth in point-light figures to be a flexible processinvolving both bottom-up and top-down components.     

Multiplicative effects of intention on the perception of bistable apparent motion

When viewing ambiguous displays, observers can, via intentional efforts, affect which perceptual interpretation they perceive. Specifically, observers can increase the probability of seeing the desired percept. Little is known, however, about how intentional efforts interact with sensory inputs in exerting their effects on perception. In two experiments, the current study explored the possibility that intentional efforts might operate by multiplicatively enhancing the stimulus-based activation of the desired perceptual representation. Such a possibility is suggested by recent neurophysiological research on attention. In support of this idea, when we presented bistable apparent motion displays under stimulus conditions differentially favoring one motion percept over the other, observers' intentional efforts to see a particular motion were generally more effective under conditions in which stimulus factors favored the intended motion percept.     

The eyeglass reversal

Some figures, such as the Necker cube, are spontaneously reversible between alternative percepts. Before learning those skilled reversals, how do people achieve reversals for the very first time? It has been known that, in the case of a first reversal, peoplecan be expected to see the reversal when given specific information about how the figuresareambiguous. This point was confirmed by using drawing versions of reversible figures. To demonstrate how intention plays a role in the initial reversal of a real object, a pair of regular eyeglasses, reversible in perspective, were presented to naïve observers in monocular vision. When the eyeglasses were viewed inwardly and the observers were given information that the eyeglasses could be ambiguous, they were able to easily see the reversal. When the eyeglasses were viewed outwardly, observers saw it only after they had been informed of exactly what the two alternative percepts were.Interestingly, many observers often mistakenly saw the inwardly viewed eyeglasses as placed outwardly from the beginning of the observation, while they saw the outwardly viewed eyeglasses correctly. Taking these results together, for the first reversal of a real object, the specificity of intention varies with the ambiguity of the object.     

Mental images can be ambiguous: Reconstruals and reference-frame reversals

Philosophers and psychologists have debated whether or not mental images of ambiguous figures are reversible as pictures of such figures are. Previously, empirical evidence both pro (Finke, Pinker, & Farah, 1989) and con (Chambers & Reisberg, 1985) has been obtained. In a series of four experiments, we identify the conditions under which images of classic ambiguous figures like the duck/rabbit and the snail/elephant are reversible. We distinguish between two types of reversal: those that entail a change in reference-frame specification as well as a reconstrual of image components (reference-frame realignments) and those that entail reconstruals only (reconstruals). We show that reference-frame realignments can occur in imagery, particularly if observers are given an explicit or an implicit suggestion; and that reconstruals of images occur commonly, regardless of experimental conditions. In addition, we show that images constructed from good parts are more likely to reverse than images constructed from poor parts. On the basis of these results, we propose a functional organization of shape memory that is consistent with shape recognition findings as well as with our reversal findings.     

Illusory figures based on local kinematics.

A new type of motion-induced illusory figure determined by local kinematic information is investigated. The new figure is induced by radial line patterns subjected to either figure motion (the lines change as if they were stationary and a triangle was rotating in front of them) or background motion (the lines change as if they were being rotated behind a stationary triangle). Although the two kinds of motion are equivalent from the viewpoint of relative displacements, perceptually they yield very different results. With background motion, observers tend to perceive rigid figures that have a triangular shape. With figure motion, observers report seeing deforming figures with shapes that vary depending on the number of lines in the display. We consider two alternative accounts for this asymmetry which we term the background superiority effect (BSE). The first account proposes that the effect is due to retinal persistence and to figure stability. Against this line of explanation, we demonstrate that observers also see rigid triangular shapes in displays where both the figure and the radial lines rotate (double motion displays). The second account proposes that the effect depends on the availability of local kinematic information constraining contour orientation. This second line of explanation is consistent with observers' reports of bowed edges in double motion displays rotating in phase or in counterphase. Candidate mechanisms for extracting local kinematic information are discussed.     

Visual mental images can be ambiguous: insights from individual differences in spatial transformation abilities

The debate about whether objects in mental images can be ambiguous has produced ambiguous results. In some studies, participants could not reinterpret objects in images, but even in the studies where participants could reinterpret visualized patterns, the results are not conclusive. The present study used a novel task to investigate the reinterpretation of ambiguous figures in imagery, which required the participants to mentally rotate a figure 180 degrees before attempting to "see" an alternate interpretation. In addition, the participants did not know the purpose of the study in advance, nor did they see alternate interpretations of the stimuli; moreover, we explicitly measured individual differences in key mental imagery abilities. Eight of the 44 participants discovered the alternate version while they were memorizing the figure; 16 reported it after mentally rotating an image; and 20 were not able to "see" the alternate version. The ability to rotate images, assessed with an independent task, was highly associated with reports of image reversals, whereas measures of other imagery abilities were not.     

Asymmetric priming effects in visual processing of occlusion patterns

In three experiments, we examined the effect of temporal context in amodal completion of partly occluded nontarget figures. In a primed same-different task, test pairs were preceded by a sequence of two primes, one of which was a single, the other a composite figure. Single figures reappeared in the composite ones, which also contained a square that could be viewed, alternatively, as an occluder or as yielding a mosaic fit to the other shape. To measure context influences between single and composite figures, both of which were nontargets, we studied their combined effect as primes on the test pairs of the same-different task, expecting that congruency between both primes should lead to a superadditive priming effect on the task. We found that single figures presented first provided facilitatory context for local and global occlusion as well as for mosaic interpretations of subsequently presented composite figures. These effects occurred only when the composite figure was presented briefly (50 msec). No superadditive facilitation occurred when composite figures were presented first and single figures followed them. The restriction of the effect to short presentations and its temporal asymmetry were taken as evidence that prior context biases possible occlusion interpretations during the process of completion, rather than afterward.     

Illusory contour figures are perceived as occluding surfaces by 8‐month‐old infants

Infants have been demonstrated to be able to perceive illusory contours in Kanizsa figures. This study tested whether they also perceive these illusory figures as having the properties of real objects, such as depth and capability of occluding other objects. Eight‐ and five‐month‐old infants were presented with scenes that included a Kanizsa square and further depth cues provided by the deletion and accretion pattern of a moving duck. The 8‐month‐old infants looked significantly longer at the scene when the two types of occlusion cues were inconsistent than when they were consistent with each other, which provides evidence that they interpreted the Kanizsa square as a depth cue. In contrast, 5‐month‐olds did not show this difference. This finding demonstrates that 8‐month‐olds perceive the figure formed by the illusory contours as having properties of a real object that can act as an occluder.