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We examined whether symmetry-based grouping can take place in the absence of visual awareness. To this end, we used a priming paradigm, sandwich masking as an invisibility-inducing method, and primes and targets composed of two vertical... more
We examined whether symmetry-based grouping can take place in the absence of visual awareness. To this end, we used a priming paradigm, sandwich masking as an invisibility-inducing method, and primes and targets composed of two vertical symmetric or asymmetric lines. The target could be congruent or incongruent with the prime in symmetry. In Experiment 1, participants were presented with masked primes and clearly visible targets. In each trial, the participants performed a two-alternative discrimination task on the target, and then rated the visibility of the prime on a subjective visibility four-point scale (used to assess prime awareness). Subjectively invisible primes failed to produce response priming, suggesting that symmetry processing might depend on visual awareness. However, participants barely saw the prime, and the results for the visible primes were inconclusive, even when we used a conservative criterion for awareness. To rule out the possibility that our prime stimuli ...
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In visual crowding, identification of a peripheral object is impaired by nearby objects. Recent studies have demonstrated that crowding is not limited only to interaction between low-level features or parts, as presumed by most models of... more
In visual crowding, identification of a peripheral object is impaired by nearby objects. Recent studies have demonstrated that crowding is not limited only to interaction between low-level features or parts, as presumed by most models of crowding, but can also occur between high-level, configural representations of objects. In this study we show that the relative strength of crowding at the part level versus the configural level is dependent on the strength of the target's perceptual organization. The target's strength of organization was manipulated by presence or absence of closure and good continuation or by proximity between the target's parts. The flankers were similar either to the target parts or to the target configuration. The stronger the target's organization was, the weaker the crowding was by part flankers (Experiments 1 and 2). Most importantly, the target's strength of organization interacted with target-flanker similarity, such that crowding by ta...
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An early functional onset of perceptual completion has been extensively documented during the first several months after birth. However, there is no indication for the developmental time periods at which these skills become fully... more
An early functional onset of perceptual completion has been extensively documented during the first several months after birth. However, there is no indication for the developmental time periods at which these skills become fully developed. We used a version of an object-based attention task in which children and adults performed a same-different size judgment of two features appearing at two of four possible ends of overlapping objects. Single-object over two-object superiority (i.e., faster judgments when the features appeared on the same object than when they appeared on different objects) was observed for a complete object as early as at 4 years of age. However, it is only at 5 years of age that such a single-object advantage was obtained also for an occluded object, and even then the advantage of the single-object and occluded-object conditions over the two-object condition was observed only when the two features in the two-object condition were spatially distant, demonstrating...
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In this study we examined whether grouping by luminance similarity and grouping by connectedness can occur in the absence of visual awareness, using a priming paradigm and two methods to render the prime invisible, CFS and sandwich... more
In this study we examined whether grouping by luminance similarity and grouping by connectedness can occur in the absence of visual awareness, using a priming paradigm and two methods to render the prime invisible, CFS and sandwich masking under matched conditions. For both groupings, significant response priming effects were observed when the prime was reported invisible under sandwich masking, but none were obtained under CFS. These results provide evidence for unconscious grouping, converging with previous findings showing that visual awareness is not essential for certain perceptual organization processes to occur. They are also consistent with findings indicating that processing during CFS is limited, and suggest the involvement of higher visual areas in perceptual organization. Moreover, these results demonstrate that whether a process can occur without awareness is dependent on the level at which the suppression induced by the method used for rendering the stimulus inaccessib...
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Interest in the study of attention control under dichoptic conditions is instigated by the contemporary development of night-vision systems based on single-eye helmet-mounted displays. Two experiments were conducted to investigate the... more
Interest in the study of attention control under dichoptic conditions is instigated by the contemporary development of night-vision systems based on single-eye helmet-mounted displays. Two experiments were conducted to investigate the concurrent performance of a tracking task and letter classification under dichoptic display conditions. Subjects were required to fly a simulated helicopter path while classifying letter pairs presented intermittently. Experimental instructions in Experiment A specifically emphasized a two-dimensional interpretation of the visual field. Under these instructions, the presentation of a common visual axis to the two eyes provided by the flight-tunnel did not aid subjects, and their performance deteriorated in dichoptic conditions. In Experiment B, the instructions to subjects were changed to advocate a three-dimensional interpretation of the display. Under these instructions, dichoptic performance-levels were substantially improved when the tunnel was pre...
We examined the possible dissociation between two modes of valence: affective valence (valence of e emotional response) and semantic valence (stored knowledge about valence of an object or event). In Experiment 1, 50 participants viewed... more
We examined the possible dissociation between two modes of valence: affective valence (valence of e emotional response) and semantic valence (stored knowledge about valence of an object or event). In Experiment 1, 50 participants viewed affective pictures that were repeatedly presented while their facial electromyography (EMG) activation and heart rate response were continuously recorded. Half of the participants provided self-report ratings about the valence of their feelings and half about the valence of the stimulus. Next, all participants performed an affective Simon task. In Experiment 2, 30 new participants performed the affective Simon task with the repeated exposure embedded within the task. The results showed that measures related to affective valence (feelings-focused self-reports, heart rate, and facial EMG activations) attenuated with repeated exposure to pleasant and unpleasant pictures, whereas measures related to semantic valence (knowledge-focused self-reports and congruency effect of affective Simon task) did not. These findings strongly suggest that affective and semantic valence represent two distinct psychological constructs. (PsycINFO Database Record
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Two scales were constructed to separately evaluate the perceptual and motor difficulty of the finger chords employed to enter letters in a newly designed chord keyboard, developed to provide an efficient alternative to the existing QWERTY... more
Two scales were constructed to separately evaluate the perceptual and motor difficulty of the finger chords employed to enter letters in a newly designed chord keyboard, developed to provide an efficient alternative to the existing QWERTY keyboard. The index of motor difficulty evaluated the biomechanical problems associated with the execution of the 31 possible chord combinations of five-fingers. The perceptual index scaled the difficulty of identifying the spatial pattern created by each of the 31 chords. A regression equation that was based on the two indexes accounted for about 60% of the variance of actual typing on the chord keyboard. Perceptual and motor determinants appear to be equally potent and mostly independent in their influence on efficient data entry performance.
Page 1. PROCEEDINGS of the HUMAN FACTORS SOCIETY 33rd ANNUAL MEETING-1989 ATTENTION IN DICHOPTIC AND BINOCULAR VISION Ruth Kimchi Department of Psychology University of Haifa Haifa, 31999, Israel ...
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Previous research on the competition between grouping organizations focused mainly on their relative strength as measured by subjective reports of the final percept. Considerably less is known about the underlying representations of the... more
Previous research on the competition between grouping organizations focused mainly on their relative strength as measured by subjective reports of the final percept. Considerably less is known about the underlying representations of the competing organizations. We hypothesized that when more than 1 organization is possible, multiple representations are constructed for the alternative organizations. We tested this hypothesis using the primed-matching paradigm. Our primes depicted either a single grouping principle (grouping into columns or rows by brightness similarity, connectedness, or proximity) or 2 grouping principles (brightness similarity and connectedness, or brightness similarity and proximity) that led to competing organizations (e.g., grouping into columns by brightness similarity and into rows by connectedness, or vice versa). The time course of representation construction was examined by varying prime duration. Significant priming effects of similar magnitude were found for the individual grouping organizations. These effects were modified when 2 competing organizations were present in the prime, indicating that both organizations were represented and competed for dominancy. (PsycINFO Database Record
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Nelson and Palmer (2007) concluded that figures/figural properties automatically attract attention, after they found that participants were faster to detect/discriminate targets appearing where a portion of a familiar object was suggested... more
Nelson and Palmer (2007) concluded that figures/figural properties automatically attract attention, after they found that participants were faster to detect/discriminate targets appearing where a portion of a familiar object was suggested in an otherwise ambiguous display. We investigated whether these effects are truly automatic and whether they generalize to another figural property-convexity. We found that Nelson and Palmer's results do generalize to convexity, but only when participants are uncertain regarding when and where the target will appear. Dependence on uncertainty regarding target location/timing was also observed for familiarity. Thus, although we could replicate and extend Nelson and Palmer's results, our experiments showed that figures do not automatically draw attention. In addition, our research went beyond Nelson and Palmer's, in that we were able to separate figural properties from perceived figures. Because figural properties are regularities that p...
Research Interests: Psychology, Cognitive Science, Attention, Uncertainty, Humans, and 4 moreFemale, Male, Young Adult, and Adult
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Research Interests: Cognitive Science, Cognition, Face Recognition, Face, Cognitive Neuroscience, and 15 moreCognitive, Brain Mapping, Humans, Female, Face processing, Functional Imaging, Adult, Analysis of Variance, Functional Neuroimaging, Fusiform Gyrus, Block Design, Line Drawings, Brain Damage, Case Control Studies, and Functional Laterality
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We used primed matching to examine the microgenesis of perceptual organization for familiar (upright letters) and unfamiliar (inverted letters) visual configurations that varied in the connectedness between their line components. The... more
We used primed matching to examine the microgenesis of perceptual organization for familiar (upright letters) and unfamiliar (inverted letters) visual configurations that varied in the connectedness between their line components. The configurations of upright letters were available for priming as early as 40 ms, irrespective of connectedness between their line components. The configurations of connected inverted-letter primes were also available this early, but the configurations of disconnected inverted letters were not available until later These results show that past experience contributes to the early grouping of disconnected line segments into configurations. These findings suggest an interactive model of perceptual organization in which both image-based properties (e.g., connectedness) and input from object memories contribute to perceptual organization.
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Three experiments investigated subjects' ability to allocate attention and cope with task requirements under dichoptic versus binocular viewing conditions. Experiments 1 and 2 employed a target detection task in compound and... more
Three experiments investigated subjects' ability to allocate attention and cope with task requirements under dichoptic versus binocular viewing conditions. Experiments 1 and 2 employed a target detection task in compound and noncompound stimuli, and Experiment 3 employed a relative-proximity judgment task. The tasks were performed in a focused attention condition in which subjects had to attend to the stimulus presented to one eye or field (under dichoptic and binocular viewing conditions, respectively) while ignoring the stimulus presented to the other eye or field, and in a divided attention condition in which subjects had to attend the stimuli presented to both eyes or fields. Subjects' performance was affected by the interaction of attention conditions with task requirements, but it was generally the same under dichoptic and binocular viewing conditions. The more dependent the task was on finer discrimination, the more performance was impaired by divided attention. These...
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Perceptual organization--the processes structuring visual information into coherent units--and visual attention--the processes by which some visual information in a scene is selected--are crucial for the perception of our visual... more
Perceptual organization--the processes structuring visual information into coherent units--and visual attention--the processes by which some visual information in a scene is selected--are crucial for the perception of our visual environment and to visuomotor behavior. Recent research points to important relations between attentional and organizational processes. Several studies demonstrated that perceptual organization constrains attentional selectivity, and other studies suggest that attention can also constrain perceptual organization. In this chapter I focus on two aspects of the relationship between perceptual organization and attention. The first addresses the question of whether or not perceptual organization can take place without attention. I present findings demonstrating that some forms of grouping and figure-ground segmentation can occur without attention, whereas others require controlled attentional processing, depending on the processes involved and the conditions prevailing for each process. These findings challenge the traditional view, which assumes that perceptual organization is a unitary entity that operates preattentively. The second issue addresses the question of whether perceptual organization can affect the automatic deployment of attention. I present findings showing that the mere organization of some elements in the visual field by Gestalt factors into a coherent perceptual unit (an "object"), with no abrupt onset or any other unique transient, can capture attention automatically in a stimulus-driven manner. Taken together, the findings discussed in this chapter demonstrate the multifaceted, interactive relations between perceptual organization and visual attention.
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Studies of the perceptual performance of individuals with autism have focused, to a large extent, on two domains of visual behavior, one associated with face processing and the other associated with global or holistic processing. Whether... more
Studies of the perceptual performance of individuals with autism have focused, to a large extent, on two domains of visual behavior, one associated with face processing and the other associated with global or holistic processing. Whether autistic individuals differ from neurotypical individuals in these domains is debatable and, moreover, the relationship between the behaviors in these two domains remains unclear. We first compared the face processing ability of 14 adult individuals with autism with that of neurotypical controls and showed that the autistic individuals were slowed in their speed of face discrimination. We then showed that the two groups differed in their ability to derive the global whole in two different tasks, one using hierarchical compound letters and the other using a microgenetic primed matching task with geometric shapes, with the autistic group showing a bias in favor of local information. A significant correlation was also observed between performance on the face task and the configural tasks. We then confirmed the prediction that the ability to derive the global whole is not only critical for faces but also for other objects as well, as the autistic individuals performed more slowly than the control group in discriminating between objects. Taken together, the results suggest that the bias for local processing seen in autistic individuals might have an adverse impact on their ability to process faces and objects.
Research Interests: Cognitive Science, Face, Objects, Humans, Faces, and 15 moreFemale, Face processing, Male, Mental processes, Configural Processing, Middle Aged, Adult, Neuropsychologia, Individual Difference, Neurosciences, Control Group, Case Control Studies, Neuropsychological Tests, Autistic disorder, and photic stimulation
ABSTRACT The role of top-down processes in general, and of attention in particular, in object recognition is a controversial issue. The study of object recognition has focused mainly on bottom-up processes that analyze the visual input... more
ABSTRACT The role of top-down processes in general, and of attention in particular, in object recognition is a controversial issue. The study of object recognition has focused mainly on bottom-up processes that analyze the visual input (Peissig & Tarr. 2007). Findings that object recognition is remarkably fast (Thorpe, Fize & Marlot, 1996), have been taken by some researchers as evidence that object recognition can occur largely with feed-forward processing alone. Moreover, some studies demonstrated that object recognition can be accomplished in the near absence of attention (Li et al, 2002). Some proposals, however, have challenged the “strictly bottom-up” view (Bar, 2003), suggesting top-down influences on the recognition process. A few studies suggested specifically that top-down attention is involved in object recognition (Evans & Treisman, 2005). The present work was motivated by a framework that treats object recognition as a process of discrimination between probable alternatives, in which bottom-up and top-down processes interact (iteratively when necessary), with attention playing a crucial role in this interaction. A series of experiments tested the basic hypothesis derived from this framework: in the course of object recognition attention is directed to distinguishing features— features that are diagnostic of object identity in a particular context (Experiment 1-3). As distinguishing features are not necessarily the most salient features, there may be competition between bottom-up (salience-based) and top-down (goal-driven) influences on attention, resolved by a goal-driven bias toward task-relevant information (i.e. the distinguishing features) (Experiment 4). In all experiments, observers performed a recognition task of artificial fish, and differences in the allocation of attention to distinguishing and non-distinguishing features were examined using several methods, including primed-matching, visual probe, and spatial cuing.
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The relative dominance of component and configural properties in face processing is a controversial issue. We examined this issue by testing whether the discriminability of components predicts the discrimination of faces with similar... more
The relative dominance of component and configural properties in face processing is a controversial issue. We examined this issue by testing whether the discriminability of components predicts the discrimination of faces with similar versus dissimilar configurations. Discrimination of faces with similar configurations was determined by components discriminability, indicating independent processing of facial components. The presence of configural variation had no effect on discriminating faces with highly discriminable components, suggesting that discrimination was based on the components. The presence of configural variation, however, facilitated the discrimination of faces with more difficult-to-discriminate components, above and beyond what would be predicted by the configural or componential discriminability, indicating interactive processing. No effect of configural variation was observed in discriminating inverted faces. These results suggest that both component and configural properties contribute to the processing of upright faces and no property necessarily dominates the other. Upright face discrimination can rely on components, configural properties, or interactive processing of component and configural properties, depending on the information available and the discriminability of the properties. Inverted faces are dominated by componential processing. The finding that interactive processing of component and configural properties surfaced when the properties were of similar, not very high discriminability, suggests that such interactive processing may be the dominant form of face processing in everyday life.
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Perception of object continuity depends on establishing correspondence between objects viewed across disruptions in visual information. The role of spatiotemporal information in guiding object continuity is well documented; the role of... more
Perception of object continuity depends on establishing correspondence between objects viewed across disruptions in visual information. The role of spatiotemporal information in guiding object continuity is well documented; the role of surface features, however, is controversial. Some researchers have shown an object-specific preview benefit (OSPB)-a standard index of object continuity-only when correspondence could be based on an object's spatiotemporal information, whereas others have found color-based OSPB, suggesting that surface features can also guide object continuity. This study shows that surface feature-based OSPB is dependent on the task memory demands. When the task involved letters and matching just one target letter to the preview ones, no color congruency effect was found under spatiotemporal discontinuity and spatiotemporal ambiguity (Experiments 1-3), indicating that the absence of feature-based OSPB cannot be accounted for by salient spatiotemporal discontinuity. When the task involved complex shapes and matching two target shapes to the preview ones, color-based OSPB was obtained. Critically, however, when a visual working memory task was performed concurrently with the matching task, the presence of a nonspatial (but not a spatial) working memory load eliminated the color-based OSPB (Experiments 4 and 5). These results suggest that the surface feature congruency effects that are observed in the object-reviewing paradigm (with the matching task) reflect memory-based strategies that participants use to solve a memory-demanding task; therefore, they are not reliable measures of online object continuity and cannot be taken as evidence for the role of surface features in establishing object correspondence.