The role of convexity in perception of symmetry and in visual short-term memory

Visual perception of shape is affected by coding of local convexities and concavities. For instance, a recent study reported that deviations from symmetry carried by convexities were easier to detect than deviations carried by concavities. We removed some confounds and extended this work from a detection of reflection of a contour (i.e., bilateral symmetry), to a detection of repetition of a contour (i.e., translational symmetry). We tested whether any convexity advantage is specific to bilateral symmetry in a two-interval (Experiment 1) and a single-interval (Experiment 2) detection task. In both, we found a convexity advantage only for repetition. When we removed the need to choose which region of the contour to monitor (Experiment 3) the effect disappeared. In a second series of studies, we again used shapes with multiple convex or concave features. Participants performed a change detection task in which only one of the features could change. We did not find any evidence that convexities are special in visual short-term memory, when the to-be-remembered features only changed shape (Experiment 4), when they changed shape and changed from concave to convex and vice versa (Experiment 5), or when these conditions were mixed (Experiment 6). We did find a small advantage for coding convexity as well as concavity over an isolated (and thus ambiguous) contour. The latter is consistent with the known effect of closure on processing of shape. We conclude that convexity plays a role in many perceptual tasks but that it does not have a basic encoding advantage over concavity.     

Perception of symmetry and repetition within and across visual shapes: Part-descriptions and object-based attention

In five experiments, we investigated the detection of symmetry (i.e., translation plus reflection) or repetition (i.e., translation alone) between two vertical jagged contours. The complexity of the two contours was manipulated, as was their figure-ground assignment; the two contours either belonged to a common object "inside" them, to two separate objects "outside" them, or to two separate objects each to the right of one contour. Replicating Baylis and Driver (1994), symmetry judgements were unaffected by contour complexity when made within a single shape, implying a parallel process operating efficiently across contour discontinuities. However, all the other conditions yielded substantially slower judgements as complexity increased, suggesting either effortful point-by-point comparisons, or a highly inefficient parallel process. In agreement with Baylis and Driver (1995a), symmetry perception was harder when figure-ground assignment turned convexities along one contour into concavities along the other contour; and likewise for repetition detection. However, even when convex parts matched between the two contours, judgements were still affected by complexity unless they belonged to a common object. This supports Baylis and Driver's (1993) proposal that effortless comparisons for the layout of multiple convex parts can only be made within single perceptual objects.     

The Systematic Distortion Hypothesis: A Confirmatory Test of the Implicit Covariance and General Impression Models

Supervisory ratings of subordinate performance were used to compare two variations of the systematic distortion hypothesis: an implicit covariance model and a general impression (GI) model. Our purpose was to assess whether a model specifying a set of correlated performance dimensions or a model specifying a single, GI factor provided the best representation of actual supervisory performance ratings (N = 491). Confirmatory factor analysis was used to test a first-order correlated factor (i.e., implicit covariance) model against a second-order hierarchical (i.e., GI) model. The results generally supported the latter perspective whereby a GI is thought to serve as the basis for subsequent dimensional judgments, which in turn serve as the basis for individual item ratings. The implications of these results with respect to rater training and rating accuracy are discussed.     

Further consideration of size illusions in random dot stereograms.

It has been suggested that many geometric illusions are caused by the application of depth or size constancy rules to an image which does not have sufficient cues to establish that the elements lie in a flat plane. Thus, converging lines are taken as depth cues, and the attributed depth provides the basis for adjusting the perceived size of stimulus elements. It this is the case, one should not see a distortion of relative size if the disparity cues provide for strong statification, i.e., localization in depth of the linear perspective cues. This expectation is challenged by demonstrations that show distortions of relative size using random-dot stereograms. In 1971 Julesz provided such examples but did not comment on the implications for theories of depth. Here we redemonstrate these distortion of length and size in autostereograms which contain the Ponzo and Corridor configurations. The illusory distortions can be seen in the cyclopean view even though the linear perspective elements are well stratified. We suggest that the processing of binocular disparity cues, as required for judgments of absolute distance, may involve the dorsal stream of vision, i.e., activity passing into and including the parietal lobe. Pictorial cues, on the other hand, are likely passed through the ventral stream into the temporal lobe. The analysis of depth by this system provides for size constancy and, possibly, the calibration of relative motion.     

The perceptual analysis of structure from motion for rotating objects undergoing affine stretching transformations

In two experiments, we evaluated the ability of human observers to make use of second-order temporal relations across three or more views of an apparent motion sequence for the perceptual analysis of three-dimensional form. Ratings of perceived rigidity were obtained in Experiment 1 for objects rotating in depth that were simultaneously subjected to sinusoidal affine stretching transformations along the line of sight or in a direction parallel to the image plane. Such transformations are theoretically interesting because they cannot be detected by analyses that are restricted to first-order temporal relations (i.e., two views), but they can be detected by more conventional analyses of structure from motion in which second-order temporal relations over three or more views are used. The current results show that human observers can perceive stretching transformations of a rotating 3-D object in a direction parallel to the image plane but that they fail to perceive stretching transformations along the line of sight. This result suggests that human observers can make use of some limited second-order temporal information. This finding was confirmed in Experiment 2, in which we investigated the effects of several specific optical consequences of sinusoidal stretching transformations applied in different directions. The results indicate that observers may be sensitive to the sign of acceleration, but that. they cannot make use of the precise magnitude of second-order relations necessary to recover euclidean metric structure.     

Self as a second-order object: Reinterpreting the Jamesian “Me”

Existing definitions of the self can be lumped into three groups: self as self-reflectivity, self as self-concept, and self as the individual. This article traces current disagreements over the definition of the self to a crucial ambiguity in William James's original delineation of the “Me.” Implicit in James's delineation was a distinction between first-order objects and second-order objects: while first-order objects are things as they are, independent of the perception of a knowing subject, second-order objects are things as perceived by a knowing subject. This article makes this distinction explicit and argues that the self is a second-order object associated with the first-person or “emic” perspective. Defined as the empirical existence of the individual (first order) perceived by the individual as “me” or “mine” (second order), the self is distinguished from the “I” which is the mental capacity for self-reflection; the self-concept which is the mental representation of the individual's existence; and the individual which is the empirical referent of the self-concept. As a second-order object, the “Me,” i.e., the self, is the unity of the existence and perception of the individual.     

Factor Analytic Studies Of Human Brain Damage: I. First And Second-Order Factors And Their Brain Correlates

This report is concerned with identifying the first and second-order cognitive factors underlying a battery of 49 measures taken from 22 brain damage tests. The test scores from 176 brain damaged patients between 16 and 65 years of age were intercorrelated and subjected to first-order alpha factoring followed by promax rotation to oblique simple structure. Ten of the 13 first-order factors extracted were interpretable, six of them being perceptual in nature and four being of a more conceptual nature. The perceptual factors include: perceptual organization, perceptual-motor speed, pattern recognition, temporal resolution, spatial orientation, and figure-ground identification. The conceptual factors include verbal comprehension, memory, and two abstraction factors. A second-order alpha factoring was performed on the matrix of correlations among the 13 primaries. Three of the five second-order factors extracted were interpretable. They were identified as perceptual integration (subsuming the first-order factors of perceptual organization, perceptual-motor speed, and temporal resolution), verbal memory (subsuming verbal comprehension and memory), and visualization (subsuming spatial orientation and figure-ground identification). Although factor interpretations were based primarily on the patterns of high loading variables, they were also influenced by lesion effects observed in this and related studies. About half the interpretable factors are relatively localized (i.e., confined to one or two lobes of one hemisphere), with the other half more diffuse (i.e., multi-lobed, combined with laterality or bilaterality). The more localized factors include the right hemisphere factors of perceptual-motor speed, temporal resolution, and spatial orientation, and the left hemisphere factors of verbal comprehension, memory, and verbal memory. The more neurally diffuse factors include the second-order factors and such broad gauged first-order factors as abstraction I and II, and pattern recognition. Furthermore, same lobe, bilaterally hemispheric effects were rare, and only four factors (memory, verbal memory, visualization, and abstraction I) were correlated with sub-cortical lesions.     

Detection of symmetry in tachistoscopically presented dot patterns: effects of multiple axes and skewing.

We examined the effects of multiple axes and skewing on the detectability of symmetry in tachistoscopically presented (100-msec) dot patterns to test the role of normal grouping processes based on higher order regularities in element positions. In addition to the first-order regularities of orientational uniformity and midpoint collinearity (Jenkins, 1983), bilateral symmetry (BS) gives rise to second-order relations between two pairs of symmetric elements (represented by correlation quadrangles). We suggest that they allow the regularity (i.e., BS) to emerge simply as a result of the position-based grouping that takes place normally, so that no special symmetry-detection mechanism has to be postulated. In combination with previously investigated variables--number and orientation of axes--we introduced skewing (resulting from orthographic projection of BS) to manipulate the kind and number of higher order regularities. In agreement with our predictions, the data show that the effect of skewing angle (varied at three 15 degrees steps, clockwise and counterclockwise) on the preattentive detectability of symmetry (measured with d') increases as the number of axes decreases. On the basis of some more specific findings, we suggest that it is not as much the number of correlation quadrangles that determines the saliency of a regularity as it is the degree to which they facilitate or "bootstrap" each other.     

Detection of symmetry in tachistoscopically presented dot patterns: Effects of multiple axes and skewing

We examined the effects of multiple axes and skewing on the detectability of symmetry in tachistoscopically presented (100-msec) dot patterns to test the role of normal grouping processes based on higher order regularities in element positions. In addition to the first-order regularities of orientational uniformity and midpoint collinearity (Jenkins, 1983), bilateral symmetry (BS) gives rise to second-order relations between two pairs of symmetric elements (represented by correlation quadrangles). We suggest that they allow the regularity (i.e., BS) to emerge simply as a result of the position-based grouping that takes place normally, so that no special symmetry-detection mechanism has to be postulated. In combination with previously investigated variables— number and orientation of axes—we introduced skewing (resulting from orthographic projection of BS) to manipulate the kind and number of higher order regularities. In agreement with our predictions, the data show that the effect of skewing angle (varied at three 15° steps, clockwise and counterclockwise) on the preattentive detectability of symmetry (measured with d’) increases as the number of axes decreases. On the basis of some more specific findings, we suggest that it is not as much the number of correlation quadrangles that determines the saliency of a regularity as it is the degree to which they facilitate or “bootstrap” each other.     

Perceptual and conceptual sources of priming on a word generation task

Repetition of any number of cognitive processes can facilitate subsequent performance (i.e., repetition priming). In this study, we explored several candidate mechanisms that could account for repetition priming on a word generation task. In Experiment 1, we examined whether repetition of semantic processing is necessary for priming on this task. In Experiment 2, we examined whether repetition of semantic processing is sufficient for priming on this task. In both experiments, we additionally examined the effect of changing the specific nature of the semantic retrieval task (i.e., from visual to functional, and vice versa) on performance. The results from these experiments indicated that repetition of semantic processing is both necessary and sufficient to produce a facilitation effect on the word generation task. However, semantic processing of the same attribute does not need to be repeated for facilitation effects to occur. Implications of these findings for theories of the representation and retrieval of semantic knowledge are discussed.     

Dissociating cue-related and task-related processes in task inhibition: evidence from using a 2:1 cue-to-task mapping.

Performance of task sequences is assumed to rely on activation and inhibition of tasks. An empirical marker of task inhibition is the so-called n-2 repetition cost, which is assessed by comparing performance in trial n-2 task repetitions (i.e., ABA) with that in n-2 task switches (i.e., CBA). Current theoretical accounts assume that inhibition acts on the level of task representations (i.e., task sets). However, another potential target of task inhibition could be the representation of the task cue. To decide between these two alternatives, the authors used a 2:1 cue-to-task mapping design. They found significant n-2 task repetition costs both with n-2 cue repetitions and n-2 cue switches. These costs were about equal (Experiment 1), and this data pattern was found for both short and long cuing intervals (Experiment 2). Together, the data suggest that task inhibition acts on task sets and not on cue representations.     

Structure mapping in spatial reasoning

Four experiments examined whether spatial reasoning about non-spatial concepts is based on mapping concepts to space according to similarities in relational structure. Six- and 7-year-old children without any prior graphing experience were asked to reason with graph-like diagrams. In Experiments 1 and 2, children were taught to map time and quantity to vertical and horizontal lines, and then were asked to judge the relative value of a second-order variable (rate) or a first-order variable (quantity) represented in a function line. Children’s judgments indicated that they mapped concepts to space by aligning similar relational structures: quantity judgments corresponded to line height, and rate judgments corresponded to line slope. These correspondences entail a mapping of first-order concepts to first-order spatial dimensions and second-order concepts to second-order spatial dimensions. Experiments 3 and 4 investigated the role of context in establishing relational structure. Children were taught to map age and rate (Experiment 3) or age and size (Experiment 4) to vertical and horizontal lines, and were then asked to judge the rate or the size represented by a function line. In this context, both rate and size were first-order variables, and children’s judgments corresponded to line height, also a first-order variable. The results indicate that spatial reasoning involves a structure-sensitive mapping between concepts and space.     

The roles of axes of symmetry in orientation illusions

The lines of a surrounding figure can induce illusory distortion in the apparent orientation of an enclosed line. The axes of symmetry of the figure have been implicated in this distortion. A series of experiments showed generally that the effects are attributable to the axes of bilateral symmetry rather than to less restrictively defined axes of topological symmetry, although those axes may produce other illusory effects. Furthermore, the distortions affect the whole line rather than only parts of it. These results are consistent with interactions of the lines in the orientation rather than position domain. It is suggested that axes of symmetry may play an important role in pattern recognition.     

Orientational Effects and Component Processes in Symmetry Detection

In previous research on symmetry detection, factors contributing to orientational effects (axis and virtual lines connecting symmetrically positioned dots) and component processes (axis selection and pointwise evaluation) have always been confounded. The reason is the restriction to bilateral symmetry (BS), with pointwise correspondences being orthogonal to the axis of symmetry. In our experiments, subjects had to discriminate random dot patterns from symmetries defined by combining 12 axis orientations (every 15°) with seven reflection angles (0°, yielding BS, and three clockwise and counterclockwise 15° steps, yielding skewed symmetry, SS). In Experiment 1, with completely randomized trial order, a significant interaction between axis and skewing angle was obtained, indicating that classically observed orientational effects are restricted to BS and that the orientation of the pointwise correspondences is important. These basic findings were replicated in three subsequent experiments, which differed in that they used blocks containing patterns with the same axis (Experiment 2), virtual lines orientation (Experiment 3), or their combination (Experiment 4). Based on a comparison between the results obtained by these manipulations, we suggest a possible reason for the failure of preattentive symmetry detection in the case of dot patterns with SS.     

Judging body weight from faces: the height-weight illusion

Being able to exploit features of the human face to predict health and fitness can serve as an evolutionary advantage. Surface features such as facial symmetry, averageness, and skin colour are known to influence attractiveness. We sought to determine whether observers are able to extract more complex features, namely body weight. If possible, it could be used as a predictor for health and fitness. For instance, facial adiposity could be taken to indicate a cardiovascular challenge or proneness to infections. Observers seem to be able to glean body weight information from frontal views of a face. Is weight estimation robust across different viewing angles? We showed that participants strongly overestimated body weight for faces photographed from a lower vantage point while underestimating it for faces photographed from a higher vantage point. The perspective distortions of simple facial measures (e.g., width-to-height ratio) that accompany changes in vantage point do not suffice to predict body weight. Instead, more complex patterns must be involved in the height-weight illusion.     

Motion aftereffect of combined first-order and second-order motion

When, after prolonged viewing of a moving stimulus, a stationary (test) pattern is presented to an observer, this results in an illusory movement in the direction opposite to the adapting motion. Typically, this motion aftereffect (MAE) does not occur after adaptation to a second-order motion stimulus (i.e. an equiluminous stimulus where the movement is defined by a contrast or texture border, not by a luminance border). However, a MAE of second-order motion is perceived when, instead of a static test pattern, a dynamic test pattern is used. Here, we investigate whether a second-order motion stimulus does affect the MAE on a static test pattern (sMAE), when second-order motion is presented in combination with first-order motion during adaptation. The results show that this is indeed the case. Although the second-order motion stimulus is too weak to produce a convincing sMAE on its own, its influence on the sMAE is of equal strength to that of the first-order motion component, when they are adapted to simultaneously. The results suggest that the perceptual appearance of the sMAE originates from the site where first-order and second-order motion are integrated.     

应对量表(COPE)测评维度结构研究

该文旨在对应对量表(COPE)的测评维度结构进行进一步的鉴别分析和验证研究。研究一对736名大学生的应对量表中文修订本(C-COPE)测评数据进行探索性二阶因素分析;研究二根据已有研究关于应对量表测评维度组构模式的不同结论,以及研究一的结果,提出十个假设模型,采用验证性因素分析测试这些模型与另一大学生样本(N：465)测评数据的拟合度。研究结果支持C-COPE八因子斜交模型。该量表如何进一步修订也在文中予以讨论。     

The effects of lorazepam on visual integration processes: How useful for neuroscientists?

The effects of psychotropic drugs can be seen as a reversible lesion of the central nervous system. We studied the effect of lorazepam, a benzodiazepine facilitating the fixation of GABA on the GABA_A receptor. Evidence will be reviewed that lorazepam affects integration processes, using static fragmented pictures or compound stimuli. It will be shown how these effects can be dissociated from other peripheral or central effects of the drug. As a whole, the results suggest that lorazepam improves the detection of discontinuities between collinear elements, but impairs the detection of discontinuities between two parallel line-ends. Recent results will be presented that support the hypothesis that lorazepam does not affect integration processes themselves but modulates the mechanisms involved in the processing of discontinuities, i.e., the processing of line-ends and/or the production of virtual lines orthogonal to the line-ends. An understanding of the effects of the drug might give insights into the way these signals are used and modulated by the visual system.     

Probing Theories of Individual Well-being: A Comparison of Quality-of-life Models Assessing Neighborhood Satisfaction

The extensively documented approach to quality of life proposed by Campbell, Converse, and Rodgers (1976) is translated into a testable theoretical model. Herein labeled the "first-order structural model," this approach springs from a popular interpretation of Lewinian concepts. Critical examination of this interpretation leads to several modifications of the measurement and causal structures hypothesized by Campbell et al., each of which is submitted to test. Likewise, an alternative theoretical approach based on a second, less well known interpretation of the same Lewinian concepts, herein labeled the "second-order structural model," is tested. These models are evaluated by structural equation techniques on a sample of 419 respondents dealing with neighborhood satisfaction. Analyses indicate that both the first-order and second-order structural models yield statistically acceptable accounts of neighborhood satisfaction, but that the second-order model performs better on several modeling criteria. The implications for using structural equation techniques to evaluate competing theory-motivated models are discussed.     

Sequential effects on speeded information processing: a developmental study

Two experiments were performed to assess age-related changes in sequential effects on choice reaction time (RT). Sequential effects portray the influence of previous trials on the RT to the current stimulus. In Experiment 1, three age groups (7-9, 10-12, and 18-25 years) performed a spatially compatible choice task, with response-to-stimulus intervals (RSIs) of 50 and 500 ms varied between trial blocks. In Experiment 2, three age groups (7-9, 15-16, and 18-25 years) performed the task with spatial stimulus-response (S-R) mappings (compatible versus incompatible) varied between participants. For adults, the experiments yielded a pattern of sequential effects suggestive of "automatic facilitation" (i.e., a first-order repetition effect and a higher order benefit-only pattern for short RSIs) and "subjective expectancy" (i.e., a first-order alternation effect and a higher order cost-benefit pattern for long RSIs). Automatic facilitation was more pronounced for incompatible responses than for compatible responses. Both experiments showed the anticipated decrease in automatic facilitation with advancing age. Finally, the first-order alternation effect showed the predicted age-related increase, but the cost-benefit pattern revealed an opposite trend, suggesting that the first-order and higher order indexes of subjective expectancy may relate to dissociable mechanisms.