The bicycle illusion: Sidewalk science informs the integration of motion and shape perception.

The authors describe a new visual illusion first discovered in a natural setting. A cyclist riding beside a pair of sagging chains that connect fence posts appears to move up and down with the chains. In this illusion, a static shape (the chains) affects the perception of a moving shape (the bicycle), and this influence involves assimilation (averaging) rather than opposition (differentiation). These features distinguish the illusion from illusions of motion capture and induced motion. The authors take this bicycle illusion into the laboratory and report 4 findings: Na?ve viewers experience the illusion when discriminating horizontal from sinusoidal motion of a disc in the context of stationary curved lines; the illusion shifts from motion assimilation to motion opposition as the visual size of the display is increased; the assimilation and opposition illusions are dissociated by variations in luminance contrast of the stationary lines and the moving disc; and the illusion does not occur when simply comparing two stationary objects at different locations along the curved lines. The bicycle illusion provides a unique opportunity for studying the interactions between shape and motion perception. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Temporal integration in face perception: Evidence of configural processing of temporally separated face parts.

Temporal integration is the process by which temporally separated visual components are combined into a unified representation. Although this process has been studied in object recognition, little is known about temporal integration in face perception and recognition. In the present study, the authors investigated the characteristics and time boundaries of facial temporal integration. Whole faces of nonfamous and famous people were segmented horizontally into 3 parts and presented in sequence, with varying interval lengths between parts. Inversion and misalignment effects were found at short intervals (0-200 ms). Moreover, their magnitude was comparable to those found with whole-face presentations. These effects were eliminated, or substantially reduced, when the delay interval was 700 ms. Order of parts presentation did not influence the pattern of inversion effects obtained within each temporal delay condition. These results demonstrate that temporal integration of faces occurs in a temporary and limited visual buffer. Moreover, they indicate that only integrated faces can undergo configural processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Head shape and the perception of cuteness.

Investigated in 3 experiments with 25 undergraduates the ethological hypothesis that the perception of cuteness can be elicited by certain physical characteristics of infants. A transformation that models the morphological changes in head shape during development was applied to 1 frontal and 2 profile drawings of human heads to create 3 series varying only in global cephalic shape. The responses of Ss to these drawings indicated that perceived cuteness decreases as the shape of the head changes due to aging. (27 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Social perception and the motivational structure of interpersonal relations.

An extension of a previous research (see 28: 673). The introduction of another variable, viz., the knowledge of the result of cooperative or competitive ventures, affected the perception of the partner. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Auditory-visual integration of temporal relations in infants.

A total of 100 3–4 mo old infants in 2 experiments were assigned to 1 of 2 groups: one group was first presented with temporally synchronous auditory and visual signals during habituation trials and then nonsynchronous signals during recovery; the other groups received the opposite sequence. The auditory and visual signals were spatially congruous in Exp I, but were separated in Exp II. Since the pulse rate of the visual stimuli was changed for the nonsynchronous trials, a control group was tested that received only the light during habituation and recovery trials. The groups initially presented synchronous signals showed habituation and recovery. Neither group presented nonsynchronous stimuli showed recovery. The group with the spatially separated sources habituated, while the group with the spatially congruous signals did not. Results suggest that infants coordinate the temporal relations. (French abstract) (12 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Influence of shape on haptic curvature perception

Curvature discrimination of hand-sized doubly curved surfaces by means of static touch was investigated. Stimuli consisted of hyperbolical, cylindrical, elliptical and spherical surfaces of various curvatures. In the first experiment subjects had to discriminate the curvature along a specified orientation (the discrimination orientation) of a doubly curved surface from a flat surface. The curvature to be discriminated was oriented either along the middle finger or across the middle finger of the right hand. Independent of the shape of the surface, thresholds were found to be about 1.6 times smaller along the middle finger than across the middle finger. Discrimination biases were found to be strongly influenced by the shape of the surface; subjects judged a curvature to be more convex when the perpendicular curvature was convex than when this curvature was concave. With the results of the second experiment it could be ruled out that the influence of shape on curvature perception was simply due to a systematic error made by the subject regarding the discrimination orientation.     

Characterization of the spatial-frequency spectrum in the perception of shape from texture

The major cue to shape from texture is the compression of texture as a function of surface curvature [J. Exp. Psychol. 13, 242 (1987); Vision Res. 33, 827 (1993)]. A number of computational models have been proposed in which compression is measured by detection of changes in the spatial-frequency spectrum [Comput. Graphics Image Process. 5, (1976)]. We propose that the visual system uses a strategy of characterizing the frequency spectrum by a simple set of measures and of tracking the changes in this characterization rather than determining changes in the shape of the actual spectra. Our evidence is based on a number of psychophysical demonstrations that use stimuli with specifically tailored frequency spectra, constructed from white noise filtered in the frequency domain. Our evidence suggests that the visual system determines the average peak frequency of the spectrum and uses this measure as its characterization. Changes in fp are strongly correlated with the degree of surface curvature, and, over a range of stimuli, fp takes account of the variance in local estimates of the frequency spectrum. One computes fp by determining the peak frequency at each spatial location and then averaging these frequency values over a local spatial region. We show that fp is related to the second-order moment but is more biologically plausible and shows superior ability to function in the presence of noise. As a test of this model, we have constructed a neural network architecture for computing shape from texture. Our model is limited to orthographically projected, homogeneous textures without in-surface rotation. The early stages of the model consist of multiple simple-cell units tuned to different orientations and spatial frequencies. We show that these simple cells are inadequate for the determination of compression but that the outputs of complex-cell-like units after normalization generate estimates of surface slant and tilt. The network shows qualitative agreement with human perception of shape from texture over a wide range of real and artificial stimuli.     

Critique: articulatory-acoustic relations and their role in speech perception

These remarks are in response to "Role of articulation in speech perception: Clues from production"ony Bj?rn Lindblom. It is suggested that the form in which the lexicon is stored includes both segments and distinctive features, and this representation is neutral with respect to articulatory and the acoustic domains. The process by which features are determined from the sound requires that patterns of acoustic properties be identified. In developing models of speech perception, knowledge of articulatory-acoustic relations can be a guide in defining these properties, but it is not necessary for the models to assign primary status to articulation.     

The quantitative study of shape and pattern perception.

There is a need to extend the traditional psycho-physical methods to include the analysis of shapes or patterns. Heretofore studies designed to determine how form perception is influenced by various extrinsic factors have employed arbitrarily designed stimuli. This paper proposes several methods "for drawing 'random' patterns and shapes from clearly defined hypothetical populations, to which experimental results may then be generalized with measurable confidence." 27 references. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hemispheric contributions to the integration of visual and auditory information in speech perception

Differential hemispheric contributions to the perceptual phenomenon known as the McGurk effect were examined in normal subjects, 1 callosotomy patient, and 4 patients with intractable epilepsy. Twenty-five right-handed subjects were more likely to demonstrate an influence of a mouthed word on identification of a dubbed acoustic word when the speaker's face was lateralized to the LVF as compared with the RVF. In contrast, display of printed response alternatives in the RVF elicited a greater percentage of McGurk responses than display in the LVF. Visual field differences were absent in a group of 15 left-handed subjects. These results suggest that in right-handers, the two hemispheres may make distinct contributions to the McGurk effect. The callosotomy patient demonstrated reliable McGurk effects, but at a lower rate than the normal subjects and the epileptic control subjects. These data support the view that both the right and left hemisphere can make significant contributions to the McGurk effect.     

Inhibitory competition between shape properties in figure-ground perception.

Theories of figure-ground perception entail inhibitory competition between either low-level units (edge or feature units) or high-level shape properties. Extant computational models instantiate the 1st type of theory. The authors investigated a prediction of the 2nd type of theory: that shape properties suggested on the ground side of an edge are suppressed when they lose the figure-ground competition. In Experiment 1, the authors present behavioral evidence of the predicted suppression: Object decisions were slower for line drawings that followed silhouettes suggesting portions of objects from the same rather than a different category on their ground sides. In Experiment 2, the authors reversed the silhouette's figure-ground relationships and obtained speeding rather than slowing in the same category condition, thereby demonstrating that the Experiment 1 results reflect suppression of those shape properties that lose the figure-ground competition. These experiments provide the first clear empirical evidence that figure-ground perception entails inhibitory competition between high-level shape properties and demonstrate the need for amendments to existing computational models. Furthermore, these results suggest that figure-ground perception may itself be an instance of biased competition in shape perception. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Visual and tactual perception of shape by young children.

Gave 3-4 yr olds a series of 2-choice matching problems involving visual and/or tactual perception. Contrary to S. A. Rose et al (1972) some shape discriminations were more difficult tactually than visually. Predicted differences between dissimilar and similar discrimination were not obtained. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Development of the perception of musical relations: Semitone and diatonic structure.

Examined the development of sensitivity to 2 musical relations significant in Western tonal music, the semitone and diatonic structure, in 2 experiments with 30 preschoolers (aged 4.2–5.9 yrs) and 40 infants (aged 9.1–11 mo). Ss were tested for their detection of a semitone change in any position of a 5-note melody. Two standard melodies were used, one composed of diatonic tones only and the other containing a nondiatonic tone. In Exp I, preschoolers were superior in detecting the semitone change in the diatonic context compared with the nondiatonic context. In Exp II, infants detected the semitone change in all positions, but their performance was not influenced by diatonic context. It is concluded that infants and children can discriminate a semitone in a musical context and that the priority of diatonic structure emerges by 4–6 yrs of age. (32 ref) (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Relation of visual perception and visual-motor integration for clumsy children

Rac1 small GTPase plays pivotal roles in various cell functions such as cell morphology, cell polarity, and cell proliferation. We have previously identified IQGAP1 from bovine brain cytosol as a target for Rac1 by an affinity purification method. By using the same method, we purified a specifically Rac1-associated protein with a molecular mass of about 140 kDa (p140) from bovine brain cytosol. This protein interacted with guanosine 5'-(3-O-thio)triphosphate (GTPgammaS).glutathione S-transferase (GST)-Rac1 but not with the GDP.GST-Rac1, GTPgammaS.GST-Cdc42, or GTPgammaS.GST-RhoA. The amino acid sequences of this protein revealed that p140 is identified as a product of KIAA0068 gene. We denoted this protein as Sra-1 (Specifically Rac1-associated protein). Recombinant Sra-1 interacted with GTPgammaS.GST-Rac1 and weakly with GDP.Rac1 but not with GST-Cdc42 or GST-RhoA. The N-terminal domain of Sra-1 (1-407 amino acids) was responsible for the interaction with Rac1. Myc-tagged Sra-1 and the deletion mutant capable of interacting with Rac1, but not the mutants unable to bind Rac1, were colocalized with dominant active Rac1(Val-12) and cortical actin filament at the Rac1(Val-12)-induced membrane ruffling area in KB cells. Sra-1 was cosedimented with filamentous actin (F-actin), indicating that Sra-1 directly interacts with F-actin. These results suggest that Sra-1 is a novel and specific target for Rac1.     

Enhanced co-orientation in the perception of friends: A social relations analysis.

Newcomb's (1953) idea of co-orientation (interdependence between two persons' attitudes or perceptions) is used as a framework within which interpersonal perception between friends and acquaintances is examined. The principal question is whether co-orientation effects are stronger for friendship dyads than for acquaintance dyads. More specifically, the study examines the degree to which consensus, assimilation, self–other agreement, and assumed similarity differ. The social relations model is used to analyze a data set that included 16 living groups with 119 friend dyads and 1,668 acquaintance dyads. Results indicate that co-orientation effects are more pronounced in friendship dyads. The increment in co-orientation effects is largely due to similarities in the unique or idiosyncratic perceptions that people have of friendship pairs as well as the unique agreement about others that friends have with one another. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Accuracy in interpersonal perception: A social relations analysis.

For the past 30 years, the study of accuracy in person perception has been a neglected topic in social and personality psychology. Research in this area was stopped by a critique of global accuracy scores by Cronbach and Gage. They argued that accuracy should be measured in terms of components. Currently, interest in the topic of accuracy is rekindling. This interest is motivated, in part, by a reaction to the bias literature. We argue that modern accuracy research should (a) focus on measuring when and how people are accurate and not on who is accurate, (b) use each person as both judge and target, and (c) partition accuracy into components. The social relations model (Kenny & La Voie, 1984) can be used as a paradigm to meet these requirements. According to this model, there are four types of accuracy, only two of which are generally conceptually interesting. The first, called individual accuracy, measures the degree to which people's judgments of an individual correspond to how that individual tends to behave across interaction partners. The second, called dyadic accuracy, measures the degree to which people can uniquely judge how a specific individual will behave with them. We present an example that shows high levels of individual accuracy and lower levels of dyadic accuracy. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Infants' perception of musical relations in short transposed tone sequences.

Tested 104 infants (aged 7–11 mo) for their detection of a frequency relational change of 1 semitone in a 5-note melody. In Exp I, Ss were able to discriminate contrasting melodies that differed from the background melodies by 1 semitone. In Exp II, Ss detected a semitone difference more easily when the major triad was background and a relatively uncommon triad, the augmented triad, was the contrast. In Exp III, Ss discriminated the major and minor backgrounds used in Exps I and II from contrasting variations, called inversions, that did not differ in triad quality. Results indicate that infants can respond to precise relations between the component tones of a melody based on familiar or stable structures. Findings also imply that sets of tones that are unfamiliar or unstable may present encoding or memory difficulties for infants, as has been found for children and adults. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Frames of reference and distinctive figural characteristics affect shape perception.

In 4 experiments it was found that global frameworks and local distinctive figural characteristics influenced the perception of shape and of pointing. In Exps 1 and 2, Ss were asked to mark the center of the middle figure in array of 3 aligned figures (either triangles or squares). Displacements of the center indicated a perceived deformation of the shapes. In Exp 3, Ss were asked to adjust the height of triangles in arrays similar to those in Exp 1. Height adjustments made along the axis of apparent pointing resulted in extents that were shorter than the height necessary to form equilateral triangles. In Exp 4, stimuli were isosceles triangles in which the apparent distortion had been nulled; however, Ss continued to perceive them as pointing in a direction consistent with their alignment, and hence shape distortion cannot be the cause of pointing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)