首页期刊导航|Vision Research
期刊信息/Journal information
Vision Research
Pergamon
Vision Research

Pergamon

0042-6989

Vision Research/Journal Vision ResearchSCIAHCIISTP
正式出版
收录年代

    The size of attentional focus modulates the perception of object location

    Kirsch, WladimirKunde, Wilfried
    8页
    查看更多>>摘要:The present study examined how the size of attended area affects the repulsion of perceived object location from the focus of attention reported previously (attentional repulsion effect). We induced sustained changes in the size of attentional focus and tested the impact of this experimental variation on the perception of object location. The results of three experiments revealed reliable repulsion effects for each size of attentional focus. However, the magnitude of the effect decreased substantially with an increase in focus size. This outcome extends the knowledge about how spatial attention affects visual perception.

    Number of flankers influences foveal crowding and contour interaction differently

    Pluhacek, FrantisekMusilova, LenkaBedell, Harold E.Siderov, John...
    10页
    查看更多>>摘要:Nearby flanking objects degrade visual resolution. If the flankers are similar to the acuity target, this influence is called crowding (CW), whereas if the flanking stimuli are simple bars then the phenomenon is known as contour interaction (CI). The aim of this study was to compare the influence of the number and position of flankers on foveal CW and CI to investigate possible differences in mechanism of these two effects. Five normal observers viewed single, foveally presented Sloan letters surrounded by 1, 2 or 4 flankers (either a Sloan letter or one-stroke-width bars), presented at several edge-to-edge separations. Single flankers were presented in the right, left, top or bottom position, 2 flankers were placed equally to the right and left or top and bottom of the central target, and 4 flankers were equally spaced in all four directions. Percent correct letter identification was determined for each type, number, position and separation of flankers and confusion matrices were constructed for separations equal to 20% and 100% letter width. Increasing the number of flankers caused an increase in the magnitude of both phenomena. CW showed a greater magnitude than CI for higher numbers of flankers. Analysis of confusion matrices suggests that in addition to the edge-to-edge interaction that appears to mediate CI, letter substitution and feature pooling contribute significantly to CW when higher numbers of flankers are presented. Foveal CW is more strongly influenced by an increase in the number of flankers than CI, which can be explained by the presence of additional interaction effects.

    Interocular transfer effects of linear perspective cues and texture gradients in the perceptual rescaling of size

    Yildiz, Gizem Y.Sperandio, IreneKettle, ChristineChouinard, Philippe A....
    15页
    查看更多>>摘要:Our objective was to determine whether the influence of linear perspective cues and texture gradients in the perceptual rescaling of stimulus size transfers from one eye to the other. In experiment 1, we systematically added linear perspective cues and texture gradients in a background image of the corridor illusion. To determine whether perceptual size rescaling takes place at earlier or later stages, we tested how the perceived size of top and bottom rings changed under binocular (rings and background presented to both eyes), monocular (rings and background presented to the dominant eye only), and dichoptic (rings and background presented separately to the dominant and nondominant eyes, respectively) viewing conditions. We found differences between viewing conditions in the perceived size of the rings when linear perspective cues, but not texture gradients, were presented. Specifically, linear perspective cues produced a stronger illusion under the monocular compared to the dichoptic viewing condition. Hence, there was partial interocular transfer from the linear perspective cues, suggesting a dominant role of monocular neural populations in mediating the corridor illusion. In experiment 2, we repeated similar procedures with a more traditional Ponzo illusion background. Contrary to findings from experiment 1, there was a full interocular transfer with the presence of the converging lines, suggesting a dominant role of binocular neural populations. We conclude that higher order visual areas, which contain binocular neural populations, are more involved in the perceptual rescaling of size evoked by linear perspective cues in the Ponzo compared to the corridor illusion.

    Reorganization in the representation of face-race categories from 6 to 9 months of age: Behavioral and computational evidence

    Quinn, Paul C.Balas, Benjamin J.Pascalis, Olivier
    8页
    查看更多>>摘要:Prior research has reported developmental change in how infants represent categories of other-race faces (Developmental Science 19 (2016) 362-371). In particular, Caucasian 6-month-olds were shown to represent African versus Asian face categories, whereas Caucasian 9 month-olds represented different classes of other-race faces in one category, inclusive of African and Asian faces but exclusive of Caucasian faces. The current investigation sought to provide stronger evidence that is convergent with these findings by asking whether infants will generalize looking-time responsiveness from one to another other-race category. In Experiment 1, an experimental group of Caucasian 6-month-olds was familiarized with African (or Asian) faces and then given a novel category preference test with an Asian (or African) face versus a Caucasian face, while a control group of Caucasian 6-month-olds viewed the test faces without prior familiarization. Infants in the experimental group divided attention between the test faces and infants in the control group did not manifest a spontaneous preference. Experiment 2 used the same procedure, but was conducted with Caucasian 9-month-olds. Infants in the experimental group displayed a robust preference for Caucasian faces when considered against the finding that infants in the control group displayed a spontaneous preference for other-race faces. The results offer confirmation that between 6 and 9 months, infants transition to representing own-race versus other-race face categories, with the latter inclusive of multiple other-race face classes with clear perceptual differences. Computational modeling of infant responding suggests that the developmental change is rooted in the statistics of experience with majority versus minority group faces.

    Uncertainty-based overestimation in the perception of group actions

    Khaw, Mel W.Nichols, PhoebeFreedberg, David
    11页
    查看更多>>摘要:Individuals are adept at estimating average properties of group visual stimuli, even following brief presentations. In estimating the directional heading of walking human figures, judgments are biased in a peculiar manner: groups facing intermediate directions are perceived to be more leftward- or rightward-facing than actual averages. This effect was previously explained as a repulsive bias away from a central category boundary; groups along this boundary (directly facing the observer) are estimated with lower variability and with relatively greater accuracy. Here we show that: (i) the original effect replicates and is constant over time in a novel estimation task with persistent directional states; and, (ii) novel patterns of response variability and durations align with the entire range of overestimation. A simple model of additive errors proportional to viewer uncertainty matches the observed bias magnitudes. We furthermore show that the bias generalizes beyond approaching walkers with the use of rearward-facing walkers presented at a nonparallel angle. Overall, the recurring relation between bias and uncertainty is also consistent with top-down and post-perceptual causes of misestimation.

    Binocular summation and efficient coding

    Kingdom, Frederick A. A.Woessner, Philipp
    11页
    查看更多>>摘要:Two eyes are better than one at detecting a pattern, an advantage termed binocular summation. It is widely believed that binocular summation is mediated by neurons that sum the two eyes' inputs. Here we suggest an alternative model based on a model of binocular interactions proposed by Cohn, Leong & Lasley (Vision Research, 1981, 21, 1017-1023) and further motivated by the efficient coding framework proposed by Li & Atick (Network: Computation in Neural Systems, 1994, 5, 157-174). In the model, termed MAX(S+S-), binocular summation is mediated by channels that compute the sum, S+, and difference, S-, of the two eyes' monocular signals. The S+ and S- signals are assumed to be perturbed by independent noise, have independent gains and contribute independently to detection via the MAX rule. To test the model we measured binocular summation for horizontally-oriented Gabor patches at a range of spatial-frequencies and bandwidths, at both contrast detection threshold and for increment thresholds on binocular pedestals at contrasts set to 10x detection threshold. The model's performance was compared to that of two conventional models of binocular summation, one in which the two eyes' signals remain separate at the decision stage, termed MAX(LR), the other in which the two eye's signals are summed by a single channel, termed B+, with both models incorporating interocular inhibition. The MAX(S+S-) model gave as good a performance as the other two models. Together with the evidence for the involvement of separately gain controlled S+ and S- signals underpinning a wide range of binocular behaviors, we conclude that the MAX(S+S-) model can and should be considered as a viable model for binocular summation.

    Dyslexia and the magnocellular-parvocellular coactivaton hypothesis

    Ciavarelli, AmbraContemori, GiulioBattaglini, LucaBarollo, Michele...
    11页
    查看更多>>摘要:Previous studies showed that the lateral masking of a fast-moving low spatial frequency (SF) target was strong when exerted by static flankers of lower or equal to the target SF and absent when flankers' SF was higher than the target's one. These masking and unmasking effects have been interpreted as due to Magnocellular-Magnocellular (M-M) inhibition and Parvocellular-on-Magnocellular (P-M) disinhibitory coactivation, respectively. Based on the hypothesis that the balance between the two systems is perturbed in Developmental Dyslexia (DD), we asked whether dyslexic children (DDs) behaved differently than Typically Developing children (TDs) in conditions of lateral masking. DDs and TDs performed a motion discrimination task, of a. 5c/deg Gabor target moving at 16 deg/sec, either isolated or flanked by static Gabors with a SF of.125,.5 or 2 c/deg (Experiment 1). As a control, they also performed a contrast detection task of a static target, either isolated or flanked (Experiment 2). DDs did not perform any different from TDs with either a static target or an isolated moving target of low spatial frequency, thus suggesting efficient feedforward Magnocellular (M) and Parvocellular (P) processing. Also, DDs showed similar contrast thresholds to TDs in the M-M inhibition condition. Conversely, DDs did not recover from lateral masking in the M-P coactivation condition. In addition, their performance in this condition negatively correlated with non-words accuracy, supporting the suggestion that an inefficient Magno-Parvo coactivation may possibly be associated to both higher visual suppression and reduced perceptual stability during reading.

    Adaptation to geometrically skewed moving images: An asymmetrical effect on the double-drift illusion

    Rifai, KatharinaWahl, SiegfriedWatson, TamaraGarcia, Miguel Garcia...
    10页
    查看更多>>摘要:Progressive addition lenses introduce distortions in the peripheral visual field that alter both form and motion perception. Here we seek to understand how our peripheral visual field adapts to complex distortions. The adaptation was induced across the visual field by geometrically skewed image sequences, and aftereffects were measured via changes in perception of the double-drift illusion. The double-drift or curveball stimulus contains both local and object motion. Therefore, the aftereffects induced by geometrical distortions might be indicative of how this adaptation interacts with the local and object motion signals.

    Motion direction tuning in centre-surround suppression of contrast

    Phillips, Daisy J.McDougall, Thomas J.Dickinson, J. EdwinBadcock, David R....
    9页
    查看更多>>摘要:The perceived contrast of a central stimulus is reduced in the presence of a high contrast surround. A number of stimulus features influence the amount of suppression. A two-mechanism model has been proposed for stationary patterns involving a narrowly-tuned process, requiring very similar stimuli in the centre and surround, and a weaker, untuned or very broadly tuned process unselective for stimulus features. This study examines whether a similar model applies to the motion pathway in human participants by varying the orientation and direction of motion of the surround relative to the centre. Four experienced observers completed a two-interval forced-choice contrast matching task. The stimuli were drifting sinusoidal grating patterns with high contrast surrounds (95%) differing in direction of motion and orientation relative to the centre grating. All surround conditions produced suppression but a common orientation and direction of motion produced significantly more suppression than either opposite direction of motion conditions or orthogonal direction conditions. The tuning for motion direction differences was assessed for same and opposite directions of motion. These findings support the extension of the two-mechanism model of contrast suppression to motion direction.