Perception最新文献

The Two-Visual-Streams Hypothesis (TVSH) of vision proposes a functional separation between the perception of a visual stimulus and the control of visually guided action toward that stimulus. This study tested whether the separation of perception and action proposed by the TVSH is also demonstrated when executing visually guided cursor movements toward onscreen targets. Participants used a trackpad to click onscreen circular targets embedded within the Ebbinghaus ("Titchener Circles") illusion and were thus perceived as either larger or smaller than their true size. Participants were more accurate when clicking on the perceived larger target compared to the perceived smaller target, indicating their performance was influenced by their perception of target size (Experiment 1). There was no effect of the illusion when visual feedback of the target was removed at the beginning of the trial (Experiment 2) or removed following a 2-second target-viewing period (Experiment 3). Conclusion: The perceptual features of an onscreen stimulus mediate the guidance of cursor movements toward visible targets. Illusion-based perceptions of target size do not affect actions toward disappeared targets, however. These results contribute to the theoretical principles of the TVSH by testing its predictions in a novel onscreen environment.

Perceptual load theory states that there are limited processing resources, but that these must always be fully employed. It has been used to predict and explain the commonly reported finding that irrelevant distractors influence behaviour when the task has low load (such as processing just one target element) but not when the task has high load (processing many target elements). We attempted to replicate this effect over a series of six experiments that manipulated the location of the distractor, the duration of the display, and different levels of load. We examined both the distracting effects caused by a "neutral" distractor, and response-biases (congruence effects) that occur when the distractor is either congruent or incongruent with the target. Strong distraction and congruence effects were found with central distractors and weaker effects were found with peripheral distractors. These effects appeared to be independent of the level of perceptual load in all conditions. Our findings thus do not support the tenants of perceptual load theory and fail to replicate the many findings that do support this theory.

Stepping over obstacles requires adjusting the foot trajectory to avoid contact with surfaces that may be hazardous or unpleasant to step on. While it is well established that obstacle height and stability influence stepping behaviour, little is known about how perceptual affective evaluations, such as dangerousness, unpleasantness, and painfulness, modulate avoidance strategies. In Experiment 1 (N = 20), participants stepped over obstacles covered with stones varying in size and density while rating their perceived unpleasantness. Visual uncertainty was manipulated by comparing monocular and binocular viewing. Lead minimum foot clearance (MFC) was initially higher under monocular vision but decreased to binocular levels over trials. While obstacle unpleasantness did not systematically affect MFC or crossing step length, perceived unpleasantness ratings correlated weakly with crossing step length. However, because dangerousness and painfulness ratings were not collected, it remained unclear whether unpleasantness directly influenced avoidance behaviour or served as a proxy for perceived risk. To address this, Experiment 2 (N = 22) introduced obstacles covered with metal stud spikes or smooth surfaces, with additional ratings of dangerousness and painfulness. Results showed that MFC was higher for spiky than smooth obstacles. Crucially, in this experiment, ratings of perceived dangerousness, not unpleasantness, correlated positively with crossing step length, after controlling for other perceptual ratings. These findings suggest that perceptual affective properties modulate avoidance parameters. However, the nature of those modulations is stimulus specific and highly depends on task demands.

The fovea, with its high concentration of cone photoreceptors, results in increased sensitivity and visual acuity, while the periphery, with its lower contrast sensitivity and resolution, provides better spatial summation. Despite these differences, our experience of the visual field remains detailed and uniform, supported by the influence of central vision on peripheral vision. There is evidence that recognition of simple shapes in the periphery is enhanced by the presence of a similar shape in central vision. However, it is unclear whether such mechanisms generalise to more complex stimuli, such as faces. In a face matching task, we found that having a similar face in central vision improved face matching performance in the periphery. This suggests that general mechanisms govern the interaction between central and peripheral vision in recognising faces.

The composite effect, originally demonstrated for faces, has recently been shown to suggest holistic processing of words. The effect is associated with reading fluency in Latin script, but not in nonalphabetic Chinese script, suggesting that script properties influence its relationship with reading expertise. We measured the composite effect for Arabic, a visually complex alphabetic script that offers a useful contrast against Latin and Chinese. Arabic-English bilinguals ($N=$ 24), and English-only readers ($N=$ 22) completed a composite effect task, in which they judged whether the left or right halves of word pairs were the same or different. The unattended half was either congruent or incongruent with the judgement, and the halves were presented in aligned or misaligned blocks. The composite effect, a reduction in the effect of congruency when the halves are misaligned, typically is interpreted as evidence for holistic processing. Arabic-English readers showed the composite effect for Arabic words, whereas English-only readers did not. Both groups showed the effect for English words. The effect size for the two scripts was equivalent in Arabic-English readers. These findings suggest that the composite effect for Arabic words, like that of Latin script words, requires the ability to read the script. Graphemic complexity or the cursive property of the script appears not to play a role in the composite effect in skilled readers.

Cognitive associations between stimulus intensity and spatial response codes are thought to influence perceptual discrimination. We examined lateral response-set effects on auditory and visual intensity discrimination in a preregistered study with a large sample (N = 98). Participants responded to loud and bright stimuli using a button located to the left or right of the button used for soft and dim stimuli. In the auditory task, stimulus-response (SR)-mapping affected task-averaged error rates (ERs) but not task-averaged response times (RTs). However, loudness predicted response-side differences in both latency (${\text{RT}}_{\text{Left}}-{\text{RT}}_{\text{Right}}$) and accuracy (${\text{ER}}_{\text{Left}}-{\text{ER}}_{\text{Right}}$). By comparison, all tests of brightness discrimination supported the null or were inconclusive. Assessments of cross-modality correlations in SR-mapping effects were also inconclusive. These results replicate prior findings of lateral SR-mapping effects in auditory intensity discrimination and clarify inconsistencies in the visual domain. The lack of SR-mapping effects in brightness discrimination, along with inconclusive cross-modal correlations, challenges the notion of a common spatial processing mechanism for auditory and visual intensity comparison. If such a mechanism exists, its effects on visual judgments appear too subtle to be detected even in a large sample.

Evidence suggested that stimulus-response bindings could occur automatically as a result of the co-occurrence of a stimulus and a response, without requiring additional attentional involvement for features or objects. Considering that stimuli used in previous research often involved high-discriminability features processed automatically, the current study investigated the role of feature types in attention-modulated stimulus-response binding. Using the classic partial repetition cost (PRC) paradigm, the study manipulated the task relevance of features during the binding phase to modulate feature-based attention, with color and Landolt-C gap orientation as experimental features. The study found that when the stimulus feature was color (a high-discriminability feature), no significant difference was observed in the PRC effect during the retrieval phase, regardless of whether attention was directed to the color during the binding phase. When the stimulus feature was the gap orientation of the Landolt-C (a fine-grained feature), the PRC effect appeared during the retrieval phase, regardless of attention to gap orientation during the binding phase. However, the PRC effect was stronger when attention was directed to gap orientation, indicating that feature-based attention during the binding phase enhanced the binding strength between the gap orientation of the Landolt-C and the response. This study suggests that stimulus-response binding occurs automatically, but its binding strength is modulated by attention, with the type of stimulus feature playing a critical role in this process. Stimulus-driven and goal-driven factors jointly influence the strength of stimulus-response binding.

Visual adaptation to extreme body types is known to produce contrastive adaptation aftereffects on the subsequent perception of human bodies. This approach has been exploited to probe the perceptual mechanisms underlying body perception by measuring the extent to which aftereffects occur when the adapting and test stimuli differ in specific characteristics (cross adaptation). The present study used this approach to investigate the body-part specificity of adaptation to body muscularity. Participants made judgments of the muscularity of torsos and arms both before and after adaptation to muscular torsos (Experiment 1) or muscular arms (Experiment 2). Across experiments, we report a double dissociation in the effects of adaptation. In Experiment 1, adaptation to muscular torsos produced aftereffects for torso judgments, but not arm judgments. In Experiment 2, adaptation to muscular arms produced aftereffects for arm judgments, but not torso judgments. These results demonstrate body-part specificity of the visual mechanisms underlying perception of body muscularity.