Suboptimal but intact integration of Bayesian components during perceptual decision-making in autism.

Background: Alterations in sensory perception, a core phenotype of autism, are attributed to imbalanced integration of sensory information and prior knowledge during perceptual statistical (Bayesian) inference. This hypothesis has gained momentum in recent years, partly because it can be implemented both at the computational level, as in Bayesian perception, and at the level of canonical neural microcircuitry, as in predictive coding. However, empirical investigations have yielded conflicting results with evidence remaining limited.

When periphery rules: Enhanced sampling weights of the visual periphery in crowding across dimensions.

Crowding, our inability to identify a feature or object - the target - due to its proximity to adjacent features or objects - flankers - exhibits a notable inner-outer asymmetry. This asymmetry is characterized by the outer flanker - more peripheral - creating stronger interference than the inner one - closer to the fovea. But crowding is not uniform across different feature dimensions.

Language-universal and script-specific factors in the recognition of letters in visual crowding: The effects of lexicality, hemifield, and transitional probabilities in a right-to-left script.

Peripheral letter recognition is fundamentally limited not by the visibility of letters but by the spacing between them, i.e., 'crowding'.

The role of spatial attention in crowding and feature binding.

Crowding refers to the failure to identify a peripheral object due to nearby objects (flankers). A hallmark of crowding is inner-outer asymmetry; that is, the outer flanker (more peripheral) produces stronger interference than the inner one. Here, by manipulating attention, we tested the predictions of two competing accounts: the attentional account, which predicts a positive attentional effect on the inner-outer asymmetry (i.

Transient attention equally reduces visual crowding in radial and tangential axes.

Crowding refers to the failure to identify a peripheral object due to its proximity to other objects (flankers). This phenomenon can lead to reading and object recognition impairments and is associated with macular degeneration, amblyopia, and dyslexia. Crucially, the maximal target-flanker spacing required for the crowding interference (critical spacing) increases with eccentricity.

Sensory Perception in Autism: What Can We Learn?

Autism is a neurodevelopmental disorder of unknown etiology. Recently, there has been a growing interest in sensory processing in autism as a core phenotype. However, basic questions remain unanswered.

Mixture-modeling approach reveals global and local processes in visual crowding.

Crowding refers to the inability to recognize objects in clutter, setting a fundamental limit on various perceptual tasks such as reading and facial recognition. While prevailing models suggest that crowding is a unitary phenomenon occurring at an early level of processing, recent studies have shown that crowding might also occur at higher levels of representation. Here we investigated whether local and global crowding interference co-occurs within the same display.

Mixture model investigation of the inner-outer asymmetry in visual crowding reveals a heavier weight towards the visual periphery.

Crowding, the failure to identify a peripheral item in clutter, is an essential bottleneck in visual information processing. A hallmark characteristic of crowding is the inner-outer asymmetry in which the outer flanker (more eccentric) produces stronger interference than the inner one (closer to the fovea). We tested the contribution of the inner-outer asymmetry to the pattern of crowding errors in a typical radial crowding display in which both flankers are presented simultaneously on the horizontal meridian.

Crowding and Binding: Not All Feature Dimensions Behave in the Same Way.

Humans often fail to identify a target because of nearby flankers. The nature and stages at which this occurs are unclear, and whether crowding operates via a common mechanism across visual dimensions is unknown. Using a dual-estimation report ( = 42), we quantitatively assessed the processing of features alone and in conjunction with another feature both within and between dimensions.

Feature reliability determines specificity and transfer of perceptual learning in orientation search.

Training can modify the visual system to produce a substantial improvement on perceptual tasks and therefore has applications for treating visual deficits. Visual perceptual learning (VPL) is often specific to the trained feature, which gives insight into processes underlying brain plasticity, but limits VPL's effectiveness in rehabilitation. Under what circumstances VPL transfers to untrained stimuli is poorly understood.

Feature singletons attract spatial attention independently of feature priming.

People perform better in visual search when the target feature repeats across trials (intertrial feature priming [IFP]). Here, we investigated whether repetition of a feature singleton's color modulates stimulus-driven shifts of spatial attention by presenting a probe stimulus immediately after each singleton display. The task alternated every two trials between a probe discrimination task and a singleton search task.

Rapid and long-lasting learning of feature binding.

How are features integrated (bound) into objects and how can this process be facilitated? Here we investigated the role of rapid perceptual learning in feature binding and its long-lasting effects. By isolating thecontributions of individual features from their conjunctionsbetween training and test displays, we demonstrate for the first time that training can rapidly and substantially improve feature binding. Observers trained on a conjunction search task consisting of a rapid display with one target-conjunction, then tested with a new target-conjunction.

Rapid and long-lasting reduction of crowding through training.

Crowding is the failure to identify an object in the peripheral visual field in the presence of nearby objects. Recent studies have shown that crowding can be alleviated after several days of training, but the processes underlying this improvement are still unclear. Here we tested whether a few hundred trials within a short period of training can alleviate crowding, whether the learning is location specific, and whether the improvement reflects facilitation by target enhancement or flankers suppression.

Inter-trial priming does not affect attentional priority in asymmetric visual search.

Visual search is considerably speeded when the target's characteristics remain constant across successive selections. Here, we investigated whether such inter-trial priming increases the target's attentional priority, by examining whether target repetition reduces search efficiency during serial search. As the study of inter-trial priming requires the target and distractors to exchange roles unpredictably, it has mostly been confined to singleton searches, which typically yield efficient search.

The role of motor response in implicit encoding: evidence from intertrial priming in pop-out search.

Perception and motor control jointly act to meet our current needs. Recent evidence shows that the generation of motor action significantly affects perception. Here, we examined the role of motor response in inter-trial priming, namely, in Priming of Pop-out (PoP): when searching for a singleton target, performance is improved when the target and distractors features repeat on consecutive search trials than when they switch.

Orientation search is mediated by distractor suppression: evidence from priming of pop-out.

In search for a singleton target, performance is considerably improved when the target and distractors repeat than when they switch roles, an effect called priming of pop-out or PoP (Maljkovic & Nakayama, 1994). Although this phenomenon has been replicated across a variety of dimensions, orientation PoP has proved to be volatile. Recent research has shown that target activation and distractor inhibition mechanisms underlie PoP (Lamy, Antebi, et al.

Temporal position priming: memory traces of recent experience bias the allocation of attention in time.

Explicit expectations can guide attention toward the time at which an upcoming target is likely to appear. However, in real-life situations, explicit preknowledge of upcoming events' temporal occurrence is rarely provided. We investigated whether implicit memory traces can guide attention in time, as they guide attention to recently attended features and locations (priming of pop-out and priming of location; V.

The role of search difficulty in intertrial feature priming.

Previous research has shown that intertrial repetition of target and distractors task-relevant properties speeds visual search performance, an effect known as priming of pop-out (PoP). Recent accounts suggest that such priming results, at least in part, from a mechanism that speeds post-selectional, response-related processes, the marker of which is an interaction between repetition of the target and distractor features and repetition of the response from the previous trial. However, this response-based component of inter-trial priming has been elusive, and it remains unclear what its boundary conditions might be.

Refining the dual-stage account of intertrial feature priming: does motor response or response feature matter?

Numerous studies have shown that repetition of search-relevant attributes facilitates visual search performance. For example, Maljkovic and Nakayama (1994) showed that when observers search for a target defined by its color and report its shape, repetition of the target color speeds search, an effect known as priming of pop-out. While intertrial feature priming in search was initially thought to affect perceptual processes, the idea that it also affects postselection stages of processing is increasingly acknowledged.

Intertrial repetition affects perception: the role of focused attention.

Implicit short-term memory plays an important role in visual search. For instance, singleton search is faster when the target and distractor features repeat on two consecutive trials than when they switch, an effect called Priming of Popout (PoP). However, whether or not PoP facilitates early perceptual/attentional processes remains controversial.

Intertrial repetition facilitates selection in time: common mechanisms underlie spatial and temporal search.

Recent research has demonstrated that what observers attend to at a given time affects how their attention is deployed in the few moments that follow. When an observer searches for a discrepant target, repetition of the target feature from the previous trial speeds search, an effect known as priming of pop-out (PoP). Previous PoP studies have relied exclusively on spatial search tasks.

A dual-stage account of inter-trial priming effects.

The study of inter-trial effects in visual search has generated an increasing amount of research in recent years. However, the mechanisms underlying these effects are still a matter of debate. Two rival accounts have been suggested.

Intertrial target-feature changes do not lead to more distraction by singletons: target uncertainty does.

The presence of an irrelevant singleton disrupts search for a singleton target substantially more when the target feature varies unpredictably (mixed-singleton search) than when it is known in advance (fixed-singleton search). This finding suggests that advance knowledge of the target feature guides singleton search. Pinto et al.