Hand position alters vision by biasing processing through different visual pathways

The present study investigated the mechanisms responsible for the difference between visual processing of stimuli near and far from the observer's hands. The idea that objects near the hands are immediate candidates for action led us to hypothesize that vision near the hands would be biased toward the action-oriented magnocellular visual pathway that supports processing with high temporal resolution but low spatial resolution. Conversely, objects away from the hands are not immediate candidates for action and, therefore, would benefit from a bias toward the perception-oriented parvocellular visual pathway that supports processing with high spatial resolution but low temporal resolution. We tested this hypothesis based on the psychophysical characteristics of the two pathways. Namely, we presented subjects with two tasks: a temporal-gap detection task which required the high temporal acuity of the magnocellular pathway and a spatial-gap detection task that required the spatial acuity of the parvocellular pathway. Consistent with our prediction, we found better performance on the temporal-gap detection task and worse performance on the spatial-gap detection task when stimuli were presented near the hands compared to when they were far from the hands. These findings suggest that altered visual processing near the hands may be due to changes in the contribution of the two visual pathways.     

手近效应：研究内容、影响因素与神经机制

把手放在刺激旁边,会对知觉、记忆、语义和执行控制等认知加工产生影响,这类现象被称为手近效应。手近效应反映了身体与环境的互动对认知的塑造作用,为具身认知提供了新证据。本文从手近效应的内容,影响因素,及其认知、神经机制等方面对相关研究进行梳理。并从手近效应的神经机制,应用研究,以及动作意图和人际社会因素的调节作用等方面探讨当前手近效应还未解决的问题。     

Trade-offs in visual processing for stimuli near the hands

It is known that stimuli near the hands receive preferential processing. In the present study, we explored changes in early vision near the hands. Participants were more sensitive to low-spatial-frequency information and less sensitive to high-spatial-frequency information for stimuli presented close to the hands. This pattern suggests enhanced processing in the magnocellular visual pathway for such stimuli, and impaired processing in the parvocellular pathway. Consistent with that possibility, we found that the effects of hand proximity in several tasks were eliminated by illumination with red diffuse light—a manipulation known to impair magnocellular processing. These results help clarify how the hands affect vision.     

The left visual hemispace bias for the perception of chimeric faces: a further test of the difficulty of discrimination hypothesis

When people make judgments of visual-spatial forms, they generally perform better if the information is presented in their left visual hemispace (LVH), whereas for verbal material, they generally show a right visual hemispace (RVH) bias. For verbal material, the strength and direction of the effect also has been linked to task difficulty, with the bias shifting toward the RVH as task difficulty increases. Two experiments are presented that show the reverse direction of change for a nonverbal task; that is, when a nonverbal task is more difficult, the usual LVH effect shifts toward an RVH bias. Taking into account recent developments in theory and research on hemispheric differences in styles of information processing, we propose that task difficulty is related more generally to changes in processing style.     

Oculomotion mediates attentional guidance toward temporarily close objects

Previous research has identified multiple features of individual objects that are capable of guiding visual attention. However, in dynamic multi-element displays not only individual object features but also changing spatial relations between two or more objects might signal relevance. Here we report a series of experiments that investigated the hypothesis that reduced inter-object spacing guides visual attention toward the corresponding objects. Our participants discriminated between different probes that appeared on moving objects while we manipulated spatial proximity between the objects at the moment of probe onset. Indeed, our results confirm that there is a bias toward temporarily close objects, which persists even when such a bias is harmful for the actual task (Experiments 1a and 1b). Remarkably, this bias is mediated by oculomotor processes. Controlling for eye-movements reverses the pattern of results (Experiment 2a), whereas the location of the gaze tends toward the temporarily close objects under free viewing conditions (Experiment 2b). Taken together, our results provide insights into the interplay of attentional and oculomotor processes during dynamic scene processing. Thereby, they also add to the growing body of evidence showing that within dynamic perception, attentional and oculomotor processes act conjointly and are hardly separable.     

Separating value from selection frequency in rapid reaching biases to visual targets

Stimuli associated with positive rewards in one task often receive preferential processing in a subsequent task, even when those associations are no longer relevant. Here we use a rapid reaching task to investigate these biases. In Experiment 1 we first replicated the learning procedure of Raymond and O'Brien (2009), for a set of arbitrary shapes that varied in value (positive, negative) and probability (20%, 80%). In a subsequent task, participants rapidly reached toward one of two shapes, except now the previously learned associations were irrelevant. As in the previous studies, we found significant reach biases toward shapes previously associated with a high probable, positive outcome. Unexpectedly, we also found a bias toward shapes previously associated with a low probable, negative outcome. Closer inspection of the learning task revealed a potential second factor that might account for these results; since a low probable negative shape was always paired with a high probable negative shape, it was selected with disproportionate frequency. To assess how selection frequency and reward value might both contribute to reaching biases we performed a second experiment. The results of this experiment at a group level replicated the reach-bias toward positively rewarding stimuli, but also revealed a separate bias toward stimuli that had been more frequently selected. At the level of individual participants, we observed a variety of preference profiles, with some participants biased primarily by reward value, others by frequency, and a few actually biased away from both highly rewarding and high frequency targets. These findings highlight that: (1) rapid reaching provides a sensitive readout of preferential processing; (2) target reward value and target selection frequency are separate sources of bias; and (3) group-level analyses in complex decision-making tasks can obscure important and varied individual differences in preference profiles.     

Top-down influences mediate hand bias in spatial attention

Spatial attention can be biased to locations near the hand. Some studies have found facilitated processing of targets appearing within hand-grasping space. In this study, we investigated how changing top-down task priorities alters hand bias during visual processing. In Experiment 1, we used a covert orienting paradigm with nonpredictive cues and emphasized the location of the hand relative to the target. Hands or visual anchors (boards) were placed next to potential target locations, and responses were made with the contralateral hand. Results indicated a hand-specific processing bias: Hand location, but not board location, speeded responses to targets near the hand. This pattern of results replicated previous studies using covert orienting paradigms with highly predictive cues. In Experiment 2, we used the same basic paradigm but emphasized the location of the response hand. Results now showed speeded responses to targets near response locations. Together these experiments demonstrated that top-down instructional sets (i.e., what is considered to be most relevant to task performance) can change the processing priority of hand location by influencing the strength of top-down, as compared with bottom-up, inputs competing for attention resources.     

Reduced visual feature binding in the near-hand space

Growing evidence suggests that visual information is processed differently in the near-hand space, relative to the space far from the hands. To account for the existing literature, we recently proposed that the costs and benefits of hand proximity may be due to differential contributions of the action-oriented magnocellular (M) and the perception-oriented parvocellular (P) pathways. Evidence suggests that, relative to the space far from the hands, in near-hand space the contribution of the M pathway increases while the contribution of the P pathway decreases. The present study tested an important consequence of this account for visual representation. Given the P pathway’s role in feeding regions in which visual representations of unified objects (with bound features) are formed, we predicted that hand proximity would reduce feature binding. Consistent with this prediction, two experiments revealed signs of reduced feature binding in the near-hand space, relative to the far-hand space. We propose that the higher contribution of the M pathway, along with the reduced contribution of the P pathway, shifts visual perception away from an object-based perceptual mode toward a feature-based mode. These results are discussed in light of the distinction between action-oriented and perception-oriented vision.     

Differential effect of one versus two hands on visual processing

Hand position in the visual field influences performance in several visual tasks. Recent theoretical accounts have proposed that hand position either (a) influences the allocation of spatial attention, or (b) biases processing toward the magnocellular visual pathway. Comparing these accounts is difficult as some studies manipulate the distance of one hand in the visual field while others vary the distance of both hands, and it is unclear whether single and dual hand manipulations have the same impact on perception. We ask if hand position affects the spatial distribution of attention, with a broader distribution of attention when both hands are near a visual display and a narrower distribution when one hand is near a display. We examined the effects of four hand positions near the screen (left hand, right hand, both hands, no hands) on both temporal and spatial discrimination tasks. Placing two hands near the display compared to two hands distant resulted in improved sensitivity for the temporal task and reduced sensitivity in the spatial task, replicating previous results. However, the single hand manipulations showed the opposite pattern of results. Together these results suggest that visual attention is focused on the graspable space for a single hand, and expanded when two hands frame an area of the visual field.     

Interpersonal self‐support and attentional bias on negative and positive interpersonal information

Interpersonal self‐support is an indigenous Chinese personality concept. It represents the idealized notion of the kind of personality traits that help individuals deal with interpersonal problems and develop and maintain the harmonic and appropriate social relationships required in China's collectivistic and interdependent culture. It also was assumed to be a protective personality factor with regard to mental health and was found to be negatively related to psychosomatic symptoms. In the current study, cognitive processing of interpersonal information is assumed to be an underlying mechanism that connects interpersonal self‐support with interpersonal relationships and mental health. To test this hypothesis, we conducted two experiments to investigate whether attentional bias on positive and negative interpersonal information was related to high and low interpersonal self‐support. A spatial cueing task and the emotional Stroop task were administered to two samples of high and low interpersonal self‐support Chinese undergraduate students to measure attentional bias. The results from both experiments suggested that high interpersonal self‐support students had an attentional bias toward positive interpersonal information, while low interpersonal self‐support students preferentially attended to negative interpersonal information. Study 1 indicated that attentional bias toward positive interpersonal information was easily engaged in the high interpersonal self‐support group, while attentional bias toward negative interpersonal information was both easy to engage and difficult to disengage in the low interpersonal self‐support students. These results support our hypotheses that high interpersonal self‐support people engage in positive processing of interpersonal information, whereas low interpersonal self‐support people engage in negative processing of interpersonal information. The differential balance between positive and negative processing on interpersonal information may explain why interpersonal self‐support predicts both mental health and interpersonal relationships. In addition, the relational schema may explain why interpersonal self‐support is associated with an attentional bias toward interpersonal information.     

Do you see what I see? Co-actor posture modulates visual processing in joint tasks

ABSTRACT

Interacting with other people is a ubiquitous part of daily life. A complex set of processes enable our successful interactions with others. The present research was conducted to investigate how the processing of visual stimuli may be affected by the presence and the hand posture of a co-actor. Experiments conducted with participants acting alone have revealed that the distance from the stimulus to the hand of a participant can alter visual processing. In the main experiment of the present paper, we asked whether this posture-related source of visual bias persists when participants share the task with another person. The effect of personal and co-actor hand-proximity on visual processing was assessed through object-specific benefits to visual recognition in a task performed by two co-actors. Pairs of participants completed a joint visual recognition task and, across different blocks of trials, the position of their own hands and of their partner's hands varied relative to the stimuli. In contrast to control studies conducted with participants acting alone, an object-specific recognition benefit was found across all hand location conditions. These data suggest that visual processing is, in some cases, sensitive to the posture of a co-actor.     

Target animacy influences chimpanzee handedness

We employed a bottom-up, quantitative method to investigate great ape handedness. Our previous investigation of gorillas (Gorilla gorilla gorilla) demonstrated that contextual information influenced an individual’s handedness toward target objects. Specifically, we found a significant right-hand bias for unimanual actions directed toward inanimate target objects but not for actions directed to animate target objects (Forrester et al. in Anim Cogn 14(6):903–907, 2011). Using the identical methodological technique, we investigated the spontaneous hand actions of nine captive chimpanzees (Pan troglodytes) during naturalistic, spontaneous behavior. We assessed both the frequencies and proportions of lateralized hand actions directed toward animate and inanimate targets employing focal follow video sampling. Like the gorillas, the chimpanzees demonstrated a right-handed bias for actions directed toward inanimate targets, but not toward animate targets. This pattern was evident at the group level and for the majority of subjects at the individual level. We postulate that a right-hand bias for only inanimate targets reflects the left hemisphere’s dominant neural processing capabilities for objects that have functional properties (inanimate objects). We further speculate that a population-level right-hand bias is not a human-unique characteristic, but one that was inherited from a common human-ape ancestor.     

An evaluation of early and late stage attentional processing of positive and negative information in dysphoria

Depressive disorders may be characterised by hyperattention toward negative information, hypoattention toward positive information, or a combination of both processing biases. In two studies, a dot-probe task was utilised to better ascertain the specific direction and time-course of these biases. In both studies, the dysphoric group showed significantly less attentional allocation toward positive stimuli than the non-dysphoric group. In study two, the dysphoric group also showed greater attentional allocation toward depression-specific stimuli. Importantly, the bias toward depression-specific stimuli, and the bias away from positive stimuli, were uncorrelated with each other. It may be that both biases can act as sufficient, but not necessary, characteristics of dysphoric processing. An additional possibility is that the relative level of each bias type may best characterise dysphoric processing. Each of these possibilities is discussed in turn.     

Near-hand effects are robust: Three OSF pre-registered replications of visual biases in perihand space

ABSTRACT

Although previous work provides evidence that observers experience biases in visual processing when they view stimuli in perihand space, a few recent investigations have questioned the reliability of these near-hand effects. We addressed this controversy by running three pre-registered replication experiments. Experiment 1 was a replication of one of the initial studies on facilitated target detection near the hands in which participants performed an attentional cueing task while placing a single hand either near or far from the display. Experiment 2 tested the same paradigm while adopting the design of a recent experiment that called into question near-hand facilitation. Experiment 3 was a replication of a study in which hand proximity influenced working memory performance in a change detection paradigm. Across all three experiments, we found significant interactions between hand position and stimulus characteristics that indicated the hands’ presence altered visual processing, bolstering evidence favouring the robustness of near-hand effects.     

Evidence from a response choice task reveals a selection bias in the attentional cueing paradigm

In a typical attentional cueing paradigm, irrelevant peripheral cues produce early facilitation (fast responses) followed by later inhibition (slow responses) to cued locations. Here we examine whether cues not only influence the speed with which responses are produced, but also impact or bias which location is ultimately selected as requiring a response. Specifically, can cues influence not only the speed with which we respond but also influence the behavior produced? To examine this question, a choice localization task was used in which no targets were presented, and subjects were asked to choose which effector (left hand, right hand) to use in response to a centrally presented tone. Thus, following either a left or right peripheral cue, and then a central tone, subjects were free to respond with either their left or right hand. Early facilitation and later inhibition with this choice procedure were found in both response times and the proportion of responses to the cued and uncued locations. These results suggest that there are processes which initially bias response selection toward cued locations and then subsequently bias response selection away from cued locations.     

Selective attention and emotional vulnerability: assessing the causal basis of their association through the experimental manipulation of attentional bias

Although it is well-established that vulnerability to negative emotion is associated with attentional bias toward aversive information, the causal basis of this association remains undetermined. Two studies addressed this issue by experimentally inducing differential attentional responses to emotional stimuli using a modified dot probe task, and then examining the impact of such attentional manipulation on subsequent emotional vulnerability. The results supported the hypothesis that the induction of attentional bias should serve to modify emotional vulnerability, as revealed by participants' emotional reactions to a final standardized stress task. These findings provide a sound empirical basis for the previously speculative proposal that attentional bias can causally mediate emotional vulnerability, and they suggest the possibility that cognitive-experimental procedures designed to modify selective information processing may have potential therapeutic value.     

Lack of an Attention Bias Away From Relatively Negative Faces in Dysphoria Is Not Related to Biased Emotion Identification

Eye-tracking-based attention research has consistently shown a lack of a normative attentional bias away from dysphoric face stimuli in depression, characterizing the attention system of non-depressed individuals. However, this more equal attention allocation pattern could also be related to biased emotion identification, namely, an inclination of depressed individuals to attribute negative emotions to non-negative stimuli when processing mood-congruent stimuli. Here, we examined emotion identification as a possible mechanism associated with attention allocation when processing emotional faces in depression. Attention allocation and emotion identification of participants with high (HD; n = 30) and low (LD; n = 30) levels of depression symptoms were assessed using two corresponding tasks previously shown to yield significant findings in depression, using the same face stimuli (sad, happy, and neutral faces) across both tasks. We examined group differences on each task and possible between-task associations. Results showed that while LD participants dwelled longer on relatively positive faces compared with relatively negative faces on the attention allocation task, HD participants showed no such bias, dwelling equally on both. Trait anxiety did not affect these results. No group differences were noted for emotion identification, and no between-task associations emerged. Present results suggest that depression is characterized by a lack of a general attention bias toward relatively positive faces over relatively negative faces, which is not related to a corresponding bias in emotion identification.     

Consistent left gaze bias in processing different facial cues

While viewing faces, humans often demonstrate a natural gaze bias towards the left visual field, that is, the right side of the viewee’s face is often inspected first and for longer periods. Previous studies have suggested that this gaze asymmetry is a part of the gaze pattern associated with face exploration, but its relation with perceptual processing of facial cues is unclear. In this study we recorded participants’ saccadic eye movements while exploring face images under different task instructions (free viewing, judging familiarity and judging facial expression). We observed a consistent left gaze bias in face viewing irrespective of task demands. The probability of the first fixation and the proportion of overall fixations directed at the left hemiface were indistinguishable across different task instructions or across different facial expressions. It seems that the left gaze bias is an automatic reflection of hemispheric lateralisation in face processing, and is not necessarily correlated with the perceptual processing of a specific type of facial information.     

Engagement Attentional Bias toward Value-Associated Stimuli

Recent evidence has shown that learning to associate the value of behavioral outcomes with specific stimuli (i.e., value learning/association) can induce attentional capture in a subsequent visual search task. Here we investigated the component of attentional bias toward value-associated stimuli in the dot-probe paradigm. In the training phase, participants learned to associate nonsense shape outlines with monetary wins or losses. The shapes were then used as cues in an explicit no feedback dot-probe task. Probe appeared at either the salient (congruent trial) or nonsalient location (incongruent trial). Results indicate attentional bias toward value-associated stimuli, futher more this attentional bias is driven by an engagement bias.     

Nonattentional effects of nonpredictive central cues

Recent evidence suggests that nonpredictive gaze, hand, arrow, and peripheral cues elicit shifts of reflexive attention. In the present article, we address whether these cues also influence the decision criterion in a go/no-go task. Nonpredictive central gaze and hand cues pointed toward or away from the location of an imminent target. Responses to the targets were faster, and false alarm errors were more frequent, when cues pointed toward the target than when they were directed away from it. Although a similar pattern was observed with nonpredictive arrow cues, it was not seen with nonpredictive peripheral cues. These results suggest that nonpredictive central cues not only affect attention, but also bias decision processes.