Eye movements may cause motor contagion effects

When a person executes a movement, the movement is more errorful while observing another person’s actions that are incongruent rather than congruent with the executed action. This effect is known as “motor contagion”. Accounts of this effect are often grounded in simulation mechanisms: increased movement error emerges because the motor codes associated with observed actions compete with motor codes of the goal action. It is also possible, however, that the increased movement error is linked to eye movements that are executed simultaneously with the hand movement because oculomotor and manual-motor systems are highly interconnected. In the present study, participants performed a motor contagion task in which they executed horizontal arm movements while observing a model making either vertical (incongruent) or horizontal (congruent) movements under three conditions: no instruction, maintain central fixation, or track the model’s hand with the eyes. A significant motor contagion-like effect was only found in the ‘track’ condition. Thus, ‘motor contagion’ in the present task may be an artifact of simultaneously executed incongruent eye movements. These data are discussed in the context of stimulation and associative learning theories, and raise eye movements as a critical methodological consideration for future work on motor contagion.     

A PRP-study to determine the locus of target priming effects

Visual stimuli that are made invisible by a following mask can nonetheless affect motor responses. To localize the origin of these target priming effects we used the psychological refractory period paradigm. Participants classified tones as high or low, and responded to the position of a visual target that was preceded by a prime. The stimulus onset asynchrony (SOA) between both tasks varied. In Experiment 1 the tone task was followed by the position task and SOA dependent target priming effects were observed. When the visual position task preceded the tone task in Experiment 2, with short SOA the priming effect propagated entirely to the tone task yielding faster responses to tones on visually congruent trials and delayed responses to tones on visually incongruent trials. Together, results suggest that target priming effects arise from processing before and at the level of the central bottleneck such as sensory analysis and response selection.     

Action effects in saccade control

According to the ideomotor principle, action preparation involves the activation of associations between actions and their effects. However, there is only sparse research on the role of action effects in saccade control. Here, participants responded to lateralized auditory stimuli with spatially compatible saccades toward peripheral targets (e.g., a rhombus in the left hemifield and a square in the right hemifield). Prior to the imperative auditory stimulus (e.g., a left tone), an irrelevant central visual stimulus was presented that was congruent (e.g., a rhombus), incongruent (e.g., a square), or unrelated (e.g., a circle) to the peripheral saccade target (i.e., the visual effect of the saccade). Saccade targets were present throughout a trial (Experiment 1) or appeared after saccade initiation (Experiment 2). Results showed shorter response times and fewer errors in congruent (vs. incongruent) conditions, suggesting that associations between oculomotor actions and their visual effects play an important role in saccade control.     

Action for perception: a motor-visual attentional effect

Five experiments investigated whether preparation of a grasping movement affects detection and discrimination of visual stimuli. Normal human participants were required to prepare to grasp a bar and then to grasp it as fast as possible on presentation of a visual stimulus. On the basis of the degree of sharing of their intrinsic properties with those of the to-be-grasped bar, visual stimuli were categorized as "congruent" or "incongruent." Results showed that grasping reaction times to congruent visual stimuli were faster than reaction times to incongruent ones. These data indicate that preparation to act on an object produces faster processing of stimuli congruent with that object. The same facilitation was present also when, after the preparation of hand grasping, participants were suddenly instructed to inhibit the prepared grasping movement and to respond with a different motor effector. The authors suggest that these findings could represent an extension of the premotor theory of attention, from orienting of attention to spatial locations to orienting of attention to graspable objects.     

Automatic auditory disambiguation of visual awareness

Multisensory integration can play a critical role in producing unified and reliable perceptual experience. When sensory information in one modality is degraded or ambiguous, information from other senses can crossmodally resolve perceptual ambiguities. Prior research suggests that auditory information can disambiguate the contents of visual awareness by facilitating perception of intermodally consistent stimuli. However, it is unclear whether these effects are truly due to crossmodal facilitation or are mediated by voluntary selective attention to audiovisually congruent stimuli. Here, we demonstrate that sounds can bias competition in binocular rivalry toward audiovisually congruent percepts, even when participants have no recognition of the congruency. When speech sounds were presented in synchrony with speech-like deformations of rivalling ellipses, ellipses with crossmodally congruent deformations were perceptually dominant over those with incongruent deformations. This effect was observed in participants who could not identify the crossmodal congruency in an open-ended interview (Experiment 1) or detect it in a simple 2AFC task (Experiment 2), suggesting that the effect was not due to voluntary selective attention or response bias. These results suggest that sound can automatically disambiguate the contents of visual awareness by facilitating perception of audiovisually congruent stimuli.     

The influence of environmental context in interpersonal observation–execution

Cyclical upper-limb movements involuntarily deviate from a primary movement direction when the actor concurrently observes incongruent biological motion. We examined whether environmental context influences such motor interference during interpersonal observation–execution. Participants executed continuous horizontal arm movements while observing congruent horizontal or incongruent curvilinear biological movements with or without the presence of an object positioned as an obstacle or distractor. When participants were observing a curvilinear movement, an object located within the movement space became an obstacle, and, thus, the curvilinear trajectory was essential to reach into horizontal space. When acting as a distractor, or with no object, the curvilinear trajectory was no longer essential. For observing horizontal movements, objects were located at the same relative locations as in the curvilinear movement condition. We found greater involuntary movement deviation when observing curvilinear than horizontal movements. Also, there was an influence of context only when observing horizontal movements, with greater deviation exhibited in the presence of a large obstacle. These findings suggest that the influence of environmental context is underpinned by the (mis-)matching of observed and executed actions as incongruent biological motion is primarily coded via bottom-up sensorimotor processes, whilst the congruent condition incorporates surrounding environmental features to modulate the bottom-up sensorimotor processes.     

Speech perception and vocal expression of emotion

Two experiments using identical stimuli were run to determine whether the vocal expression of emotion affects the speed with which listeners can identify emotion words. Sentences were spoken in an emotional tone of voice (Happy, Disgusted, or Petrified), or in a Neutral tone of voice. Participants made speeded lexical decisions about the word or pseudoword in sentence-final position. Critical stimuli were emotion words that were either semantically congruent or incongruent with the tone of voice of the sentence. Experiment 1, with randomised presentation of tone of voice, showed no effect of congruence or incongruence. Experiment 2, with blocked presentation of tone of voice, did show such effects: Reaction times for congruent trials were faster than those for baseline trials and incongruent trials. Results are discussed in terms of expectation (e.g., Kitayama, 1990, 1991, 1996) and emotional connotation, and implications for models of word recognition are considered.     

On the interplay of visuospatial and audiotemporal dominance: Evidence from a multimodal kappa effect

When participants judge multimodal audiovisual stimuli, the auditory information strongly dominates temporal judgments, whereas the visual information dominates spatial judgments. However, temporal judgments are not independent of spatial features. For example, in the kappa effect, the time interval between two marker stimuli appears longer when they originate from spatially distant sources rather than from the same source. We investigated the kappa effect for auditory markers presented with accompanying irrelevant visual stimuli. The spatial sources of the markers were varied such that they were either congruent or incongruent across modalities. In two experiments, we demonstrated that the spatial layout of the visual stimuli affected perceived auditory interval duration. This effect occurred although the visual stimuli were designated to be task-irrelevant for the duration reproduction task in Experiment 1, and even when the visual stimuli did not contain sufficient temporal information to perform a two-interval comparison task in Experiment 2. We conclude that the visual and auditory marker stimuli were integrated into a combined multisensory percept containing temporal as well as task-irrelevant spatial aspects of the stimulation. Through this multisensory integration process, visuospatial information affected even temporal judgments, which are typically dominated by the auditory modality.     

视听刺激突显性对视觉主导效应的影响

本研究使用空间任务-转换范式,控制视、听刺激的突显性,探讨自下而上注意对视觉主导效应的影响。结果表明视、听刺激突显性显著地影响视觉主导效应,实验一中当听觉刺激为高突显性时,视觉主导效应显著减弱。实验二中当听觉刺激为高突显性并且视觉刺激为低突显性时,视觉主导效应进一步减弱但依然存在。结果支持偏向竞争理论,在跨通道视听交互过程中视觉刺激更具突显性,在多感觉整合过程中更具加工优势。     

Multisensory synesthetic interactions in the speeded classification of visual size

In the present study, we attempted to demonstrate a synesthetic relationship between auditory frequency and visual size. In Experiment 1, participants performed a speeded visual size discrimination task in which they had to judge whether a variable-sized disk was bigger or smaller than a standard reference disk. A task-irrelevant sound that was either synesthetically congruent with the relative size of the disk (e.g., a low-frequency sound presented with a bigger disk) or synesthetically incongruent with it (e.g., a low-frequency sound presented with a smaller disk) was sometimes presented together with the variable disk. Reaction times were shorter in the synesthetically congruent condition than in the incongruent condition. Verbal labeling and semantic mediation interpretations of this interaction were explored in Experiment 2, in which high- and low-frequency sounds were presented in separate blocks of trials, and in Experiment 3, in which the tones were replaced by the spoken words "high" and "low." Response priming/bias explanations were ruled out in Experiment 4, in which a synesthetic congruency effect was still reported even when participants made same-versus-different discrimination responses regarding the relative sizes of the two disks. Taken together, these results provide the first empirical demonstration that the relative frequency of an irrelevant sound can influence the speed with which participants judge the size of visual stimuli when the sound varies on a trial-by-trial basis along a synesthetically compatible dimension. The possible cognitive bases for this synesthetic association are also discussed.     

When hearing turns into playing: Movement induction by auditory stimuli in pianists

In this study, pianists were tested for learned associations between actions (movements on the piano) and their perceivable sensory effects (piano tones). Actions were examined that required the playing of two-tone sequences (intervals) in a four-choice paradigm. In Experiment 1, the intervals to be played were denoted by visual note stimuli. Concurrently with these imperative stimuli, task-irrelevant auditory distractor intervals were presented (“potential” action effects, congruent or incongruent). In Experiment 2, imperative stimuli were coloured squares, in order to exclude possible influences of spatial relationships of notes, responses, and auditory stimuli. In both experiments responses in the incongruent conditions were slower than those in the congruent conditions. Also, heard intervals actually “induced” false responses. The reaction time effects were more pronounced in Experiment 2. In nonmusicians (Experiment 3), no evidence for interference could be observed. Thus, our results show that in expert pianists potential action effects are able to induce corresponding actions, which demonstrates the existence of acquired action-effect associations in pianists.     

Inhibition and decay of motor and nonmotor priming

Motor responses can be facilitated by congruent visual stimuli and prolonged by incongruent visual stimuli that are made invisible by masking (direct motor priming). Recent studies on direct motor priming showed a reversal of these priming effects when a three-stimulus paradigm was used in which a prime was followed by a mask and a target stimulus was presented after a delay. A similar three-stimulus paradigm on nonmotor priming, however, showed no reversal of priming effects when the mask was used as a cue for processing of the following target stimulus (cue priming). Experiment 1 showed that the time interval between mask and target is crucial for the reversal of priming. Therefore, the time interval between mask and target was varied in three experiments to see whether cue priming is also subject to inhibition at a certain time interval. Cues indicated (1) the stimulus modality of the target stimulus, (2) the task to be performed on a multidimensional auditory stimulus, or (3) part of the motor response. Whereas direct motor priming showed the reversal of priming about 100 msec after mask presentation, cue priming effects simply decayed during the 300 msec after mask presentation. These findings provide boundary conditions for accounts of inverse priming effects.     

Probing Representations of Gymnastics Movements: A Visual Priming Study

In this study, we designed a visual short‐term priming paradigm to investigate the mechanisms underlying the priming of movements and to probe movement representations in motor experts and matched controls. We employed static visual stimuli that implied or not human whole‐body movements, that is, gymnastics movements and static positions. Twelve elite female gymnasts and twelve matched controls performed a speeded two‐choice response time task. The participants were presented with congruent and incongruent prime‐target pairs and had to decide whether the target stimulus represented a gymnastics movement or a static position. First, a visual priming effect was observed in the two groups. Second, a stimulus–response rote association could not easily account for our results. Novel primes never presented as targets could also prime the targets. Third, by manipulating three levels of prime‐target relations in moving congruent pairs, we demonstrated that the more similar prime‐target pairs, the greater the facilitation in target. Lastly, gymnastics motor expertise impacted on priming effects.     

Sensitivity to auditory‐tactile colocation in early infancy

An ability to detect the common location of multisensory stimulation is essential for us to perceive a coherent environment, to represent the interface between the body and the external world, and to act on sensory information. Regarding the tactile environment “at hand”, we need to represent somatosensory stimuli impinging on the skin surface in the same spatial reference frame as distal stimuli, such as those transduced by vision and audition. Across two experiments we investigated whether 6‐ (n = 14; Experiment 1) and 4‐month‐old (n = 14; Experiment 2) infants were sensitive to the colocation of tactile and auditory signals delivered to the hands. We recorded infants’ visual preferences for spatially congruent and incongruent auditory‐tactile events delivered to their hands. At 6 months, infants looked longer toward incongruent stimuli, whilst at 4 months infants looked longer toward congruent stimuli. Thus, even from 4 months of age, infants are sensitive to the colocation of simultaneously presented auditory and tactile stimuli. We conclude that 4‐ and 6‐month‐old infants can represent auditory and tactile stimuli in a common spatial frame of reference. We explain the age‐wise shift in infants’ preferences from congruent to incongruent in terms of an increased preference for novel crossmodal spatial relations based on the accumulation of experience. A comparison of looking preferences across the congruent and incongruent conditions with a unisensory control condition indicates that the ability to perceive auditory‐tactile colocation is based on a crossmodal rather than a supramodal spatial code by 6 months of age at least.     

Coding processes in preselected and constrained movements: effect of vision

Three experiments were conducted in which visual information was manipulated either at the endpoint or during preselected, subject defined and constrained, experimenter-defined movements. In Experiments 1 and 2 the subject's task was to reproduce the movement in the absence of vision. Augmenting the terminal location of the criterion movement with vision had no differential effect on reproduction in Experiment 1, although preselected movement accuracy was significantly superior to constrained. Providing vision throughout the criterion movement in Experiment 2 not only failed to improve the accuracy of constrained movements but decreased reproduction performance in preselected movements. In Experiment 3 procedures were adopted to control the allocation of the subjects' attention during the criterion movement. The subjects reproduced by vision alone, movement alone, or with both visual and movement information available. When subjects were informed of the modality of reproduction prior to criterion presentation, they were able to ignore concurrent input from vision and attend to movement information. In the absence of precues visual information was spontaneously attended. The data were interpreted as contrary to closed-loop assumptions that additional information necessarily enhances the strength of a motor memory representation. Rather, they can be accommodated in terms of Posner, Nissen and Klein's (1976) theoretical account of visual dominance and serve to illustrate the importance of selective attention effects in movement coding.     

Acquired equivalence and distinctiveness of cues: I. Exploring a neural network approach

Rats were placed in 4 contexts (A, B, C, D) where they received 2 auditory stimuli (X, Y); in A and B, presentations of X were paired with food and those of Y were not, and in C and D, Y was paired with food and X was not. Rats then received combinations of contexts that had provided congruent (AB, CD) or incongruent (AD, CB) information about X and Y's relationship to food. Responding was more variable during congruent than incongruent trials (Experiment 1) and was systematically increased and decreased during congruent (relative to incongruent) trials by the presentation of food or no food, respectively (Experiment 2). These results support a connectionist approach to acquired changes in stimulus distinctiveness.     

Does crossmodal correspondence modulate the facilitatory effect of auditory cues on visual search?

The ??pip-and-pop effect?? refers to the facilitation of search for a visual target (a horizontal or vertical bar whose color changes frequently) among multiple visual distractors (tilted bars also changing color unpredictably) by the presentation of a spatially uninformative auditory cue synchronized with the color change of the visual target. In the present study, the visual stimuli in the search display changed brightness instead of color, and the crossmodal congruency between the pitch of the auditory cue and the brightness of the visual target was manipulated. When cue presence and cue congruency were randomly varied between trials (Experiment 1), both congruent cues (low-frequency tones synchronized with dark target states or high-frequency tones synchronized with bright target states) and incongruent cues (the reversed mapping) facilitated visual search performance equally, relative to a no-cue baseline condition. However, when cue congruency was blocked and the participants were informed about the pitch?Cbrightness mapping in the cue-present blocks (Experiment 2), performance was significantly enhanced when the cue and target were crossmodally congruent as compared to when they were incongruent. These results therefore suggest that the crossmodal congruency between auditory pitch and visual brightness can influence performance in the pip-and-pop task by means of top-down facilitation.     

面孔表情和声音情绪信息整合对返回抑制的影响

返回抑制(inhibition of return, IOR)与情绪刺激都具有引导注意偏向、提高搜索效率的特点, 但二者间是否存在一定的交互作用迄今为止尚不明确。研究采用“线索-目标”范式并在视听双通道呈现情绪刺激来考察情绪刺激的加工与IOR的交互作用。实验1中情绪刺激以单通道视觉面孔或一致的视听双通道呈现, 实验2通过在视听通道呈现不一致的情绪刺激进一步考察视听双通道情绪一致刺激对IOR的影响是否是由听觉通道一致的情绪刺激导致的, 即是否对听觉通道的情绪刺激进行了加工。结果发现, 视听双通道情绪一致刺激能够削弱IOR, 但情绪不一致刺激与IOR之间不存在交互作用, 并且单双通道的IOR不存在显著差异。研究结果表明仅在视听双通道呈现情绪一致刺激时, 才会影响同一阶段的IOR, 这进一步支持了IOR的知觉抑制理论。     

The temporal dynamics of the perceptual consequences of action-effect prediction

An essential aspect of voluntary action control is the ability to predict the perceptual effects of our actions. Although the influence of action-effect prediction on humans’ behavior and perception is unequivocal, it remains unclear when action-effect prediction is generated by the brain. The present study investigates the dynamics of action effect anticipation by tracing the time course of its perceptual consequences. Participants completed an acquisition phase during which specific actions (left and right key-presses) were associated with specific visual effects (upward and downward dots motion). In the test phase they performed a 2 AFC identification task in which they were required to indicate whether the dots moved upward or downward. To isolate any effects of action-effect prediction on perception, participants were presented with congruent and incongruent dot motion in which the association participants learned in the previous acquisition phase was respected and violated, respectively. Crucially, to assess the temporal dynamics of action prediction, congruent and incongruent stimuli were presented at different intervals before or after action execution. We observed higher sensitivity (d′) to motion discrimination in congruent vs. incongruent trials only when stimuli were presented from about 220 ms before the action to 280 ms after the action. The temporal dynamics of our effect suggest that action-effect prediction modulates perception at later stages of motor preparation.     

Painful semantic context modulates the relationship between action words and biological movement perception

Studies have revealed a close relationship between action–word processing and the detection of point-light biological movements and that this effect can be modulated by the context of action-verb presentation. The goal of the present study was to further examine the extent to which motor representation activation plays a role in this relationship by testing the influence of painless/painful sentence understanding during a listening task. Participants judged the presence or absence of a point-light biological movement that was embedded in a scrambled mask after a congruent or incongruent action sentence was presented. The sentences varied according to the context of action-verb presentation (painful, painless). Perceptual judgments of human movements improved after a prior presentation of a congruent action sentence but only in the painless context. Thus, our findings show that pain included in a semantic context of sentence presentation can preclude the relationship between action–word understanding and point-light biological movement judgments.