Gender recognition depends on type of movement and motor skill. Analyzing and perceiving biological motion in musical and nonmusical tasks

Gender recognition in point-light displays was investigated with regard to body morphology cues and motion cues of human motion performed with different levels of technical skill. Gestures of male and female orchestral conductors were recorded with a motion capture system while they conducted excerpts from a Mendelssohn string symphony to musicians. Point-light displays of conductors were presented to observers under the following conditions: visual-only, auditory-only, audiovisual, and two non-conducting conditions (walking and static images). Observers distinguished between male and female conductors in gait and static images, but not in visual-only and auditory-only conducting conditions. Across all conductors, gender recognition for audiovisual stimuli was better than chance, yet significantly less reliable than for gait. Separate analyses for two groups of conductors indicated an expertise effect in that novice conductors' gender was perceived above chance level for visual-only and audiovisual conducting, while skilled conducting gestures of experts did not afford gender-specific cues. In these conditions, participants may have ignored the body morphology cues that led to correct judgments for static images. Results point to a response bias such that conductors were more often judged to be male. Thus judgment accuracy depended both on the conductors' level of expertise as well as on the observers' concepts, suggesting that perceivable differences between men and women may diminish for highly trained movements of experienced individuals.     

The handedness of imagined bodies in action and the role of perspective taking

Past research at the nexus of motor control and perception investigated the role of perspective taking in many behavioral and neuroimaging studies. Some investigators addressed the issue of one's own vs. others' action imagination, but the possible effects of a front or a back view in imagining others' actions have so far been neglected. We report two 'single trial' experiments in which a total of 640 participants were asked to imagine a person performing a manual action - either in a front or in a back view - and then to indicate the hand used by the imagined person during movement execution. In such a task, we assume the existence of two distinct biases: a perceptual-mnemonic bias due to subjects' visual experience of others' actions, encouraging them to imagine right-handed movements, and a motor bias due to subjects' experience of self-made actions, encouraging them to imagine movements performed with the same hand as their dominant hand. We hypothesized that a greater involvement of motor representations in the back view compared to the front view could result in an increased correspondence between one's own manual preference and the hand used by the imagined agent in the former condition. The results of both experiments were consistent with this hypothesis, suggesting that while imagining others' actions we employ motor simulations in different degrees according to the perspective adopted.     

Apraxia in corticobasal degeneration.

Corticobasal degeneration (CBD) is a degenerative disease that often presents with an asymmetric progressive ideomotor limb apraxia. Some apraxic subjects may fail to perform skilled purposive movements on command because they have lost the memories or representations that specify how these movements should be performed (representational deficit). In contrast, other apraxic subjects may have the movement representations but are unable to utilize the information contained in them to execute skilled purposive movements (production-execution deficit). To learn if the apraxic deficit in CBD is induced by a representational or a production-execution deficit, we tested three nondemented subjects with CBD on tasks requiring production of meaningful or meaningless gestures to command, gesture imitation, gesture discrimination, and novel gesture learning. A fourth subject with incomplete data also is presented. The results suggest that the apraxia associated with CBD is initially induced by a production-execution defect with relative sparing of the movement representations.     

Neuropsychological functions of hand movements and gestures change in the presence or absence of speech

In order to address previous controversies whether hand movements and gestures are linked to mental concepts or solely to the process of speaking, in the present study we investigate the neuropsychological functions of the entire spectrum of unimanual and bimanual hand movements and gestures when they either accompany speaking or when they act as the only means to communicate in the absence of speech. The results showed that the hand movement activity regarding all types of hand movements and gestures stayed constant with and without speaking. The analysis of the Structure of hand movements showed that executions shifted from in space hand movements with a phase structure during the condition without speech to more irregular on body hand movements without a phase structure during the co-speech condition. The gestural analysis revealed that pantomime gestures increase under conditions without speech whereas emotional motions and subject-oriented actions primarily occur when speaking. The present results provide evidence that the overall hand movement activity does not differ between co-speech conditions and conditions without speech, but that the hands adopt different neuropsychological functions. We conclude that the hands primarily externalise mental concepts in conditions without speaking but that their use shifts to more self-regulation and to endorsing verbal output with emotional connotations when they accompany speech.     

Recognizing people from their movement

Human observers demonstrate impressive visual sensitivity to human movement. What defines this sensitivity? If motor experience influences the visual analysis of action, then observers should be most sensitive to their own movements. If view-dependent visual experience determines visual sensitivity to human movement, then observers should be most sensitive to the movements of their friends. To test these predictions, participants viewed sagittal displays of point-light depictions of themselves, their friends, and strangers performing various actions. In actor identification and discrimination tasks, sensitivity to one's own motion was highest. Visual sensitivity to friends', but not strangers', actions was above chance. Performance was action dependent. Control studies yielded chance performance with inverted and static displays, suggesting that form and low-motion cues did not define performance. These results suggest that both motor and visual experience define visual sensitivity to human action.     

社会场景下联合表征的整合机制

人们在交互过程中会同时表征自我和他人相关的信息,形成社会性联合表征.然而,自我和他人相关信息是以整合还是分离的形式存在,这一问题尚未厘清.本研究以工作记忆蓬佐错觉为指标展开了探讨.实验中要求两名被试分别记忆部分构成蓬佐错觉的线段并回忆.结果发现,竞争和合作场景下的个体不仅表征了他人相关的信息,还将其和自身相关的信息进行了整合,形成工作记忆蓬佐错觉效应,表明社会交互条件下会自动整合成社会性共同表征.     

Eye movements of highly skilled and average readers: Differential effects of frequency and predictability

This study offers a glimpse of the moment-by-moment processes used by highly skilled and average readers during silent reading. The eye movements of adult readers were monitored while they silently read sentences. Fixation durations and the spatial-temporal patterns of eye movements were examined to see whether the two groups of readers exhibited differential effects of frequency and/or predictability. In Experiment 1, high- and low-frequency target words were embedded in nonconstraining sentence contexts. In Experiment 2, the same participants read high- and low-frequency target words that were either predictable or unpredictable, embedded in highly constraining sentence contexts. Results indicated that when target words appeared in highly constraining sentence contexts, the average readers showed different effects of frequency and predictability from those shown in the highly skilled readers. It appears that reading skill can interact with predictability to affect the word recognition processes used during silent reading.     

Action information from classification learning

University of Illinois at Urbana-Champaign, Urbana, Illinois Much of our learning comes from interacting with objects. Two experiments investigated whether or not arbitrary actions used during category learning with objects might be incorporated into object representations and influence later recognition judgments. In a virtual-reality chamber, participants used distinct arm movements to make different classification responses. During a recognition test phase, these same objects required arm movements that were consistent or inconsistent with the classification movement. In both experiments, consistent movements were facilitated relative to inconsistent movements, suggesting that arbitrary action information is incorporated into the representations.     

The eyes know: eye movements as a veridical index of memory

In two experiments, we examined whether observers' eye movements distinguish studied faces from highly similar novel faces. Participants' eye movements were monitored while they viewed three-face displays. Target-present displays contained a studied face and two morphed faces that were visually similar to it; target-absent displays contained three morphed faces that were visually similar to a studied, but not tested, face. On each trial in a test session, participants were instructed to choose the studied face if it was present or a random face if it was not and then to indicate whether the chosen face was studied. Whereas manipulating visual similarity in target-absent displays influenced the rate of false endorsements of nonstudied items as studied, eye movements proved impervious to this manipulation. Studied faces were viewed disproportionately from 1,000 to 2,000 ms after display onset and from 1,000 to 500 ms before explicit identification. Early viewing also distinguished studied faces from faces incorrectly endorsed as studied. Our findings show that eye movements provide a relatively pure index of past experience that is uninfluenced by explicit response strategies, and suggest that eye movement measures may be of practical use in applied settings.     

The Social Nature of Perception and Action

ABSTRACT— Humans engage in a wide range of social activities. Previous research has focused on the role of higher cognitive functions, such as mentalizing (the ability to infer others' mental states) and language processing, in social exchange. This article reviews recent studies on action perception and joint action suggesting that basic perception–action links are crucial for many social interactions. Mapping perceived actions to one's own action repertoire enables direct understanding of others' actions and supports action identification. Joint action relies on shared action representations and involves modeling of others' performance in relation to one's own. Taking the social nature of perception and action seriously not only contributes to the understanding of dedicated social processes but has the potential to create a new perspective on the individual mind and brain.     

Premovement activity of the pre-supplementary motor area and the readiness for action: studies of time-resolved event-related functional MRI

The supplementary motor area (SMA) is thought to play in important role in the preparation and organisation of voluntary movement. It has long been known that cortical activity begins to increase up to 2s prior to voluntary self-initiated movement. This increasing premovement activity measured in EEG is known as the Bereitschaftspotential or readiness potential. Modern functional brain imaging methods, using event-related and time-resolved functional MRI techniques, are beginning to reveal the role of the SMA, and in particular the more anterior pre-SMA, in premovement activity associated with the readiness for action. In this paper we review recent studies using event-related time-resolved fMRI methods to examine the time-course of activation changes within the SMA throughout the preparation, readiness and execution of action. These studies suggest that the pre-SMA plays a common role in encoding or representing actions prior to our own voluntary self-initiated movements, during motor imagery, and from the observation of others' actions. We suggest that the pre-SMA generates and encodes motor representations which are then maintained in readiness for action.     

The action congruency effect on the feelings of agency

Previous studies suggest that the sense of agency (SoA), the feeling of control about one’s own actions and ensuing effects is also generated during action selection processes. We investigate whether the conflict at the action selection stage induced by a supraliminal stimulus, modulates an implicit measure of SoA, namely intentional binding. Furthermore, we were interested to investigate the influence of different types of stimulus-response compatibility on SoA. To this aim we compared the influence of an automatic imitation task and a stroop-like task on intentional binding. In both tasks participants performed congruent and incongruent fingers movements (key release) in response to an external stimulus. Their movements caused an effect and participants estimated the time between their action and the ensuing effect. We found a reduced intentional binding effect in incongruent compared to congruent conditions in both tasks. The results are discussed within the theoretical framework of the fluency of action.     

Factors that affect action possibility judgments: The assumed abilities of other people

Judging what actions are possible and impossible to complete is a skill that is critical for planning and executing movements in both individual and joint actions contexts. The present experiments explored the ability to adapt action possibility judgments to the assumed characteristics of another person. Participants watched alternating pictures of a person's hand moving at different speeds between targets of different indexes of difficulty (according to Fitts' Law) and judged whether or not it was possible for individuals with different characteristics to maintain movement accuracy at the presented speed. Across four studies, the person in the pictures and the background information about the person were manipulated to determine how and under what conditions participants adapted their judgments. Results revealed that participants adjusted their possibility judgments to the assumed motor capabilities of the individual they were judging. However, these adjustments only occurred when participants were instructed to take the other person into consideration suggesting that the adaption process is a voluntary process. Further, it was observed that the slopes of the regression equations relating movement time and index of difficulty did not differ across conditions. All differences between conditions were in the y-intercept of the regression lines. This pattern of findings suggests that participants formed the action possibility judgments by first simulating their own performance, and then adjusted the “possibility” threshold by adding or subtracting a correction factor to determine what is and is not possible for the other person to perform.     

The role of emotional context in facilitating imitative actions

In two experiments, we explored whether emotional context influences imitative action tendencies. To this end, we examined how emotional pictures, presented as primes, affect imitative tendencies using a compatibility paradigm. In Experiment 1, when seen index finger movements (lifting or tapping) and pre-instructed finger movements (tapping) were the same (tapping–tapping, compatible trials), participants were faster than when they were different (lifting–tapping, incompatible trials). This compatibility effect was enhanced when the seen finger movement was preceded by negative primes compared with positive or neutral primes. In Experiment 2, using only negative and neutral primes, the influence of negative primes on the compatibility effect was replicated with participants performing two types of pre-instructed finger movements (tapping and lifting). This emotional modulation of the compatibility effect was independent of the participants' trait anxiety level. Moreover, the emotional modulation pertained primarily to the compatible conditions, suggesting facilitated imitation due to negatively valent primes rather than increased interference. We speculate that negative stimuli increase imitative tendencies as a natural response in potential flight-or-fight situations.     

What Am I Looking at? Interpreting Dynamic and Static Gaze Displays

Displays of eye movements may convey information about cognitive processes but require interpretation. We investigated whether participants were able to interpret displays of their own or others' eye movements. In Experiments 1 and 2, participants observed an image under three different viewing instructions. Then they were shown static or dynamic gaze displays and had to judge whether it was their own or someone else's eye movements and what instruction was reflected. Participants were capable of recognizing the instruction reflected in their own and someone else's gaze display. Instruction recognition was better for dynamic displays, and only this condition yielded above chance performance in recognizing the display as one's own or another person's (Experiments 1 and 2). Experiment 3 revealed that order information in the gaze displays facilitated instruction recognition when transitions between fixated regions distinguish one viewing instruction from another. Implications of these findings are discussed.     

Interpersonal Understanding Fuels Knowledge Acquisition

Beginning in infancy, humans acquire knowledge at a pace far outstripping that found in any other species. Recent evidence indicates that interpersonal understanding—in particular, skill at inferring others' intentions—plays a pivotal role in this achievement. Infants as young as 12 to 18 months actively utilize clues to others' intentions to guide their interpretation of language, emotion, and action more generally. In the language domain, for example, on hearing a new word, infants spontaneously check the speaker for intentional clues such as gaze direction, emotional expression, gestures, and body posture, and interpret the word in light of such information. By capitalizing on information about intentions, infants are able to avoid a wide range of potential errors, and to quickly learn relevant new skills. Current research is exploring the origins and developmental course of such early-emerging interpersonal skill, ultimately with an eye to understanding how disruptions in such abilities affect children's cognitive and social development.     

The informational properties of the throwing arm for anticipation of goal-directed action

We examined the informational value of biological motion from the arm in predicting the location of a thrown ball. In three experiments, participants were classified as being skilled and less skilled based on their actual performance on the task (i.e., using a within-task criterion). We then presented participants with a range of stick figure representations and required them to predict throw direction. In Experiment 1, we presented stick figure movies of a full body throwing action, right throwing arm plus left shoulder and throwing arm only. Participants were able to anticipate throw direction above chance under all conditions irrespective of perceptual skill level, with the perceptually skilled participants excelling under full body conditions. In Experiment 2, we neutralized dynamical differences in motion to opposing throw directions from the shoulder, elbow and wrist of the throwing arm. Neutralizing the wrist location negatively affected anticipation performance in all participants reducing accuracy to below chance. In Experiment 3, we presented movies of the motion wrist location alone and the upper section of the throwing arm (shoulder-elbow). Participants were able to successfully anticipate above chance in these latter two conditions. Our findings suggest that motion of the throwing arm contains multiple sources of information that can help facilitate the anticipation of goal-directed action. Perceptually skilled participants were superior in extracting informational value from motion at both the local and global levels when compared to less skilled counterparts.     

他人面孔情绪知觉中自我参照与母亲参照的一致性：来自ERP的证据

本研究采用不同参照语境下的面孔情绪评定任务, 使用事件相关电位技术, 考察了自我参照、母亲参照及他人参照对面孔情绪知觉加工的影响。行为结果显示, 与他人参照相比, 在自我参照与母亲参照的消极语境中的面孔被认为更消极, 积极语境中的面孔被认为更积极。ERP的结果显示, 相比他人参照, 自我参照与母亲参照都能诱发更大的EPN波幅; 自我参照与母亲参照对EPN和LPP波幅的影响差异并不显著。这些研究结果表明, 自我参照和母亲参照在面孔情绪知觉上具有一致性, 本研究从他人面孔情绪加工的角度为中国人的自我结构中包含“母亲”成分提供了进一步的证据。     

A minimal limit-cycle model to profile movement patterns of individuals during agility drill performance: Effects of skill level

Identification of control strategies during agility performance is significant in understanding movement behavior. This study aimed at providing a fundamental mathematical model for describing the motion of participants during an agility drill and to determine whether skill level constrained model components. Motion patterns of two groups of skilled and unskilled participants (n = 8 in each) during performance of a forward/backward agility drill modeled as limit-cycles. Participant movements were recorded by motion capture of a reflective marker attached to the sacrum of each individual. Graphical and regression analyses of movement kinematics in Hooke’s plane, phase plane and velocity profile were performed to determine components of the models. Results showed that the models of both skilled and unskilled groups had terms from Duffing stiffness as well as Van der Pol damping oscillators. Data also indicated that the proposed models captured on average 97% of the variance for both skilled and unskilled groups. Findings from this study revealed the movement patterning associated with skilled and unskilled performance in a typical forward/backward agility drill which might be helpful for trainers and physiotherapists in enhancing agility.     

Level of agency in sub-clinical checking

This study examined cognitive representations of routine action, through the assessment of level of agency, in individuals with sub-clinical checking. The level of agency stems from Action Identification Theory [Vallacher, R. R., Wegner, D. M. (1989). Levels of personal agency: Individual variation in action identification. Journal of Personality and Social Psychology 57, 660-671], which states that how actions are usually identified (based on instrumental aspects or purpose) reflects the predominant accessibility of internal representation (movements executed vs. goal pursued). Furthermore, this framework proposed that altered action regulation is related to low-level of agency (i.e., action identification at an instrumental level). In the current study, the main result indicated that checking symptoms were related to a low-level of agency, that is, individuals with sub-clinical checking identified habitual actions on the basis of instrumental aspects. This seems to indicate that checkers may act with a lack of goal representations. The results are discussed in terms of the role of low-level of agency in checking phenomena and related cognitive dysfunction.