The Effect of Load Uncertainty on Neuromotor Control in Catching: Gender Differences and Short Foreperiods

Abstract

To reveal how the CNS copes with load uncertainty in catching, electromyography (EMG) was recorded in 15 females and 14 males while catching visually identical balls of known and unknown weights under varied (1–10?s) and constant (1?s) foreperiods (warning time). EMG integrals, which represented total muscle activity, were computed for three time intervals prior to the catch (anticipatory), and one interval after (compensatory). Load uncertainty caused the CNS to utilize an anticipatory strategy in several muscles, primarily during the ball-flight interval, characterized by preparation to catch balls of unknown weight by utilizing an average of 99.7% of the muscle activation used to catch the heaviest ball under the known weight condition. The constant 1?s foreperiod, which permitted precise temporal anticipation of ball release, did not influence the anticipatory strategy adopted by the CNS to cope with load uncertainty. There were no observed differences in the neuromotor control used by men and women to manage load uncertainty in catching, although there was an interesting difference in the way men and women employed the triceps to prepare to catch balls of a known weight.     

Enactivism and the Unity of Perception and Action

This paper contrasts two enactive theories of visual experience: the sensorimotor theory (O’Regan and Noë, Behav Brain Sci 24(5):939–1031, 2001; Noë and O’Regan, Vision and mind, 2002; Noë, Action in perception, 2004) and Susan Hurley’s (Consciousness in action, 1998, Synthese 129:3–40, 2001) theory of active perception. We criticise the sensorimotor theory for its commitment to a distinction between mere sensorimotor behaviour and cognition. This is a distinction that is firmly rejected by Hurley. Hurley argues that personal level cognitive abilities emerge out of a complex dynamic feedback system at the subpersonal level. Moreover reflection on the role of eye movements in visual perception establishes a further sense in which a distinction between sensorimotor behaviour and cognition cannot be sustained. The sensorimotor theory has recently come under critical fire (see e.g. Block, J Philos CII(5):259–272, 2005; Prinz, Psyche, 12(1):1–19, 2006; Aizawa, J Philos CIV(1), 2007) for mistaking a merely causal contribution of action to perception for a constitutive contribution. We further argue that the sensorimotor theory is particularly vulnerable to this objection in a way that Hurley’s active perception theory is not. This presents an additional reason for preferring Hurley’s theory as providing a conceptual framework for the enactive programme.     

Factors that affect action possibility judgements: Recent experience with the action and the current body state

It has been suggested that action possibility judgements are formed through a covert simulation of the to-be-executed action. We sought to determine whether the motor system (via a common coding mechanism) influences this simulation, by investigating whether action possibility judgements are influenced by experience with the movement task (Experiments 1 and 2) and current body states (Experiment 3). The judgement task in each experiment involved judging whether it was possible for a person's hand to accurately move between two targets at presented speeds. In Experiment 1, participants completed the action judgements before and after executing the movement they were required to judge. Results were that judged movement times after execution were closer to the actual execution time than those prior to execution. The results of Experiment 2 suggest that the effects of execution on judgements were not due to motor activation or perceptual task experience—alternative explanations of the execution-mediated judgement effects. Experiment 3 examined how judged movement times were influenced by participants wearing weights. Results revealed that wearing weights increased judged movement times. These results suggest that the simulation underlying the judgement process is connected to the motor system, and that simulations are dynamically generated, taking into account recent experience and current body state.     

Egocentric Space

Abstract

I discuss the relation between egocentric spatial perception and the capacity for bodily activity, with specific reference to Merleau-Ponty.     

Reaction time to a word in different orientations with letters rotated separately in different orientations

Six men and six women were timed as they made judgments about a word whose line of letters and individual letters were separately turned in different angular orientations. The subjects were asked to indicate by manual key-pressing responses whether the letters in the word were normal letters or reflected, mirror-image letters. Analysis showed that (1) reaction time (RT) was slower for reflected letters than for normal letters, and for subjects using the left (nondominant) hand rather than the right (dominant) hand for responding to normal letters. (2) RT generally increased in relation to the deviation of the individual letters from normal upright orientation but increased more reliably for normal than for reflected letters. (3) Although there were exceptions, RT for words composed of normal letters generally increased in relation to the deviation of the individual letters from normal upright, regardless of the orientation of the line of letters.     

Visual and haptic matching of perceived orientations of lines

In this study we investigated the perception and production of line orientations in a vertical plane. Previous studies have shown that systematic errors are made when participants have to match oblique orientations visually and haptically. Differences in the setup for visual and haptic matching did not allow for a quantitative comparison of the errors. To investigate whether matching errors are the same for different modalities, we asked participants to match a visually presented orientation visually, haptically with visual feedback, and haptically without visual feedback. The matching errors were the same in all three matching conditions. Horizontal and vertical orientations were matched correctly, but systematic errors were made for the oblique orientations. The errors depended on the viewing position from which the stimuli were seen, and on the distance of the stimulus from the observer.     

Captured by motion: dance, action understanding, and social cognition

In this review article, we summarize the main findings from empirical studies that used dance-related forms of rhythmical full body movement as a research tool for investigating action understanding and social cognition. This work has proven to be informative about behavioral and brain mechanisms that mediate links between perceptual and motor processes invoked during the observation and execution of spatially–temporally coordinated action and interpersonal interaction. The review focuses specifically on processes related to (a) motor experience and expertise, (b) learning and memory, (c) action, intention, and emotion understanding, and (d) audio-visual synchrony and timing. Consideration is given to the relationship between research on dance and more general embodied cognition accounts of action understanding and social cognition. Finally, open questions and issues concerning experimental design are discussed with a view to stimulating future research on social-cognitive aspects of dance.     

Empathy in sports,exercise, and the performing arts

ObjectivesThis review article provides a summary of the main findings from empirical studies that used empathy measurements in the domains of sports, exercise, and the performing arts (i.e., music, dance, and theatrical acting).Method & resultsThe use of body movement is considered a common denominator across performance domains. Embodied accounts of cognition claim that the capacity to understand an individual's cognitive and affective states depend on the observer's sensorimotor experience and seek to identify the factors influencing this process. To describe the bidirectional links between empathy and performance domains, we divided the empirical studies into two categories: those that investigated factors influencing or inducing empathy, and those that investigated possible influences of empathic tendencies on neurocognitive functions and performance. Therefore, the review includes sections on (1) effects on empathy, including (a) gender, (b) learning and performance, and (c) prosocial contexts; and (2) the effects of empathy on (a) the brain and physiology, (b) perception–performance relations, and (c) prosocial behavior. This work has proven to be informative in unraveling the links between empathy and perceptual-motor processes across intrapersonal, interpersonal, and intergroup levels of analysis.ConclusionsThe reported findings are examined in relation to embodied accounts of perceptual-motor performance. Issues related to interdisciplinary dialog, implications for research, and applied practice are also discussed.     

A working memory model improves cognitive control in agents and robots

Cognition entails those mental processes enabling understanding the current situation through senses, experience, and thought, and supporting the acquisition of new knowledge. A fundamental contribution in cognition is offered by the working memory, that is a small, short-term memory containing and protecting from interference goal-relevant pieces of information. Grounding our work on biological and neuroscientific studies, we modeled and implemented working memory processes in a software model, IDRA-WM, that can simultaneously act as short-term memory and actions generator, thanks to the use of a reinforcement-driven mechanism for chunk selection. Moreover our system integrates the functions of the working memory with a basic action planner. We tested the model with robot relevant tasks to assess whether the proposed solution can learn to solve a problem on the basis of a delayed reward. The experimental results indicate that IDRA-WM is able to solve even those tasks that do not provide immediate reward after an action.     

Effet de l’action motrice sur les asynchronies perceptives

In agreement with the hypothesis of differential treatment of the intrinsic (color, shape, category…) and extrinsic (position, orientation…) visual characteristics along the ventral and dorsal pathways of the visual system (Milner & Goodale, 1995), the study of temporal order judgment (TOJ) of the variation of two visual attributes highlighted the perceptual asynchrony even though these changes occur synchronously. In this context, we investigated the role of action in the perception of perceptual asynchrony, especially the effect of a reaching movement on the TOJ of position and color changes of a target occurring at different times of movement execution. In the absence of voluntary action, the point of subjective simultaneity (PSS) shows that the color changes must occurr 46.6 ms before the change of position to give rise to a synchronous perception of these two changes. Performing a reaching movement reduced significantly the PSS (12.4 ms), but only if the changes occur near movement end-point. If changes occur during movement execution, the PSS (40.2 ms) was not different from that obtained in the perceptual condition. These results suggest that endogenous signals associated with voluntary motor action contribute to the reduction of perceptual asynchrony in relation to the goal of the action. We discuss the possibility that, in the context of the action, the motor system contributes to the binding of objects sensory attributes as well as to the sense of agency.     

Individual differences in athletes' perception of expressive body movements

ObjectivesUnderstanding others' actions depends on the observer's individual characteristics and sensorimotor experience. Motor performance domains, such as sports and the performing arts, provide optimal situations to investigate the determinants of action perception. We investigated athletes' perceptual identification of expression intensity in body movements.DesignA within-subjects design was used.MethodParticipants watched point-light displays (1000 ms long) depicting expressive and inexpressive dance movements. The task was to identify the dancer's intended expression intensity.ResultsThe results indicate that expressive body movements can be reliably identified, with judgement accuracy correlating with self-report empathy indices, intuitive/deliberate decision-making preferences, and indices of sports training. Only years of sports training could predict perceptual identification accuracy.ConclusionsWe discuss the findings in relation to motor and cognitive–emotional contributions to action simulation. The potential of cross-domain transfer of motor expertise for boosting perceptual judgements and a hierarchical role of factors eliciting action simulation are also outlined.     

Negative-based prominence: the role of negative features in matching and choice

Previous research related to the prominence effect (e.g., Tversky, Sattath, & Slovic, 1988) has mainly focused on the causes and boundary conditions of the effect. This article investigates the determinants of prominence and explores a negative-based prominence effect in which the negative attribute becomes the prominent one. Using a matching-choice procedure, Experiments 1 and 2 show that the negative dimension became the prominent one under two different cover stories, suggesting that the negative feature looms larger in choice than in matching. The robustness of negative-based prominence was further demonstrated in a direct choice task without matching (Experiment 3) and was shown to be resistant to the impact of added positive features (Experiment 4). Finally, Experiments 5 and 6 distinguish between two determinants of prominence: intrinsic prominence caused by attribute importance and negative-based prominence caused by negative attribute values. By lowering the values on the positive dimension and enhancing the values on the negative dimension, one can reverse the prominence effect. The results suggest that, compared to a matching task, choice leads to enhanced sensitivity to negative features. The relations between negative characteristics of an attribute and other factors that determine prominence are discussed in the final section.     

Towards an ecologically grounded functional practice in rehabilitation

According to the International Classification of Functioning, Disability and Health, effective rehabilitation requires interventions that go beyond minimizing pathological conditions and associated symptoms. The scope of practice must include promoting an individual’s activity within relevant contexts. We argue that best practice requires decisions that are not only evidence-based but also theory-based. Perception and action theories are essential for interpreting evidence and clinical phenomena as well as for developing new interventions. It is our contention that rehabilitation goals can best be achieved if inspired by the ecological approach to perception and action, an approach that focuses on the dynamics of interacting constraints of performer, task and environment. This contrasts with organism-limited motor control theories that have important influence in clinical practice. Parallels between such theories and the medical model of care highlight their fundamental inconsistency with the current understanding of functioning. We contend that incorporating ecological principles into rehabilitation research and practice can help advance our understanding of the complexity of action and provide better grounding for the development of effective functional practice. Implications and initial suggestions for an ecologically grounded functional practice are outlined.     

Tone‐affect compatibility with affective stimuli and affective responses

Three experiments examine multimodal integration of tone pitch (high/low), facial expression stimuli (happy/angry), and responses (happy/angry) in a compatibility paradigm. When the participants' task is to imitate facial expressions (Experiment 1), smiles are facilitated by high tones whereas frowns are facilitated by low tones. Experiments 2 and 3 further analyse this effect and show that there is both integration between the tone stimulus and the facial stimulus and between the tone stimulus and the facial response. Results suggest that pitch height is associated with emotion. An interpretation in terms of an embodied cognition approach that emphasizes an interweavement of perception and action is discussed.     

Temporal resolution of figures and grounds

Recent studies have demonstrated that establishing figure–ground organization influences other perceptual processes. Specifically, figures undergo perceptual processing earlier than ground regions (Lester, Hecht, & Vecera, 2009), and they are processed for longer durations relative to ground regions (Hecht & Vecera, 2011). One potential consequence of figures' extended processing is degraded temporal resolution compared to ground regions. To test this hypothesis, observers completed a modified flicker-fusion task while viewing either displays that contained well-defined figures and grounds or displays that were ambiguous. As evidenced by increased sensitivity for flickering targets on the ground regions, the current results support the claim that figures have poorer temporal resolution than ground regions.     

The meaning of indifference in choice behavior: Asymmetries in adjustments embodied in matching

Measuring and assessing people’s preferences is an intricate task that can be realized by different methods. Evidently, the different methods do not necessarily yield consistent results. In the present paper we examine the matching procedure and demonstrate inconsistencies within the method itself. It is shown that the inconsistencies stem from: (1) asymmetry in upward and downward matching (i.e., matching options by increasing or lowering values do not yield the same tradeoffs) and (2) participants’ tendency to match (adjust) the options such that they become more similar, eventually facilitating the choice process. Matching is the most straightforward method of eliciting indifference. Hence, the observed inconsistencies, encapsulated in the matching procedure, have direct implications for the construction of indifference curves (equal-utility contours) that are examined in the final section.     

Sequential aiming with one and two limbs: Effects of target size

It is well reported that movement times to the first target in a two-target sequence are slower than when a single target response is required. This one-target advantage has been shown to emerge when the two-target sequence is performed with the same limb and when the first and second segments within the sequence are performed with different limbs (i.e., when there is a switch between limbs at the first target). The present study examined the functional dependency between response segments in both single and two limb sequential aiming by varying the accuracy demands at the first and second target. Results revealed that, for both one and two limb conditions, the one-target advantage was present with large first targets but not with small first targets. Additionally, when the first target was large and the second target was small, spatial variability at the first target was significantly less (or constrained more) in both one and two limb conditions compared to conditions requiring only a single target response. These findings suggest that similar principles underlie the one-target advantage in both single and two limb sequential movements.     

Different defense mechanisms among men with different sex role orientations

Thirty male college students completed the Bem Sex Role Inventory and the Defense Mechanism Inventory. Results demonstrated that sex role orientation moderates the use of defense mechanisms in men, so that men with different orientations differed in the defenses they used. Masculine men used externalizing defenses such as turning against object and rationalizing defenses such as principalization more often than feminine men. Feminine men used an internalizing mode of defense, such as turning against self, more often than masculine and androgynous men. Results were compared with similar studies and the implications were discussed.The order of the authors was alphabetically determined. The authors wish to thank Michal T. Lewy and Jacqueline Franko for their help in conducting the study.     

Discrimination of two neighboring intra- and intermodal empty time intervals marked by three successive stimuli

We investigated the discrimination of two neighboring intra- or inter-modal empty time intervals marked by three successive stimuli. Each of the three markers was a flash (visual—V) or a sound (auditory—A). The first and last markers were of the same modality, while the second one was either A or V, resulting in four conditions: VVV, VAV, AVA and AAA. Participants judged whether the second interval, whose duration was systematically varied, was shorter or longer than the 500-ms first interval. Compared with VVV and AAA, discrimination was impaired with VAV, but not so much with AVA (in Experiment 1). Whereas VAV and AVA consisted of the same set of single intermodal intervals (VA and AV), discrimination was impaired in the VAV compared to the AVA condition. This difference between VAV and AVA could not be attributed to the participants' strategy to perform the discrimination task, e.g., ignoring the standard interval or replacing the visual stimuli with sounds in their mind (in Experiment 2). These results are discussed in terms of sequential grouping according to sensory similarity.     

Image-size disparity reduces difference detection in face matching

Face matching is the act of deciding whether two facial images depict the same person or different people. The real-world face-matching task of checking photo IDs typically occurs under conditions of image-size disparity: A small picture is compared with a life-size face. We examined the effect of image-size disparity on face-matching accuracy. In three experiments, subjects were presented with pairs of equivalently or disparately sized images that depicted the same person or different people. Subjects made same/different judgments and, in two experiments, also reported confidence. Difference detection was significantly poorer given disparate (versus equivalent) image size. Confidence was significantly higher when responses were correct versus incorrect. These findings held whether viewing and decision time was unlimited or limited. Our results raise the practical concern that image-size disparity may undermine difference detection in ID checking, while also indicating that people have some insight into the accuracy of their face-matching judgments.