Determinants of offline processing of visual information for the control of reaching movements

The authors investigated the use of visual feedback as a form of knowledge of results (KR) for the control of rapid (200-250 ms) reaching movements in 40 participants. They compared endpoint accuracy and intraindividual variability of a full-vision group (FV) with those of no-vision groups provided with KR regarding (a) the endpoint in numerical form, (b) the endpoint in visual form, or (c) the endpoint and the trajectory in visual form (DEL). The FV group was more accurate and less variable than were the no-vision groups, and the analysis of limb trajectory variability indicated that their superior performance resulted primarily from better movement planning rather than from online visual processes. The FV group outperformed the DEL group even though both groups were obtaining the same amount of spatial visual information from every movement. That finding suggests that the effectiveness with which visual feedback is processed offline is not a simple function of the amount of visual information available, but depends on how that information is presented.     

Attention shifts and the Simon effect: a failure to replicate Stoffer (1991)

The Simon effect refers to the intrusion of an irrelevant spatial dimension in the selection of a response to a stimulus. Recently, Stoffer (1991) proposed a specific role for attention orienting in the Simon effect. According to Stoffer, attentional shifts from an initial fixation point to a stimulus location are associated with the generation of a spatial code which specifies the position of the stimulus in relation to the last attended location. This spatial code forms the basis for the Simon effect because it is used to specify the selection of the right or left response. Three experiments were performed to examine further the attention-shift hypothesis forwarded by Stoffer. Experiment 1 was an attempt to replicate Stoffer (1991), but failed to do so. Experiments 2 and 3 were designed to optimize conditions for replicating crucial aspects of Stoffer's findings, but also failed to yield support for the attention-shift account.     

Touch noise increases vibrotactile sensitivity in old and young

Stochastic resonance (SR) occurs when the detection of a subthreshold signal is aided by the presence of random energy fluctuations in the signal modality, commonly called noise. SR is counterintuitive because such noise usually worsens performance. Nonetheless, SR has been demonstrated both theoretically and experimentally in human sensory systems. Using a psychophysically sophisticated paradigm, we show that SR aids the detection of vibrating touch stimuli presented to the foot soles of both healthy elderly people with elevated vibrotactile thresholds and healthy young people with normal vibrotactile thresholds. The results also suggest that it is possible to know a priori the amount of noise needed for optimal SR effects given the degree to which the signal is subthreshold. Thus, SR may be practical as a rehabilitative aid for individuals with elevated sensory thresholds.     

Assessment of tripartite efficacy beliefs within school-based physical education: Instrument development and reliability and validity evidence

Objectives

In educational contexts, Lent and Lopez (2002) proposed that students develop a tripartite network of efficacy beliefs, comprising their confidence in their own capabilities (i.e., self-efficacy), their confidence in their teacher’s ability (i.e., other-efficacy), and their estimation of their teacher’s confidence in their ability (i.e., relation-inferred self-efficacy). In spite of the potential for school-based physical education (PE) to stimulate leisure-time activity patterns among adolescents, it is noteworthy that this framework has yet to be explored in school PE contexts.

Design and methods

In Phase 1, we recruited 62 Australian high school students (aged 11-13) in order to develop instruments designed to assess self-efficacy, other-efficacy, and relation-inferred self-efficacy within PE settings. In Phases 2 and 3, we sought to provide evidence for measurement reliability, validity, and invariance with cross-sectional and prospective data derived from Australian (N = 602, M_age = 13.54, SD = .76) as well as Singaporean (N = 606; M_age = 14.10, SD = 1.01) students.

Results

Results revealed (a) support for the factorial validity of these measures in both locations, (b) evidence of gender-related and cross-national measurement invariance, (c) positive inter-relationships between students’ tripartite efficacy perceptions that were consistent with theory, and (d) positive correlations with key in-class (e.g., effort, enjoyment) and leisure-time (e.g., physical activity levels) outcomes.

Conclusions

Taken together, the results provide preliminary evidence for the reliability and validity of measures derived from these tripartite efficacy instruments, and support their use in future research designed to examine PE engagement.     

On-line control of pointing is modified by unseen visual shapes

Shapes that are rendered invisible through backward masking are still able to influence motor responses: this is called masked priming. Yet it is unknown whether this influence is on the control of ongoing action, or whether it merely influences the initiation of an already-programmed action. We modified a masked priming procedure (Schmidt, 2002) such that the critical prime-mask sequence was displayed during the execution of an already-initiated goal-directed pointing movement. Psychophysical tests of prime visibility indicated that the identity of the prime shapes were not accessible to participants for conscious report. Yet detailed kinematic analysis of the finger in motion revealed that masked primes had an influence on the pointing trajectories within 277ms of their appearance, 56ms earlier than the trajectory deviations observed in response to the visible masks. These results indicate that subliminal shapes can indeed influence the control of ongoing motor activity.