Online versus offline processing of visual feedback in the control of movement amplitude

Researchers have suggested that visual feedback not only plays a role in the correction of errors during movement execution but that visual feedback from a completed movement is processed offline to improve programming on upcoming trials. In the present study, we examined the potential contribution of online and offline processing of visual feedback by analysing spatial variability at various kinematic landmarks in the limb trajectory (peak acceleration, peak velocity, peak negative acceleration and movement end). Participants performed a single degree of freedom video aiming task with and without vision of the cursor under four criterion movement times (225, 300, 375 and 450 ms). For movement times of 225 and 300 ms, the full vision condition was less variable than the no vision condition. However, the form of the variability profiles did not differ between visual conditions suggesting that the contribution of visual feedback was due to offline processes. In the 375 and 450 ms conditions, there was evidence for both online and offline control as the form of the variability profiles differed significantly between visual conditions.     

Estimating the quantitative relation between incongruent information and response time

In Eriksen's flanker paradigm, participants' responses are slower and more error-prone when task-relevant and simultaneously available task-irrelevant cues are incongruent. The influence of task-irrelevant information decreases as its distance from the task-relevant information increases. Here, we manipulated the quantity of task-irrelevant information while keeping the distance constant. We asked whether when the impact on response selection processes was stronger the more incongruent information was available, or whether the impact on response selection depended only on its presence or absence. We conducted an experiment, in which subjects had to discriminate the direction of motion of a central point-light-walker that was flanked by two, four, or eight point-light-walkers at an equal distance from the center. The experiment showed that reaction times increased with the number of incongruent walkers. This effect was modulated by the total number of walkers, showing that the effect of incongruent information saturates when the display is cluttered.     

Inhibition and blindness to response-compatible stimuli: a reappraisal

Recent studies show that the preparation of an action can interfere with the concurrent detection and identification of objects that share features with this action, a phenomenon termed blindness to response-compatible stimuli. In order to account for the blindness effect, an integration mechanism for response features similar to the one suggested for object features has been proposed. In the present article, we propose an alternative explanation, namely an action-effect inhibition mechanism. This mechanism was demonstrated in two versions of a dual-task experiment using a primary stop-signal task. The results showed that when the primary response was withheld (signal-inhibit trials), this resulted in lower identification rates for compatible secondary task stimuli. On the other hand, we did not find any evidence for a blindness effect when the primary response was executed (no-signal trials). Additionally we found that identification rates depended on the time course of the inhibition process as estimated from our data. Consequently, the blindness effect seems to result from the requirement to inhibit the response, perhaps even if only temporary.     

Inhibition of return for expected and unexpected targets

Inhibition of return (IOR) refers to slower reaction times (RTs) to targets that occur in the same, rather than in a different, location as a preceding onset cue. The present study examined IOR for expected (likely) and unexpected (unlikely) targets under conditions in which stimulus-response (S-R) expectancies were generated on a trial-by-trial basis or maintained across a block of trials. Three boxes were aligned along the vertical midline. In Experiments 1 and 2, the appearance of a cue in the upper or lower box was a signal to generate an expectancy about the most likely color of an impending discrimination target. In Experiment 3, one target color was more likely than another across a block of trials. In all cases, cue location did not predict target location. When S-R expectancies were generated on a trial-by-trial basis, IOR occurred for Unlikely targets but not for Likely targets; this was true across a range of cue-target stimulus onset asynchronies. In contrast, when S-R expectancies were maintained over a block of trials, IOR was larger for Likely than for Unlikely targets. These findings reveal a critical interaction of S-R expectancies with IOR. This interaction not only demonstrates the modulation of IOR by cognitive expectancies, but in doing so also provides evidence that is consistent with the view that IOR reflects a conservative response bias.     

Motor plans persist to influence subsequent actions with four or more response alternatives

Motor activity has the potential to persist after action and influence subsequent behaviour. A standard approach to isolating a motoric influence is to map two stimuli onto each response, so that response and stimulus repetition can be dissociated. A response-only response-repetition (RoRR) effect can then be assessed, arising if the same response made to two unrelated stimuli is nonetheless produced more rapidly. This kind of motoric behavioural influence of one response on the next has proved elusive in reaction time tasks involving choices between key presses, at least when stimuli mapped to each response are difficult to categorise together. However, such tasks have traditionally involved only a few response alternatives. We hypothesised that a larger load on the motor system might prevent participants from holding all possible action plans active throughout an experiment, and thus reveal trial-to-trial motor priming in the form of an RoRR effect. In our first experiment, increasing the number of response alternatives to four or eight yielded a reliable RoRR effect. This effect was replicated in Experiment 2, where it also proved persistent across practice and resistant to changes in response configuration. Our results are consistent with evidence of motoric perseveration in other kinds of motor task, such as reaching and grasping, and have implications for the generation of speeded decisions in a range of activities.     

Knowledge of response location alone is not sufficient to generate social inhibition of return

Previous research has revealed that the inhibition of return (IOR) effect emerges when individuals respond to a target at the same location as their own previous response or the previous response of a co-actor. The latter social IOR effect is thought to occur because the observation of co-actor's response evokes a representation of that action in the observer and that the observation-evoked response code subsequently activates the inhibitory mechanisms underlying IOR. The present study was conducted to determine if knowledge of the co-actor's response alone is sufficient to evoke social IOR. Pairs of participants completed responses to targets that appeared at different button locations. Button contact generated location-contingent auditory stimuli (high and low tones in Experiment 1 and colour words in Experiment 2). In the Full condition, the observer saw the response and heard the auditory stimuli. In the Auditory Only condition, the observer did not see the co-actor's response, but heard the auditory stimuli generated via button contact to indicate response endpoint. It was found that, although significant individual and social IOR effects emerged in the Full conditions, there were no social IOR effects in the Auditory Only conditions. These findings suggest that knowledge of the co-actor's response alone via auditory information is not sufficient to activate the inhibitory processes leading to IOR. The activation of the mechanisms that lead to social IOR seems to be dependent on processing channels that code the spatial characteristics of action.     

Summarizing slant perception with words and hands; an empirical alternative to correlations in Shaffer,McManama, Swank,Williams & Durgin (2014)

The paper by Shaffer, McManama, Swank, Williams & Durgin (2014) uses correlations between palm-board and verbal estimates of geographical slant to argue against dissociation of the two measures. This paper reports the correlations between the verbal, visual and palm-board measures of geographical slant used by Proffitt and co-workers as a counterpoint to the analyses presented by Shaffer and colleagues. The data are for slant perception of staircases in a station (N = 269), a shopping mall (N = 229) and a civic square (N = 109). In all three studies, modest correlations between the palm-board matches and the verbal reports were obtained. Multiple-regression analyses of potential contributors to verbal reports, however, indicated no unique association between verbal and palm-board measures. Data from three further studies (combined N = 528) also show no evidence of any relationship. Shared method variance between visual and palm-board matches could account for the modest association between palm-boards and verbal reports.     

What's up? Emotion-specific activation of vertical space during language processing

The relationship between language processing and vertical space has been shown for various groups of words including valence words, implicit location words, and words referring to religious concepts. However, it remains unclear whether these are single phenomena or whether there is an underlying common mechanism. Here, we show that the evaluation of word valence interacts with motor responses in the vertical dimension, with positive (negative) evaluations facilitating upward (downward) responses. When valence evaluation was not required, implicit location words (e.g., bird, shoe) influenced motor responses whereas valence words (e.g., kiss, hate) did not. Importantly, a subset of specific emotional valence words that are commonly associated with particular bodily postures (e.g., proud → upright; sad → slouched) did automatically influence motor responses. Together, this suggests that while the vertical spatial dimension is not directly activated by word valence, it is activated when processing words referring to emotional states with stereotypical bodily-postures. These results provide strong evidence that the activation of spatial associations during language processing is experience-specific in nature and cannot be explained with reference to a general mapping between all valence words and space (i.e., all positive and negative words generally relate to spatial processing). These findings support the experiential view of language comprehension, suggesting that the automatic reactivation of bodily experiences is limited to word groups referring to emotions or entities directly associated with spatial experiences (e.g., posture or location in the world).     

When motor congruency modulates immediate memory for objects

In line with the embodied cognition view, some researchers have suggested that our capacity to retain information relies on the perceptual and motor systems used to interact with our environment (Barsalou, 1999; Glenberg, 1997). For instance, the language production architecture would be responsible for the retention of verbal materials such as a list of words (Acheson & MacDonald, 2009). However, evidence for the role of the motor system in object memory is still limited. In the present experiments, participants were asked to retain lists of objects in memory. During encoding, participants had to pantomime an action to grasp (Experiments 1A & 1B) or to use the objects (Experiment 2) that was either congruent or incongruent with the objects to be retained. The results showed that performing an incongruent action impaired memory performance compared to a congruent action. This suggests that motor affordances play a role during object retention. The results are discussed in light of the embodied cognition view.     

Co-variation between graphic pattern stability and attentional cost: A clue for the difficulty to produce handwritten traces

Attentional cost incurred for generating handwritten graphic patterns was investigated using a classic dual-task procedure, in which a concurrent reaction time (RT) task was used as an index of the attentional cost incurred by the primary graphic task. Eight right-handed adults had to trace graphic patterns, characterized by a 0°, 45°, 90°, 135° or 180° relative phase and corresponding to shapes ranging from lines to ellipses to circles, while responding by a key press as fast as possible to an auditory signal. The results evidenced a strong and significant correlation between the stability of the produced pattern and the associated attentional cost. The amplitude of the minor and major axes of the produced ellipsoids decreased with the increase of movement frequency, as expected by nonlinear models of oscillatory pattern generation. These findings pave the way to the study for the (coordinative) processes for letter (mal)formation in cursive handwriting.