The role of effect grouping in free-choice response selection

Which motor actions are preferred to replace an initially planned but momentary not executable action? Previous research (Khan, Mourton, Buckolz, Adams, & Hayes, 2010, Acta Psychologica) suggests that anatomical constraints seem to be a major determinant for such choices: For example, participants more frequently chose to respond with the finger homologous to the prepared one. We argue that in this case finger homology is confounded with action effect similarity, and action effects have been ascribed a crucial role in action selection. We report two experiments. Experiment 1 replicated the results obtained by Khan et al. In Experiment 2, we introduced visual action effects in the paradigm. Results from this experiment clearly point to a role of effect similarity in addition to mere finger homology status for the choice frequency effect.     

A test of motor skill-specific action embodiment in ice-hockey players

To further our understanding of the role of the motor system in comprehending action-related sentences, we compared action experts (athletes) to visual experts (fans) and novices when responding with an action-specific effector (either hand or foot). These conditions allowed inferences about the degree and specificity of embodiment in language comprehension. Ice hockey players, fans and novices made speeded judgments regarding the congruence between an auditorily presented sentence and a subsequently presented picture. Picture stimuli consisted of either hockey or everyday items. Half of these pictures ‘matched’ the action implied in the preceding sentence. Further, the action in these images involved either primarily the hand or the foot. For everyday items, action-matched items were responded to faster than action-mismatched items. However, only the players and fans showed the action-match effect for hockey items. There were no consistent effector-stimuli compatibility effects, nor skill-based interactions with compatibility, suggesting that the action-match effect was not based on motor ability per se, but rather a construction of the action based on knowledge or visual experience with the hockey related sentences.     

Balancing cognitive control: How observed movements influence motor performance in a task with balance constraints

We investigated the influence of observed movements on executed movements in a task requiring lifting one foot from the floor while maintaining whole-body balance. Sixteen young participants (20–30 years) performed foot lift movements, which were either cued symbolically by a letter (L/R, indicating to lift the left/right foot) or by a short movie showing a foot lift movement. In the symbol cue condition, stimuli from the movie cue condition were used as distractors, and vice versa. Anticipatory postural adjustments (APAs) and actual foot lifts were recorded using force plates and optical motion capture. Foot lift responses were generally faster in response to the movie compared to the symbol cue condition. Moreover, incongruent movement distractors interfered with performance in the symbol cue condition, as shown by longer response times and increased number of APAs. Latencies of the first (potentially wrong) APA in a trial were shorter for movie compared to symbol cues but were not affected by cue-distractor congruency. Amplitude of the first APA was smaller when it was followed by additional APAs compared to trials with a single APA. Our results show that automatic imitation tendencies are integrated with postural control in a task with balance constraints. Analysis of the number, timing and amplitude of APAs indicates that conflicts between intended and observed movements are not resolved at a purely cognitive level but directly influence overt motor performance, emphasizing the intimate link between perception, cognition and action.     

Costs and benefits of tool-use on the perception of reachable space

Previous studies have shown that using a tool modifies in a short time-scale both near-body space perception and arm-length representation in the body schema. However, to date no research has specifically investigated the effect of tool-use on an action-related perceptual task. We report here a study assessing the effect of tool-use on the perception of reachable space for perceptual estimates made in reference to either the tool or the hand. Using the tool on distal objects resulted in an extension of perceived reachable space with the tool and reduced the variability of reachability estimates. Tool use also extended perceived reachable space with the hand, but with a concomitant increase of the variability of reachability estimates. These findings suggest that tool incorporation into the represented arm following tool-use improves the anticipation of action possibilities with the tool, while hand representation becomes less accurate.     

When two actions are easier than one: How inhibitory control demands affect response processing

Numerous studies showed that the simultaneous execution of multiple actions is associated with performance costs. Here, we demonstrate that when highly automatic responses are involved, performance in single-response conditions can actually be worse than in dual-response conditions. Participants responded to peripheral visual stimuli with an eye movement (saccade), a manual key press, or both. To manipulate saccade automaticity, a central fixation cross either remained present throughout the trial (overlap condition, lower automaticity) or disappeared 200 ms before visual target onset (gap condition, greater automaticity). Crucially, single-response conditions yielded more performance errors than dual-response conditions (i.e., dual-response benefit), especially in gap trials. This was due to difficulties associated with inhibiting saccades when only manual responses were required, suggesting that response inhibition (remaining fixated) can be even more resource-demanding than overt response execution (saccade to peripheral target).     

Motor resources in peripersonal space are intrinsic to spatial encoding: Evidence from motor interference

The aim of this study was to explore the role of motor resources in peripersonal space encoding: are they intrinsic to spatial processes or due to action potentiality of objects? To answer this question, we disentangled the effects of motor resources on object manipulability and spatial processing in peripersonal and extrapersonal spaces. Participants had to localize manipulable and non-manipulable 3-D stimuli presented within peripersonal or extrapersonal spaces of an immersive virtual reality scenario. To assess the contribution of motor resources to the spatial task a motor interference paradigm was used. In Experiment 1, localization judgments were provided with the left hand while the right dominant arm could be free or blocked. Results showed that participants were faster and more accurate in localizing both manipulable and non-manipulable stimuli in peripersonal space with their arms free. On the other hand, in extrapersonal space there was no significant effect of motor interference. Experiment 2 replicated these results by using alternatively both hands to give the response and controlling the possible effect of the orientation of object handles. Overall, the pattern of results suggests that the encoding of peripersonal space involves motor processes per se, and not because of the presence of manipulable stimuli. It is argued that this motor grounding reflects the adaptive need of anticipating what may happen near the body and preparing to react in time.     

Implicit transfer of spatial structure in visuomotor sequence learning

Implicit learning and transfer in sequence learning are essential in daily life. Here, we investigated the implicit transfer of visuomotor sequences following a spatial transformation. In the two experiments, participants used trial and error to learn a sequence consisting of several button presses, known as the m × n task (Hikosaka et al., 1995). After this learning session, participants learned another sequence in which the button configuration was spatially transformed in one of the following ways: mirrored, rotated, and random arrangement. Our results showed that even when participants were unaware of the transformation rules, accuracy of transfer session in the mirrored and rotated groups was higher than that in the random group (i.e., implicit transfer occurred). Both those who noticed the transformation rules and those who did not (i.e., explicit and implicit transfer instances, respectively) showed faster performance in the mirrored sequences than in the rotated sequences. Taken together, the present results suggest that people can use their implicit visuomotor knowledge to spatially transform sequences and that implicit transfers are modulated by a transformation cost, similar to that in explicit transfer.     

Reading direction shifts visuospatial attention: An Interactive Account of attentional biases

A growing amount of evidence confirms the influence of reading and writing habits on visuospatial processing, although this phenomenon has been so far testified mainly as a lateralized shift of a single behavioral sign (e.g., line bisection), with lack of proof from pure right-to-left readers. The present study contributed to this issue by analyzing multiple attentional and motor indexes in monolingual Italian (i.e., reading from left-to-right), and monolingual (i.e., reading from right-to-left) and bilingual Israeli (i.e., reading from right-to-left in Hebrew but also from left-to-right in English) participants' visuospatial performance. Subjects were administered a computerized standard star cancellation task and a modified version in which English letters and words were replaced by Hebrew ones. Tasks were presented on a graphics tablet, allowing recording of both chronometric and spatial parameters (i.e., measured in (x, y) vector coordinates). Results showed that reading direction modulated the on-line visuomotor performance (i.e., left-to-right vs. right-to-left shifts) from the beginning (i.e., first mark) to the end of the task (i.e., spatial distribution of omissions and subjective epicenter). Additionally, the spatial bias observed in a computerized line bisection task was also related to the participants' habitual reading direction. Overall, the results favor the proposal of an Interactive Account of visuospatial asymmetries, according to which both cultural factors, such as the directional scanning associated with language processing, and biological factors, such as hemispheric specialization, modulate visuospatial processing. Results are discussed in light of recent behavioral and neuroanatomical findings.     

What hands know about objects; taking perception of hills out of context: A response to Durgin (2013)

In a recent paper, we provided independent evidence on the accuracy of ‘haptically’ measured geographical slant perception (Taylor-Covill & Eves, 2013). Durgin (2013) argues that the devices used in our work, namely the palm-board, and palm-controlled inclinometer (PCI), are not measures of perception. In response, we outline four failures of replication in the laboratory work of Durgin and colleagues on which they base their model of slant perception. We also highlight fundamental differences between the perceptual tasks Durgin and colleagues ask of participants relative to those of Proffitt and colleagues' traditional measures. These subtle differences might help explain how the two groups have arrived at discrepant conclusions.     

Grasp posture planning during multi-segment object manipulation tasks — Interaction between cognitive and biomechanical factors

The present study examined adaptations in the planning of initial grasp postures during a multi-segment object manipulation task. Participants performed a grasping and placing task that consisted of one, two, or three movement segments. The position of the targets was manipulated such that the degree of object rotation between the home and temporally proximal positions, and between the temporally proximal and distal target positions, varied. Participants selected initial grasp postures based on the specific requirements of the temporally proximal and temporally distal action segments, and adjustments in initial grasp posture depended on the temporal order of target location. In addition, during the initial stages of the experimental session initial grasp postures were influenced to a larger extent by the demands of the temporally proximal segment. However, over time, participants overcame these cognitive limitations and adjusted their initial grasp postures more strongly to the requirements of the temporally distal segment. Taken together, these results indicate that grasp posture planning is influenced by cognitive and biomechanical factors, and that participants learn to anticipate the task demands of temporally distal task demands, which we hypothesize, reduce the burden on the central nervous system.