Response-repetition costs in choice-RT tasks: Biased expectancies or response inhibition?

Repetition effects are often viewed as informative regarding the cognitive mechanisms of action control. One particular finding, namely costs for repeating the same response in subsequent trials, especially challenges theorizing. Costs for response repetitions have recently been reported in task-switch studies on task-switch trials (whereas benefits usually arise in task-repetition trials), but also in some choice-RT task studies. In three experiments, two of the most successful accounts for the response-repetition costs in choice-RT task studies and task switching were tested: an expectancy-based explanation, and an inhibition-based account. Using a choice-RT task introduced by Smith (1968) and manipulating the response–stimulus interval (RSI) and the categorizability of the stimuli, some specific predictions of the two accounts were tested. The results clearly revealed that expectancy-based explanations fail to account for the observed patterns of effects, whereas they are well in line with the predictions from the inhibition-based account. Finally, the results are further discussed with respect to alternative accounts from the field of task switching.     

Pliers,not fingers: Tool-action effect in a motor intention paradigm

Tool-use representations have been suggested to be supported by the representation of hand actions and/or by the representation of tool actions. A major issue is to know which one of these two representations is preferentially activated when people intend to use a tool. To address this issue, we developed a paradigm in which, in 20% of trials, participants had to press a button and actually use pliers to move an object in response to a predefined target symbol. Importantly, two masks hiding the symbols performed “opening” or “closing” actions before symbols appeared. In Experiment 1, participants used normal pliers: Hand’s opening actions induced pliers’ opening actions and vice versa for hands’ closing actions. Results indicated a compatibility effect between masks’ actions and pliers’ actions. Participants were faster to press the button in response to the target symbol when opening and closing actions of the masks were congruent with the corresponding actions of the hand. In Experiment 2 participants used inverse pliers: Hand’s opening actions involved pliers’ closing actions and vice versa. In this situation, results showed that the congruency of masks’ actions occurred with pliers’ actions and not hand’s actions. Altogether, these findings demonstrate that intention of use is preferentially based on the representation of tool actions, and have important implications for the domain of neuropsychology of tool use and the theories of goal-directed behavior.     

The temporal dynamics of the perceptual consequences of action-effect prediction

An essential aspect of voluntary action control is the ability to predict the perceptual effects of our actions. Although the influence of action-effect prediction on humans’ behavior and perception is unequivocal, it remains unclear when action-effect prediction is generated by the brain. The present study investigates the dynamics of action effect anticipation by tracing the time course of its perceptual consequences. Participants completed an acquisition phase during which specific actions (left and right key-presses) were associated with specific visual effects (upward and downward dots motion). In the test phase they performed a 2 AFC identification task in which they were required to indicate whether the dots moved upward or downward. To isolate any effects of action-effect prediction on perception, participants were presented with congruent and incongruent dot motion in which the association participants learned in the previous acquisition phase was respected and violated, respectively. Crucially, to assess the temporal dynamics of action prediction, congruent and incongruent stimuli were presented at different intervals before or after action execution. We observed higher sensitivity (d′) to motion discrimination in congruent vs. incongruent trials only when stimuli were presented from about 220 ms before the action to 280 ms after the action. The temporal dynamics of our effect suggest that action-effect prediction modulates perception at later stages of motor preparation.     

Development of oral motor behavior related to the skill assisted spoon feeding

Milestones in the typical development of eating skills are considered to be nippling (breast or bottle), eating from a spoon, drinking from a cup, biting and chewing.The purpose of this research was to study the development and consolidation of oral motor behavior related to the skill assisted spoon feeding in young infants. The present study longitudinally investigated the development of this skill in 39 healthy children from the start of spoon feeding until the skill was acquired. The Observation List Spoon Feeding with 7 observation items for oral motor behavior and 6 items for abnormal behavior was used. Results showed that infants between 4 and 8 months of age needed 5.7 weeks (SD 2.1), with a range of 8 weeks (from 2 to 10 weeks) to acquire this skill. No significant correlation (p = .109) between age at start spoon feeding and weeks needed to develop the skill was found. During this period oral motor behavior consolidated and abnormal behavior diminished.With this study it is shown that the period in weeks needed to acquire the oral motor behavior for the skill assisted spoon feeding is important in case of feeding problems.     

An integrative model of rational imitation in infancy

It has been proposed that infants selectively imitate based on a rational evaluation of an observed action (Gergely, Bekkering, & Király, 2002). This rational-imitation account has been rejected based on findings which suggested that infant imitation depends on: (a) the similarity between the infant's and the model's body posture; and (b) the presence of action effects (Paulus, Hunnius, Vissers, & Bekkering, 2011). Despite this controversy, we show that both accounts have received empirical support from different fields of research. We propose that both accounts operate on different levels, and we present an integrative model, which combines the two seemingly competing accounts. Motor resonance is perceived as a mechanism that enables infants to imitate, and a rational evaluation of the model's action is conceived as a mechanism that guides infants’ imitative behavior.     

The relationship between motor development,gestures and language production in the second year of life: A mediational analysis

This longitudinal study investigated the relationships between motor, gestural and linguistic abilities using two parent report instruments. Motor skills at 12 months significantly correlated with language production at 16, 20 and 23 months, but these associations were mediated by the use of representational gestures.     

The effect of chronic low back pain on tactile suppression during back movements

The aim of the present study was to examine whether tactile suppression, the phenomenon whereby tactile perception is suppressed during movement, would occur in the context of back movements. Of particular interest, it was investigated if tactile suppression in the back would be attenuated in those suffering from chronic low back pain. Individuals with chronic low back pain (N = 30) and a matched control group (N = 24) detected tactile stimuli on three possible locations (back, arm, chest) while performing a back or arm movement, or no movement. We hypothesized that the movements would induce tactile suppression, and that this effect would be largest for low-intense stimuli on the moving body part. We further hypothesized that, during back movements, tactile suppression on the back would be less pronounced in the chronic low back pain group than in the control group. The results showed the expected general tactile suppression effects. The hypothesis of back-specific attenuation of tactile suppression in the chronic low back pain group was not supported. However, back-specific tactile suppression in the chronic low back pain group was less pronounced in those who performed the back movements more slowly.     

Cerebral cortical activity associated with non-experts’ most accurate motor performance

This study’s specific aim was to determine if non-experts’ most accurate motor performance is associated with verbal-analytic- and working memory-related cerebral cortical activity during motor preparation. To assess this, EEG was recorded from non-expert golfers executing putts; EEG spectral power and coherence were calculated for the epoch preceding putt execution; and spectral power and coherence for the five most accurate putts were contrasted with that for the five least accurate. Results revealed marked power in the theta frequency bandwidth at all cerebral cortical regions for the most accurate putts relative to the least accurate, and considerable power in the low-beta frequency bandwidth at the left temporal region for the most accurate compared to the least. As theta power is associated with working memory and low-beta power at the left temporal region with verbal analysis, results suggest non-experts’ most accurate motor performance is associated with verbal-analytic- and working memory-related cerebral cortical activity during motor preparation.     

Object-based and egocentric mental rotation performance in older adults: The importance of gender differences and motor ability

In this study, mental rotation performance was assessed in both an object-based task, human figures and letters as stimuli, and in an egocentric-based task, a human figure as a stimulus, in 60 older persons between 60 and 71 years old (30 women, 30 men). Additionally all participants completed three motor tests measuring balance and mobility. The results show that the reaction time was slower for letters than for both human figure tasks and the mental rotation speed was faster over all for egocentric mental rotation tasks. Gender differences were found in the accuracy measurement, favoring males, and were independent of stimulus type, kind of transformation, and angular disparity. Furthermore, a regression analysis showed that the accuracy rate for object-based transformations with body stimuli could be predicted by gender and balance ability. This study showed that the mental rotation performance in older adults depends on stimulus type, kind of transformation, and gender and that performance partially relates to motor ability.     

The moving rubber hand illusion revisited: Comparing movements and visuotactile stimulation to induce illusory ownership

The rubber hand illusion is a perceptual illusion in which a model hand is experienced as part of one’s own body. In the present study we directly compared the classical illusion, based on visuotactile stimulation, with a rubber hand illusion based on active and passive movements. We examined the question of which combinations of sensory and motor cues are the most potent in inducing the illusion by subjective ratings and an objective measure (proprioceptive drift). In particular, we were interested in whether the combination of afferent and efferent signals in active movements results in the same illusion as in the purely passive modes. Our results show that the illusion is equally strong in all three cases. This demonstrates that different combinations of sensory input can lead to a very similar phenomenological experience and indicates that the illusion can be induced by any combination of multisensory information.