Flexible weighting of body-related effects in action production

The size coding of responses: The size of switches and the force feedback

We aimed to understand which factors have a functional role in the size coding of responses, either the size of the switches or the force required to trigger each switch. This question is of relevance because it allows a better understanding of processes underlying action coding. In each trial, participants saw a small or large object. Depending on its colour, the participants had to press one of two switches. In the "size" condition, the response device consisted of two switches of different visual size, but both required the same amount of force. In the "force-feedback" condition, the response device consisted in two switches of identical visual size, but one switch required more force than the other. We found a compatibility effect in the "size," not in the "force-feedback" condition, supporting that the size-coding of responses would be due to the size of the switches.

Action representations in prevention behavior: Evidence from motor execution

Human actions sometimes aim at preventing an event from occurring. How these to-be-prevented events are represented, however, is poorly understood. Recent proposals in the literature point to a possible divide between effect-producing, operant actions, and effect-precluding, prevention actions, suggesting that the control of operant actions relies on codes of environment-related effects whereas prevention actions do not. Here we report two experiments on this issue, showing that spatial features (Experiment 1) as well as temporal features (Experiment 2) of to-be-prevented events influence actions in the same way as corresponding features of to-be-produced effects. This implies that selecting and executing prevention actions relies on anticipated environmental changes, comparable to operant actions.

Force and electromyography reflections of sensory action-effect weighting during pinching

Ideomotor theories suggest that different action-effects are not equally important in goal-directed actions, and that task-relevant information are weighted stronger during the representation of actions. This stronger weighting of task-relevant action-effects might also enable to utilize them as retrieval cues of the corresponding motor patterns. The aim of the present study was to investigate how the consistent presence or absence of a sound action-effect influenced the retrieval of the motor components of a simple, everyday action (pinching) as reflected by the pattern of force application and surface electromyogram (sEMG) recorded from the abductor pollicis brevis (APB) and first dorsal interosseous (FDI). Participants applied pairs of pinch impulses to a force sensitive resistor (FSR). The presence or absence of a sound action-effect and the between-action interval (BAI, 2 or 4 s) were manipulated blockwise, whereas the target force level (low or high) was randomly cued from trial to trial. When actions resulted in a sound, force and sEMG activity were reduced. This effect was more pronounced for low target force level trials, which is compatible with a stronger weighting of the sound action-effect when the intensity of the tactile and proprioceptive action-effects is low. Surprisingly, the FDI activity was more variable within actions pairs in the 2 s BAI conditions, which suggests that action pairs separated by the longer time interval might have been represented differently from those separated by the shorter interval.

From Affordances to Abstract Words: The Flexibility of Sensorimotor Grounding

The sensorimotor system plays a critical role in several cognitive processes. Here, we review recent studies documenting this interplay at different levels. First, we concentrate on studies that have shown how the sensorimotor system is flexibly involved in interactions with objects. We report evidence demonstrating how social context and situations influence affordance activation, and then focus on tactile and kinesthetic components in body-object interactions. Then, we turn to word use, and review studies that have shown that not only concrete words, but also abstract words are grounded in the sensorimotor system. We report evidence that abstract concepts activate the mouth effector more than concrete concepts, and discuss this effect in light of studies on adults, children, and infants. Finally, we pinpoint possible sensorimotor mechanisms at play in the acquisition and use of abstract concepts. Overall, we show that the involvement of the sensorimotor system is flexibly modulated by context, and that its role can be integrated and flanked by that of other systems such as the linguistic system. We suggest that to unravel the role of the sensorimotor system in cognition, future research should fully explore the complexity of this intricate, and sometimes slippery, relation.

Anticipating the magnitude of response outcomes can induce a potentiation effect for manipulable objects

Merely seeing large objects (e.g., apples) potentiates power grip whereas seeing small objects (e.g., strawberries) potentiates precision grip. According to the embodied cognition account, this potentiation effect reflects automatic access to object representation, including the grip usually associated with the object. Alternatively, this effect might be due to an overlap between magnitude codes used to code manipulable objects and magnitude codes used to code responses outcomes. In Experiment 1, participants saw objects usually grasped with a power or precision grip and had to press keys either with their forefinger or with their palm, each response generating a low or high tone (i.e., a large vs. small perceptual outcome, respectively). Tones were automatically delivered by headphones after the responses have been made in line with the ideomotor theories according to which voluntary actions are carried out due to the anticipation of their outcomes. Consistent with the magnitude-coding hypothesis, response times were shorter when the object and the anticipated response outcome were of the same magnitude than when they were not. These results were also consistent with a between-experiment analysis. In Experiments 2 and 3, we investigated to what extent removing or switching the outcomes during the experiment influence the potentiation effect. Our results support that the potentiation effect of grasping behaviours could be due to the compatibility between magnitude codes rather than to the involvement of motor representations. Our results also suggest a spontaneous use of the magnitude of response outcomes to code responses, as well as the flexibility of this coding processes when responses outcomes are altered.