Obstacle avoidance. The influence of position and identity of obstacles on the reach trajectory and reaction time.
Summary
Current research suggests that obstacles can change the path of a reaching movement. So far, mainly spatial parameters such as the object’s position and width have been assessed. This experiment investigated the influence of identity of an obstacle on both the reach trajectory and reaction time. The influence of identity was examined in order to assess whether the identity of an obstacle could have a larger influence on obstacle avoidance than suspected by previous research. If this is the case, this could be regarded as evidence for cooperation between the dorsal and ventral stream. Another aim of this experiment was to find out which inhibition or attention model could better explain obstacle avoidance. All models predict the deviation of the hand as a function of the saliency of the obstacle. The saliency was varied by using proprioceptive information for one obstacle, but not for the other. Either the own hand of the participant, an imitation hand or a wooden block was used as an obstacle. The obstacle could be placed on two possible locations. Analyses revealed a significant influence of the position on the reach trajectory. In addition, evidence was found that suggests an influence of the identity of an obstacle on the reach trajectory. Neither position, nor identity displayed an effect on reaction time. This experiment confirmed the influence of the position of an obstacle on the reach trajectory. In addition, it provided evidence for a greater role of the identity in obstacle avoidance, but further research is required to strengthen support for this hypothesis. Support could be found for the response activation model, but it was unclear whether this model was the best explanation for the deviation towards the obstacles.