Outsider interference: no role for motor lateralization in determining the strength of avoidance responses during reaching

Abstract

When reaches are performed toward target objects, the presence of other non-target objects influences kinematic parameters of the reach. A typical observation has been that non-targets positioned ipsilaterally to the acting limb interfere more with the trajectory of the hand than contralateral non-targets. Here, we investigate whether this effect is mediated by motor lateralization or by the relative positioning of the objects with reference to the acting limb. Participants were asked to perform reaches toward physical target objects with their preferred or non-preferred hands while physical non-targets were present in different possible positions in the workspace. We tested both left-handers and right-handers. Our results show that a participant's handedness does not influence reaching behavior in an obstacle avoidance paradigm. Furthermore, no statistically significant differences between the use of the preferred and non-preferred hand were observed on the kinematic parameters of the reaches. We found evidence that non-targets positioned on the outside of the reaching limb influenced the reaching behavior more strongly than non-targets on the inside. Moreover, the type of movement also appeared to play a role, as reaches that crossed the workspace had a stronger effect on avoidance behavior than reaches that were 'uncrossed.' We interpret these results as support for the hypothesis that the avoidance response is determined by keeping a preferred distance between the acting limb in all stages of its reach toward the target and the non-target position. This process is not biased by hand dominance or the hand preference of the actor.

It is the flash which appears, the movement will follow: Investigating the relation between spatial attention and obstacle avoidance

“…However, this effect is limited to obstacles that are already more obstructing, because the left-obstacle spatial cue did not have an effect on avoidance movements. The asymmetric avoidance responses observed here, but also previously (Chapman & Goodale, 2008 ; Dean & Bruwer, 1994 ; Menger et al, 2012 , Menger, Van der Stigchel, & Dijkerman, 2013 ; Mon-Williams et al, 2001 ), occur because only the right obstacle interferes more with the transport of the lower limb as the arm extends toward the target object (Menger et al, 2012 ). Therefore, the hand has to take a more curved trajectory around it.…”

When two worlds collide: the influence of an obstacle in peripersonal space on multisensory encoding

“…In a control experiment, we placed non-targets at the same distance but to the left of the midline, where no influence of visuotactile interactions is expected, as there is a very low likelihood of touching the non-targets (i.e. they are not obstacles, see Menger et al 2013a , b ). Ten right-handed participants volunteered, but the data of three participants had to be excluded: one participant did not carry out the tactile discrimination task at all, one participant started all hand movements before the start of the trial (and thus before kinematics was measured), and one participant had to be excluded as the marker disconnected during the experiment.…”

“…In a control experiment, we placed non-targets at the left of the midline, where no influence of visuotactile interactions is expected, as there is a very low likelihood of touching the non-targets (i.e. they are not obstacles) (Menger et al 2013a , b ).…”

“…It seems logical that your obstacle avoidance behaviour is influenced by what the obstacle is, and where it is. There are indeed a number of studies that show effects of obstacle features on the spatiotemporal characteristics of avoidance movements (Chapman and Goodale 2008 , 2010 ; de Haan et al 2014 ; Menger et al 2012 , 2013a , b , 2014 ; Mon-Williams and McIntosh 2000 ; Mon-Williams et al 2001 ; Rice et al 2006 ; Tresilian 1998 ). The response to obstacle locations has been described as subtle and precise (Mon-Williams et al 2001 ), meaning that each individual obstacle location gives rise to a unique avoidance response (see Menger et al 2014 ).…”