Automated vision occlusion-timing instrument for perception–action research
Behav Res
Automated vision occlusion-timing instrument for perception-action research
John Brenton 0 1
Sean Müller 0 1
Robbie Rhodes 0 1
Brad Finch 0 1
0 B3 Electronic Design Pty Ltd , Perth , Australia
1 School of Psychology and Exercise Science, Murdoch University , 90 South Street, Murdoch, Perth 6150 , Australia
Vision occlusion spectacles are a highly valuable instrument for visual-perception-action research in a variety of disciplines. In sports, occlusion spectacles have enabled invaluable knowledge to be obtained about the superior capability of experts to use visual information to guide actions within in-situ settings. Triggering the spectacles to occlude a performer's vision at a precise time in an opponent's action or object flight has been problematic, due to experimenter error in using a manual buttonpress approach. This article describes a new laser curtain wireless trigger for vision occlusion spectacles that is portable and fast in terms of its transmission time. The laser curtain can be positioned in a variety of orientations to accept a motion trigger, such as a cricket bowler's arm that distorts the lasers, which then activates a wireless signal for the occlusion spectacles to change from transparent to opaque, which occurs in only 8 ms. Results are reported from calculations done in an electronics laboratory, as well as from tests in a performance laboratory with a cricket bowler and a baseball pitcher, which verified this short time delay before vision occlusion. In addition, our results show that occlusion consistently occurred when it was intended-that is, near ball release and during mid-ball-flight. Only 8% of the collected data trials were unusable. The laser curtain improves upon the limitations of existing vision occlusion spectacle triggers, indicating that it is a valuable instrument for perception-action research in a variety of disciplines.
Vision occlusion spectacles; Automatic trigger; Laser curtain; Wireless
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Milgram’s (1987) invention of spectacles that can occlude the
availability of visual information to an observer has been
invaluable to researchers in different disciplines involved in
visual-perception–action research. Vision occlusion spectacles
have been used to understand the time course of visual
information that guides motor skills such as reaching to grasp an
object
(Whitwell, Lambert, & Goodale, 2008)
, interception of
a fast-moving object
(Marinovic, Plooy, & Tresilian, 2009)
,
and maintenance of balance in movement disorders
(Morris
et al., 2015)
. Over the past 20 years, an increasing number of
studies have used vision occlusion spectacles to investigate
the time course of visual information that guides complex,
whole-body, high-speed sports skills such as return of serve
in tennis and cricket batting. Vision occlusion spectacles are
popular with researchers because they allow the availability of
visual information to be manipulated within in-situ settings
and coupled to complex actions such as movements of the
whole body to strike a high-speed object such as a tennis ball.
Starkes, Edwards, Dissanayake, and Dunn (1995) were the
first to use vision occlusion spectacles to investigate the time
course of visual information pickup for anticipation in the
high-speed sports skill of serving in volleyball. Skilled and
novice volleyball players stood on a court and wore the
spectacles, which were connected by a cable to a timer on the
sideline. Participants observed opponents deliver different
types of serves that were occluded (spectacles opaque) at
different time points in the server’s action, and they had to make
a nonmotor prediction of the serve’s landing position by placing
a marker on the court. The experimenter manually triggered the
spectacles to occlude the participant’s vision of the server’s action
by simultaneously watching the server’s action unfold and
pressing the button on the timer to correspond with preplanned
kinematic events. Occlusion was targeted at events prior to, at,
and after the server’s ball–hand contact. The authors reported that
the time delay for spectacles to occlude using a cable interface
was 2 ms. However, due to error in the timing of manual
triggering (likely due to reaction time delays), a high-speed camera
was used to film the server’s action and record the created vision
occlusion conditions. The footage was sorted post-hoc to confirm
which trials could be retained for data analysis on the basis of
preplanned temporal-occlusion conditions. The findings
indicated that skilled university players could predict serve landing
locations with less error than could novices. Their study spawned
several others within in-situ settings that have used a manually
triggered and post-hoc trial-sorted approach to demonstrate that
experts have anticipation skills superior to those of less
skilled players in modified squash game scenarios
(Abernethy, Gill, Parks, & Packer, 2001)
, tennis return of
serve
(Farrow & Abernethy, 200 (...truncated)