Smeets et al. (2016) suggested that motor adjustments may be quick because they don’t require stimulus detection. We agree that these rapid adjustments probably reflect rapid perceptual processing rather than rapid motor execution, but we question whether the absence of detection is the best way to explain the effect. We suggest that it is unclear what mechanisms would be involved in detection and why detection would be required in some of the cases discussed by Smeets et al. Instead, we suggest that ultra-fast motor adjustments require very little competition among possible stimuli or responses. We suggest that escaping competition rather than avoiding detection may be the cause of the very short reaction times that Smeets et al. identified.
Bradley P. Wyble and David A. Rosenbaum
Most studies investigating movement preparation report substantial longer reaction times than studies probing response times to adjust an ongoing movement. However, both behaviors constitute control processes that transform sensory information about the environment into motor commands. Smeets, Oostwoud Wijdenes, and Brenner (2016) base their review on the hypothesis of a qualitative difference between the two sensorimotor control processes. By ruling out that the three latter movement stages proposed by Donders (1969)—identification, selection, and execution—are responsible for the difference, they argue for a specific role of the detection stage. Specifically, they reason that the detection in (target) change is only necessary for movement initiation and thus constitutes the qualitative difference between the two behaviors. In contrast to this view, I will advocate that change detection is not a qualitatively discriminating feature between the two processes. Instead, the difference in response time might rather stem from different decision criteria (Wolpert & Landy, 2012) set on the detection threshold. This threshold is rather conservative for movement initiation and more relaxed for online adjustments. However, both are states on the same continuum. Thus, movement initiation and online adjustments might even not be qualitatively different at all.
Robert L. Sainburg and Pratik K. Mutha
The target article (Smeets, Oostwoud Wijdenes, & Brenner, 2016) proposes that short latency responses to changes in target location during reaching reflect an unconscious, continuous, and incremental minimization of the distance between the hand and the target, which does not require detection of the change in target location. We, instead, propose that short-latency visuomotor responses invoke reflex- or startle-like mechanisms, an idea supported by evidence that such responses are both automatic and resistant to cognitive influences. In addition, the target article fails to address the biological underpinnings for the range of response latencies reported across the literature, including the circuits that might underlie the proposed sensorimotor loops. When considering the range of latencies reported in the literature, we propose that mechanisms grounded in neurophysiology should be more informative than the simple information processing perspective adopted by the target article.
Tyler Cluff and Stephen H. Scott
David W. Franklin
Romeo Chua, Brendan D. Cameron, and Jarrod Blinch
In the article by Caetano FG, et al, “Characterization of the Sprint and Repeated-Sprint Sequences Performed by Professional Futsal Players, According to Playing Position, During Official Matches,” in the J Appl Biomech, 31(6), pp. 423–429, http://dx.doi.org/10.1123/jab.2014-0159, the second author’s name was incorrectly listed as Murilo José de Oliveira. The second author’s name should have been listed as Murilo José de Oliveira Bueno.
Justin A. Haegele, Jihyun Lee, and David L. Porretta
In the article by Haegele, J.A., Lee, L., and Porretta, D.L., “Research trends in Adapted Physical Activity Quarterly from 2004 to 2013”, in Adapted Physical Activity Quarterly, 32(3), 187–205, an incorrect DOI was printed. The correct DOI for that article is http://dx.doi.org/10.1123/APAQ.2014-0232.