In the present study, when trials were missed in AL and SP conditions, we computed the distance to cover the distance between paddle starting position and ball arrival position, for the balls that had to be intercepted by the participant. It means that to evaluate the distance to cover, we excluded from AL results all the missed balls that ended in the area where stationary paddle was positioned in SP condition. This distance could thus be seen as the distance that participant should have covered to intercept the ball: the smaller this mean value, the closer to participant's starting position the missed balls ended.
This way, we evaluated if participants missed trials in SP they were able to intercept in AL, as previously found in the pilot study. More generally, we Spain phone number list explored whether or not interference between participants could appear during collaborative conditions, and how task complexity and available visual cues could influence this interference. During a trial, initiation of movement was defined as the first moment when participant's hand velocity reached the threshold of 0.5 m/s with a minimal displacement of 10 cm on X-axis. When the ball was intercepted, the location of the interception was computed, and when not, the ending position of ball was collected. Data post-processing, variables analysis and statistics were made with R software (R Core-Team, 2016), and significance level was set to 0.05. Normality of data was tested with Shapiro-Wilk test.
Toward the real participant. To better quantify the area of uncertainty previously defined, the steepness of the slopes of the logistic curve was used, and in particular, we looked at the amount of overlap, defined by Cox and Snell (1989) as the distance between the 5% and 95% points of this curve. We made the choice to adopt the same approach as Benerink et al. (2016) in order to better discuss our results on overlap. Overlap in SP was of 38.5 cm and represents a mathematical quantification of the area of uncertainty. This means that, in this 38.5 cm-wide area, participants had difficulties to judge whether or not they should intercept the ball. Figure 5 frontiersin FIGURE 5. Mean distance that participants would have to cover in missed trials, when the ball had to be intercepted by them, in AL and SP.