Measured response parameters Sample Clauses

Measured response parameters. Picture display, auditory tones, data collection and data analyses were controlled and conducted using Matlab software. The alpha level was set to 0.05 for all statistical procedures. Autocorrelation measures. Inter-response intervals (IRIs) were measured as the time intervals between the onsets of successive taps. Asynchronies were calculated as the difference in time between the onset of a tap and the start of the nearest auditory tone. After omitting the first six IRIs and asynchronies of each trial, autocorrelation values were calculated up to six lags. Confidence intervals were used to assess whether the autocorrelation values were significantly different from zero (bounds = 0 ± Z(1−α/2)/√N = 0 ± 1.96/√68 = ±0.23, see Box & Xxxxxxx, 1976). These measures served as an indicator of the presence or absence of action control through an internal clock. Timing and spatial errors. The IRIerror was computed as the percentage of difference between each IRI and the reference inter-onset interval (IOI) of a given trial (IRIerror(i) = (IRIi − IOI)/IOI ∗ 100). The IRIerrors were then averaged for each position, IOI and participant. This measure served as an indicator of the timing error. Asynchronies were also averaged for each position, IOI and participant and served as an indicator of synchronisation error with an external metronome. The endpoint distributions of the pointing actions were plotted for each target position (Figure II.2a). Using principal component analysis, spatial ellipses were then fitted to the movement endpoint distributions (Figure II.2b, for details on the calculations, see Xxxxxx, Xxxxxxxx, & Xxxx, 1994). The confidence intervals were set to 95% on axis length. The area of spatial ellipses was then computed and used as an indicator of the spatial error.