Now and then: Hand choice is influenced by recent action history

Abstract

Action choices are influenced by recent past and predicted future action states. Here, we demonstrate that recent hand-choice history affects both current hand choices and response times to initiate actions. Participants reach to contact visible targets using one hand. Hand choice is biased in favour of which hand was used recently, in particular, when the biomechanical costs of responding with either hand are similar, and repeated choices lead to reduced response times. These effects are also found to positively correlate. Participants who show strong effects of recent history on hand choice also tend to show strong effects of recent history on response times. The data are consistent with a computational efficiency interpretation whereby repeated action choices confer computational gains in the efficiency of underpinning processes. We discuss our results within the framework of this model, and with respect to balancing predicted gains and losses, and speculate about the possible underlying mechanisms in neural terms.

Keywords: Action planning; Action selection; Hand choice; Hysteresis; Motor history; Motor programming; Priming; Sensorimotor control.

Fig. 1

Choice-hysteresis as point of subjective equality (PSE) values. a Participants reach to contact targets at 10 positions. Squares represent the start positions of each hand. The “+” represents fixation. b Group mean proportions of right-hand use per target position per left-prime (light grey) and right-prime (dark grey) conditions are shown. Error bars indicate 95% confidence intervals. c Data from three participants illustrate individual-level fits of probability functions used to estimate PSE values per left-prime and right-prime conditions. Boxes drawn on curves show PSEs. d PSE data are shown as a function of left-prime and right-prime conditions (left), and as difference scores (left-prime − right-prime; right). Solid lines indicate group means with 95% confidence intervals, and open (light grey) circles show individual scores. Xs indicate outliers, shown for descriptive purposes, excluded from statistical analyses. ** indicates significance at p < .01

Fig. 2

Choice hysteresis as proportions of right-hand use. a Proportions of right-hand use are shown as difference scores (right-prime − left-prime) as a function of target eccentricity. Positive values are consistent with predicted effects of history (choice hysteresis). Solid lines indicate group means with 95% confidence intervals, and open circles show individual scores. Xs indicate outliers, shown for descriptive purposes only. Untransformed data are shown, for ease of interpretation. Statistical analyses are performed on arcsine transformed data (see Hand Choice section). * indicates significant post hoc pairwise comparisons at p < .05, Bonferroni corrected. b Same as a, shown for extreme and PSE target positions. *** indicates significance at p < .001

Fig. 3

RT hysteresis. a Response-time data are plotted as a function of repeat and switch conditions (left), and as difference scores (switch − repeat) (right). Solid lines indicate group means with 95% confidence intervals, and open circles show individual scores. Xs denote outliers, shown for descriptive purposes only. b Same as a, shown for extreme and PSE target positions. *** indicates significance at p < .001

Fig. 4

The relationship between choice hysteresis and RT hysteresis. Individual-level choice hysteresis (left-prime PSE − right-prime PSE) data are plotted as a function of individual-level RT hysteresis (switch RT − repeat RT) data. Linear regression indicates a significant positive relationship at p < .05. Outliers are excluded (see Figs. 1d and 3a, respectively)