Abstract
Previous studies have shown that reaching movements can be influenced by attentional selection processes. Critical evidence for this effect stems from reach trajectories in colour-oddity tasks. These experiments showed that the modulation of reach curvature is linked to colour priming—i.e., colour repetitions lead to smaller curvatures compared to trials where the target colour switches (e.g., Song & Nakayama, 2008; Moher & Song, 2016). Following this evidence, Heinke and colleagues developed a neurologically inspired robotics model for colour priming (Strauss et al., 2015). Critically, the model shows that attentional selection processes easily leak into movement planning causing the curvature effect. Here, we capture this leakage effect through the assumption that reaching movements are composed of submovements (e.g., Flash & Henis, 1991; Friedman, Brown, & Finkbeiner, 2013). Submovements are defined as discrete, ballistic movements with predetermined amplitude, direction, and duration prior to their onset. Each submovement is a straight-line trajectory but their superposition can create a curved trajectory. Friedman et al. (2013) showed that perceptual decision-making processes are reflected in submovements. In this research, we demonstrate that submovements provide deeper insights into the curvature effect. For instance, we found that switch trials are characterized by more submovements. Hence, submovement decomposition reflected attentional selection processes in choice reaching tasks. Future work will aim to analyse the timing of submovements e.g., at what point of time the submovements which create the curved trajectories occur. These timings should reflect the timing of attentional selection.