Abstract
A fundamental decision when interacting with objects involves hand selection. Two major factors that influence this decision include handedness, which relates to the proficiency of one hand over the other; and attentional information, which typically refers to the spatial relationships perceived between objects (Gabbard & Rabb, 2000). Attentional information has been studied by altering the location of an object in the workspace, however other forms of attentional information different from spatial relationships have also been examined, such as task complexity (Bryden et al., 2003; Gabbard et al., 2003; Mamalo et al., 2006). This study aimed to investigate attentional information in the form of different hand locations and planned reaches on hand choice decisions. Different hand locations changed the spatial relationships between effectors and the target, and planned reaches represented a cognitive form of attentional information. Participants reached toward a series of 3-target sequences in one of two groups: reactive reaches, selecting a hand to reach each target as it appeared; and planned reaches, where the 3-target sequence was presented prior to completing a reach. With the hands at different locations, reactive reaches demonstrated that object proximity drove hand choice decisions by selecting the effector that afforded the shortest travel distance. Planned reaches initially seemed to violate hand selection based on object proximity, performing longer reaches earlier in the sequence to ensure that object proximity was maximized later. Planned reaches resemble the end-state comfort phenomenon (Rosenbaum, 1992), where participants changed their approach to executing reaches depending on targets that followed.
