Angular distance between targets and non-targets influences the direction of early deviation in stylus-based hand trajectories

Abstract

Research into saccadic eye trajectories has revealed much about the attentional mechanisms underlying target selection and distracter suppression. Previous research has supported the notion that a system based on population vector coding may explain both the behaviour of saccades and targeting hand movements. While studies have been conducted with reaching and grasping, no studies to date have explored the behaviour of stylus-based hand movements on tablet computers. Tablets could become a useful tool for quick diagnostics in a clinical setting, once our operative behaviour can be quantitatively linked to the processes of attention. In this study, stylus-based hand movements on a tablet were observed in a task similar to those used in saccadic eye movements. It was found that the angular distance between the target and distracting element was most informative in determining the direction of the deviation. Shorter distances (20°) led to relatively more attraction (deviation) towards the distracter as compared to longer distances (40° and 65°). The pattern found with regard to angular distance between target and distracter as well as distance between the hand and the distracter, is suggestive of an interaction between the attention and inhibition not unlike what is seen in saccade research.

An integrated model of knowledge regarding the mechanisms behind attention in humans can be beneficial for many aspects of society and science. Examples include the development of attentional structures in robots and other agents and the development of software and tools that function as an extension of human capabilities (e.g. support systems in military defence, layout design of control systems of transport vehicles, devices that integrate the digital and real world). With tablets being one of the recent big trends in commercial technology, understanding how attention is reflected in the stylus-based movements of the hand can be beneficial both for the advancement of new technology as well as the development of diagnostic tools in a clinical setting.

(Note: figure numbers for figures 3 and 4 should be reversed)