On-line and model-based approaches to the visual control of action

Abstract

Two general approaches to the visual control of action have emerged in last few decades, known as the on-line and model-based approaches. The key difference between them is whether action is controlled by current visual information or on the basis of an internal world model. In this paper, we evaluate three hypotheses: strong on-line control, strong model-based control, and a hybrid solution that combines on-line control with weak off-line strategies. We review experimental research on the control of locomotion and manual actions, which indicates that (a) an internal world model is neither sufficient nor necessary to control action at normal levels of performance; (b) current visual information is necessary and sufficient to control action at normal levels; and (c) under certain conditions (e.g. occlusion) action is controlled by less accurate, simple strategies such as heuristics, visual-motor mappings, or spatial memory. We conclude that the strong model-based hypothesis is not sustainable. Action is normally controlled on-line when current information is available, consistent with the strong on-line control hypothesis. In exceptional circumstances, action is controlled by weak, context-specific, off-line strategies. This hybrid solution is comprehensive, parsimonious, and able to account for a variety of tasks under a range of visual conditions.

Sensorimotor basis of motor vehicle control

“…In a follow-up study in 2000, Hildreth et al (Hildreth, Beusmans et al 2000) investigated So, what causes these systematic errors? Firstly, it was not because of the longer duration of visual occlusion suggested by Zhao et al (Zhao and Warren 2015). The duration of visual occlusion needs to cover the entire lane-change period or it may not reflect participants' real intention.…”

“…Without visual feedback, drivers only turn the vehicle towards the destination lane (the first steering phase, see Figure 3) but never return the vehicle to the original heading (the second, return steering phase, see (Wallis, Chatziastros et al 2002). Recently, Zhao and Warren attributed this failure to the longer visual occlusion used in Wallis et al's studies (Zhao and Warren 2015). Based on the results from this thesis, as well as other previous studies, we would argue that a typical lane change cannot be done within just 2 seconds (which was used in previous studies).…”

“…For example, a driver would know in advance that his/her retinal images are going to be shifted if he/she is about to make a turn. Such predictions or expectations can form an important part of an internal control model (Kawato 1999, Shadmehr, Smith et al 2010, or can act as a simple heuristic or mapping strategy (Zhao and Warren 2015). However, in these settings it is diffcult to completely eliminate the effects of a visual direction cue caused by the addition of a target and/or other objects.…”

“…On the basis of such results one might ask whether drivers actually operate an internal model at all, since an incorrect model is likely to be, at best useless, or at worst actually interferes with successful execution. To answer this, it is important to look to the literature on reaching and interception tasks, where the existence of internal models is widely accepted (for reviews see (Kawato 1999, Zago, McIntyre et al 2008, Shadmehr, Smith et al 2010, Zhao and Warren 2015). In studies investigating catching a free-falling object, for example, researchers have found that humans appear to use an internal model to estimate linear acceleration, such as that due to earth's gravity (Kawato 1999, Merfeld, Zupan et al 1999, Snyder 1999, Shadmehr, Smith et al 2010.…”

“…Proponents of this approach argue that a predicative control model (i.e. internal model) is uneconomic for the brain to incorporate since online information is sufficient for a wide range of tasks (Baures, Benguigui et al 2007, Zhao andWarren 2015). Zhao and Warren suggest that a simple heuristic, mapping strategy can be used to explain much of the studies claiming to support an internal model (e.g.…”