Rapid recalibration based on optic flow in visually guided action

Abstract

Action capabilities are always subject to limits. Whether on foot or in a vehicle, people can only move so fast, slow down so quickly, and turn so sharply. The successful performance of almost any perceptual-motor task requires actors to learn and continually relearn their ever-changing action capabilities. Such learning can be considered an example of perceptual-motor calibration. The present study includes two experiments designed to address basic questions about the nature of this calibration process. Subjects performed a simulated braking task, using a foot pedal to slow down to a stop in front of an obstacle in the path of motion. At one point in the experiment, the strength of the brake was increased or decreased unbeknownst to subjects, and behavior before and after the change in brake strength was analyzed for evidence of recalibration. Experiment 1 showed that actors rapidly recalibrate following a change in brake dynamics, even when they are unaware of the change. In Experiment 2, the scene turned black one second after braking was initiated. Subjects still recalibrated following the change in brake strength, suggesting that information in the sensory consequences of the initial brake adjustment is sufficient for recalibration, even in the absence of feedback about the outcome (i.e., in terms of final position error) of the task. Discussion focuses on the critical but often overlooked role of calibration in continuously controlled visually guided action, and the nature of the information used for recalibration.

Learning novel mappings from optic flow to the control of action

“…This is important because learning in a ballistic task must be based on feedback about the outcome of the trial. By comparison, learning in a continuously controlled task such as visually guided braking is likely to be based on information in the optical consequences of ongoing adjustments (Fajen, 2007).…”

Does Perceptual-Motor Calibration Generalize across Two Different Forms of Locomotion? Investigations of Walking and Wheelchairs

“…For example, Fajen [41] has framed learning to brake to avoid collisions and to rapidly adjust braking behaviors in the context of perceptual-motor calibration More generally, Fajen [42] has described several other visually-guided actions such as intercepting a target and steering in the context of continuous calibration between visual information and the body’s actions or potential for action. It is likely that many types of perceptual-motor skill learning involve initial and ongoing calibration.…”

Early Alzheimer's disease blocks responses to accelerating self-movement

“…Age-related cognitive impairment is a strong predictor of driving cessation (Edwards, et al, 2010) with speed regulation errors correlated with crash-related injuries (Classen, et al, 2010). Optic flow is crucial for speed adjustments and braking during vehicular navigation (Bardy and Warren, 1997) (Fajen, 2007). …”