Perceptual and cognitive processes in time-to-contact estimation: Analysis of prediction-motion and relative judgment tasks

Abstract

Three classes of task appear to involve time-to-contact (TTC) information: coincidence anticipation (CA)tasks, relative judgment (RJ) tasks, and interceptive actions (lAs). An important type of CA task used to study the perception of TTCis the prediction-motion (PM) task. The question of whether it is possible to study the perceptual processes involved in the timing of lAs using PM and RJ tasks is considered. Arevised version of the tau hypothesis is proposed as an account of the perceptual information processing involved in the control of fast lAs. This draws on the distinction between "motor" and "cognitive"visual systems. It is argued that task variables affect whether "cognitive" information processing is involved in performance and can determine whether TTCinformation is used at all. Evidence is reviewed that suggests that PM and RJ tasks involve cognitive processing. It is argued that target viewing time, TTC at response initiation, amount of practice, and whether there is a period between target disappearance and response are task variables that determine whether cognitive processing will influence responding.

Time-to-Contact Estimation of Accelerated Stimuli Is Based on First-Order Information.

“…In sum, it can be inferred that indirect interceptive actions involve a ballistic-type (e.g., Shea, 1980) or impulse-type of control (Tresilian, 1995). The intervention of mechanisms permitting regulation of the movement during its execution could be therefore excluded (e.g., Schmidt & Russel, 1972).…”

“…TTC ϭ time to contact. retical issue is raised by authors who have questioned the general and exclusive character of the tau hypothesis and suggested that other sources of information could be used to time actions (e.g., Michaels et al, 2001;Tresilian, 1995Tresilian, , 1999aTresilian, , 1999b.…”

Effects of a moving distractor object on time-to-contact judgments.

“…As in the previous experiments, distractor objects with a TTP either earlier or later than target TTC were presented. As Tresilian (1995) has pointed out, in a PM task the observers are required to delay their response after the disappearance of the target from the screen, and thus "cognitive" mechanisms such as clocking or cognitive motion extrapolation are likely to play a role. In contrast, in the AI task, this type of cognitive influences is minimized (cf.…”

“…A large body of literature suggests that the visual system possesses a dedicated processor that continuously computes tau. The constantly available tau information is then taken by the visual system to inform decisions such as when to start swinging the baseball bat or when to initiate a braking motion (see, e.g., Tresilian, 1995). More recently, a growing body of literature has suggested that the processor uses simpler, alternate optical variables, such as expansion rates or even simple image velocities (see, e.g., Kerzel, Hecht, & Kim, 2001;Smith, Flach, Dittman, & Stanard, 2001).…”

“…Hence, most experiments involving two or more moving objects used a relative judgment task (cf. Tresilian, 1995). For example, in a study by Law et al (1993), the observers decided which of two objects would arrive sooner at a designated stationary target.…”