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

Abstract

The effects of moving task-irrelevant objects on time-to-contact (TTC) judgments were examined in 5 experiments. Observers viewed a directly approaching target in the presence of a distractor object moving in parallel with the target. In Experiments 1 to 4, observers decided whether the target would have collided with them earlier or later than a standard (absolute identification task). A contrast effect was observed: If the distractor arrived later than the target, it caused a bias toward early responses, relative to the condition without a distractor. The early-arriving distractor had no significant effect. The pattern of results was unaltered when potentially confounding information from individual visual cues was removed. The availability of stereoscopic information reduced the effect. The contrast effect was also observed if target and distractor were abstract geometric objects rather than simulations of real-world vehicles, rendering less likely a simple safety strategy activated by a potentially threatening distractor. Experiment 5 showed that the effect of the late-arriving distractor generalized to a prediction-motion task. The results indicate that task-irrelevant information in the background has to be considered in revision of time-to-contact theory.

Estimating the relative weights of visual and auditory tau versus heuristic-based cues for time-to-contact judgments in realistic, familiar scenes by older and younger adults

“…This finding is consistent with previous studies (e.g., Oberfeld & Hecht, 2008;Petzoldt, 2014), and can be attributed to either a size-arrival effect (DeLucia, 1991) or a distance bias (Law et al, 1993), because the slower speed condition had a larger final optical vehicle size and a closer final distance than did the faster condition. A significant interaction between TTC level and speed, F(2, 80) = 27.397,ε = 1.000, p < .001, η p 2 = .407, indicated larger differences in TTC estimates between the two speeds with increasing actual TTC (see Fig.…”

“…We also observed a significant effect of vehicle speed on TTC estimates, indicating that estimates were shorter when vehicle speed was slower. This finding is consistent with previous studies (e.g., Oberfeld & Hecht, 2008;Petzoldt, 2014) and can be attributed to a size-arrival effect (DeLucia, 1991) or to a distance bias (Law et al, 1993). Specifically, at slower speeds, when the screen goes blank, the final optical vehicle size is larger, and the vehicle is closer in terms of final distance, than in the faster condition.…”

“…Error bars show 95% confidence intervals (CIs). squares, younger adults; circles, older adults reported underestimations, particularly as actual TTC increased above 1 s (e.g., Heuer, 1993;Oberfeld & Hecht, 2008;Schiff & Detwiler, 1979). In our earlier study (DeLucia et al, 2016), we also observed overestimations.…”

“…Only the auditory and visual TTCs from a single TTC level were combined, so that the auditory and visual stimuli were perceived as belonging to a single object rather than to two separate objects, which might occur at large differences between auditory and visual TTC. Because the sensitivity for discriminating TTCs is slightly lower at shorter than at longer TTCs (Oberfeld & Hecht, 2008), a higher proportional difference in visual versus auditory arrival times was selected for the shorter than for the longer TTC levels (i.e., 30% deviation at TTC level 1.0, 20% deviation at TTC level 2.0, and 12.5% deviation at TTC level 3.2).…”

Temporal estimation with two moving objects: overt and covert pursuit

“…The observer is required to make a simple response (e.g., press a button) at the time the object would have reached the target, had it continued along its trajectory. Using the PM task (see Lugtigheid & Welchman 2011), it is generally found that participants overestimate shorter TTC and underestimate longer TTC, with the transition point occurring at approximately 1000 ms (e.g., Manser & Hancock 1996;Schiff & Detwiler 1979;Oberfeld & Hecht 2008). Overt pursuit of the moving object is the default response in the PM task (Rosenbaum 1975) and is important for achieving accurate TTC estimation, with greater error exhibited if participants are instructed to fixate on a static location compared to when permitted to freely move their eyes (Bennett, Baurès, Hecht & Benguigui 2010;Makin & Poliakoff 2011;Peterken et al 1991).…”