Biomedical subjects

Alexander Pollatsek

Publications and source records attributed to Alexander Pollatsek.

22 records · Page 2Linked to original sources

PubMed2002

Viewpoint-dependent recognition of scenes.

Three experiments investigated scene recognition across viewpoint changes, involving same/different judgements on scenes consisting of three objects on a desktop. On same trials, the comparison scene appeared either from the same viewpoint as the standard scene or from a different viewpoint with the desktop rotated about one or more axes. Different trials were created either by interchanging the locations of two or three of the objects (location change condition), or by rotating either one or all three of the objects around their vertical axes (orientation change condition). Response times and errors increased as a function of the angular distance between the standard and comparison views, but this effect was bigger for rotations around the vertical axis than for those about the line of sight or horizontal axis. Furthermore, the time to detect location changes was less than that to detect orientation changes, and this difference increased with increasing angular disparity between the standard and comparison scenes. Rotation times estimated in a double-axis rotation were no longer than other rotations in depth, indicating that alignment was not necessarily simpler around a "natural" axis of rotation. These results are consistent with the hypothesis that scenes, like many objects, may be represented in a viewpoint dependent manner and recognized by aligning standard and comparison views, but that the alignment of scenes is not a holistic process.

Feedback↗

PubMed2002

Use of a fixed-base driving simulator to evaluate the effects of experience and PC-based risk awareness training on drivers' decisions.

Driver education classes were once seen as a remedy for young drivers' overinvolvement in crashes, but research results from the early 1970s were disappointing. Few changes in the content or methods of instruction occurred until recently, but this could change rapidly. Personal computers (PCs) can now present videos or photorealistic simulations of risky, cognitively demanding traffic scenarios that require quick responses without putting the participant at risk. As such programs proliferate, evaluating their effectiveness poses a major challenge. We report the use of a fixed-base driving simulator to study the effects of both experience on the road and PC-based risk awareness training on younger drivers' part-task simulator driving performance in risky traffic scenarios. We ran three groups of drivers on the simulator: one group first trained on the PC (younger, inexperienced drivers) and two groups who received no PC training (younger, inexperienced and experienced drivers). Overall, the younger, inexperienced drivers who were trained on a PC operated their vehicles in risky scenarios in ways that differed measurably from those of the untrained younger, inexperienced drivers and, more important, in ways that we believe would decrease their exposure to risk considering that, on average, their behavior was more similar to the behavior of the untrained, experienced drivers. More research is needed to demonstrate whether these findings apply on the open road to the larger population of younger drivers. However, at least initially, the research suggests that PC-based risk awareness training programs have the potential to reduce the high crash rate among younger, inexperienced drivers.

Accidents, Traffic↗

PubMed2002

Simple rotary motion is integrated across fixations.

Participants were shown a line rotating at a constant angular velocity and were asked to judge whether motion was continuous or whether the line jumped (i.e., moved either forward or backward in the rotary cycle). In two experiments, the participants were significantly better than chance in detecting these jumps in simple rotary motion even when the jumps occurred during a saccade. Moreover, in Experiment 2, when the jump occurred during a saccade followed by a masking flash, perception of the jump was at least as good as when it occurred during a fixation followed by a masking flash. These results complement and extend the findings of Verfaillie and co-workers, who found that perceptions of some changes in biological motion were as good across fixations as when they occurred during a fixation. These findings are in contrast to the common finding, in the reading literature, that people are consciously "blind" to many changes in the text and to those, in the scene perception literature, in which detection of static changes across fixations is above chance but plausibly well below the level that would be expected if the change occurred during a fixation.

Fixation, Ocular↗

PubMed2002

The processing of consonants and vowels in reading: evidence from the fast priming paradigm.

We assessed the early encoding of consonant and vowel information in the reading of English, using the fast priming paradigm. With 30-msec prime durations, gaze durations on target words were shorter when preceded by high-frequency consonant-same primes (which shared consonant information with the target word; e.g., lake-like) than when preceded by vowel-same primes (which shared vowel information with the target word; e.g., line-like), but there were no priming effects for low-frequency primes. With 45-msec prime durations, however, there was no effect of prime frequency and gaze durations on target words were shortened equally when they were preceded by consonant-same primes and vowel-same primes, as compared with control primes (e.g., late-like). The results suggest that the processing of consonants is more rapid than that of vowels, providing further evidence for the distinction between consonant and vowel processing in the reading of English.

Adult↗