Biomedical subjects

Anne Treisman

Publications and source records attributed to Anne Treisman.

4 recordsLinked to original sources

PubMed2005

Statistical processing: computing the average size in perceptual groups.

This paper explores some structural constraints on computing the mean sizes of sets of elements. Neither number nor density had much effect on judgments of mean size. Intermingled sets of circles segregated only by color gave mean discrimination thresholds for size that were as accurate as sets segregated by location. They were about the same when the relevant color was cued, when it was not cued, and when no distractor set was present. The results suggest that means are computed automatically and in parallel after an initial preattentive segregation by color.

Attention↗

PubMed2005

Perception of objects in natural scenes: is it really attention free?

Studies have suggested attention-free semantic processing of natural scenes in which concurrent tasks leave category detection unimpaired (e.g., F. Li, R. VanRullen, C. Koch, & P. Perona, 2002). Could this ability reflect detection of disjunctive feature sets rather than high-level binding? Participants detected an animal target in a rapid serial visual presentation (RSVP) sequence and then reported its identity and location. They frequently failed to identify or to localize targets that they had correctly detected, suggesting that detection was based only on partial processing. Detection of targets was considerably worse in sequences that also contained humans, presumably because of shared features. When 2 targets were presented in RSVP, a prolonged attentional blink appeared that was almost eliminated when both targets were detected without being identified. The results suggest rapid feature analysis mediating detection, followed by attention-demanding binding for identification and localization.

Adolescent↗

PubMed2005

Attentional spread in the statistical processing of visual displays.

We tested the hypothesis that distributing attention over an array of similar items makes its statistical properties automatically available. We found that extracting the mean size of sets of circles was easier to combine with tasks requiring distributed or global attention than with tasks requiring focused attention. One explanation may be that extracting the statistical descriptors requires parallel access to all the information in the array. Consistent with this claim, we found an advantage for simultaneous over successive presentation when the total time available was matched. However, the advantage was small; parallel access facilitates statistical processing without being essential. Evidence that statistical processing is automatic when attention is distributed over a display came from the finding that there was no decrement in accuracy relative to single-task performance when mean judgments were made concurrently with another task that required distributed or global attention.

Attention↗

PubMed2003

Representation of statistical properties.

Everyday scenes often contain sets of similar objects. Perceptual representations may summarize these with statistical descriptors. After determining the psychological mean of two sizes, we measured thresholds for judging the mean with arrays of 12 circles of heterogeneous sizes. They were close to those for the size of elements in homogeneous arrays and single elements, and were little affected by either exposure duration (50-1000 ms) or memory delays (up to 2s). They were only slightly more accurate within the same distribution than across different distributions (normal, uniform, two-peaks, and homogeneous), confirming that subjects were indeed averaging sizes.

Discrimination, Psychological↗