Biomedical subjects

Elizabeth S Olds

Publications and source records attributed to Elizabeth S Olds.

3 recordsLinked to original sources

PubMed2003

Search of jumping items: visual marking and discrete motion.

Watson and Humphreys (1997 Psychological Review 104 90-122) showed that when searching for a target, observers can ignore a previewed set of distractors (other items), effectively decreasing the number of relevant items in a difficult search display and thus speeding performance ('visual marking'). Other researchers have more recently investigated visual marking for continuously moving items, finding that shared features, and preserved inter-item spatial relationships, are helpful. Here, we tested whether visual marking occurs for a set of initial items that moves in one discrete jump (preserving shared features and inter-item spatial relationships). Marking did not occur in these displays, and we interpret this result in the context of previous research on visual marking.

Analysis of Variance↗

PubMed2003

Does partial difficult search help difficult search?

Olds, Cowan, and Jolicoeur (2000a, 2000b) showed that exposure to a display that affords pop-out search a target among distractors of only one color) can assist processing of a related display that requires difficult search. They added distractors of an additional color to the initial simple display and analyzed response time distributions to show that exposure to the initial display aided subsequent search in the difficult portion (this finding was called search assistance). To test whether search assistance depends on perceptual grouping of the initial items, we presented initial items that were more difficult to group (two colors of distractors, instead of just one). The target appeared (on 50% of the trials) among distractors of two colors, and then after a delay, more distractors of those two colors were added to the display. Exposure to the initial easier portion of the display did not assist processing of the second portion of the display when the initial display contained a large number of items; we found tentative evidence for assistance with small numbers of initial items. In the Olds et al. (2000a, 2000b) studies, it was easy to group the initial distractor items, because they were all the same color. In contrast, in the present study, it was difficult to group the heterogeneous initial distractor items. Search assistance is found only when initial item grouping is relatively easy, and thus we conclude that search assistance depends on grouping.

Attention↗

PubMed2002

The decay and interruption of interactions between search mechanisms.

The attentional mechanisms in the brain responsible for fast pop-out search and slower difficult search have been shown to interact. Even if pop-out search is interrupted, by the addition of extra distractors to an initially simple search display, the partial computations calculated by the mechanisms responsible for pop-out can facilitate subsequent difficult search ("search assistance"; Psychon. Bull. Rev. 7 (2000) 292; Vision Res. 40 (2000) 891). With the present experiments, we aimed to discover whether search assistance is disrupted when the display that affords pop-out search disappears before the appearance of the display that must be examined by difficult search. Search assistance was not disrupted by the insertion of a blank screen in between the first and second portions of the display (Experiment 1). Search assistance for target-present trials was not disrupted by the insertion of black disks in between the first and second portions of the display (Experiment 2), but this manipulation did disrupt search assistance for target-absent trials. Implications for the relationship between search assistance and visual marking of distractors (Psychol. Rev. 104 (1997) 90) are discussed.

Adult↗