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J M Wolfe

Publications and source records attributed to J M Wolfe.

13 recordsLinked to original sources
PubMed1992

"Effortless" texture segmentation and "parallel" visual search are not the same thing.

If a region composed of one set of texture elements is effortlessly perceived on a background composed of another set, the texture segmentation is said to occur "preattentively". If the time required to find a target item among distractor items is independent of the number of distractor items, the visual search is said to occur with all items processed "in parallel". Effortless, preattentive texture segmentation and parallel visual search are sometimes assumed to be equivalent measures of the same parallel processing stage in the visual system. The demonstrations presented here show that this is not the case. Parallel processing can occur with stimuli that do not support effortless texture segmentation and vice versa.

Humans↗
PubMed1992

The role of categorization in visual search for orientation.

Visual search for 1 target orientation is fast and virtually independent of set size if all of the distractors are of a single, different orientation. However, in the presence of distractors of several orientations, search can become inefficient and strongly dependent on set size (Exp. 1). Search can be inefficient even if only 2 distractor orientations are used and even if those orientations are quite remote from the target orientation (e.g. 20 degrees or even 40 degrees away, Exp. 2). Search for 1 orientation among heterogeneous distractor orientations becomes more efficient if the target orientation is the only item possessing a categorical attribute such as steep, shallow (Exp. 3), tilted left or tilted right (Exp. 4), or simply tilted (Exps. 5 and 6). Orientation categories appear to be 1 of several strategies used in visual search for orientation. These serve as a compromise between the limits on parallel visual processing and the demands of a complex visual world.

Attention↗
PubMed1992

Curvature is a basic feature for visual search tasks.

A curved target can be found efficiently among straight distractors in a visual search task. This could reflect the status of curvature as a basic feature for visual search. Alternatively, curvature could be detected as a locus of high variation in orientation. In a series of experiments it is shown that efficient search for curvature is possible even if local variation in orientation is eliminated as a cue. This suggests that curvature is part of the set of basic features for visual search and that this set is derived relatively late in the course of visual processing.

Adult↗
PubMed1992

Isolation of Mycobacterium thermoresistibile following augmentation mammaplasty.

This is the first case report of a Mycobacterium thermoresistibile infection following augmentation mammaplasty and is the fourth human case report of M. thermoresistibile infection. Antimicrobial susceptibility results determined by a modified proportion method using a 3-day incubation were the same as those determined by the standard 3-week assay.

Adult↗
PubMed1992

Visual search for oriented lines: the role of angular relations between targets and distractors.

Subjects can perform parallel visual search for an item of unique orientation when it is presented on a background texture composed of lines of two other orientations. A number of cues can be used to speed this search. It helps if the target has a unique categorical status (e.g., it is the only 'steep' item) (Wolfe et al., J. Exp. Psychol. Hum. Percept. Perf. 18, 34-49 1992). It helps if the two background orientations are symmetrical about a vertical axis (Wolfe and Friedman-Hill, Psychol. Sci. 3, 194-198, 1992). The experiments presented here show that it helps if the angles formed by the target with one of the distractor types are smaller than the angles formed by the two distractor orientations. These results illustrate that stimulus similarity is a complex concept even for a simple feature like orientation.

Adaptation, Ocular↗
PubMed1990

Modeling the role of parallel processing in visual search.

Treisman's Feature Integration Theory and Julesz's Texton Theory explain many aspects of visual search. However, these theories require that parallel processing mechanisms not be used in many visual searches for which they would be useful, and they imply that visual processing should be much slower than it is. Most importantly, they cannot account for recent data showing that some subjects can perform some conjunction searches very efficiently. Feature Integration Theory can be modified so that it accounts for these data and helps to answer these questions. In this new theory, which we call Guided Search, the parallel stage guides the serial stage as it chooses display elements to process. A computer simulation of Guided Search produces the same general patterns as human subjects in a number of different types of visual search.

Attention↗
PubMed1990

Limitations on the parallel guidance of visual search: color x color and orientation x orientation conjunctions.

In visual search for a conjunction it is much more difficult to search for the conjunction of 2 colors or 2 orientations than for Color x Orientation or Color x Shape conjunctions. The result is not limited to particular colors or shapes. Two colors cannot occupy the same spatial location in Color x Color searches. However, Experiments 6 and 7 show that Color x Shape searches remain efficient even if the color and shape are spatially separated. Our guided search model suggests that in searches for Color x Shape, a parallel color module can guide attention toward the correct color, whereas the shape module guides attention toward the correct shape. Together these 2 sources of guidance lead attention to the target. However, if a target is red and green among red-blue and green-blue distractors, it is not possible to guide search independently toward red items and green items or away from all blue items.

Adult↗
PubMed1990

Inhibitory tagging in visual search: a failure to replicate.

Klein (1988) reported that increased reaction times for the detection of small light probes could be used as an indicator of inhibitory tagging of rejected distractors in serial visual search tasks. Such a paradigm would be very useful in the study of the mechanics of visual search. Unfortunately, we cannot replicate the result. In this study, we found that probe reaction times were elevated at all distractor locations, relative to empty locations, following both parallel and serial search tasks. This appears to be a forward masking effect.

Adolescent↗
PubMed1989

Guided search: an alternative to the feature integration model for visual search.

Subjects searched sets of items for targets defined by conjunctions of color and form, color and orientation, or color and size. Set size was varied and reaction times (RT) were measured. For many unpracticed subjects, the slopes of the resulting RT X Set Size functions are too shallow to be consistent with Treisman's feature integration model, which proposes serial, self-terminating search for conjunctions. Searches for triple conjunctions (Color X Size X Form) are easier than searches for standard conjunctions and can be independent of set size. A guided search model similar to Hoffman's (1979) two-stage model can account for these data. In the model, parallel processes use information about simple features to guide attention in the search for conjunctions. Triple conjunctions are found more efficiently than standard conjunctions because three parallel processes can guide attention more effectively than two.

Adult↗
PubMed1979

Evidence for separable binocular processes differentially affected by artificially induced anisometropia.

Two measurable effects are produced by viewing a large disk rotating about the line of sight: a perceived displacement of the apparent horizon (tilt) and cyclotorsion of the eye (torsion). Previous results in our laboratory (see Refs.) using dichoptic presentation techniques show that both effects demonstrate binocular enhancement in normal subjects. Further, stereoblind subjects maintain enhancement for the oculomotor effect, torsion, but not for the perceptual effect, tilt. In this study we have found that this stereoblind pattern of results can be produced optically in normals by introducing a three diopter myopia in one eye. This renders the subject stereoblind and causes suppression of the artificially myopic eye. In this condition torsion still shows enhancement; tilt does not. This procedure may be useful in isolating causes of stereoblindness and in locating different sites of binocular interaction.

Adult↗