Effect of feature similarity on illusory conjunctions (original) (raw)

A measurement theory of illusory conjunctions

Journal of Experimental Psychology: Human Perception and Performance, 2002

Illusory conjunctions are the incorrect perceptual combination of correctly perceived features, such as color and shape. Research on the phenomenon has been hampered by the lack of a measurement theory that accounts for guessing features, and well as the incorrect combination of correctly perceived features. Recently several investigators have suggested using multinomial models as a tool for measuring feature integration. We test the adequacy of these models in two experiments by testing whether model parameters reflect changes in stimulus factors. In a third experiment, we use confidence ratings as a tool for testing the model. Multinomial models accurately reflected both variations in stimulus factors and observers trial-by-trial confidence ratings.,

The role of attention in illusory conjunctions

1994

Abstract In five experiments, we investigated the effects of attention on illusory conjunctions formed between features of unrelated objects. The first three experiments used a weak manipulation of attention and found that illusory conjunctions formed either among features receiving high attentional priority or among features receiving low attentional priority were not more frequent than were conjunctions formed between mixed features of different attentional priority.

Weighting common and distinctive features in perceptual and conceptual judgments*1

Cognitive Psychology, 1984

By adding the same component (e.g., glasses) to two stimuli (e.g., schematic faces) or to one stimulus only, it is possible to assess the impact of that component as a common or as a distinctive feature. A formal procedure, based on the contrast model (A. Tversky, 1977, Psychological Review, 84, 327-3.52), for estimating the relative weight of common to distinctive features from similarity judgments between separable stimuli with independent components, was developed. The results show that in verbal stimuli (e.g., descriptions of persons, meals, trips) common features loom larger than distinctive features. On the other hand, in pictorial stimuli (e.g., schematic faces, landscapes) distinctive features loom larger than common features. Verbal descriptions of pictorial stimuli were evaluated like other verbal stimuli and unlike their pictorial counterparts. In conceptual comparisons, the relative weight of common to distinctive features was higher in judgments of similarity than in judgments of dissimilarity.

Weighting common and distinctive features in perceptual and conceptual judgments

Cognitive Psychology, 1984

By adding the same component (e.g., glasses) to two stimuli (e.g., schematic faces) or to one stimulus only, it is possible to assess the impact of that component as a common or as a distinctive feature. A formal procedure, based on the contrast model (A. Tversky, 1977, Psychological Review, 84, 327-3.52), for estimating the relative weight of common to distinctive features from similarity judgments between separable stimuli with independent components, was developed. The results show that in verbal stimuli (e.g., descriptions of persons, meals, trips) common features loom larger than distinctive features. On the other hand, in pictorial stimuli (e.g., schematic faces, landscapes) distinctive features loom larger than common features. Verbal descriptions of pictorial stimuli were evaluated like other verbal stimuli and unlike their pictorial counterparts. In conceptual comparisons, the relative weight of common to distinctive features was higher in judgments of similarity than in judgments of dissimilarity.

Perception of Visual Similarity: Modeling Feature-Based Effects

Proceedings of the Annual Meeting of the Cognitive Science Society, 2010

Similarity is central to human cognition. Its relevance is apparent in nearly all theories of cognitive science. Concept acquisition, metaphor, pattern recognition, priming, predictions, inferences; all these processes rely on similarity. Despite its relevance, relatively little is understood about how similarity is processed. In particular, there is a need to better understand the scope in which our perceptual systems constrain our judgments of similarity. The current study investigates this question in the area of visual cognition. By attempting to control for the influence of categorical knowledge, the goal was to understand how different types of feature-dimensions and category boundaries influence the perception of similarity. A connectionist model was developed to explain these findings.

When do letter features migrate? A boundary condition for feature-integration theory

Feature-integration theory postulates that a lapse ofattention will allow letter features to-change position and to recombine as illusory conjunctions . To study such errors, we used a set of uppercase letters known to yield illusory conjunctions in each of three tasks. The first, a bar-probe task, showed whole-character mislocations but not errors based on feature migration and recombination. The second, atwo-alternative forced-choice detection task, allowed subjects to focus on the presence or absence of subletter features and showed illusory conjunctions based on feature migration and recombination. The third was also a two-alternative forced-choice detection task, but we manipulated the subjects' knowledge of the shape of the stimuli: In the case-certain condition, the stimuli were always in uppercase, but in the case-uncertain condition, the stimuli could appear in either upper-or lowercase. Subjects in the case-certain condition produced illusory conjunctions based on feature recombination, whereas subjects in the case-uncertain condition did not. The results suggest that when subjects can view the stimuli as feature groups, letter features regroup as illusory conjunctions; when subjects encode the stimuli as letters, whole items may be mislocated, but subletter features are not. Thus, illusory conjunctions reflect the subject's processing strategy, rather than the architecture of the visual system.

Integration of local features as a function of global goodness and spacing

Perception & Psychophysics, 1991

In two experiments, the accuracy with which subjects detected a conjunction of features was examined as a function of the spacing between items and the goodness of the axis along which they were located. In each array, two items were arranged along a vertical, a horizontal, or a diagonal axis. Based on the well-established oblique effect, the vertical and horizontal axes were considered to be good global patterns and the diagonals were considered to be poor. In Experiment I, the two items in an array could be two horizontal lines, two vertical lines, a vertical and a horizontal line, or a plus sign with one of the single lines. In Experiment 2, a positiveand a negative-diagonal line were used as the individual features, and an "X" was used as the conjunction. The results from Experiment 1 indicated that global goodness influenced only the rate of illusory conjunctions, and not of feature errors. lllusory conjunctions of vertical and horizontal line segments were more likely to occur in vertical and horizontal arrangements. The results from Experiment 2 revealed a reversal of the effect of global goodness on the rate of illusory conjunctions: Illusory conjunctions of negative-and positive-diagonal line segments were more likely to occur in diagonal arrangements. The results of both experiments taken together showed the existence of an important and new factor that influences the likelihood that features of shape will be conjoined: the ease with which line segments conjoin when they are translated along their extent toward each other. In both experiments, greater spacing between items produced more feature-identification errors and fewer feature-integration errors than did less spacing.

The structure of illusory conjunctions reveals hierarchical binding of multipart objects

Attention, Perception, & Psychophysics

The world around us is filled with complex objects, full of color, motion, shape, and texture, and these features seem to be represented separately in the early visual system. Anne Treisman pointed out that binding these separate features together into coherent conscious percepts is a serious challenge, and she argued that selective attention plays a critical role in this process. Treisman also showed that, consistent with this view, outside the focus of attention we suffer from illusory conjunctions: misperceived pairings of features into objects. Here we used Treisman's logic to study the structure of pre-attentive representations of multipart, multicolor objects, by exploring the patterns of illusory conjunctions that arise outside the focus of attention. We found consistent evidence of some preattentive binding of colors to their parts, and weaker evidence of binding multiple colors of the same object. The extent to which such hierarchical binding occurs seems to depend on the geometric structure of multipart objects: Objects whose parts are easier to separate seem to exhibit greater pre-attentive binding. Together, these results suggest that representations outside the focus of attention are not entirely a Bshapeless bundles of features,^but preserve some meaningful object structure.