Biomedical subjects
Publications and source records attributed to B Tversky.
Subjects studied maps with the expectation that they would draw or describe them from memory. In fact, subjects did both. Order of drawing or describing landmarks revealed the mental organization of environments. Organization was quite similar across maps and descriptions of the same environments, revealing hierarchical structures based on spatial and functional features of the environments and on conventions for sequencing the landmarks.
In six experiments, subjects read narratives describing varying spatial scenes with more than one point of view. They were probed with questions about objects located in six directions from each character's point of view. Subjects' response times were consistent with a one place-one perspective rule. They seemed to form separate mental models for separate places and to take a character's perspective when there was only one relevant character in a scene, but they seemed to take a neutral perspective when there was more than one probed point of view, rather than switch perspectives.
Tversky and Schiano (1989) found a systematic bias toward the 45 degrees line in memory for the slopes of identical lines when embedded in graphs, but not in maps, suggesting the use of a cognitive reference frame specifically for encoding meaningful graphs. The present experiments explore this issue further using the linear configurations alone as stimuli. Experiments 1 and 2 demonstrate that perception and immediate memory for the slope of a test line within orthogonal "axes" are predictable from purely structural considerations. In Experiments 3 and 4, subjects were instructed to use a diagonal-reference strategy in viewing the stimuli, which were described as "graphs" only in Experiment 3. Results for both studies showed the diagonal bias previously found only for graphs. This pattern provides converging evidence for the diagonal as a cognitive reference frame in encoding linear graphs, and demonstrates that even in highly simplified displays, strategic factors can produce encoding biases not predictable solely from stimulus structure alone.
Natural taxonomies consist of categories that vary in level of abstraction. Categories at the basic level, such as chair and apple, are preferred in a broad range of situations (Rosch, Mervis, Gray, Johnson, & Boyes-Braem, 1976). Several studies have revealed qualitative differences between the basic level and other levels. For example, Tversky and Hemenway (1984) presented evidence that parts proliferative at the basic level; they proposed that parts link the appearance of category members with their functions. Although not taking issue with these findings, Murphy (1991) investigated whether parts are necessary or sufficient for a basic level. In an attempt to demonstrate that parts are not necessary, Murphy used artificial stimuli that did not capture the essential features of natural taxonomies. These discrepancies preclude any conclusions based on his studies. Murphy's data also do not support his claim that parts are not sufficient for a basic level. Finally, it is unlikely that pursuing questions of necessity or sufficiency will produce insights into human categorization.
We propose that representations of visual stimuli are a consequence of both perceptual and conceptual factors that may be revealed in systematic errors in memory. Three experiments demonstrated increased (horizontal or vertical) symmetry in perception and memory of nearly symmetric curves in graphs and rivers in maps. Next, a conceptual factor, an accompanying description biasing toward symmetry or asymmetry, also distorted memory in the expected direction for the symmetric descriptions. In the two final experiments, we investigated conceptual factors in selection of a frame of reference. Subjects remembered lines in graphs, but not in maps, as closer to the imaginary 45 degrees line. Combined with earlier research, this suggests that the reference frame for map lines is the canonical axes and for graph lines, the imaginary 45 degrees line.
Many tasks (e.g., solving algebraic equations and running errands) require the execution of several component processes in an unconstrained order. The research reported here uses the geometric analogy task as a paradigm case for studying the ordering of component processes in this type of task. In solving geometric analogies by applying mental transformations such as rotate, change size, and add a part, the order of performing the transformations is unconstrained and does not in principle affect solution accuracy. Nevertheless, solvers may bring cognitive constraints with them to the analogy task that influence the ordering of the transformations. First, we demonstrate that solvers have a preferred order for performing mental transformations during analogy solution. We then investigate three classes of explanations for the preferred order, one based on general information processing considerations, another based on task-specific considerations, and a third based on individual differences in analogy ability. In the first and third experiments, college students solved geometric analogies requiring two or three transformations and indicated the order in which they performed the transformations. There was close agreement on nearly the same order for both types of analogies. In the second experiment, subjects were directed to perform pairs of transformations in the preferred or unpreferred order. Both speed and accuracy were greater for the preferred orders, thus validating subjects' reported orders. Ability differences were observed for only the more difficult three-transformation problems: High- and middle-ability subjects agreed on an overall performance order, but the highs were more consistent in their use of this order. Low-ability subjects did not consistently order the transformations for these difficult problems. The general information processing factor examined was working-memory load. A number of task factors have been shown to affect working-memory load during the solution of inductive reasoning problems. Of these, we chose to examine process difficulty. Because analogies are solved in working memory, performing more difficult transformations earlier may reduce working-memory load and facilitate problem solution. However, the observed performance order was not correlated with transformation difficulty. The first task-specific factor considered was that some transformations may be identified earlier, possibly because of perceptual salience, and that the performance order follows the identification order.(ABSTRACT TRUNCATED AT 400 WORDS)
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Concepts may be organized into taxonomies varying in inclusiveness or abstraction, such as furniture, table, card table or animal, bird, robin. For taxonomies of common objects and organisms, the basic level, the level of table and bird, has been determined to be most informative (Rosch, Mervis, Gray, Johnson, & Boyes-Braem, 1976). Psychology, linguistics, and anthropology have produced a variety of measures of perception, behavior, and communication that converge on the basic level. Here, we present data showing that the basic level differs qualitatively from other levels in taxonomies of objects and of living things and present an explanation for why so many measures converge at that level. We have found that part terms proliferate in subjects' listings of attributes characterizing category members at the basic level, but are rarely listed at a general level. At a more specific level, fewer parts are listed, though more are judged to be true. Basic level objects are distinguished from one another by parts, but members of subordinate categories share parts and differ from one another on other attributes. Informants agree on the parts of objects, and also on relative "goodness" of the various parts. Perceptual salience and functional significance both appear to contribute to perceived part goodness. Names of parts frequently enjoy a duality not evident in names of other attributes; they refer at once to a particular appearance and to a particular function. We propose that part configuration underlies the various empirical operations of perception, behavior, and communication that converge at the basic level. Part configuration underlies the perceptual measures because it determines the shapes of objects to a large degree. Parts underlie the behavioral tasks because most of our behaviors is indirect toward parts of objects. Labeling appears to follow the natural breaks of perception and behavior; consequently, part configuration also underlies communication measures. Because elements of more abstract taxonomies, such as scenes and events, can also be decomposed into parts, this analysis provides a bridge to organization in other domains of knowledge. Knowledge organization by parts (partonomy) is contrasted to organization by kinds (taxonomy). Taxonomies serve to organize numerous classes of entities and to allow inference from larger sets to sets included in them. Partonomies serve to separate entities into their structural components and to organize knowledge of function by components of structure. The informativeness of the basic level may originate from the availability of inference from structure to function at that level.
Many objects, natural and manufactured, have at least one axis of symmetry; thus, the detection of symmetry could facilitate the detection and representation of objects. Literature is reviewed that supports the notion that humans have effective and efficient symmetry-detection ability. The question addressed in the present research is whether symmetry detection leads to biases in representations of visual forms. Two types of experimental tasks were used: a similarity-judgment task and a matching-figures task in which reaction time to find identical figures in a display was measured. Stimuli varied in degree of measured symmetry. The results of the experiments reported here indicate that nearly symmetric standard forms are judged to be more similar to, and are more confusable with, even more symmetric forms than they are with less symmetric forms. The pull toward a more symmetric form does not occur for standard forms of lower symmetry. These findings can be accounted for by a two-stage process. First, the perceiver quickly determines the presence of overall symmetry. Then, if the form is perceived as having overall symmetry, the form is assumed, sometimes incorrectly, to have symmetry at the local level as well.
Both recognition and recall of pictures improve as picture presentation time increases and as time between pictures increases. Processing of the pictures, rehearsal and/or encoding, continues after the picture has disappeared, just as for verbal material. Both the results and conclusions stand in contrast to those of Shaffer and Shiffrin.