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PubMed1975

Effect of cognitive appraisal on d' and response bias to experimental stress.

The effects of an intellectualization-denial passage designed to modify cognitive appraisal of stressor stimuli (gory scences) were evaluated in terms of sensory-decision theory analysis. The passage was found to reduce "felt stress" ') for certain pairs of the stimuli addressed by the passage content but to less effective in reducing stress (Lx) was reduced rather than increased wi;h presentation of the passage for the included simuli only. Differences in d' between subjects classified within treatment groups as repressors versus sensitizers were obtained for certain stimulus pairs generally in the direction of lower sensitivity for repressors. Results are discussed in terms of the effects of altered cognitive appraisal on the "prevention of stress" and on "defensive"denial.

Arousal↗
PubMed1985

Separability and integrality of global and local levels of hierarchical patterns.

We used a constrained classification task to examine the perceptual relations between global and local levels in hierarchical patterns composed of many, relatively small elements and those composed of few, relatively large elements. In Experiments 1 and 3 subjects were asked to make classifications based on "form" or "texture." In Experiments 2 and 4 they were asked to classify according to the "shape" of the configuration or the elements. The results indicate that configural and elemental levels are perceptually separable for many-element patterns when processed as form and texture: Subjects could attend to either level without being affected by variation along the irrelevant dimension. However, when the same many-element patterns were processed for global and local shape, subjects could not selectively attend to either level. For few-element patterns, global configuration and local elements appeared to be perceptually integral dimensions. These results are relevant to two issues: the global precedence hypothesis and the explanations of integral and separable dimensions.

Adolescent↗
PubMed1989

Evidence for two types of spatial representations: hemispheric specialization for categorical and coordinate relations.

Analyses of human object recognition abilities led to the hypothesis that 2 kinds of spatial relation representations are used in human vision. Evidence for the distinction between abstract categorical spatial relation representations and specific coordinate spatial relation representations was provided in 4 experiments. These results indicate that Ss make categorical judgments--on/off, left/right, and above/below--faster when stimuli are initially presented to the left cerebral hemisphere, whereas they make evaluations of distance--in relation to 2 mm, 3 mm, or 1 in. (2.54 cm)--faster when stimuli are initially presented to the right cerebral hemisphere. In addition, there was evidence that categorical representations developed with practice.

Adult↗
PubMed1990

Attentional limits on the perception and memory of visual information.

Attentional limits on perception and memory were measured by the decline in performance with increasing numbers of objects in a display. Multiple objects were presented to Ss who discriminated visual attributes. In a representative condition, 4 lines were briefly presented followed by a single line in 1 of the same locations. Ss were required to judge if the single line in the 2nd display was longer or shorter than the line in the corresponding location of the 1st display. The length difference threshold was calculated as a function of the number of objects. The difference thresholds doubled when the number of objects was increased from 1 to 4. This effect was generalized in several ways, and nonattentional explanations were ruled out. Further analyses showed that the attentional processes must share information from at least 4 objects and can be described by a simple model.

Adult↗
PubMed1991

Olfactory sensitivity: reliability, generality, and association with aging.

Thirty-two Ss between 22 and 59 years of age yielded detection thresholds for 4 odorants over 4 sessions. The thresholds decreased and reliability increased over the course of testing. High intercorrelations between odorants and the stability of an S's relative position within the threshold distributions showed that a general factor of sensitivity dominated the outcome. Age contributed strongly to intersubject variation. Even among these nonelderly individuals, it accounted for up to 2 orders of magnitude in threshold performance. Other important factors included superiority of the right nostril and a negative correlation between the mean and variance of threshold distributions. Scant attention to the correlation may have contributed to overestimation of the frequency and specificity of specific anosmia. A clinically relevant outcome was that measurement of threshold for diagnostic purposes can generally rely on just 1 odorant.

Adult↗
PubMed1994

Seeing morphemes: loss of visibility during the retinal stabilization of compound and pseudocompound words.

When stabilized, a retinal image fades from vision. Earlier studies suggested that knowledge constrains the loss of vision, as disappearing images fragment into familiar subpatterns. Effects of image stabilization on word perception were used in the current study to examine effects of morphemic knowledge on stimulus fragmentations. Bimorphemic compound words (in which beginning and ending trigrams formed morphemic subword units) and monomorphemic pseudo-compound words (with a similar trigram structure) were stabilized. Stimulus fragmentations generally resulted in the visibility of lexically nondistinct strings of letters. However, internal morpheme boundaries also affected the loss of vision when compound words were stabilized. Two follow-up experiments indicated that morpheme-related loss of vision was neither the result of differential forgetting rates nor of guessing bias.

Fixation, Ocular↗
PubMed1995

Auditory coding, cues, and coherence in phonetic perception.

C. T. Best, M. Studdert-Kennedy, S. Manuel, and J. Rubin-Spitz (1989) reported that listeners given speech labels showed categorical-like perception of a series of complex tone analogs to a /la/-/ra/ speech series, whereas nonspeech listeners were unable to classify the stimuli consistently. In 2 experiments, a new training and testing procedure was used with adult listeners given nonspeech instructions. They classified the /la/-/ra/ tone analogs consistently, showed categorical-like perception, and generalized their training to a new, /li/-/ri/ tone analog series. Two sets of auditory attributes were described for coding the /l/-/r/ distinction, and 1 was shown to quantitatively predict listeners' classification of both series. These results are consistent with models of perception in which a rich, abstract auditory code is computed and forms the basis for both speech and nonspeech auditory categories.

Adult↗
PubMed1996

Selective attention and the formation of linear decision boundaries.

Classification experiments were designed to compare the predictions of a linear decision bound model with those of an exemplar-similarity model incorporating an explicit selective attention mechanism. Linear boundaries could account for the data only in tasks involving separable dimension stimuli and where the boundary separating the categories was orthogonal to the psychological dimensions. Linear boundaries provided poor fits to the classification data in situations involving integral dimensions or when the boundary needed to be oriented in oblique directions in the space. The results were consistent with the selection-attention assumptions embodied in the exemplar model. It was argued that similar assumptions about selective attention need to be incorporated within decision bound models.

Adult↗
PubMed2000

Transsaccadic memory for position and orientation of saccade source and target.

Participants made a saccade from one biological-motion figure to another and had to detect saccadecontingent changes in either the walker to which the eyes were sent (the target) or the walker that served as launch site (the source). Intrasaccadic displacements in both source and target were relatively hard to detect, whereas changes in the walkers' depth orientation were readily noticed, indicating that previous findings on within-object saccades generalize to between-objects saccades. Contrary to predictions derived from theories that assign a privileged status to the saccade target, transsaccadic memory for the target's position and orientation was not more accurate than memory for the source. Displacements or rotations of one object toward the other object were more detectable than the same changes away from each other, suggesting that relational coding plays a prominent role in the integration of information across saccades.

Adult↗
PubMed1983

Global and local precedence: selective attention in form and motion perception.

This study explores the perception of stimuli at two levels: local parts and the wholes that comprise these parts. Previous research has produced contradictory results. Some studies (e.g., Pomerantz & Sager, 1975) show local precedence, in which the local parts are more difficult to ignore in selective attention tasks. Other studies (e.g., Navon, 1977) have shown the opposite effect, global precedence. The present five experiments trace the causes of this discrepancy by exploring the effects of the relative discriminabilities of the local and global levels of the stimuli and the differences between two different measures of selective attention, namely, Stroop-type interference (attributable to incongruity on the irrelevant dimension) and Garner-type interference (attributable to variability on the irrelevant dimension). The experiments also examine whether the precedence effects previously examined in form perception generalize to motion perception. The results show that (a) some cases of global precedence are due solely to the greater perceptual discriminability of the global level and thus demonstrate only that more discriminable stimuli are harder to ignore; (b) instances of both local and global precedence can be demonstrated for certain types of stimuli, even when the discriminabilities of their local and global levels have been equated; and (c) the Stroop and Garner measures of selective attention are not equivalent but instead measure different types of interference. In addition, a distinction is made between two fundamentally different types of part-whole relationships that exist in visual configurations, one based only on the positions of the parts (Type P) and one based also on the nature of the parts (Type N). Previous research has focused on Type P, which appears to be irrelevant to the broader questions of Gestalt and top-down effects in perception. It is concluded that bona fide cases of both local and global precedence have been amply documented but that no general theory can account for why or when these effects will appear until we better understand both the nature of part-whole relationships and the perceptual processes that are tapped by different measures of selective attention.

Adult↗
PubMed1986

Attention, similarity, and the identification-categorization relationship.

A unified quantitative approach to modeling subjects' identification and categorization of multidimensional perceptual stimuli is proposed and tested. Two subjects identified and categorized the same set of perceptually confusable stimuli varying on separable dimensions. The identification data were modeled using Shepard's (1957) multidimensional scaling-choice framework. This framework was then extended to model the subjects' categorization performance. The categorization model, which generalizes the context theory of classification developed by Medin and Schaffer (1978), assumes that subjects store category exemplars in memory. Classification decisions are based on the similarity of stimuli to the stored exemplars. It is assumed that the same multidimensional perceptual representation underlies performance in both the identification and categorization paradigms. However, because of the influence of selective attention, similarity relationships change systematically across the two paradigms. Some support was gained for the hypothesis that subjects distribute attention among component dimensions so as to optimize categorization performance. Evidence was also obtained that subjects may have augmented their category representations with inferred exemplars. Implications of the results for theories of multidimensional scaling and categorization are discussed.

Attention↗
PubMed1991

Are names ever mapped onto preexisting categories?

Support for Mervis's (1987) proposal that youngsters map new common nouns onto attribute cluster categories was obtained. In 3 studies, preschoolers interpreted a novel noun as if it designated a preexposed category. Experiment 3 included a group of adults who behaved similarly. Mapping was independent of the tendency to generalize according to shape. Neither age group mapped onto preexisting categories when making object similarity judgments, but preexposure did bias their naming of the objects' colors. Those who had examined sets containing 2 colors, both of which covaried with other bivalent dimensions, used more distinctive names for these hues than those preexposed to sets containing 6 colors, none of which covaried with bivalent dimensions.

Child, Preschool↗
PubMed1991

Chunking during serial learning by a pigeon: I. Basic evidence.

Chunking by pigeons was demonstrated by comparing performance on different types of lists. Experiment 1 showed that Groups II and IV (who learned lists in which colors and achromatic geometric forms were segregated: A----B----C----D'----E' and A----B----C----D----E', respectively) executed lists more rapidly than did Group I (who learned a homogeneous list of colors: A----B----C----D----E) or Groups II and III (who learned lists consisting of unsegregated colors and forms: A----B'----C----D'----E and A----B----C'----D----E, respectively). Experiment 2 showed that Groups II and IV tolerated interruptions of the list better than did Groups I, III, and V. The accuracy of responding of Groups I, III, and V decreased as a function of the duration of the interruption and the point in the sequence at which it occurred. The performance of Group II was unaffected by interruptions; Group IV was minimally affected. These results indicate that Groups II and IV organized their lists as ordered chunks.

Animals↗
PubMed1991

Chunking during serial learning by a pigeon: II. Integrity of a chunk on a new list.

Can a group of items that a pigeon chunks on one list function as such on a second list? In Experiment 1, the ordinal position of the chunk was held constant across both lists. Following training on a list of colors and achromatic geometric forms (A----B----C----D'----E'), the integrity of the color chunk [A----B----C] was maintained on a list of five colors (A----B----C----F----G) even though the basis for establishing that chunk was eliminated. The integrity of the chunk [A----B----C] was also maintained on a new list of colors and forms (A----B----C----D*----E*). In Experiment 2, the ordinal position of a chunk established on list1 (A----B----C'----D') was changed on list 2. As shown by positive transfer between lists 1 and 2, the integrity of the chunks [A----B] and [C'----D'] was maintained on lists X'----A----B----Y' and X'----C'----D'----Y', respectively. Conversely, the heterogeneous list X'----B----C'----Y' took longer to learn than the original list.

Animals↗
PubMed1991

Reexamination of contextual conditioning with massed versus distributed unconditioned stimuli.

Sprague-Dawley rats were placed in the black compartment of a 2 compartment choice apparatus and received a series of unsignaled footshocks at fixed intertrial intervals (ITIs), with ITI duration varied across groups. Contextual conditioning was assessed using place preference and freezing tests. In Experiments 1 and 3, time spent in the unshocked, white compartment in a preference test decreased monotonically with increasing ITI. In Experiment 2, less freezing occurred in the 3-s than in the 60-s groups. An inverted U-shaped relationship between ITI and freezing emerged when a full range of ITIs was used in Experiment 3. The results have implications for the learning-performance distinction and suggest that short ITIs may promote contextual conditioning.

Animals↗
PubMed1976

Natural concepts in pigeons.

Pigeons learned to discriminate pictures of trees, bodies of water, or a particular person in three separate experiments. Pictures being seen for the first time were discriminated almost as well as pictures seen in training. The pigeons in each experiment showed similar patterns of errors and correct discrimination.

Animals↗
PubMed2000

Factors influencing the salience of temporal cues in the discrimination of synthetic Japanese monkey (Macaca fuscata) coo calls.

If temporal position of a frequency inflection is the most salient communication cue in Japanese macaque smooth early and smooth late high coos, then macaques should perceive coos differing only along the early-late dimension as belonging to different classes. The perceived similarity of synthetic coos and temporally reversed variants were evaluated, using multidimensional scaling of macaque discrimination latencies. Original calls and calls temporally reversed in the frequency domain could be discriminated if the peak was near a call endpoint but not if the frequency peak in the original call was near the coo midpoint. Perceived similarity of such calls was inversely related to the amount of frequency modulation. Temporal reversals of amplitude contours were also conducted. Although macaques are quite sensitive to amplitude increments, reversal of the relatively flat amplitude contours of these calls did not affect discrimination responses.

Animals↗
PubMed1979

Acquisition, generalization, and discrimination reversal of a natural concept.

Pigeons rapidly acquired a discrimination between 40 pictures containing trees and 40 not containing trees. Differential reinforcement did not affect the discriminability of individual instances of trees. Generalization to new instances of tree pictures was better than to new instances of non-tree pictures. The level of discrimination did not depend on whether trees constituted the reinforced or the unreinforced category.

Animals↗