Comparative judgments with numerical reference points

A model of subjective magnitude comparisons is explored, which assumes that subjects compare symbolic stimulus magnitudes with respect to a reference point. The reference point may be established implicitly by the question (e.g., “Which is larger?” vs “Which is smaller?”) or be presented explicitly (e.g., “Choose the stimulus closer to X.”). The model was tested in five experiments in which subjects judged which of two comparison digits was closer to (or further from) a reference digit. Regression analyses in three experiments revealed that reaction time depended on the ratio of the distances from the comparison items to the reference point. The other two experiments provided evidence that subjects can strategically vary the processes by which they compare stimuli to a reference point. The results indicated that subjects can perform various types of “analog arithmetic” using either the linear number scale or a nonlinear scale of subjective digit magnitude.     

Laterally induced impedance effects in vision

A linear integral equation for a system of mutually impeding points is developed and solved explicitly. Particular solutions are shown to be subharmonic functions for a large class of stimuli. Specialized forms of the general equation presented in this paper occur within a number of mathematical models of Mach bands. In addition to these known spatial properties, our results also show that the time course of this basic equation may be useful in developing models of transient neural activity as well as of temporal psychophysical phenomena, such as the Broca-Sulzer effect. Further, a spatial transfer function much like the low-frequency cutoff of empirically derived modulation transfer functions follows directly from our basic integral equation if the additional assumption of spatial homogeneity is imposed.     

Individualized behavior therapy for alcoholics: a third year independent double-blind follow-up.

An independently conducted double-blind study providing third year follow-up data for 53 of 70 male alcoholics who served as subjects in an experiment evaluating “Individualized Behavior Therapy (IBT)” techniques is reported. In the original study, subjects were initially assigned to either a controlled drinking or non-drinking (abstinence) treatment goal, and were then randomly assigned to either an experimental group receiving IBT or a control group receiving conventional state hospital treatment oriented towards abstinence. Previously reported results showed that IBT subjects functioned significantly better than control subjects throughout the first year of follow-up. Second year follow-up results found that IBT subjects treated with a controlled drinking goal functioned significantly better than their respective control subjects on a variety of measures, including drinking behavior. Differences between IBT subjects treated with a non-drinking goal and their control subjects did not retain statistical significance during the second year of follow-up. The independently determined follow-up data showed that during the third post-treatment year, subjects in the experimental groups generally functioned better than their respective control subjects. Comparison of the controlled drinking experimental group with its control group showed the significantly better functioning of subjects in the experimental condition on a number of drinking and other life functioning measures. Comparison of the non-drinking groups indicated only one possible difference on the drinking related measures involving a trend for subjects in the experimental condition to abstain more than those in the non-drinker control group. On other life functioning measures, however, subjects in the non-drinking experimental condition showed consistent improvement over their respective control subjects. Both of the controlled drinking groups reported more controlled drinking days than the non-drinking groups throughout the third year follow-up period.     

On knowing how well one is remembering: The persistence of strategy use during transfer

A potential cause for children's failure to transfer learning strategies was explored in the present study. A self-monitoring process was suggested to be essential for evaluating one's own level of performance and the effectiveness of various mnemonic strategies. Matched on free recall scores in this study's first sort-and-recall phase, first, third, and fifth graders (ages 7, 9, and 11 years, respectively) were assigned to one of three treatment groups or a control group. During Phase II, the treatment groups received instruction in sorting pictures according to semantic similarities in preparation for future recall. In addition, Groups 3 and 4 later received feedback indicating their Phase II improvement in performance. A cause-and-effect relationship between strategy use and enhanced recall was further suggested to Group 4. Among third graders, only those provided with feedback and strategy instruction continued to rely upon the input organization strategy when faced with transfer tasks in Phase III. Both enhanced recall and improved sorting styles were observed for these subjects in Phase III. Some first graders also showed improved sorting styles and improved recall following feedback, while fifth graders showed enhanced recall even without experimenter-provided feedback. Subject's responses to a metamemory interview provided additional support for the hypothesis that the self-monitoring of memory performance is more likely to be part of fifth graders' (than first graders') memory abilities.     

Development of differences in response latencies to right and left visual fields

Robust lateralization developed in right-handed adults who were asked to judge letter pairs as "same" or "different" during 4608 trials. By the end of the first two blocks (768 trials) "same" responses were favored when presented in the RVF (transmitted directly to the left hemisphere) and "different" responses were favored when presented in the LVF (transmitted direction to the right hemisphere). This gradually reversed over sessions with "same" responses becoming faster for letters presented in the LVF, and "different" responses becoming faster for stimuli presented in the RVF. The laterality acquired under these conditions was cumulative and reproducible, appeared in all 16 subjects, and was preserved between sessions a week apart. The data suggest that laterality is a flexible and reversible characteristic of the human brain even when stimulus and task remain constant.     

Interpersonal problem solving in preschool children: A comparison of assessment procedures using two-dimensional versus three-dimensional stimuli

Two procedures for assessing the social problem-solving strategies of young children were compared: a traditional measure using pictorial stimuli and an alternative measure in which problems were presented using three-dimensional props. Subjects were 48 preschool children ages 3, 4 and 5. Using a counterbalanced, repeated measures design, the two tasks were presented to the children on consecutive days. Children also received the PPVT, and teacher ratings of behavioral adjustment were completed. Children gave more responses and suggested a greater variety of problem-solving strategies when tested with props than when tested with pictures. Response differences to the two testing procedures were greatest for children who were rated by their teachers as impulsive. Results are discussed in terms of the representational competence of the preschool child. Implications of the findings for intervention strategies also are discussed.     

Sensitivity to lexical denotation and connotation in brain-damaged patients: A double dissociation?

Sets of words can be grouped in terms of their denotation (cold and warm both refer literally to temperature) or in terms of their connotation (cold and warm connote remoteness and intimacy, respectively). To assess whether these two facets of meaning are dissociable, unilaterally left- and right-hemisphere-damaged patients were presented with word triads and asked to group together the two words that were closest in meaning. Right-hemisphere-damaged patients showed a preserved sensitivity to denotation, and a selective insensitivity to connotative facets of meanings. In contrast, left-hemisphere-damaged patients exhibited a preserved sensitivity to connotation as well as a selective insensitivity to denotative aspects of meanings. Inasmuch as normal control subjects displayed a flexible sensitivity to both denotative and connotative aspects of meaning, the results suggest that unilateral brain damage selectively curtails use of one or the other major aspect of word meaning.