Intersensory substitution in the blind

This study looks at the implications for theories of development of an intersensory surrogate for the blind—the Sonicguide. Results of both short- and longterm studies suggest that there is a critical age, before which use of the Sonicguide is qualitatively more effective than attempts at intervention begun after this age. Similarly the young infants in the sample show a much more rapid acquisition of ability to use the guide effectively. The importance of such results for theories of perceptual development is discussed.     

Nontransitive measurable utility

A new theory of preferences under risk is presented that does not use the transitivity and independence axioms of the von Neumann-Morgenstern linear utility theory. Utilities in the new theory are unique up to a similarity transformation (ratio scale measurement). They key to this generalization of the traditional linear theory lies in its representation of binary preferences by a bivariate rather than univariate real valued function. Linear theory obtains a linear function u on a set P of probability measures for which u(p) > u(q) if and only if p is preferred to q. The new theory obtains a skew-symmetric bilinear function φ on P × P for which φ(p, q) > 0 if and only if p is preferred to q. Continuity, dominance, and symmetry axioms are shown to be necessary and sufficient for the new representation.     

A mental-health locus of control scale

The purpose of this study was to develop and seek initial validation of a mental- health locus of control scale. Twenty-six mental-health professionals rated each of the 14 statements of a previously-designed mental-health service request form along a 5-point locus of control scale. Six of the 14 items met the study's criteria for inclusion in the mental-health locus of control scale. Discriminant validity of the scale was provided by a study demonstrating that psychotic patients were more external in their perceived locus of control than were a nonpsychotic patient comparison group. Other validation studies and research are suggested.     

Images of engineering and liberal arts majors

In an attempt to gain insight into social-psychological barriers that inhibit women from entering engineering, 110 male and 84 female undergraduate students completed a variant of the Semantic Differential questionnaire. Subjects evaluated either male or female liberal arts and engineering majors. While female engineering majors were judged similar to male engineers on work-related traits, they were evaluated as less attractive than their female liberal arts counterparts. In particular, the data revealed reciprocal negative social images held by male engineering students for female engineers and by female engineering students for male engineers.     

Disfluent speech associated with brain damage

The frequency and type of disfluencies in the spontaneous speech of 15 people with Broca's aphasia and right hemiplegia was studied. Two aged-matched control groups (15 nonaphasic stroke patients with left hemiplegia and 15 normals) were also studied. The frequency of disfluencies in the speech of aphasics was three times greater than that in the speech of either control group. However, most of the disfluencies uttered by aphasics were of the types commonly found in speech of normals.     

Vocal and nonvocal discriminative performance in monkeys

Discriminative performance of a lever press and a vocal call was compared in five macaques. The animals exhibited similar scores for Response Rate, Efficiency, and Error Index. Total vocal responses were slightly higher than total lever responses. Latency for vocal responses was significantly greater than lever press. Similar scores in measures of performance of the two behaviors indicate that discriminative vocalization is not exceedingly difficult. Failure by others to achieve discriminative vocalization in studies employing weak positive-reinforcement contingencies suggest that certain experimental paradigms are unsatisfactory for vocal conditioning.     

A critical comparison of two random-walk models for two-choice reaction time

Two random-walk models for two-choice reaction time, being the sequential probability ratio test model initially suggested by Stone and the relative judgment theory recently proposed by Link, are here compared. The comparison shows the precise mathematical relation between the models, the predictions they have in common, and two points at which they differ. Three experiments concerned with the effect of stimulus probability on two-choice reaction time are examined with respect to three predictions from the models. In this three-way comparison the two models are more like each other than either is to the data; a greater variety of phenomena is revealed than either model can at present accommodate.     

Autocorrelation of choice-reaction times.

A choice-reaction (CR) task requires that the subject estimate, raking the warning signal or his response on the preceding trial as a reference point, the time when the reaction stimulus is due, so that he can begin deciding on his response at an appropriate time. This paper presents a model for the reproduction of temporal intervals, with particular emphasis on the sequential statistics of a series of such reproductions. When this model is concatenated with the sequential probability ratio test model for 2CRT, it provides a quantitative account of the pattern of autocorrelation found in a series of RTs. There is no corresponding autocorrelation in the incidence of errors, however, because after an error the subject systematically adjusts the epoch at which he begins sampling as a precaution against a further error. These post-error adjustments can readily be incorporated into the model. The ideas presented enable several different CR phenomena to be related, and they have implications for the relation between speed and accuracy, for the form of empirical distributions of RTs, and for the effects of temporal uncertainty.