Fred L. Royer

Age differences in symbol-digit substitution task performance

A decline in performance on the Digit Symbol Substitution test related to aging is well documented. There is no agreement on the reason for the decline, however. In part, the lack of consensus with regard to changes on the test may be attributed to the limitations imposed by comparing groups on a single performance measure. In the present study, three forms of a Symbol-Digit Substitution task that varied in difficulty level were administered to 125 persons between the ages of 30 and 92. On all forms there was a clear performance decline associated with age. The differences observed among the age groups were interpreted as evidence for a change in a sensorimotor component and in two information-processing operations: Symbol encoding and visual search.

Normative data for the symbol digit substitution task

Administered three forms of a Symbol-Digit Substitution task to normals, 16 to over 80 years of age, to schizophrenic and other hospitalized groups. Their data are presented for normative purposes. The three forms vary in difficulty and provide a measure of visual information processing ability, Clinical and research implications of the data are discussed.

Stimulus parameters that produce age differences in block design performance

Administered block designs that varied according to two parameters, Task Uncertainty and Perceptual Cohensiveness, to 83 persons 49 years of age or older. Performance was adjusted to remove motor speed differences. Performance changed significantly over the age span as a function of Task Uncertainty. From 49 years up, performance did not change as a function of Perceptual Cohesiveness. An analysis that included a group of 20 persons 30 years of age or younger yielded an interaction of Age and Perceptual Cohesiveness. From 49 years on, analytic or image segmentation processes do not seem to change, but other information processing becomes slower.

On the perceived unitization of repetitive auditory patterns

When a cyclic pattern of sound bursts occurs, a rhythmic pattern will be heard at certain rates of presentation. When rate is increased sufficiently, the pattern is heard as a repeating unit—a repeating packet of sound bursts consisting of the whole cycle. The temporal parameters of the process of unitization that produces the perceptual phenomenon were examined. Critical burst duration for fixed interburst intervals and critical interval for fixed burst durations were obtained. An inverse linear relationship between duration and interval was found. The sum of duration and interval yielded a constant that increased as the number of elements in the pattern increased. The results are interpreted as supporting a lowpass filter model of temporal pattern organization in the auditory system.

Models of contrast sensitivity in human vision

Eight models are examined as input-output representations of steady-state vision in humans at moderate to low level illumination. Three new models for visual contrast sensitivity are introduced and evaluated using contrast sensitivity function (CSF) data with samples on both narrow and wide frequency ranges. Additionally, five variations of previously published models are evaluated using the same data. A nonlinear least squares fitting algorithm produced the optimal parameters for each model. The eight models are compared on the basis of RMS error in their fit to the CSF data. The three new models, based on second-, third-, and fourth-order filter functions, provided the best fit to the data. They appear to more-closely approximate the underlying sensory mechanisms, and thus they provide a more useful input-output representation of the overall human visual system. >

Intelligence and the Processing of Stimulus Structure.

Abstract It has been demonstrated in a number of experiments that the difficulty level of several performance type intelligence test tasks is determined directly by stimulus and task variables that vary the information to be processed. The variables are quantifiable. The implications of these findings for intelligence and the problems of an experimental approach to the measurement of intelligence are discussed.

Case history: Averison therapy for fire setting by a deteriorated schizophrenic

This report concerns a chronic, deteriorated schizophrenic patient whose persistent fire-setting behavior presented a major management problem. His verbal communications were generally incoherent. The fire-setting behavior was successfully eliminated by an aversive technique in which electric shocks were made contingent on setting fire to paper with a match. There has been no recurrence in nearly four years.

Cutaneous vasomotor components of the orienting reflex

Abstract Eight normal male Ss were tested for vasomotor responses of four skin areas to the presentation of novel auditory stimuli. The reciprocal vasomotor responses of the finger (vasoconstriction) and head (vasodilatation) reported by Vinogradova and Sokolov (1957) were confirmed. These responses are consistent with the known dominant vasomotor tone of these areas. Measurement of the activity of the ear with a dominant constrictive tone and of the skin of the neck with a dominant dilatative tone indicate that the vasomotor component of the orienting reflex is an enhancement of the normal dominant vasomotor control.

Performance of process and reactive schizophrenics on a symbol-digit substitution task.

Schizophrenic patients were classified into process and reactive groups on the basis of ratings on the Phillips Symptoms Checklist. There were 18 Ss in each group. Each group was administered 3 forms of a symbol-digit substitution task. The forms differed in the symbol array used. After adjustment for covariance of age, a significant difference in performance was found between the 2 groups. Also, significant differences among the means for forms were obtained, as well as significant interaction of groups and forms. The rate of information processing of this type of visual material is slower in the process schizophrenic. Since other work has shown that performance involving short-term memory is affected by the set of symbols used, the relatively deficient performance of the process schizophrenic may be attributable to a short-term memory deficit for dealing with this type of visual material.

Computer generation of symmetric, semisymmetric, antisymmetric, and asymmetric patterns

A computer algorithm generates selected symmetric, semisymmetric, antisymmetric, and asymmetric patterns on a square field, using random number generation as the seed. All possible combinations of the geometric operations of 90-deg rotation and reflection have exactly equivalent operations on the “bytes” and “words” that make up the binary descriptions of the horizontal and vertical arrangements of visual information. Dot, checkerboard, oblique line, orthogonal line segment, and other more complex pattern types can be generated using this algorithm.