Computer signal detection by monitoring auditory evoked potentials

A digital computer, using a simple decision algorithm, attempted to determine when an acoustical signal had been presented to a cat by monitoring the amplitude of the evoked potentials (EP) at brainstem auditory nuclei. The signal-to-noise level at threshold and the shape and range of the decision model “psychometric functions” were similar to those obtained from humans in the same task. In addition, the detection performance obeys Weber’s law, the mean amplitude of the EP increases monotmonically with signal level, the variance of the amplitude is independent of both signal and noise level, and both the mean latency and the variance of the latency of the peaks decrease with increasing signal level. These findings suggest that the synchronization in firing of a population of single units plays a part in determining the amplitude of the EP. Interaural effects in detection performance were found at the inferior colliculus and, to a lesser extent, at the superior olive.     

Explorations of individual differences relevant to high level skill

Past research has uncovered few broad abilities that underlie high skill. In this paper, attempts to isolate three different abilities of potential relevance to skill are described. No evidence was found for a general time-sharing ability in common to different kinds of tasks. Modest evidence was found for a trait of attentional flexibility. That trait could potentially be of use in predicting success for skills that require rapid shifts of attention because of rapidly changing task demands. Finally, the rate of repetitive activity is correlated across different muscle groups. For example, finger tapping speed is correlated with foot tapping speed, suggesting a common rate limiting factor. In turn, those rates predict handwriting speed and, according to Book (1924), championship typing.     

Rhythmical body movement in sleep: a brief review and treatment study

Vigorous and damaging head-banging and head and body-rocking can occur in normal subjects of average intelligence before and during sleep. Reports of behavioural treatments for this are reviewed. Data from the present case and others suggest that waking plus efficient response prevention is sufficient to substantially reduce or eliminate the activity even when the treatment has been withdrawn for up to one year. The aetiology of the activity is not understood. However, this case suggests that head- and body-rolling, when long-established, need not enhance the quality of sleep since this was unimpaired on completion of treatment and was possibly even improved by the elimination of the movements. The present case also demonstrates that the behaviour can be treated successfully even when considerable environmental stresses occur.     

An elementary student as a behavioral engineer

Four first-grade public school students exhibited non-study behaviors during a period when all children were to study individually. A fifth-grade student modified the maladaptive behaviors of the four first-grade students. Lights on the four students' desks, which were associated with opportunity for reinforcement, rapidly brought study behavior under stimulus control. Differential reinforcement of other behaviors dramatically decreased studying. Reinforcement was reinstituted and studying returned to a high and stable rate. Surreptitious post-experimental observation using closed-circuit TV indicated that the behavioral changes effected during the experimental phases were partially maintained by the regular classroom environment. A replication of the baseline phase with the observer in the classroom produced an increase in the rate of study behavior, indicating that the observer's presence acted as a discriminative stimulus for studying. An additional contingency requiring improved academic behavior was imposed before the fifth grader was given the opportunity to engage in the behavior modification experiment.     

Attention and multidimensional discrimination1

Observers’ ability to perform several discrimination tasks at the same time was tested using a two-alternative temporal forced-choice procedure. Discrimination of two auditory dimensions (pitch and intensity) and two visual dimensions (horizontal position and vertical position) was measured under conditions where one, two or all four dimensions required attention. Three signal durations were used: 67, 133, and 200 msec. Increasing the number of dimensions requiring attention systematically reduces the precisions of discrimination for each dimension. Auditory and visual discrimination is affected similarly. The amount of reduction in discrimination is independent of whether the dimensions requiring attention involve the same or different sensory modalities. The data are analyzed for evidence of a constant processing capacity employed in both single and multidimensional discrimination. The possibility that the observed performance levels could be achieved by sequentially processing the simultaneous inputs is also considered.