The Modality Specificity of the Slow Negative Wave

Event-related potentials were recorded in a simple reaction time task using a 3-sec interval between S₁ and S₂. The sensory modalities of S₁ and S₂ were varied across 4 conditions to yield all possible combinations of tones and flashes. A negative component which peaked between 600 and 800 msec after S₁ was specific in scalp distribution to the modality of S₁ but not S₂. It was concluded that this negative component is a response to S₁ and not related to processes associated with anticipation of S₂. A slow negative shift which peaked at S₂ was largest at the vertex in all conditions, suggesting its motor origin. A trend for the latter activity to be more negative in posterior recordings when S₂ was visual than auditory leaves open the possibility that the terminal CNV is a combination of motor activities and anticipation of the sensory modality of S₂.     

Impaired performance by adult humans: Learned helplessness or wrong hypotheses?

Seligman and his associates demonstrated that following a series of uncontrollable, stressful events dogs fail to respond on simple tasks. Seligman accounted for this with a learned-helplessness hypothesis, that uncontrollable events produce a subject who perceives that response is useless and whose motivation to respond is weakened. Recently, analogous experiments have been performed with adult human subjects. Impairment of problem solving has been demonstrated following failure on a prior task. The same learned-helplessness hypothesis has been invoked for this result. The present thesis is that these human experiments may be equally well interpreted by Hypothesis Theory. According to Hypothesis Theory, failure produces subsequent impairment in performance not because subjects are helpless but because they are misdirected about the nature of the solution. That is, these subjects are not passive. Rather, they test incorrect hypotheses. Experimental data are presented to suggest the validity of the Hypothesis Theory interpretation.This study was supported by Grant MH 11857 from the National Institutes of Mental Health. The authors wish to thank Mr. James Eder and the students and faculty of Northport High School, Northport, New York, for their cooperation with the experiment.     

Neurobehavioral Performance of Lowbirthweight Infants at 40 Weeks Conceptional Age: Comparison with Normal Full term Infants

This study compares the neurobehavioral status of 118 low-birthweight infants tested at 40 weeks conceptional age with that of 76 normal fullterm infants. A neonatal neurobehavioral examination comprising 21 test and four summary items was used. The most striking differences between the groups were found in visual and auditory orienting, with approximately two-thirds of the low-birthweight infants falling below the range of performance of the fullterm group. Items testing motor performance showed a lower incidence of deviant performance among the low-birthweight infants. Of the 21 test items, 19 could be assigned cut-off scores, below which infants can be considered deviant on the specific items.