No abstract

The literature on cutaneous communication suggests that a square wave electro-pulse may be a more effective tactile stimulus for cross modality comparisons of reaction times than more traditional stimuli. It was hypothesized that the electro-pulse would give faster reaction times than either light or sound, when presented independently or in simultaneous combinations with the other stimuli. Mean reaction times of 10 male subjects, analysis of variance and mean separation test all indicated that the electro-pulse resulted in faster reaction times and less variability of responses than the other stimuli in both single and combined presentations. The hypotheses were supported and an ordering of reaction times was statistically established as following from the hypotheses. Pooling of stimuli effectiveness was offered as an explanation for the rapid reaction times of combined stimuli.

Sequence length in an irregular step function tracking task was varied in order to evaluate the effect of sequence length on acquisition and retention of a motor skill. A5X2X2X2 factorial design was used with 5 sequence lengths, 2 degrees of task coherence, 2 training criteria (equal practice vs. equal repetitions), and 2 long-term retention intervals. The results support Deese's contention, based on verbal serial learning, that repetitions per item do not increase with length of the series, although total learning time and total number of repetitions do increase approximately as suggested by Thurstone's exponential equation.

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20 3. 4. 1 Imp lementation Factors 20~. 4. 2 O r g a n i z a t i o n a l F a c t o r s 27 3. 4. 3 Management Factors 32 3. 4. 4 I'er s on ne l , R e s o u r c e s , and Facilities. 43 3. 4. S R e l a t i o n s h ip to Other Agencies! Activities 4 CONCLUSION 4. 1 Scope of ISD 4. 2 Status of ISD 4. 3 State of ISD