Date of Award


Document Type


Degree Name

Master of Arts (MA)



First Advisor

Gaylon L. Oswalt

Second Advisor

Shelton Hendricks

Third Advisor

L. Michael Leibowitz


The relationship between physiological response patterns and intellectual deficiencies was investigated by examining heart rate changes during a sustained attention-demanding task with institutionalized mentally retarded adults classified into three different I.Q. levels. The task consisted of simple motor responses made to a visual display within which was "hidden" the stimulus cue of Santa Claus. The findings indicated that changes in the within-trial heart rate response were significantly different between groups. Consistent with previous research on retarded adolescents, the retarded adults in the present study were characterized by a significant increase in heart rate variability upon stimulus onset. However, the high I.Q. group (X I.Q.=61) and the middle I.Q. group (X I.Q.=48) displayed significantly less variability in heart rate within the trials than did the low I.Q. group (X I.Q.=36) who remained well above their base rates. Moreover, measures of latency indicated that the high I.Q. group responded significantly faster to the stimulus cues than did the other two groups. The present findings are discussed in terms of viewing peripheral deficits as manifestations of central nervous system deficits paralleling I.Q.


A Thesis Presented to the Department of Psychology and the Faculty of the Graduate College University of Nebraska In Partial Fulfillment of the Requirements for the Degree Masters of Arts University of Nebraska at Omaha.

Included in

Psychology Commons