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Aged-related differences in the elicitation and habituation of orienting responses to the onset and offset of stimuli have been suggested by several authors. Electrodermal and cardiac orienting responses to the onset and offset of a visual stimulus were measured in three age groups (4 yr., 7 yr., and undergraduate). Each S made one of three judgments: non-signal (observe stimulus), content (color of stimulus), and duration (length of time stimulus presented). Few age differences were found in elicitation or habituation of orienting responses to stimulus onset or offset. There was a trend for elicitation of orienting responses to stimulus offset to be age-related, but the failure to find any other age-related changes made this difference somewhat questionable. Instructions as to the judgement to be made by S were the primary determinants of orienting responses to stimulus onset and offset across all age groups.

The efficacy of the Mp and X minus zero scales of the MMPI in identifying fake-good profiles was investigated. 30 volunteers from the admissions unit of a state mental hospital were administered the MMPI once under instructions to fake good and once under standard instructions. Under fake-good instructions, psychiatric inpatients were able to produce profiles similar to those of normal college students. Both the Mp and X minus zero scales discriminated significantly between the standard and fake-good profiles. Interactions with order of administration occurred for the Mp scale.

Two experiments were designed to assess the relationship between task difficulty and arousal. Electrodermal measures of tonic and phasic arousal to four levels of task difficulty at stimulus onset and offset were studied in college students for intramodal and intermodal tasks. The students were presented for 18 trails with visual-auditory or visual-visual stimuli with either 2.0-, 0.2-, or 0.02-sec difference between stimuli onset or offset, and asked to judge which stimulus came on or went off first or merely to observe the stimuli. Both frequency and amplitude of skin conductance responses reliably differentiated the levels of task difficulty for both the intramodal and the intermodal task. None of the measures of tonic level of arousal was reliable. Electrodermal measures of phasic responses accurately reflected the task demands.