Heart rate, recall, and reaction-time measures of levels of processing

A problem of circularity emerges in any attempt to index depth by retention alone. In the present study, reaction time (RT), and heart-rate response were used to index the three qualitatively distinct levels of physical, phonemic, and semantic processing. An additional objective was to distinguish between the three levels under incidental vs intentional learning conditions. Subjects were 46 male undergraduates who were given 30 trials. A trial consisted of the presentation of an orienting question and an imperative word-stimulus separated by a 6-sec. interval. There were three types of questions in order to induce processing to one of the three target levels. The results indicated that recall as well as heart-rate acceleration distinguished between two (physical vs phonemic and semantic) rather than three levels of processing in the incidental condition. Heart-rate change differentiated between incidental and intentional, the intentional condition showing a smaller change. Semantic and phonemic RTs were faster than physical RT, but there were no differences between semantic and phonemic RTs. Intentional recall was superior to incidental recall. It is suggested that psychophysiological indices can provide independent evidence for 'levels of processing.'     

Time and rate measures in choice transitions

Three experiments with pigeons studied the relation between time and rate measures of behavior under conditions of changing preference. Experiment 1 studied a concurrent chain schedule with random-interval initial links and fixed-interval terminal links; Experiment 2 studied a multiple chained random-interval fixed-interval schedule; and Experiment 3 studied simple concurrent random-interval random-interval schedules. In Experiment 1, and to a lesser extent in the other two experiments, session-average initial-link wait-time differences were linearly related to session-average response-rate differences. In Experiment 1, and to a lesser extent in Experiment 3, ratios of session-average initial-link wait times and response rates were related by a power function. The weaker relations between wait and response measures in Experiment 2 appear to be due to the absence of competition between responses. In Experiments 1 and 2, initial-link changes lagged behind terminal-link changes. These findings may have implications for the relations between fixed- and variable-interval procedures and suggest that more attention should be paid to temporal measures in studies of free-operant choice.     

The distinctiveness of hardiness, positive emotionality, and negative emotionality in National Guard soldiers

Exploratory and confirmatory factor analyses were used to investigate the distinctiveness of hardiness (using the Short Hardiness Scale; Bartone, 1995) from the broader personality traits of negative emotionality and positive emotionality (NEM and PEM; assessed with items from the MMPI-2 PSY-5 scales); in a sample of 981 Army National Guard soldiers. Exploratory factor analyses demonstrated that hardiness items loaded on a separate factor from PEM and NEM items, and confirmatory factor analysis suggested that hardiness is not simply a sub-facet of either PEM or NEM. However, subsequent regression analyses found that hardiness did not predict symptoms of PTSD or depression beyond the effects of PEM and NEM among combat exposed soldiers.