The Journal of general psychology
-
Review
Are effect sizes and confidence levels problems for or solutions to the null hypothesis test?
Some have proposed that the null hypothesis significance test, as usually conducted using the t test of the difference between means, is an impediment to progress in psychology. To improve its prospects, using Neyman-Pearson confidence intervals and Cohen's standardized effect sizes, d, is recommended. ⋯ This essay was written to remind us that the t test, based on the sample--not the true--standard deviation, does not apply solely to distance between means. The t test pertains to a much more ambiguous specification: the difference between samples, including sampling variations of the standard deviation.
-
Presentation of maternal stimuli to an isolated rat pup results in what has been called "comfort" responses, as indicated by both behavioral and physiological quieting. This experiment investigated the role of passive maternal stimuli on tonic immobility and dorsal immobility in 9- and 16-day-old rat pups. Although these stimuli appeared ineffective in inducing tonic immobility, presentation of the mother did produce an increase in duration of dorsal immobility in 16-day-old pups. This increase in the dorsal immobility response may reduce struggling in the presence of the mother and thereby aid the mother in transporting the infant back to the nest.
-
Building on the work of Henley and Dixon (1974) and Mykel and Daves (1979), we investigated the effects of mellow and frenetic music on reported cognitions resulting from auditory subliminal stimuli. College students (N = 120) were randomly assembled into six groups. ⋯ Either mellow or frenetic masking music was played for half the students in each group. Students reported more word-related imagery in the mellow music conditions than in the frenetic conditions, although the reported imagery did not correspond with the subliminal messages presented.
-
Transitory changes of primacy and recency in successive single-trial free recall were investigated in three experiments. A trial-by-trial analysis of the serial position curves indicated a pronounced primacy and a moderate recency on the very first recall trial. The primacy reduced and the recency increased rapidly afterward with a concurrent shift in correlation (from positive to negative) between the input and output order of the items recalled and an increase in output priority of end items. ⋯ Release of interlist PI recovered and maintained the pronounced primacy and the overall recall performance. In addition, the output priority of end items and the correlation between the input and output order of the recalled items did not change significantly when the interlist PI was controlled. Therefore, interlist PI affected the primacy; recall strategy or output priority affected the recency; and the development of recall strategy relied on the presence of interlist PI.
-
An experiment was carried out to investigate unconditioned response diminution in the skin resistance response. By using an alternating series of paired and unpaired stimuli the differential predictions of the hypotheses of response interference, conditioned inhibition and expectancy could be tested. Ss were 27 young adult male students. ⋯ Unconditioned response diminution was found. This diminution showed no significant change over trials and showed no correlation with amplitude of the conditioned response. This result is best explained in terms of expectancy.