FREE RECALL OF REPEATED WORDS AS A FUNCTION OF INTRALIST VARIABILITY

von W right J. M. Free recall of repeated words as a function of intralist variability. Scand. J. Psychol ., 1972, 13 , 39–42.—Five "critical" words were repeated 4 times each in constant positions within lists of 80 items. The number of different filler words, and the order of the repeated filler words, was varied between lists. In free recall tests total recall was approximately constant, but the recall of the critical words was significantly better the greater the variation in the intralist context of these words, especially the greater the number of different filler words. The results are interpreted in terms of the encoding variability hypothesis.     

Temporal characteristics of a comparator in adaptation to optical tilt

Two groups of eight Ss each and one group of seven Ss were exposed to optical tilts (T) of 50, 40, 30, 20, and 10 deg in succession. Exposure time at each tilt was 3, 15, and 27 min in Groups 1, 2, and 3, respectively. Trend analyses of the functions relating level of adaptation to T showed significant quadratic components for Group 1, quadratic and linear components for Group 2, and only linear components for Group 3. These results were consistent with derivations from a memory-comparator model of perceptual adaptation.     

Interaction of fear effects with habit strength

Four groups of rats received 0, 3, 6 or 9 days of overtraining after having reached stable performance on a continuous reinforcement bar pressing schedule. Half the subjects in each group had previously been designated emotionally reactive or non-reactive in terms of defecation rates in an open-field test. Following training, there were four test days in which bar pressing in each group was examined in the presence or absence of white noise. The major findings were that, in both the reactive and non-reactive groups, white noise produced a fear reaction which significantly depressed bar pressing at low levels of habit strength while having an energizing effect at higher levels. The results were interpreted as supporting Bardach's (1960) hypothesis that anxiety introduced early in practice is more disruptive than when introduced late in practice.     

Looking time: Experimenter and instruction effects

A 2 by 3 factorial design was used to investigate the effects of the instructions and the presence of E on looking time. Two hundred thirty-nine college students viewed 30 colored stimuli of landscapes, single objects, and arrays of objects under three different sets of instructions, with E either present or absent while S viewed the stimuli. The results demonstrated that E’s presence depressed the time spent looking at the stimuli Evidence was also found suggesting that ambiguity in the typical instructions given Ss in looking-time experiments may result in artifactually long looking times. It was concluded that a more appropriate situation to investigate looking time would (1) utilize sham GSR instructions to reduce S’s uncertainty concerning the experiment’s purpose, and (2) arrange for E’s absence while S is viewing the stimuli     

A new challenge to ethical codes: Heart transplants

Summary We have entered into a new era of medical achievement with the development of successful transplantation of human organs. The transplantation of the heart has aroused the greatest scientific interest and at the same time created serious new problems of an ethical and legal nature. It has been necessary to develop new criteria to determine the moment of death of the donor in order to ensure continued life for the recipient. The decision of the moment of death should be made by a small team of skilled physicians interested in furthering this important development, but not as emotionally involved as are the surgeons awaiting the chance to prolong their patient's life with a new heart. Available and suitable hearts will probably always be in very short supply, and the selection of recipients will therefore become critical if the procedure proves to be widely acceptable.New laws will be essential before this process can be adopted in many states and countries. The cost in terms of total resources is so large that careful evaluation of the long-term results must be undertaken after a reasonable number of patients have been operated on and observed, perhaps at the end of the second year following the first procedure. Since the cost of each operation of this type approximates that of the education of several young physicians who could care for thousands of patients during their life span, a good hard look at the potential benefits and ultimate values is in order. At this point in time it is extremely important that this type of surgery be encouraged but limited to those prepared to undertake it with maximum skill and minimal risk. At present it must be recognized as a great experiment rather than a therapeutic triumph for general application.     

Reaction time as a function of the intensity and probability of occurrence of vibrotactile signals

Three Ss made judgments of the presence or absence of a burst of 60-cps vibration onthe index fingertip.The probability of S’s reporting the presence of a signal was found to be influenced by signal probability and signal intensity. Mean reaction time for reporting the presence of a signal decreased as a function of signal intensity and signal probability whereas mean reaction time for reporting the absence of a signal increased as a function of signal intensity and signal probability. On trials where no signal was presented mean R T for reporting a signal decreased with increases in the signal probability whereas mean RT for reporting the absence of a signal increased with increases in signal probability. The results were interpreted as support for the hypothesis that S’s decision time was longer the closer on the sensory continuum a particular observation was to his criterion.     

Frequency-selective detection at three signal amplitudes

Using the probe-signal method, frequency-response characteristics were obtained for four Os detecting signals nominally of only 1000Hz under three signal-amplitude conditions: E/N_o=10.0, 12.6, and 15.8. Detection of 1000-Hz signals decreased systematically with signal-amplitude decreases, but signals at 850 Hz and at 1150 Hz were detected at or near the chance level during all signal-amplitude conditions. From the detection performance data, the detectability was inferred for four probe-signal frequencies relative to that of 1000-Hz signals for each of the amplitude conditions. From the curvesofrelative detectability, hal[-detectability bandwidths were estimated. Neither the relative detectability curves nor the half-detectability bandwidths indicate any systematic change in the frequencyselectivebehavior of the auditory O across the signal amplitudes used.