The present study was designed to identify the memory-enhancing factor of finger-drawing strategy, and investigate the relationship between finger-drawing and semantic processing of random shapes. Forty subjects were randomly assigned to one of the five conditions: imagery encoding, verbal encoding, finger-drawing for encoding, finger-drawing for searching, and finger-drawing for both encoding and searching, and performed recognition tasks of random shapes. Results indicated that in the two conditions under which finger-drawing was used for encoding, recognition of complex shapes was superior to that of simple ones. No differences were found for those of high and low associative shapes. Verbal reports of the subjects indicated that finger-drawing for encoding prevented them from naming the shapes. In contrast, in the other three conditions under which finger-drawing was not used for encoding, recognition of simple shapes was superior to that of complex ones. Also, recognition of high associative shapes was superior to that of low ones. These results suggest that kinetic representation, rather than amount of attention, is responsible for the memory-facilitating effect of finger-drawing, and that finger-drawing for encoding inhibits active semantic processing.
This experiment tested the hypothesis that the larger the size of aircraft accidents, the more overestimated the frequency of the accidents, as well as their associated risk. Ten descriptions of fatal accidents in which everyone died, and 30 of non-fatal ones in which several were injured, some seriously, were used as experimental stimuli. The independent variable was the size of fatal accidents. An average of 250 passengeres were killed in the large disaster condition, while only 40 were killed in the small one, but the likelihood of death was kept constant across the size conditions. Subjects judged the frequencies of fatal and non-fatal accidents as well as the ratio of the former to the latter, rated risks associated with the airlines, and estimated as a manipulation check the average number of passengeres in the stimulus descriptions. Results strongly supported the hypothesis. Subjects in the large disaster condition overestimated the frequency and risk of both fatal and non-fatal accidents. It was concluded that the stronger fear aroused in the large disaster condition heightened the availability of accident information, and resulted in the illusory correlation between the accident size and its associated risk.
Two experiments were performed to clarify the mental processes and the forms of representation constructed in linear syllogistic reasoning. In both experiments, subjects (68 graduates and undergraduates) were asked to decide whether or not three terms were ordered linearly. The first experiment compared two previously known effects; one was the effect facilitating the given-new strategy, and the other was the effect of end-anchoring. Results indicated that the reaction time decreased if the given-term was at the beginning of the second premise, or if the new term was the subject of the second premise. The results of the second experiment, which was designed to elucidate the end-anchoring effect in terms of mental movement, suggested that the mental operation on the new term imitated the actual movement implied by the verb in the premise, providing evidence of spatial representation in linear syllogistic reasoning.
Two experiments were designed to separate the effects of oral repetitions from those of covert mental activity in over rehearsal on free recall. In both experiments, subjects were visually presented several lists of eight noun pairs one by one, with asterisks under the left or right noun of each pair. Subjects studied the lists by observing both nouns of each pair as well as by rehearsing aloud one noun with/without the asterisks. Each of the list presentation was followed by oral free recall test of both rehearsed and not-rehearsed nouns. It was expected that the difference of recall between rehearsed and not-rehearsed nouns would indicate the effects of the repetitions but not of the total rehearsal activity including the covert mental activity. In Experiment 1, the time lag between the study and the test was zero or 30 seconds. In Experiment 2, the time available for rehearsing each noun was four or eight seconds. The results suggest that the repetitions have only STM-maintenance function whereas the covert mental activity has only LTM-construction function.
We examined whether distress responses of rats would be a negative reinforcer or not. In Experiment 1, two rats were placed in adjacent compartments. One rat was reinforced by a food pellet for pressing either of two levers. One of the levers produced food while the other produced food plus electric shock (0.5-2.0 mA) to the other rat. All rats preferred the former lever. In addition, this tendency was more prominent in rats that had experienced shock previously than those without experience. In Experiment 2, one lever produced food while the other produced food plus auditory stimuli, a recorded distress scream (65 dB) or a pure tone (3 kHz, 65 dB). Rats that chose between food and food plus another rat's scream avoided being exposed to the scream. Rats that chose between food and food plus the pure tone chose the two levers equally. These results suggest that negative emotional responses of the conspecifics could be a negative reinforcer.
The effects of shock intensity on response types to shock (Experiment 1) and the relationship between response types and avoidance learning (Experiment 2) were investigated in four inbred strains of mice (BALB/c, C3H/He, C57BL/6 and DBA/2J). In Experiment 1, mice received a one-second inescapable shock, which ranged in intensity from .01 to .4 mA (12 levels). Response types to shock were observed, and locomotion increased in all strains as the shock intensity increased. Additionally, the C3H/He strain also increased jumping response at shocks greater than .2mA. In Experiment 2, the four strains were trained for shuttle avoidance with three shock intensities (.06, .16 and .4 mA). Two responses, locomotion into the adjacent compartment (L-typed) and rearing or jumping (R-typed), were equally effective in terminating the shock. While all strains learned the task at all the levels of shock intensities, the performance of the BALB/c strain declined as the intensity decreased. BALB/c and C57BL/6 strains avoided the shocks mainly by L-typed response across all the intensities. Likewise, the DBA/2J strain predominately displayed L-typed responses, but some R-typed responses did occur. The C3H/He strain, on the other hand, largely avoided the shocks by the R-typed response, especially in the .06 and .4mA conditions.
We recorded event-related potentials (ERPs) in nine normal adult subjects to investigate the effects of display load (number of positions to be processed) and memory load (memory set size) on ERPs in visual search tasks. The stimulus consisted of a horizontal array of five different alphabets. In search task, subjects were required to respond only to stimuli containing a target letter. In a simple reaction task, they were required to respond to all the stimuli. The results showed that display load affected N200 and NA deflections recorded at occipital and posterior temporal electrodes, although memory load did not affect them. We also found the different effects of display load and memory load on search-related negativities. That is, in latency, search-related negativities with increasing display load appeared before those with memory load. The difference in topography between display and memory load effects on search-related negativities was not confirmed statistically. The validity of ERPs as indices for the visual and memory search processes was discussed.
The present studies investigated whether or not optimism/pessimism is a cognitive mediator of future depression for people who have experienced many negative life events. Subjects were administered optimism scales, stress response scales at Time 1. They then completed the stressor scale and stress response scales at Time 2, about six weeks later. The results showed the interaction of stressor experiences and optimistic diathesis: Subjects who have higher stressor experiences and higher stable and global explanatory style for negative events showed higher depressive responses. Other indices of optimistic diathesis-Life Orientation, Cognitive Style, and Internality dimension of Attributional Style-did not produce this interaction effect. Moreover, this interaction did not appear in the psychological stress response other than depression. These results were consistent with diathesis-stress model of depression.