Depression and interpersonal stress: The mediating role of emotion regulation

Maladaptive emotion regulation is a risk factor for depression when an individual is experiencing stressful interpersonal events. Although emotion regulation has several different dimensions, little is known about which of these mediate the relationship between interpersonal stress and depressive symptoms. The current study examined self-ratings of emotion regulation, interpersonal stress, and depression in a sample of non-clinical undergraduate students (N = 152). Our results indicated that two facets of emotion regulation (i.e., lack of emotional clarity and limited access to emotion regulation strategies) fully mediate the relationship between interpersonal stress and depression. Hence, to minimize depressive symptoms when experiencing interpersonal stress, our findings suggest that it is important for individuals to be clear about their feelings and to attempt to transition from negative feelings to alternative feelings.     

Effects of chewing on cognitive processing speed

In recent years, chewing has been discussed as producing effects of maintaining and sustaining cognitive performance. We have reported that chewing may improve or recover the process of working memory; however, the mechanisms underlying these phenomena are still to be elucidated. We investigated the effect of chewing on aspects of attention and cognitive processing speed, testing the hypothesis that this effect induces higher cognitive performance. Seventeen healthy adults (20–34 years old) were studied during attention task with blood oxygenation level-dependent functional (fMRI) at 3.0 T MRI. The attentional network test (ANT) within a single task fMRI containing two cue conditions (no cue and center cue) and two target conditions (congruent and incongruent) was conducted to examine the efficiency of alerting and executive control. Participants were instructed to press a button with the right or left thumb according to the direction of a centrally presented arrow. Each participant underwent two back-to-back ANT sessions with or without chewing gum, odorless and tasteless to remove any effect other than chewing. Behavioral results showed that mean reaction time was significantly decreased during chewing condition, regardless of speed-accuracy trade-off, although there were no significant changes in behavioral effects (both alerting and conflict effects). On the other hand, fMRI analysis revealed higher activations in the anterior cingulate cortex and left frontal gyrus for the executive network and motor-related regions for both attentional networks during chewing condition. These results suggested that chewing induced an increase in the arousal level and alertness in addition to an effect on motor control and, as a consequence, these effects could lead to improvements in cognitive performance.     

Visual search asymmetry with uncertain targets

The underlying mechanism of search asymmetry is still unknown. Many computational models postulate top-down selection of target-defining features as a crucial factor. This feature selection account implies, and other theories implicitly assume, that predefined target identity is necessary for search asymmetry. The authors tested the validity of the feature selection account using a singleton search task without a predefined target. Participants conducted a target-defined and a singleton search task with a circle (O) and a circle with a vertical bar (Q). Search asymmetry was observed in both tasks with almost identical magnitude. The results were not due to trial-by-trial feature selection, because search asymmetry persisted even when the target was completely unpredictable. Asymmetry in the singleton search was also observed with more complex stimuli, Kanji characters. These results suggest that feature selection is not necessary for search asymmetry, and they impose important constraints on current visual search theories.     

Recognition of odors and identification of sources

The purpose of the present study was to investigate the accuracy of the memory for odors and for the location of odors. In Experiment 1, 5 unfamiliar odors were presented in each of 2 rooms. Twenty participants were instructed to remember only the odors (odor-only control group) and 20 were instructed to remember both the odors and the room where the odors were presented (odor place group). In Experiment 2, both the odor presentation room and the sex of the experimenters were manipulated to increase the uniqueness of the odor location. The results demonstrated that the memory for an odor is superior to the memory for the location of an odor. The results also indicated that the intention to learn the sources of an odor improves the memory for the source. These results are discussed in the context of the source monitoring framework.     

Human concurrent performances: The effects of experience, instructions, and schedule-correlated stimuli

In order to investigate the effects of separate exposures to single schedules, of unique schedule-correlated stimuli, and of independency-informing instructions upon choice under concurrent variable-interval schedules, 28 human subjects were divided into eight groups. Each subject was exposed to a baseline procedure, an experimental procedure, and a return to the baseline procedure. Different combinations of these three manipulations were applied to the different groups only during the experimental phase (except for the independency-informing instructions, which were given to half of the groups at the start of training). For the group of subjects exposed to the combination of all three manipulations, the logarithms of the ratios of response frequencies tended to be linearly related to the logarithms of the ratios of reinforcement frequencies during the experimental phase. These orderly effects were not obtained with subjects in the other groups. The results suggest that human choice was well described by the generalized matching law when the three manipulations were simultaneously in effect, and that unreported differences in the use of these three procedural variables might partly account for contradictions between results in previous studies of human concurrent performance.     

Suicidal Asian patients: recommendations for treatment

I was given an opportunity to learn how suicide prevention programs are administered in the United States. Not surprisingly, treatment for suicidal patients is conducted in terms of the basic tenets of Western culture. When American therapists are seeing Asian patients, especially suicidal individuals who are regressed and show cultural characteristics, the therapists should be aware of the importance of cultural differences. This report discusses recommendations for treating suicidal Asian patients.     

Attitudes toward suicide in Japanese and American medical students.

The Suicide Opinion Questionnaire (SOQ) was administered to two samples of medical school students, from Japan (n = 80 males and 20 females) and the United States (n = 80 males and 20 females). A MANOVA followed by univariate tests indicated significant differences on the Right to die, Normality, and Aggression scales between Japanese and United States students, and significant gender differences on the Religion and Impulsivity scales. No gender by nationality interaction was obtained. An analysis of the individual SOQ items revealed substantial differences between Japanese and United States medical students in their views on suicide.     

Analysis of ultrasonic vocalizations emitted by residents during aggressive encounters among rats (Rattus norvegicus)

This investigation was concerned with the extent to which aggressive resident rats emit 40-70-kHz vocalizations and the effect of these signals on intruders. In Experiment 1, deafened and intact intruder males were given two encounters with resident animals. Deafened intruders engaged in a higher duration of immobile or freezing postures than intact animals. Experiment 2 indicated that the augmentation of freezing found among deafened intruders was not due to an inability to detect ultrasounds made by residents since intruders encountering devocalized resident males showed no reliable differences in specific motor patterns from intruders paired with intact residents. The results further demonstrated that 40-70-kHz vocalizations are produced almost entirely by intruding animals since there were no significant changes in occurrence of these calls when resident males were devocalized. Under the constraints of the testing procedures employed, the role of ultrasonic communication during the initial formation of agonistic relations could not be determined experimentally.