Comparison of ruminative responses with negative rumination as a vulnerability factor for depression

Several studies have shown that the ruminative responses, which are defined as a coping pattern that focuses on the symptoms of depression and on the possible causes and consequences of these symptoms, are associated with depression. Recently, negative rumination, which is defined as the tendency to continue to think about something bad, harmful, or unhopeful for a long time, has been proposed as a vulnerability factor for depression. The purpose of this study was to compare depression scores associated with negative rumination and ruminative responses. We expected to find depression associated with negative rumination. The sample consisted of 188 Japanese undergraduate students (83 men: M age= 19.0 yr., SD= 1.1; 105 women: M age = 19.1 yr., SD = 1.7) taking a human sciences course at a Japanese university. Subjects participated in an 8-mo. longitudinal study. Logistic analysis indicated that negative rumination was a significant predictor of depression. However, ruminative responses as a whole were not a significant predictor of depression after controlling for negative rumination. These findings suggest that it is important to distinguish whether rumination is focused on negative or nonnegative subject matter.     

Oral perception of bolus in healthy young women

This study was designed to characterize oral perception of both weight and volume of boluses. A total of 80 healthy young female subjects was recruited and divided into bolus weight (n = 40) and bolus volume (n = 40) conditions. Tap water (25 degrees C) was the experimental material, and seven reference stimulus amounts ranging from 10 to 40 (grams and mL) were prepared. The reference stimuli, including a modulus of 20 (grams and mL), were delivered to the subjects in randomized order. The estimated magnitudes (psi) conformed to both the Fechner's and Stevens' psychophysical laws by the following equations: (1) psi(W) = 314.3 log (S+1) - 300.2 where S is stimulus intensity or weight, and psi(V) = 249.7 log (S+1) - 222.3 (volume) on logarithmic (log)-linear scales, and (2) psi(W) = 1.908 S1.297 and psi(V) = 4.097 S1.032 on log-log scales, respectively. The results indicate that oral perception of bolus weight and bolus volume conforms to the representative psychophysical laws.     

The effects of different instructions for preparatory muscle tension on simple reaction time

The effects of preparatory weak muscular contraction (pre-tension) have been investigated in a number of previous studies using tasks with either simple or choice responses to measure the reaction time (RT). These studies suggested that optimal pre-tension performed prior to a motor response tends to shorten the RTs. Using a simple RT task in which participants performed a grip response to a visual stimulus, the present study compared the RTs between two pre-tension conditions (self-selection and constraint) to investigate the effects of different instructions for pre-tension. Under the self-selection condition, participants were asked to determine their optimal pre-tension levels while attempting to give responses as fast as possible. Under the constraint condition, the participants developed a pre-tension at a target force determined by the experimenter. The target force was set at the same level as the pre-tension level maintained under the self-selection. Despite the fact that the pre-tension level manipulated was the same for both conditions, the RTs were significantly shorter under self-selection than under constraint. Moreover, the present study showed a positive correlation coefficient between the proportion of shortening in RT and the variation of pre-tension level. This indicated a performance trade-off between the stability of pre-tension and RTs. The result suggests that shorter RTs that occur under self-selection are primarily mediated by mental factors, such as attention allocation, rather than by the effects of peripheral muscular preparation.     

A new method for determining the personal constants in the Luneburg theory of binocular visual space

Based on the Luneburg theory of binocular visual space, the equation for a visual circle (an apparent circle) was derived to estimate the personal constants, o and K, in this theory. Using small points of light in an otherwise dark room, five observers were asked to construct a visual circle on the horizontal plane with a standard radius of 50 or 100 cm in the median plane. The observation distance for the small circle was 250, 450, or 700 cm, and that for the large circle was 700, 1,030, 1,300, or 1,600 cm. The personal constants calculated from the radii of six directions in each circle were found to be inconsistent with those expected from this theory. The os obtained were remarkably larger than those observed in earlier studies and increased systematically as the observation distance increased. Almost all Ks were negative, with most being less than minus one. Possible factors responsible for these inconsistencies are discussed with reference to the results of previous experiments.     

Graphical language games: interactional constraints on representational form

The emergence of shared symbol systems is considered to be a pivotal moment in human evolution and human development. These changes are normally explained by reference to changes in people's internal cognitive processes. We present 2 experiments which provide evidence that changes in the external, collaborative processes that people use to communicate can also affect the structure and organization of symbol systems independently of cognitive change. We propose that mutual-modifiability-opportunities for people to edit or manipulate each other's contributions-is a key constraint on the emergence of complex symbol systems. We discuss the implications for models of language development and the origins of compositionality.     

Yielding and strain hardening in aluminium single-crystal foils subjected to tension and bending

A series of tensile and microbend tests were conducted on aluminium single-crystal foil specimens with different thicknesses ranging from 20 to 90?µm. Two different crystal orientations relative to the tensile direction were considered in the tests: one is an orientation that was excepted to activate at least four slip systems on four different slip planes, and the other is an orientation that was expected to activate only a single-slip system. In the tensile tests, typical size dependence of initial yield strength was observed. The microbend test method was extended to include a reversal of bending direction. Using the curves of bending moment normalized by the square of foil thickness versus surface strain, which were obtained from the reversed bending tests, the total amounts of strain hardening were divided into isotropic and kinematic hardening components. In the microbend tests, a pronounced size-dependent kinematic hardening behaviour was clearly observed; meanwhile, the amounts of isotropic hardening were very small, particularly for the single-slip orientation.     

Responsiveness to terrestrial optic flow in infancy: does locomotor experience play a role?

Human infants show a peak in postural compensation to optic flow at approximately nine months of age. The current experiment tested whether the magnitude of visual-postural coupling in 9-month-olds increases when terrestrial optic flow is added to a moving room. A secondary objective was to explore whether locomotor experience plays any role in enhancing responsiveness to the additional terrestrial information. Ninety-one infants (experienced creepers, nascent creepers, and prelocomotors) were exposed to two conditions of optic flow: global optic flow (G) and global optic flow minus terrestrial optic flow (G-T). The additional terrestrial optic flow led to significantly higher visual-postural coupling. Consistent with previous findings, locomotor experience had no effect on responsiveness to the G-T condition, though there was weak evidence that the nascent creepers were more strongly influenced by the difference between flow conditions than the other infants. Unexpectedly, the prelocomotor females showed significantly lower visual-postural coupling than the prelocomotor males. These findings support the notion that the ground provides an important source of information for the control of posture and locomotion. The findings also suggest that locomotor experience most likely helps to functionalize smaller (partial), rather than larger (global), optic flow fields for postural control.     

Effects of nonconscious perception on motor response

The present study reviews the literature on the empirical evidence for the dissociation between perception and action. We first review several key studies on brain-damaged patients, such as those suffering from blindsight and visual/tactile agnosia, and on experimental findings examining pointing movements in normal people in response to a nonconsciously perceived stimulus. We then describe three experiments we conducted using simple reaction time (RT) tasks with backward masking, in which the first (weak) and second (strong) electric stimuli were consecutively presented with a 40-ms interstimulus interval (ISI). First, we compared simple RTs for three stimulus conditions: weak alone, strong alone, and double, i.e., weak plus strong (Experiment 1); then, we manipulated the intensity of the first stimulus from the threshold (T) to 1.2T and 2T, with the second stimulus at 4T (Experiment 2); finally, we tested three different ISIs (20, 40, and 60 ms) with the stimulus intensities at 1.2T and 4T for the first and second stimuli (Experiment 3). These experiments showed that simple RTs were shorter for the double condition than for the strong-alone condition, indicating that motor processes under the double condition may be triggered by sensory inputs arising from the first stimulus. Our results also showed that the first stimulus was perceived without conscious awareness. These findings suggested that motor processes may be dissociated from conscious perceptual processes and that these two processes may not take place in a series but, rather, in parallel. We discussed the likely mechanisms underlying nonconscious perception and motor response to a nonconsciously perceived stimulus.