Short-term memory for event duration: Modality specificity and goal dependency

Time perception is involved in various cognitive functions. This study investigated the characteristics of short-term memory for event duration by examining how the length of the retention period affects inter- and intramodal duration judgment. On each trial, a sample stimulus was followed by a comparison stimulus, after a variable delay period (0.5?C5?s). The sample and comparison stimuli were presented in the visual or auditory modality. The participants determined whether the comparison stimulus was longer or shorter than the sample stimulus. The distortion pattern of subjective duration during the delay period depended on the sensory modality of the comparison stimulus but was not affected by that of the sample stimulus. When the comparison stimulus was visually presented, the retained duration of the sample stimulus was shortened as the delay period increased. Contrarily, when the comparison stimulus was presented in the auditory modality, the delay period had little to no effect on the retained duration. Furthermore, whenever the participants did not know the sensory modality of the comparison stimulus beforehand, the effect of the delay period disappeared. These results suggest that the memory process for event duration is specific to sensory modality and that its performance is determined depending on the sensory modality in which the retained duration will be used subsequently.     

Spatial distortion induced by imperceptible visual stimuli

Previous studies have explored the effects of attention on spatial representation. Specifically, in the attentional repulsion effect, a transient visual cue that captures attention has been shown to alter the perceived position of a target stimulus to the direction away from the cue. The effect is also susceptible to retrospective influence, that attention appears to attract the target when the cue appears afterwards. This study examined the necessity of visual awareness of the cue in these phenomena. We found that when the cues were rendered invisible by backward visual masks, both repulsion and attraction effects were weakened but still observed. The results suggest that the effects possibly depend on processes that are not necessarily associated with conscious visual awareness of the cues. We conjecture that attentional shift produced by the weak, invisible cues may play a role in spatial distortion; but other possible accounts including non-attentional ones are also discussed.     

Influence of gender membership on sequential decisions of face attractiveness

Responses in a current trial are biased by the stimulus and response in the preceding trial. In a mixed-category sequence, the sequential dependency is weaker when the stimuli of the current and preceding trials fall under different categories. In the present study, we investigated the influence of the gender membership of faces on the sequential dependency. Forty-eight pictures of male and female faces were presented successively. Participants rated the attractiveness, roundness, or intelligence of each face on a 7-point scale. The sequential effect was robustly observed, irrespective of the property to be judged. However, between-gender sequential dependency was weaker than within-gender dependency only in the attractiveness judgment. These findings suggest that the gender of faces serves as a cue for forming category representations when face attractiveness is of interest, and hence that the formation of categories in sequential decisions is an adaptive process that depends on the property to be judged.     

Token transfer between mother and offspring chimpanzees (Pan troglodytes): mother–offspring interaction in a competitive situation

Chimpanzees can flexibly use tokens in cognitive tasks, but it is still unknown if they can share and/or compete over tokens as they do for food. This study aimed to evaluate the interactions spontaneously occurring between mother and offspring chimpanzees when tokens exchangeable for food were provided. Forty tokens were scattered on the floor in an experimental playroom. Three mother and offspring chimpanzee pairs were tested. Each token was exchangeable for a piece of food in a vending machine installed on the wall of the playroom. In the beginning of the study, both mother and offspring took tokens and exchanged them for pieces of food independently. Later, two offspring started to take more tokens than their mothers. At that time, the offspring whimpered or cried more often than during earlier sessions. This behavior compelled the mothers to abstain from taking tokens. The mothers sometimes shared their tokens with their offspring, or were tolerant of their offspring taking their tokens from their hand. For one pair, the offspring sometimes shared tokens with her mother when her mother begged for the tokens. These results suggest that chimpanzees’ cognitive abilities enable them not only to use tokens, but also to compete for tokens, as they do for food. The results also suggest that token sharing between mother and offspring may be bidirectional and that transfer of tokens mainly occurs as a result of begging, although on some occasion offspring were able to obtain a token directly from his/her mother through tolerated scrounging.     

Psychometric Properties of the Revised Chen Internet Addiction Scale (CIAS-R) in Chinese Adolescents

The Revised Chen Internet Addiction Scale (CIAS-R) was developed to assess Internet addiction in Chinese populations, but its psychometric properties in adolescents have not been examined. This study aimed to evaluate the factor structure and psychometric properties of CIAS-R in Hong Kong Chinese adolescents. 860 Grade 7 to 13 students (38 % boys) completed the CIAS-R, the Young’s Internet Addiction Test (IAT), and the Health of the Nation Outcome Scales for Children and Adolescents (HoNOSCA) in a survey. The prevalence of Internet addiction as assessed by CIAS-R was 18 %. High internal consistency and inter-item correlations were reported for the CIAS-R. Results from the confirmatory factor analysis suggested a four-factor structure of Compulsive Use and Withdrawal, Tolerance, Interpersonal and Health-related Problems, and Time Management Problems. Moreover, results of hierarchical multiple regression supported the incremental validity of the CIAS-R to predict mental health outcomes beyond the effects of demographic differences and self-reported time spent online. The CIAS is a reliable and valid measure of internet addiction problems in Hong Kong adolescents. Future study is warranted to validate the cutoffs of the CIAS-R for identification of adolescents with Internet use problems who may have mental health needs.     

Visual snake aversion in Octodon degus and C57BL/6 mice

Animal Cognition - Phobia against spiders or snakes is common in humans, and similar phobia-like behaviors have been observed in non-human animals. Visual images of snakes elicit phobia in humans,...     

Are illusory contours a cause or a consequence of apparent differences in brightness and depth in the Kanizsa square?

The causal flows between the processes responsible for illusory contour clarity, brightness, and apparent depth in the Kanizsa square were examined. The sixty-four stimuli used consisted of all possible combinations of eight disk luminances and eight centre-to-centre separations between nearest disks. Ten subjects were instructed to rate the clarity of the illusory contour and the brightness and apparent depth differences between the Kanizsa square and its surround in each stimulus. On the basis of results obtained with the causal inference method, using partial correlations and path analysis, it is suggested that clarity of illusory contour can be influenced directly by disk separation, and that the output from the process responsible for illusory contour clarity has some effect on the processes responsible for the apparent depth and brightness differences.     

Do Emotions after Receiving Test Results Predict Review Activities? An Intra‐Individual Analysis

In the present study, we examined intra‐individual relations among emotions when receiving test results and subsequent test review activities, and the direct and moderating effects of perceptions of test value. The participants, 90 first‐year students at a private girls' secondary school, self‐reported their present emotional state immediately after receiving their test results and their test review activities 1 week after the tests were returned. The same survey was conducted on four occasions. Results of multilevel analyses indicated that emotions experienced when receiving test results did not predict subsequent learning behavior. The results also showed that relations among emotions and review activities differed across students. Although we investigated whether such individual differences in relations might be attributed to perceptions of test value, no moderating effect could be observed. Furthermore, improvement‐oriented test mindsets were found to be positive predictors of review activities by investigating the direct effect of perceptions of test value. These findings suggest that modifying students' perceptions of test value may promote appropriate learning behavior.     

Threading dislocation with b=c+2a in 4H-SiC as determined by LACBED

The Burgers vectors of the so-called threading screw dislocations (a total of 28 dislocations) in 4H-SiC were determined by large-angle convergent-beam electron diffraction. A new type of TSD, that is, b = c + 2a dislocation, was identified. Thus, all of the four types of TSD predicted by Onda et al. [Phil. Mag. Lett. 93 (2013) p.591] were identified.     

Visualization of stress distribution using mechanoluminescence from Sr3Al2O6: Eu and the nature of the luminescence mechanism

We have investigated the dependence of the mechanoluminescence intensity from Sr3Al2O6: Eu on compressive stress. The distribution of the mechanoluminescence intensity, which is clearly visible to the naked eye, is consistent with the calculated stress distribution. The luminescence centre has been identified as the Eu2+ ion from spectra of the mechanoluminescence and also from photoluminescence studies of Sr3Al2O6: Eu. The mechanoluminescence intensity decreases on repetitive application of stress but recovers completely on irradiation with ultraviolet light. The Sr3Al2O6: Eu is a p-type semiconductor and has hole traps of depth 0.11 eV. It is suggested that the mechanoluminescence mechanism arises from the movement of dislocations and recombination between electrons and holes released from these traps which are associated with Eu2+ centres.