Hypnagogic imagery and EEG activity.

The relationships between hypnagogic imagery and EEG activity were studied. 7 subjects (4 women and 3 men) reported the content of hypnagogic imagery every minute and the hypnagogic EEGs were classified into 5 stages according to Hori's modified criteria. The content of the hypnagogic imagery changed as a function of the hypnagogic EEG stages.     

Standard errors for the class of orthomax-rotated factor loadings: Some matrix results

The partial derivative matrices of the class of orthomax-rotated factor loadings with respect to the unrotated maximum likelihood factor loadings are derived. The reported results are useful for obtaining standard errors of the orthomax-rotated factor loadings, with or without row normalization (standardization) of the initial factor loading matrix for rotation. Using a numerical example, we verify our analytic formulas by comparing the obtained standard error estimates with that from some existing methods. Some advantages of the current approach are discussed.Authorship is determined by alphabetical order. The authors contributed equally to the research. Kentaro Hayashi is now at the Department of Mathematics, Bucknell University, Lewisburg, PA 17837 (email: khayashi@Bucknell.edu). Yiu-Fai Yung is now at the SAS Institute, Inc., SAS Campus Drive, Cary, NC 27513 (email: yiyung@wnt.sas.com).Part of the research was completed while Yiu-Fai Yung was a visiting scholar at the Department of Psychology, the Ohio State University. The visit was supported in part by grant N4856118101 from the NIMH and the Mason and Linda Stephenson Travel Award from the Department of Psychology, University of North Carolina at Chapel Hill. The authors are grateful to Michael Browne who suggested some relevant references and provided valuable comments on the research, and to Robert Cudeck who provided the FAS program for the numerical comparison. The expert comments by the reviewers are deeply appreciated.     

Self-awakening, sleep inertia, and P3 amplitude in elderly people

It is well known that sleepiness is sometimes experienced in the afternoon. A short afternoon nap is thought to be effective in reducing sleepiness. However, sleep inertia occurs even after a short nap, and this could be a major risk factor for injuries from falling by the elderly. In the present study, the effect of self-awakening on sleep inertia after a 20-min. nap was examined. Nine participants (M=74.1 yr., SD=5.0 yr.) took part in the three experimental conditions: the self-awakened nap, the forced-awakened nap, and the control (no-nap) conditon. Analysis showed sleepiness and performance after the nap significantly improved compared with the control condition. P3 amplitude tended to be larger after self-awakening than after forced-awakening. The present study indicates a 20-min. nap reduces afternoon sleepiness, and the application of self-awakening may contribute to higher arousal after a nap taken by this elderly group.     

Effects of visual-field inversions on the reverse-perspective illusion

The 'reverse-perspective' illusion entails the apparent motion of a stationary scene painted in relief and containing misleading depth cues. We have found that, using prism goggles to induce horizontal or vertical visual-field reversals, the illusory motion is greatly reduced or eliminated in the direction for which the goggles reverse the visual field. We argue that the illusion is a consequence of the observer's inability to reconcile changes in visual information due to body movement with implicit knowledge concerning anticipated changes. As such, the reverse-perspective illusion may prove to be useful in the study of the integration of linear perspective and motion parallax information.     

Social transmission of disinhibition in young children

The present study examined whether young children's behaviors in the Dimensional Change Card Sorting task can be influenced by their observation of another person performing the task. Experiment 1 showed that after children watched an adult sorting cards according to one rule, although the children were instructed to sort the cards according to a new rule, most 3-year-olds made perseverative errors and used the observed, old rule to sort the cards instead of the new rule. However, only some 4-year-olds and few 5-year-olds made the same mistake. Experiments 2, 3 and 4 showed that the younger children took into consideration social pragmatic information displayed by the adult model when deciding to use the old rule or the new rule. When the model appeared to know that she sorted the cards incorrectly (Experiments 2 and 3), or was uncertain whether she sorted cards correctly (Experiment 4), most 3-year-olds no longer committed perseverative errors. When the adult model was confident about her sorting or oblivious to her sorting errors, most 3-year-olds made perseverative errors. These results taken together suggest that social observation can lead to disinhibitions. In other words, disinhibition can be transmitted socially from one person to another.     

Stacking of blocks by chimpanzees: developmental processes and physical understanding

The stacking-block task has been used to assess cognitive development in both humans and chimpanzees. The present study reports three aspects of stacking behavior in chimpanzees: spontaneous development, acquisition process following training, and physical understanding assessed through a cylindrical-block task. Over 3 years of longitudinal observation of block manipulation, one of three infant chimpanzees spontaneously started to stack up cubic blocks at the age of 2 years and 7 months. The other two infants began stacking up blocks at 3 years and 1 month, although only after the introduction of training by a human tester who rewarded stacking behavior. Cylindrical blocks were then introduced to assess physical understanding in object-object combinations in three infant (aged 3-4) and three adult chimpanzees. The flat surfaces of cylinders are suitable for stacking, while the rounded surface is not. Block manipulation was described using sequential codes and analyzed focusing on failure, cause, and solution in the task. Three of the six subjects (one infant and two adults) stacked up cylindrical blocks efficiently: frequently changing the cylinders' orientation without contacting the round side to other blocks. Rich experience in stacking cubes may facilitate subjects' stacking of novel, cylindrical shapes from the beginning. The other three subjects were less efficient in stacking cylinders and used variable strategies to achieve the goal. Nevertheless, they began to learn the effective way of stacking over the course of testing, after about 15 sessions (75 trials).     

Effects of contingencies of self‐worth and sensitivity to indebtedness on optimistic bias in seeking help for depression

The occurrence of the optimistic bias in seeking help for depressive symptoms has been attributed to the threat‐to‐self and equity theories. The current study tested the hierarchical relationships between contingencies of self‐worth (CSW), self‐esteem (SE), sensitivity to indebtedness (SI), and optimistic bias in seeking formal/informal help for depression. An online questionnaire survey was conducted with Japanese university students (n = 1000). Results from structural equation modeling analysis revealed the mediating effect of CSW on SE and optimistic bias. SI was positively related to optimistic bias in symptom recognition and informal help‐seeking. The results suggest that both CSW and SI are responsible for the occurrence of optimistic bias in seeking help for depression. Cognitive patterns in recognizing personal and others' depressive symptoms and needs for seeking help were discussed.     

The Power of a “Maverick” in Collaborative Problem Solving: An Experimental Investigation of Individual Perspective‐Taking Within a Group

Integrating different perspectives is a sophisticated strategy for developing constructive interactions in collaborative problem solving. However, cognitive aspects such as individuals’ knowledge and bias often obscure group consensus and produce conflict. This study investigated collaborative problem solving, focusing on a group member interacting with another member having a different perspective (a “maverick”). It was predicted that mavericks might mitigate disadvantages and facilitate perspective taking during problem solving. Thus, 344 university students participated in two laboratory‐based experiments by engaging in a simple rule‐discovery task that raised conflicts among perspectives. They interacted with virtual partners whose conversations were controlled by multiple conversational agents. Results show that when participants interacted with a maverick during the task, they were able to take others’ perspectives and integrate different perspectives to solve the problem. Moreover, when participants interacted in groups with a positive mood, groups with a maverick outperformed groups having several perspectives.     

Cultural differences in the development of cognitive shifting: East-West comparison

Prior research has documented that Japanese children's performance on the Dimensional Change Card Sorting (DCCS) task can be influenced by their observation of another person completing the task, which is referred to as social transmission of disinhibition. The current study explored whether Canadian children would also show a social transmission of disinhibition and whether their performance would be comparable to that of Japanese children. In this study, 3- and 4-year-olds in Canada and Japan were given both the standard version and social version of the DCCS. Results indicated that Canadian children displayed the social transmission of disinhibition, but their effects were significantly weaker than those with Japanese children. On the other hand, performance on the standard DCCS was comparable between children in the two countries. We discuss the results in terms of cultural differences in the relationship between self and other.