Cognitive influence on motor control in reaching

The purpose of this study was to assess the effects of objects with different attributes on motor control in the act of reaching for them. Much about reaching has been studied from the point of view of spatial relations between objects and subjects, and kinematic approaches have played an important role in this field. Recently, some researchers have proposed that factors other than spatial relations characterize reaching. Therefore, we focused on reaching for an empty glass (empty condition) and a water-filled glass (filled condition) where the positions of the glasses were the same to examine the importance of the objects when reaching for them. Eight young adults participated. We translated the position of the index finger into X-Y-Z coordinate values and examined movement time, length of trajectory, and velocity between the empty and filled conditions. It took longer to reach for an empty than a filled glass, and the filled condition showed a longer trajectory and slower velocity than the empty condition. This indicated that objects with different attributes influenced the reaching and that the role of cognition of attributes is important in the act of reaching.     

Boltzmann on Mathematics

Boltzmann’s lectures on natural philosophy point out how the principles of mathematics are both an improvement on traditional philosophy and also serve as a necessary foundation of physics or what the English call “Natura Philosophy”, a title which he will retain for his own lectures. We start with lecture #3 and the mathematical contents of his lectures plus a few philosophical comments. Because of the length of the lectures as a whole we can only give the main points of each but organized into a coherent study. Behind his mathematics stands his support of Darwinian evolution interpreted in a partly Lamarckian way. He also supported non-Euclidean geometry. Much of Boltzmann’s analysis of mathematics is an attempt to refute Kant’s static a priori categories and his identification of space with “non-sensuous intuition”. Boltzmann’s strong attention toward discreteness in mathematics can be seen throughout the lectures. Part II of this paper will touch on the historical background of atomism and focus on the discrete way of thinking with which Boltzmann approaches problems in mathematics and beyond. Part III briefly points out how Boltzmann related mathematics and discreteness to music. This revised version was published online in June 2006 with corrections to the Cover Date.     

Visual span of detection and recognition of a kanji character embedded in a horizontal row of random hiragana characters

Two experiments were conducted to determine the visual span of detection and recognition of the kanji character embedded in a horizontal row of random hiragana characters. An independent variable was the visual complexity of the kanji characters: simple and complex. In Experiment 1, visual spans of detection were determined by a staircase method. Values of visual spans were more than 15 character spaces for the complex kanji characters, and ranged from 4 to 10 character spaces (mean 7.6) for the simple kanji characters. In Experiment 2, visual spans of recognition were determined by an ascending series of limits method. Values of visual spans ranged from 0 to 4 character spaces (mean 2.3) for the complex kanji characters and from 3 to 7 character spaces (mean 4.8) for the simple kanji characters. These results are discussed in relation to reading of Japanese kanji-kana mixed texts.     

Application of the maximum-entropy method to data on short-term variability in inter-beat interval and an interpretation of the calculated powers

Sixteen young males underwent resting and mental arithmetic and were injected with 100 μg phenylephrine during the interventions. Half of them further underwent trinitroglycerine injections. Power spectral density for inter-beat interval variability was calculated using the maximum-entropy method (MEM) with a very high lag, and its validity was checked by nonlinear least-squares method. It was found that the MEM could produce a very accurate power spectral density. Results on the low- and high-frequency (LF and HF) powers indicated that the phenylephrine injection increased both the LF and HF powers, that the trinitroglycerine injection increased the LF power to some degree, and that the mental arithmetic decreased both the LF and HF powers with both phenylephrine and trinitroglycerine. Therefore, the LF power could be interpreted as a marker of both the vagal and sympathetic activities, whereas the HF power seemed to be solely associated with vagal activity. The implications of the interpretation are discussed in terms of the controversy on the LF power (vagal plus sympathetic vs. sympathetic).     

Narrowing in categorical responding to other‐race face classes by infants

Infants can form object categories based on perceptual cues, but their ability to form categories based on differential experience is less clear. Here we examined whether infants filter through perceptual differences among faces from different other‐race classes and represent them as a single other‐race class different only from own‐race faces. We used a familiarization/novelty‐preference procedure to investigate category formation for two other‐race face classes (Black vs. Asian) by White 6‐ and 9‐month‐olds. The data indicated that while White 6‐month‐olds categorically represented the distinction between Black and Asian faces, White 9‐month‐olds formed a broad other‐race category inclusive of Black and Asian faces, but exclusive of own‐race White faces. The findings provide evidence that narrowing can occur for mental processes other than discrimination: category formation is also affected. The results suggest that frequency of experience with own‐race versus other‐race classes of faces may propel infants to contrast own‐race faces with other‐race faces, but not different classes of other‐race faces with each other.     

Childhood precursors of adolescent drug use: a longitudinal analysis.

Childhood and adolescent intrapersonal and interpersonal influences on older adolescents' drug use were examined with an interactional approach. Data were obtained when subjects were 5-10, 13-18, and 15-20 years old. Latent-variable confirmatory factor analysis was used to determine the fit of the variables to the latent constructs. Next, a structural model was hypothesized and tested to assess the influences of childhood and earlier adolescent factors on later adolescent drug use. Childhood aggression and parental sociopathy affected drug use in late adolescence. Unconventionality during early and middle adolescence had an important and pervasive impact on all aspects of middle and late adolescent functioning. Finally, both intrapersonal and interpersonal factors from childhood and early adolescence affected self-drug use during middle and late adolescence.     

Problems with EM algorithms for ML factor analysis

Rubin and Thayer recently presented equations to implement maximum likelihood (ML) estimation in factor analysis via the EM algorithm. They present an example to demonstrate the efficacy of the algorithm, and propose that their recovery of multiple local maxima of the ML function “certainly should cast doubt on the general utility of second derivatives of the log likelihood as measures of precision of estimation.” It is shown here, in contrast, that these second derivatives verify that Rubin and Thayer did not find multiple local maxima as claimed. The only known maximum remains the one found by Jöreskog over a decade earlier. The standard errors obtained from the second derivatives and the Fisher information matrix thus remain appropriate where ML assumptions are met. The advantages of the EM algorithm over other algorithms for ML factor analysis remain to be demonstrated.     

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.     

Role of selective attention in artificial grammar learning

To investigate the role of selective attention in artificial grammar (AG) learning, participants were presented with “GLOCAL” strings—that is, chains of compound global and local letters. The global and local levels instantiated different grammars. The results of this experiment revealed that participants learned only the grammar for the level to which they attended. The participants were not even able to choose presented but unattended strings themselves. These results show that selective attention plays a critical role in AG learning.