Handedness and Reach-to-Place Kinematics in Adults: Left-Handers Are Not Reversed Right-Handers

The primary goal of this study was to examine the relations between limb control and handedness in adults. Participants were categorized as left or right handed for analyses using the Edinburgh Handedness Inventory. Three-dimensional recordings were made of each arm on two reach-to-place tasks: adults reached to a ball and placed it into the opening of a toy (fitting task), or reached to a Cheerio inside a cup, which they placed on a designated mark after each trial (cup task). We hypothesized that limb control and handedness were related, and we predicted that we would observe side differences favoring the dominant limb based on the dynamic dominance hypothesis of motor lateralization. Specifically, we predicted that the dominant limb would be straighter and smoother on both tasks compared with the nondominant limb (i.e., right arm in right-handers and left arm in left-handers). Our results only partially supported these predictions for right-handers, but not for left-handers. When differences between hands were observed, the right hand was favored regardless of handedness group. Our findings suggest that left-handers are not reversed right-handers when compared on interlimb kinematics for reach-to-place tasks, and reaffirm that task selection is critical when evaluating manual asymmetries.     

Cultural Competence and School Counselor Training: A Collective Case Study

This collective case study investigated the experiences of bilingual counselors‐in‐training who assessed school‐wide cultural competence in public schools. Analysis and interpretation of data resulted in the identification of 5 themes: eye‐opening experiences, recognition of strengths, the role of school leaders, road maps for change, and empowering marginalized groups. Implications and recommendations are discussed. Este estudio de caso colectivo investigó las experiencias de consejeros bilingües en formación que evaluaron la competencia cultural institucional en escuelas públicas. El análisis e interpretación de los datos dieron como resultado la identificación de 5 temas: experiencias reveladoras, reconocimiento de puntos fuertes, el papel de los líderes académicos, hojas de ruta para el cambio y empoderamiento de grupos marginalizados. Se discuten las implicaciones y recomendaciones.     

Augmenting Visual Search Performance With Transcranial Direct Current Stimulation (tDCS)

Military personnel endure rigorous and demanding man-hours designated to monitoring and locating targets in tasks such as cyber defense and Unmanned Aerial Vehicle (UAV) operators. These tasks are monotonous and repetitive, which can result in vigilance decrement. The objective of the study was to implement a form of noninvasive brain stimulation known as transcranial DC stimulation (tDCS) over the left frontal eye field (LFEF) region of the scalp to improve cognitive performance. The participants received anodal and cathodal stimulation of 2 mA for 30 min as well as placebo stimulation on 3 separate days while performing the task. The findings suggest that anodal and cathodal stimulation significantly improves detection accuracy. Also, a correlation was detected between percent of eye closure (PERCLOS) and blinking frequency in relation to stimulation condition. Our data suggest that tDCS over the LFEF would be a beneficial countermeasure to mitigate the vigilance decrement and improve visual search performance.     

Meaning and learning: Response to Moerk

In response to Moerk (1986, Developmental Review, 6, 365–385) the following points are discussed: (a) Semantic and conceptual development must be conceived in terms of systems that undergo developmental change, (b) Objects are viewed as embedded in events and as being conceptualized first within a syntagmatic and later a paradigmatic system, (c) While the nature of the input to the child is important, its effects cannot be considered independently of the state of the child's conceptual and linguistic system. (d) The neurological considerations discussed by Moerk are not relevant to the particular developmental issues discussed in my book.     

High maternal aggression in dwarf hamsters (Phodopus campbelli and P. sungorus)

The defense of offspring, termed maternal aggression, is a highly conserved behavior in mammals, including rodents. This study examined relative levels of maternal aggression in two closely related dwarf hamster species, Phodopus campbelli and P. sungorus, that normally inhabit high latitude, boreal environments. When tested with first litters and with the breeder male remaining with the female (for P. campbelli the male is necessary for successful rearing of offspring), both species exhibited high levels of maternal aggression with average duration of aggressive behavior>80 sec for a 10 min test. For P. sungorus, males are not required to rear offspring. P. sungorus females with either one or multiple litters (singly housed after impregnation) exhibited significantly higher levels of aggression (>300 sec) relative to females co‐housed with the sires. In terms of species differences in attack style, P. campbelli exhibited a boxing or clawing strategy for ～50% of total attack time, but for P. sungorus, this form of attack occurred<5% of the time. For P. sungorus, attacks to the vulnerable belly and flank constituted>90% of all attacks, but these regions were attacked ～50% of the time for P. campbelli. A survey of levels of maternal aggression of rodents in other genera suggests that maternal aggression in Phodopus is at the high end of the spectrum. Results of this study suggest that the presence of the breeder male may actually suppress aggression in P. sungorus. This fact, as well as its high level of aggression and its distant relationship to mice and rats, suggest P. sungorus as a possible model for future studies on the neurobiological basis of maternal aggression. The relationship between the high rates of maternal aggression and life history strategy in Phodopus is discussed. Aggr. Behav. 00:000–000, 2005. © 2005 Wiley‐Liss, Inc.