Parameters of digitally averaged potentials of individual motor units]

Of sixty normal subjects of different age six different muscles each were examined electromyographically. The activity pattern was recorded for moderate voluntary innervation and superposed digitally. The parameters of digitally averaged summation action potentials were compared with those of manually assessed potentials. The two methods gave identical results: The duration of potentials was between 5 and 10 ms. It increased in the younger and older age groups and showed only slight changes in middle-aged persons. Only minor differences were found between the muscles of one age group, an exception being the orbicularis oris muscle. The results obtained are compared with values reported in the literature.     

The tonic immobility reaction in chickens: Response characteristics and methodology

A total of 379 chickens were run in five studies to assess the effect of different procedures on tonic immobility and to measure some of the response components of the reaction. The optimal period of manual restraint, by way of producing the most durable immobility response, was found to be 15 sec, and pretest holding conditions were shown to exert a significant influence on the reaction in naive birds. Birds who defecated during immobility or shortly after termination, remained immobile longer than comparable nondefecators. Duration of eye closure and latency of vocalization were also found to be good predictors of the duration of an immobility episode.     

A matching-to-sample procedure for the study of visual perception and concept formation in infrahumans: A test in the pigeon

An apparatus suitable for conducting simultaneous or delayed matching-to-sample experiments with as many as eight comparison stimuli is described. Data are presented which indicate that pigeons are capable of performing such a task. It is concluded that the simultaneous matching-to-sample procedure with more than two comparison stimuli is an efficient means of obtaining information about discrimination capacity and that this procedure may be suitable for studying visual perception in infrahuman Ss.     

Children's component selection with varying degrees of training

With the component selection measure developed by Hale and Morgan (1973), children's use of selective attention was assessed at six levels of learning, ranging from undertraining to overtraining, and this function was examined at each of ages 4, 8, and 12. It was found that, as the children learned the task, they maintained a relatively wide focus of attention, acquiring information about both features of the stimuli, color and shape. Thus, contrary to the model under investigation, the children did not exercise a high degree of selectivity as they approached mastery of the task; nor did overtraining produce the expected “broadening” of attention, as the children acquired little stimulus information beyond the point at which criterion had been reached. The data were interpreted to be more consistent with a model that assumes the bulk of stimulus learning to occur prior to task mastery.     

Child‐directed teaching and social learning at 18 months of age: evidence from Yucatec Mayan and US infants

In several previous studies, 18‐month‐old infants who were directly addressed demonstrated more robust imitative behaviors than infants who simply observed another's actions, leading theorists to suggest that child‐directed interactions carried unique informational value. However, these data came exclusively from cultural communities where direct teaching is commonplace, raising the possibility that the findings reflect regularities in infants' social experiences rather than responses to innate or a priori learning mechanisms. The current studies consider infants' imitative learning from child‐directed teaching and observed interaction in two cultural communities, a Yucatec Mayan village where infants have been described as experiencing relatively limited direct instruction (Study 1) and a US city where infants are regularly directly engaged (Study 2). Eighteen‐month‐old infants from each community participated in a within‐subjects study design where they were directly taught to use novel objects on one day and observed actors using different objects on another day. Mayan infants showed relative increases in imitative behaviors on their second visit to the lab as compared to their first visit, but there was no effect of condition. US infants showed no difference in imitative behavior in the child‐directed vs. observed conditions; however, infants who were directly addressed on their first visit showed significantly higher overall imitation rates than infants who observed on their first visit. Together, these findings call into question the idea that child‐directed teaching holds automatic or universal informational value.     

Positive Feelings at School: On the Relationships Between Students’ Character Strengths,School-Related Affect,and School Functioning

The present study was designed to examine the relationships between students’ character strengths, school-related affect, positive school functioning (i.e., motivation to learn, interest, and engagement at class), and school achievement following the “engine model of well-being” that is focusing on inputs (e.g., personality traits), processes (e.g., moods, emotions), and outcomes (e.g., engagement, accomplishments) within the context of well-being research. A sample of 196 children completed the Values in Action Inventory of Strengths for Youth, which assesses 24 character strengths, and the PANAS-C that assesses school-related positive and negative affect. Additionally, homeroom teachers rated students’ positive school functioning (i.e., motivation, engagement, and interest at school) and their overall school achievement. The character strengths of zest, love of learning, perseverance, and social intelligence showed the strongest positive correlations with school-related positive affect. Teamwork, hope, self-regulation, and love were substantially negatively correlated with school-related negative affect. Certain character strengths showed positive relationships with positive school functioning and overall school achievement. A path model, testing the “engine model of well-being”, found—additionally to direct effects—indirect relationships between character strengths and positive school functioning (through school-related positive affect), which in turn leads to higher school achievement. The presented findings show character strengths as meaningful resources in the schooling context. Character strengths emerge to be crucial for students to experience school-related positive affect, which in turn supports students’ positive school functioning and their overall school achievement. The results demonstrate the complex interplay between students’ personality traits, affect, school functioning, and achievement at school.     

Source Monitoring and Executive Function in 2.5- to 3-Year-Olds

Hala, Brown, McKay, and San Juan (2013) found that children as young as 2.5 years of age demonstrated high levels of accuracy when asked to recall whether they or the experimenter had carried out a particular action. In the research reported here, we examined the relation of early-emerging source monitoring to executive function abilities. Participants were children aged 2.5- to 3-years old. For the source-monitoring procedure, we used the Hala et al. (2013) task in which children and the experimenter took turns placing a total of 20 items on a model farm (encoding phase). For the source memory test, children were asked who had placed each item (retrieval phase). Executive function measures included assessments of working memory, delay-inhibitory control, and conflict-inhibitory control. The main finding was that inhibitory control measures were significantly related to performance on the source-monitoring task. This relation held for the conflict-inhibitory control measures even when controlling for age and vocabulary. The findings of this research suggest that even at the early age of 2.5 years, development of executive control is linked to the emergence of source-monitoring ability.