P300 stimulus sequence effects in children and adults

Immediate memory capability for 12 children (8 years) and 12 adults (21 years) was assessed electrophysiologically by using P300 event-related brain potential (ERP) stimulus sequences. These were derived from an auditory discrimination paradigm in which participants detected target stimuli in a series of target (T) and standard (S) tones that were varied by randomly presenting one of four sequence patterns (SSSS, TTTT, TTTS, SSST). Short-term memory capability was assessed behaviorally by recall performance of a 20-word list. Children and adults showed virtually identical P300 amplitude sequence patterns, such that for both groups component size increased systematically as the discrepancy between standard and target stimuli increased across sequence patterns. P300 latency evinced similar, albeit weaker, stimulus sequence effects, with children having longer component peak latencies. Memory recall performance was substantially weaker for the children than for adult participants, especially for recency effects. The findings suggest that immediate memory for stimulus sequences is fully developed in young children, although long-term memory is not.     

Physical activity,motor ability,and school readiness of 6-yr.-old children

The aim of this investigation was to study the relationships between physical activity, motor ability, and school readiness in 6-yr.-old children. In total, 294 healthy children from Tartu were studied (161 boys and 133 girls). The physical activity of children was reported by parents and teachers using the questionnaire of Harro. The motor ability of children was evaluated using various tests from the Eurofit test battery as well as the 3-min. endurance shuttle run test. The Controlled Drawing Observation rest was used as a predictor of school readiness and development of mental abilities. Indoor physical activities predicted 19-25% of total variance in motor scores for these preschool children. Motor ability tests, which demand children's total attention and concentration, appear related to the chosen measures of school readiness.     

Deformation of the useful visual field with state of vigilance,task priority,and central task complexity

In a dual-task situation, peripheral perception can deteriorate due to different variables related to the experimental situation, such as central task complexity and the relative priority given to the two tasks. Recent studies have also shown that individual characteristics (such as the state of vigilance) can alter the useful visual field. The ability to perceive signals presented at different places in the visual field decreases in situations that lead to episodes of low vigilance. In Exp. 1, 27 subjects (18-29 years) had to perform a monotonous and prolonged dual-monitoring task involving central and peripheral vision. The test was carried out with two different sets of instructions regarding priority: the more important task was either the central task or the peripheral one. In Exp. 2, 18 subjects (18-30 years) performed the same test, but this time with two levels of complexity of the central task, either a simple monitoring activity or the same monitoring task coupled with a counting activity. Elliptical interpolation of the data enabled assessment of the deformation of the useful visual field in both experiments. The analysis of the parameters of the elliptical model indicated that the useful visual field mainly shrinks on the vertical axis, as the individual becomes drowsy. The useful visual field also shrinks on the horizontal axis when the peripheral task has priority and the monitoring activity is prolonged, or when the central task is complex.     

Unrealistic optimism and perceived control: role of personal competence

This work analyzed the effects of unrealistic optimism in the interaction between the emotional valence of future events, the perception of control over these events, and the person with whom one compares oneself. It was hypothesized that, if the person of comparison is judged as very competent, a pessimistic bias should be produced. Likelihood of four different types of events (positive and controllable, positive and uncontrollable, negative and controllable, and negative and uncontrollable) were rated by 133 university students (22 men and 111 women) for themselves, for an average student, for their best friend, and for a bright friend. A pessimistic bias was observed on the relative likelihood of the events when the comparison was made between oneself and a competent and bright friend, when events were perceived as controllable, especially positive ones. Not enough is known, however, to provide meaningful interpretation at present; that must await further data and theoretical development.     

The effect of sensitization and coping style on post-traumatic stress symptoms and quality of life: two longitudinal studies

The present study investigated the effects of multiple trauma exposure and coping style on post-traumatic stress symptoms and quality of life. It was hypothesized that sensitization would occur in subjects repeatedly exposed to life-threatening situations (study 1), and different coping styles would act as a resilience or facilitating factor in symptom development (study 2). The results showed that the single-exposure group revealed a decrease in trauma specific stress reactions from three weeks to four months, with a persistent reduction at 12-month follow-up, while the repeated-exposure group showed an increase in symptom reporting over the 12-month period. The same pattern emerged for perceived quality of life-measured by the General Health Questionnaire (GHQ-30). The second study revealed a correlation between scores on avoidant-focused coping style and the Impact of Event Scale-avoidance dimension, Post-traumatic Symptom Scale and GHQ-30. Furthermore, only subjects with a dominant coping style of emotion-focused or task-focused coping showed a reduction in trauma-specific symptom scores over time.     

The Cross-Modal Coordination of Interpersonal Timing: Six-Week-Olds Infants' Gaze with Adults' Vocal Behavior

The purpose of this study was to examine the hypothesis that 6-week-old infants are capable of coordinated interpersonal timing within social interactions. Coordinated interpersonal timing refers to changes in the timing of one individual's behavior as a function of the timing of another individual's behavior. Each of 45, first-born 6-week-old infants interacted with his or her mother and a stranger for a total of 14 minutes. The interactions were videotaped and coded for the gaze behavior of the infants and the vocal behavior of the mothers and strangers. Time-series regression analyses were used to assess the extent to which the timing of each of the infants' gazes was coordinated with the timing of the adults' vocal behavior. The results revealed that (a) coordinated timing occurs between infants and their mothers and between infants and strangers as early as when infants are 6 weeks old, and (b) strangers coordinated the timing of their pauses with the infants to a greater extent than did mothers. The findings are discussed in terms of the role of temporal sensitivity in social interaction.     

The nature of regularity and irregularity: evidence from Hebrew nominal inflection

Most evidence for the role of regular inflection as a default operation comes from languages that confound the morphological properties of regular and irregular forms with their phonological characteristics. For instance, regular plurals tend to faithfully preserve the base's phonology (e.g., rat-rats), whereas irregular nouns tend to alter it (e.g., mouse-mice). The distinction between regular and irregular inflection may thus be an epiphenomenon of phonological faithfulness. In Hebrew noun inflection, however, morphological regularity and phonological faithfulness can be distinguished: Nouns whose stems change in the plural may take either a regular or an irregular suffix, and nouns whose stems are preserved in the plural may take either a regular or an irregular suffix. We use this dissociation to examine two hallmarks of default inflection: its lack of dependence on analogies from similar regular nouns, and its application to nonroots such as names. We show that these hallmarks of regularity may be found whether or not the plural form preserves the stem faithfully: People apply the regular suffix to novel nouns that do not resemble existing nouns and to names that sound like irregular nouns, regardless of whether the stem is ordinarily preserved in the plural of that family of nouns. Moreover, when they pluralize names (e.g., the Barak-Barakim), they do not apply the stem changes that are found in their homophonous nouns (e.g., barak-brakim lightning), replicating an effect found in English and German. These findings show that the distinction between regular and irregular phenomena cannot be reduced to differences in the kinds of phonological changes associated with those phenomena in English. Instead, regularity and irregularity must be distinguished in terms of the kinds of mental computations that effect them: symbolic operations versus memorized idiosyncrasies. A corollary is that complex words are not generally dichotomizable as regular or irregular different aspects of a word may be regular or irregular depending on whether they violate the rule for that aspect and hence must be stored in memory.     

What did mummy say? Dyadic interactions between young "hard to manage" children and their mothers

Thirty preschoolers rated as hard to manage on Goodman's (R. Goodman, 1997) Strengths and Difficulties Questionnaire (SDQ), and a group of matched control children were observed and recorded on audiotape at home, interacting with their mothers (Time 1). At the 18-month follow-up home visits (Time 2), the children and mothers were filmed across 4 observation settings. Mother–child interactions were rated on affect, control, responsiveness and connectedness of communication. At Time 1, mothers of the hard to manage group used more negative control and engaged in fewer connected conversations than did mothers in the control group. At Time 2, mothers of the hard to manage group displayed higher levels of negative control and lower levels of positive control. These results are discussed in terms of the importance of examining connected communication and different observation contexts when examining dyadic mother–child interactions.     

Programming of endogenous and exogenous saccades: evidence for a competitive integration model

Participants were required to make a saccade to a uniquely colored target while ignoring the presentation of an onset distractor. The results provide evidence for a competitive integration model of saccade programming that assumes endogenous and exogenous saccades are programmed in a common saccade map. The model incorporates a lateral interaction structure in which saccade-related activation at a specific location spreads to neighboring locations but inhibits distant locations. In addition, there is top-down, location-specific inhibition of locations to which the saccade should not go. The time course of exogenous and endogenous activation in the saccade map can explain a variety of eye movement data, including endpoints, latencies, and trajectories of saccades and the well-known global effect.