Perceptual complexity and form class cues in novel word extension tasks: how 4-year-old children interpret adjectives and count nouns

Two experiments examined the role of perceptual complexity, object familiarity and form class cues on how children interpret novel adjectives and count nouns. Four-year-old children participated in a forced-choice match-to-target task in which an exemplar was named with a novel word and children were asked to choose another one that matched the exemplar in either shape or material In experiment 1, 56 children were provided with lexical form class cues suggestive of adjectives. The results of Experiment 1 showed that perceptual complexity and not object familiarity determined whether children made material or shape matches. In Experiment 2, 56 children were provided with lexical form class cues suggestive of count nouns. The results of Experiment 2 showed that neither perceptual complexity nor object familiarity affected children's selections in the matching task. When provided with lexical form class cues suggestive of a count noun, children selected shape matches. Thus the results suggest that the perceptual properties of the objects presented to children coupled with the particular lexical form class cue determine which features of objects children attend to when interpreting novel words.     

Specialist musical training and the octave illusion: analytical listening and veridical perception by pipe organists

The octave illusion is a useful tool for investigation of the contribution of specialist training to auditory perception. The stimulus that induces the illusion involves two tones with a frequency ratio of 2:1, presented dichotically, and with ear of presentation reversed every 250 ms. Most listeners report hearing a single tone that alternates from high in the right ear to low in the left ear [Scientific American 233 (1975) 92-104]. The first experiment investigated the hypothesis that musical training contributes to veridical perception of an ambiguous stimulus. As hypothesized, participants with the highest level of musical training were more likely to perceive the stimulus veridically. Exploring the effects of specialist training, Experiment 2 contrasted expert pipe organists with other instrumentalists. As hypothesized, participants expert in playing pipe organ--an instrument with harmonic and spatial features similar to those of the octave illusion--were more likely to perceive the stimulus veridically. The results have implications for plasticity of the auditory system and the analytical listening that accompanies specialist, intensive training and rehearsal.     

Selective hippocampal lesions disrupt a novel cue effect but fail to eliminate blocking in rabbit eyeblink conditioning

The classical conditioning task of blocking involves the adding of a novel but redundant stimulus to a previously trained stimulus. Both blocking and novelty detection are thought to involve the hippocampus. Previously, Solomon (1977) found that nonselective aspiration lesions of the hippocampal region eliminated blocking in rabbit eyeblink conditioning. We tested the effects of selective ibotenic acid lesions of the hippocampus on blocking, as well as on novelty detection, when training is switched from a tone conditioned stimulus (CS) to a compound tone-light CS in eyeblink conditioning. Selective hippocampal lesions did not eliminate blocking but did lead to a facilitation of conditioned response (CR) acquisition to the tone and to the light, but not to the tone-light compound. Selective hippocampal lesions disrupted a CR decrement observed in sham surgical controls when transferred from tone training to tone-light training. It appears that although selective hippocampal lesions do not eliminate blocking in eyeblink conditioning, they do disrupt novelty detection and may facilitate learning to a previously blocked cue.     

Mentoring college-age women: a relational approach

Despite the popularity of mentoring programs, the relational dimension of mentoring has not been elucidated. Traditional conceptions of mentoring may exclude factors that are particularly important for women and girls, thus limiting the efficacy of mentoring programs for female adolescents. We suggest that the presence of relational qualities in the mentoring relationship (e.g., empathy, engagement, authenticity, and empowerment) strongly influences the success of mentoring in the lives of young women. In this study, we use a promising new measure of mentoring, the Relational Health Index – Mentor, to explore the impact of relational aspects of mentoring in female college students. We found that mentoring relationships high in relational qualities were associated with higher self-esteem and less loneliness.     

Site-selective N-methyl-D-aspartate and alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate antagonists produce distinct effects in rats performing complex discriminations

Glutamate receptor-dependent neural plasticity is thought to be implicated in memory processes. Ionotropic N-methyl-D-aspartate- (NMDA) sensitive and alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate- (AMPA) sensitive glutamate receptors have been particularly studied for their role in synaptic plasticity. Drugs can alter AMPA and NMDA receptor neurotransmission by competing for the glutamate site or other sites on these receptor proteins. Variants of the protein subunits forming AMPA and NMDA heteromers contribute to the complexity of pharmacological activity at these receptors. The NMDA receptor has numerous modulatory centers, including the glycine binding site, NR2B protein specific binding site, and an intrachannel (PCP) binding site. In this study, the accuracy and rate of rats performing under a Fixed Consecutive Number (FCN) operant task were measured after administrations of site-selective AMPA and NMDA receptor modulators. Test compounds included two glycine site NMDA agonists [(+)HA 966 and D-cycloserine], two NR2-B site NMDA antagonists (eliprodil and ifenprodil), an NMDA channel blocking antagonist (MK 801), and a competitively acting AMPA receptor antagonist (NBQX). The accuracy of FCN performance was not affected by response-rate-altering doses of (+) HA 966, D-cycloserine, eliprodil, ifenprodil, or NBQX. MK 801, on the other hand, reduced performance accuracy at several doses. These results are consistent with earlier studies suggesting that AMPA antagonists minimally affect working memory and that glycine and NR2B protein-specific modulatory sites may have advantages as targets for the development of medications intended to alter NMDA receptor-mediated transmission.     

The epidemiology of attention-deficit/hyperactivity disorder (ADHD): a public health view

Attention-deficit/hyperactivity disorder (ADHD) is the most common neurodevelopmental disorder of childhood. However, basic information about how the prevalence of ADHD varies by race/ethnicity, sex, age, and socio-economic status remains poorly described. One reason is that difficulties in the diagnosis of ADHD have translated into difficulties developing an adequate case definition for epidemiologic studies. Diagnosis depends heavily on parent and teacher reports; no laboratory tests reliably predict ADHD. Prevalence estimates of ADHD are sensitive to who is asked what, and how information is combined. Consequently, recent systematic reviews report ADHD prevalence estimates as wide as 2%-18%. The diagnosis of ADHD is complicated by the frequent occurrence of comorbid conditions such as learning disability, conduct disorder, and anxiety disorder. Symptoms of these conditions may also mimic ADHD. Nevertheless, we suggest that developing an adequate epidemiologic case definition based on current diagnostic criteria is possible and is a prerequisite for further developing the epidemiology of ADHD. The etiology of ADHD is not known but recent studies suggest both a strong genetic link as well as environmental factors such as history of preterm delivery and perhaps, maternal smoking during pregnancy. Children and teenagers with ADHD use health and mental health services more often than their peers and engage in more health threatening behaviors such as smoking, and alcohol and substance abuse. Better methods are needed for monitoring the prevalence and understanding the public health implications of ADHD. Stimulant medication is the treatment of choice for treating ADHD but psychosocial interventions may also be warranted if comordid disorders are present. The treatment of ADHD is controversial because of the high prevalence of medication treatment. Epidemiologic studies could clarify whether the patterns of ADHD diagnosis and treatment in community settings is appropriate. Population-based epidemiologic studies may shed important new light on how we understand ADHD, its natural history, its treatment and its consequences.     

Neighborhood Disorder, Fear, and Mistrust: The Buffering Role of Social Ties with Neighbors

This paper proposes that individuals who report that they live in neighborhoods characterized by disorder—by crime, vandalism, graffiti, danger, noise, dirt, and drugs—have high levels of fear and mistrust. It further proposes that an individual's alliances and connections with neighbors can buffer the negative effects of living in a neighborhood characterized by disorder on fear and mistrust. Results from a representative sample of 2482 Illinois residents collected by telephone in 1995 support the propositions. Living in a neighborhood with a lot of perceived disorder significantly affects mistrust and the fear of victimization, adjusting for sociodemographic characteristics. Perceived neighborhood disorder and social ties significantly interact: informal social ties with neighbors reduce the fear- and mistrust-producing effects of disorder. However, formal participation in neighborhood organizations shows little buffering effect.