Modeling behavioral measures of error detection in choice tasks: response monitoring versus conflict monitoring

The present study investigated the mechanisms underlying error detection in the error signaling response. The authors tested between a response monitoring account and a conflict monitoring account. By implementing each account within the neural network model of N. Yeung, M. M. Botvinick, and J. D. Cohen (2004), they demonstrated that both accounts make different predictions as to how error signaling performance is influenced by varying the participants' response criterion. These predictions were tested in an experiment using the Eriksen-flanker task. The qualitative pattern as well as a model fit favored the response monitoring account, which states that error detection is mediated by detecting internal error corrections.     

Effect of time of day on arithmetic fact retrieval in a number-matching task

The goal of this study is aimed to investigate a possible effect of time of day on arithmetic fact retrieval in a number-matching task. We tested 96 students (age range 19-33 years) at 9 a.m. and at 1 p.m., in a counterbalanced order. The subjective alertness levels were also recorded. As regards retrieval efficiency, the results showed that the sum interference effect was significantly more pronounced in the morning (9 a.m.) than at midday (1 p.m.). As expected, participants showed higher subjective alertness levels at 1 p.m. than at 9 a.m.. However, the difference of subjective alertness did not completely explain differences in interference at two testing sessions. The results could be explained with respect to the variation of working memory efficiency during the day.     

Sex-specific clinical correlates of hoarding in obsessive-compulsive disorder

Little is known about whether the clinical correlates of hoarding behavior are different in men and women with obsessive-compulsive disorder (OCD). In the current study, we evaluated the association of hoarding with categories of obsessions and compulsions, psychiatric disorders, personality dimensions, and other clinical characteristics separately in 151 men and 358 women with OCD who were examined during the OCD Collaborative Genetics Study. We found that, among men but not women, hoarding was associated with aggressive, sexual, and religious obsessions and checking compulsions. In men, hoarding was associated with generalized anxiety disorder and tics whereas, among women, hoarding was associated with social phobia, post-traumatic stress disorder, body dysmorphic disorder, nail biting, and skin picking. In women but not men, hoarding was associated with schizotypal and dependent personality disorder dimensions, and with low conscientiousness. These findings indicate that specific clinical correlates of hoarding in OCD are different in men and women and may reflect sex-specific differences in the course, expression, and/or etiology of hoarding behavior in OCD.     

Prevalence and correlates of hoarding behavior in a community-based sample

Little is known about the prevalence and correlates of hoarding behavior in the community. We estimated the prevalence and evaluated correlates of hoarding in 742 participants in the Hopkins Epidemiology of Personality Disorder Study. The prevalence of hoarding was nearly 4% (5.3%, weighted) and was greater in older than younger age groups, greater in men than women, and inversely related to household income. Hoarding was associated with alcohol dependence; paranoid, schizotypal, avoidant, and obsessive-compulsive personality disorder traits; insecurity from home break-ins and excessive physical discipline before 16 years of age; and parental psychopathology. These findings suggest that hoarding may be relatively prevalent and that alcohol dependence, personality disorder traits, and specific childhood adversities are associated with hoarding in the community.     

Do fish count? Spontaneous discrimination of quantity in female mosquitofish

The spontaneous tendency to join the largest social group was used to investigate quantity discrimination in fish. Fish discriminated between shoals that differed by one element when the paired numbers were 1vs2, 2vs3 and 3vs4, but not when 4vs5 or larger. Using large numerosities (>4), the ability to discriminate between two numbers improved as the numerical distance between them increased and a significant discrimination was found only with ratios of 1:2 or smaller (4vs8, 8vs16 and 4vs10). Experiments to control for non-numerical variables evidenced the role played by the total area of stimuli with both large and small numerosities; the total quantity of movement of the fish within a shoal appeared also important but only when large numerosities were involved. Even though the pattern of discrimination exhibited by female mosquitofish is not fully consistent with any of the existing models of quantity representation, our results seem to suggest two distinct mechanisms in fish, one used to compare small numbers of objects and one used when larger numerosities are involved.     

A case of partial biotinidase deficiency associated with autism.

We report the case of a child with partial biotinidase deficiency and autistic developmental disorder. We arrived at the diagnosis of biotinidase deficiency when the child was almost 4 years of age. Consequently, he began cofactor biotin treatment (10 mg daily) which did not resolve his autistic behavior. His younger brother was affected by partial biotinidase deficiency diagnosed at birth through our neonatal screening program. He was precociously treated with cofactor biotin therapy (10 mg daily) and did not show any behavioral abnormality or developmental delay. Since the brain is quite vulnerable to biotin deficiency, delayed biotin therapy could result in neurological damage. Our patient is the first case of partial biotinidase deficiency associated with autism. We hypothesize that the low biotinidase activity could have caused biotin deficiency in his brain and cerebrospinal fluids and consequently serious neurological problems, such as stereotyped and autistic behaviors, which were irreversible in spite of biotin supplementation.     

Validity of the decisional process inventory

Empirical research on career indecision has been criticized for lacking theoretical conceptualization. To address this problem we examined the validity of the decisional process inventory (DPI), a measure of career decision making derived from a model based in Gestalt psychotherapy theory. Undergraduate college students (91 women, 110 men) responded to the DPI and criterion measures of career indecision and vocational identity. Results supported hypothesized relations between and among DPI items and subscales, and the ability of the measure to differentiate individuals by expressed career choice status. Significant intercorrelations among DPI subscales and criterion measures supported the concurrent validity of the DPI. Confirmatory maximum likelihood factor analysis of the DPI items did not support the hypothesized structure of the DPI to measure three career decision-making process dimensions: readiness, action, and resistance. Although results supported the basic psychometric properties of the DPI as a brief measure of career decision making, additional research is needed to clarify the underlying factor structure of the instrument.     

The Role of Distal Variables in Behavior Change: Effects of Adolescents’ Risk for Marijuana Use on Intention to Use Marijuana1

This study uses an integrative model of behavioral prediction as an account of adolescents’ intention to use marijuana regularly. Adolescents’ risk for using marijuana regularly is examined to test the theoretical assumption that distal variables affect intention indirectly. Risk affects intention indirectly if low‐risk and high‐risk adolescents differ on the strength with which beliefs about marijuana are held, or if they differ on the relative importance of predictors of intention. A model test confirmed that the effect of risk on intention is primarily indirect. Adolescents at low and high risk particularly differed in beliefs concerning social costs and costs to self‐esteem. Not surprisingly, at‐risk adolescents took a far more positive stand toward using marijuana regularly than did low‐risk adolescents. On a practical level, the integrative model proved to be an effective tool for predicting intention to use marijuana, identifying key variables for interventions, and discriminating between target populations in terms of determinants of marijuana use.     

How sleeping neonates smile

Infants over one month of age tend to produce two types of smiling during especially positive social interactions, Duchenne smiles involving cheek raising and open‐mouth smiles. Little is known, however, about the prevalence, frequency, duration and organization of these smiles among neonates. Twenty‐five full‐term, healthy neonates (12 female) were videotaped during six minutes of sleep. Smiles were identified and analysed using an anatomically based coding system (FACS/Baby FACS). One‐half of the neonates showed bilateral Duchenne smiles. One‐quarter of the neonates showed bilateral Duchenne smiles at a mature level of intensity whose median duration was 1? s. By contrast, open‐mouth bilateral smiles occurred in less than one‐tenth of the sample. The contrast between the more frequent bilateral Duchenne smiles and the less frequent open‐mouth smile is discussed in terms of the early synergistic functioning of facial muscles and contrasted with the smiling patterns of older infants.     

Programmed to learn? The ontogeny of mirror neurons

Mirror neurons are increasingly recognized as a crucial substrate for many developmental processes, including imitation and social learning. Although there has been considerable progress in describing their function and localization in the primate and adult human brain, we still know little about their ontogeny. The idea that mirror neurons result from Hebbian learning while the child observes/hears his/her own actions has received remarkable empirical support in recent years. Here we add a new element to this proposal, by suggesting that the infant's perceptual‐motor system is optimized to provide the brain with the correct input for Hebbian learning, thus facilitating the association between the perception of actions and their corresponding motor programs. We review evidence that infants (1) have a marked visual preference for hands, (2) show cyclic movement patterns with a frequency that could be in the optimal range for enhanced Hebbian learning, and (3) show synchronized theta EEG (also known to favour synaptic Hebbian learning) in mirror cortical areas during self‐observation of grasping. These conditions, taken together, would allow mirror neurons for manual actions to develop quickly and reliably through experiential canalization. Our hypothesis provides a plausible pathway for the emergence of mirror neurons that integrates learning with genetic pre‐programming, suggesting new avenues for research on the link between synaptic processes and behaviour in ontogeny.