Smoking reduces language lateralization: a dichotic listening study with control participants and schizophrenia patients

Schizophrenia has been associated with deficits in functional brain lateralization. According to some authors, the reduction of asymmetry could even promote this psychosis. At the same time, schizophrenia is accompanied by a high prevalence of nicotine dependency compared to any other population. This association is very interesting, because sex-dependent effects of smoking in auditory language asymmetries have been reported recently, and the verbal domain is also one major focus in cognitive deficit studies of schizophrenia. Thus, the altered laterality pattern in schizophrenia could, at least in part, result from secondary artefacts due to smoking rather than being a pure cause of the disease itself. To test this hypothesis, the present study examined auditory language lateralization in 67 schizophrenia patients and in 72 healthy controls in a phonemic and an emotional dichotic listening task. Our findings replicate previous research, in that smoking reduces language lateralization in men in phonemic dichotic listening. In addition, we show that smoking also reduces laterality in women in the emotional dichotic listening task. Thus, smoking alters phonemic and emotional language asymmetries differentially for men and women, with a stronger effect for men in the left hemisphere phonemic task, and a stronger effect for women in the right hemisphere emotional task. Together, these findings point towards an effect of smoking which is possibly independent of sex and hemisphere. Importantly, by testing equal numbers of smoking and non-smoking patients and controls, we found no schizophrenia-associated asymmetry effect. Possible neurobiological mechanisms with which smoking may alter auditory microcircuits and thereby diminish left-right differences are discussed.     

Entropy,semantic relatedness and proximity

Although word co-occurrences within a document have been demonstrated to be semantically useful, word interactions over a local range have been largely neglected by psychologists due to practical challenges. Shannon’s (Bell Systems Technical Journal, 27, 379–423, 623–665, 1948) conceptualization of information theory suggests that these interactions should be useful for understanding communication. Computational advances make an examination of local word–word interactions possible for a large text corpus. We used Brants and Franz’s (2006) dataset to generate conditional probabilities for 62,474 word pairs and entropy calculations for 9,917 words in Nelson, McEvoy, and Schreiber’s (Behavior Research Methods, Instruments, & Computers, 36, 402–407, 2004) free association norms. Semantic associativity correlated moderately with the probabilities and was stronger when the two words were not adjacent. The number of semantic associates for a word and the entropy of a word were also correlated. Finally, language entropy decreases from 11 bits for single words to 6 bits per word for four-word sequences. The probabilities and entropies discussed here are included in the supplemental materials for the article.     

A Bayesian Approach to Informal Argument Fallacies

We examine in detail three classic reasoning fallacies, that is, supposedly ``incorrect' forms of argument. These are the so-called argumentam ad ignorantiam, the circular argument or petitio principii, and the slippery slope argument. In each case, the argument type is shown to match structurally arguments which are widely accepted. This suggests that it is not the form of the arguments as such that is problematic but rather something about the content of those examples with which they are typically justified. This leads to a Bayesian reanalysis of these classic argument forms and a reformulation of the conditions under which they do or do not constitute legitimate forms of argumentation.     

Toward an intersectional understanding of violence and resilience: An exploratory study of young Southeast Asian men in Alameda and Contra Costa County, California

There is a nascent, but growing, literature on Southeast Asian youth violence that focuses on the role of acculturation, portraying violence as a problem of maladaptation. However, scholars overlook the ways in which violence holds meaning for the youth who experience it and how violence may be related to racial and gender identity formation. We conducted a qualitative study with young Southeast Asian men to elicit the role violence plays in their understanding of what it means for them to be Southeast Asian and male. We conducted focus groups and semi-structured individual interviews with an ethnically diverse group of 21 young Southeast Asian men 13–17 years of age from Alameda and Contra Costa Counties, California. Data were analyzed using the extended case method approach. Our findings illustrate that violence and engagement with community-based organizations are situational tools that these young Southeast Asian men use to navigate their social contexts in an attempt to be resilient in ecological contexts marked by alienation and discrimination, as well as to construct accepted and successful racial and gender identities. Furthermore, we found that their actions were guided by gendered codes of conduct, such as a “code of the street.”     

Diversity-Based Reasoning in Children

One of the hallmarks of inductive reasoning by adults is the diversity effect, namely that people draw stronger inferences from a diverse set of evidence than from a more homogenous set of evidence. However, past developmental work has not found consistent diversity effects with children age 9 and younger. We report robust sensitivity to diversity in children as young as 5, using everyday stimuli such as pictures of objects with people. Experiment 1 showed the basic diversity effect in 5- to 9-year-olds. Experiment 2 showed that, like adults, children restrict their use of diversity information when making inferences about remote categories. Experiment 3 used other stimulus sets to overcome an alternate explanation in terms of sample size rather than diversity effects. Finally, Experiment 4 showed that children more readily draw on diversity when reasoning about objects and their relations with people than when reasoning about objects' internal, hidden properties, thus partially explaining the negative findings of previous work. Relations to cross-cultural work and models of induction are discussed.     

Task coordination and aging: explorations of executive control processes in the task switching paradigm.

A number of models of cognitive aging suggest that older adults exhibit disproportionate performance decrements on tasks which require executive control processes. In a series of three studies we examined age-related differences in executive control processes and more specifically in the executive control processes which underlie performance in the task switching paradigm. Young and old adults were presented with rows of digits and were required to indicate whether the number of digits (element number task) or the value of the digits (digit value task) were greater than or less than five. Switch costs were assessed by subtracting the reaction times obtained on non-switch trials from trials following a task switch. Several theoretically interesting results were obtained. First, large age-related differences in switch costs were found early in practice. Second, and most surprising, after relatively modest amounts of practice old and young adults switch costs were equivalent. Older adults showed large practice effects on switch trials. Third, age-equivalent switch costs were maintained across a two month retention period. Finally, the main constraint on whether age equivalence was observed in task switching performance was memory load. Older adults were unable to capitalize on practice under high memory loads. These data are discussed in terms of their implications for both general and process specific cognitive aging models.     

Contextualizing Gender and Acculturative Influences on Sexual Initiation of Asian Indian Emerging Adults

Although Asian Indians represent one the fastest growing demographics in the United States, no studies exist on the sexual behavior of Asian Indian youth or its association with acculturation. Previous research has demonstrated a link between earlier sexual initiation and subsequent sexual risk and the role of acculturation and sexual initiation in other Asian groups. The present exploratory study examined gender and acculturation with regard to sexual initiation in Asian Indians (n = 37). Results reveal no significant gender differences in sexual initiation and total acculturation scores. Gender differences did emerge for the association among sexual behaviors and the influence of specific areas of acculturation on sexual initiation. Findings suggest that gender and acculturation may be important variables in understanding sexual behavior but that current acculturation measures may be insufficient to adequately assess acculturation levels of Asian Indian youth. Future research should focus on Asian Indians as an understudied minority group.