An algorithm for comparing medians

An algorithm is presented for computing a test statistic for comparing medians based on a small-sample size estimate of the variance of the usual sample median.     

Reading acquisition enhances an early visual process of contour integration

The acquisition of reading has an extensive impact on the developing brain and leads to enhanced abilities in phonological processing and visual letter perception. Could this expertise also extend to early visual abilities outside the reading domain? Here we studied the performance of illiterate, ex‐illiterate and literate adults closely matched in age, socioeconomic and cultural characteristics, on a contour integration task known to depend on early visual processing. Stimuli consisted of a closed egg‐shaped contour made of disconnected Gabor patches, within a background of randomly oriented Gabor stimuli. Subjects had to decide whether the egg was pointing left or right. Difficulty was varied by jittering the orientation of the Gabor patches forming the contour. Contour integration performance was lower in illiterates than in both ex‐illiterate and literate controls. We argue that this difference in contour perception must reflect a genuine difference in visual function. According to this view, the intensive perceptual training that accompanies reading acquisition also improves early visual abilities, suggesting that the impact of literacy on the visual system is more widespread than originally proposed.     

Theorizing Novel and Emerging Drug Use: A Motivational Typology

ABSTRACT

Novel and emerging psychoactive drugs (NEPDs), a research-based classification referencing a wide range of natural plant-derived substances and synthetic compounds, have garnered considerable academic attention in recent years. Most of the scientific literature on NEPDs presents definitional overviews of specific substances in terms of their chemical composition and toxicology or socio-legal commentary. This study presents a motivational typology of NEPD use derived from interview data from a sample of offenders participating in jail-based drug treatment. Findings indicate four primary motives for NEPD use (experimentation, drug alternative, peer influence, and availability) and inform discussion for additional research and policy implications.     

What it means to be and feel like a "true" American: perceptions and experiences of second-generation Americans

Through semistructured interviews, the authors investigated the relationships between the definition of a "true" American, the impact of 9/11, and the war in Iraq and their impact on experiences of fitting into and being excluded from the American identity with a sample of 10 2nd-generation young adults. Using consensual qualitative research methods (C. E. Hill et al., 2005; C. E. Hill, B. Thompson, & E. N. Williams, 1997) the authors identified 6 major domains that described participants' experiences, including physical characteristics of true Americans, behavioral characteristics of true Americans, beliefs and values of true Americans, the impact of 9/11 on definitions of true Americans, participants' American identity, and experiences as 2nd-generation Americans.     

Schooling in western culture promotes context-free processing

Culture has been shown to influence the way people apprehend their physical environment. Cognitive orientation is more holistic in East Asian cultures, which emphasize relationships and connectedness among objects in the field, than in Western cultures, which are more prone to focus exclusively on the object and its attributes. We investigated whether, beyond, or in conjunction with culture, literacy and/or schooling may also have an influence on this cognitive orientation. Using the Framed-Line Test both in Portugal and in Thailand, we compared literate schooled adults with two groups of unschooled adults: one of illiterates and one of ex-illiterates. As in former studies on Western people, Portuguese-schooled literates were more accurate in the absolute task than in the relative task. In contrast, Portuguese illiterates and ex-illiterates were more accurate in the relative task than in the absolute task. Such an effect of schooling was not observed in the Thai groups, all of whom performed better on the relative task. Thus, the capacity to abstract from contextual information does not stem only from passive exposure to the culture or the physical environment of Western countries. Western schooling, as part of or in addition to culture, is a crucial factor.     

The developmental turnpoint of orthographic consistency effects in speech recognition

The influence of orthography on children's online auditory word recognition was studied from the end of Grade 4 to the end of Grade 9 by examining the orthographic consistency effect in auditory lexical decision. Fourth-graders showed evidence of a widespread influence of orthography in their spoken word recognition system; words with rimes that can be spelled in two different ways (inconsistent) produced longer auditory lexical decision times and more errors than did consistent words. A similar consistency effect was also observed on pseudowords. With adult listeners, on exactly the same material, we replicated the usual pattern of an orthographic consistency effect restricted to words in lexical decision. From Grade 6 onward, this adult pattern of orthographic effect on spoken recognition is already observable.     

Bifactor and item response theory analyses of interviewer report scales of cognitive impairment in schizophrenia

A psychometric analysis of 2 interview-based measures of cognitive deficits was conducted: the 21-item Clinical Global Impression of Cognition in Schizophrenia (CGI-CogS; Ventura et al., 2008), and the 20-item Schizophrenia Cognition Rating Scale (SCoRS; Keefe et al., 2006), which were administered on 2 occasions to a sample of people with schizophrenia. Traditional psychometrics, bifactor analysis, and item response theory methods were used to explore item functioning and dimensionality and to compare instruments. Despite containing similar item content, responses to the CGI-CogS demonstrated superior psychometric properties (e.g., higher item intercorrelations, better spread of ratings across response categories) relative to the SCoRS. The authors argue that these differences arise mainly from the differential use of prompts and how the items are phrased and scored. Bifactor analysis demonstrated that although both measures capture a broad range of cognitive functioning (e.g., working memory, social cognition), the common variance on each is overwhelmingly explained by a single general factor. Item response theory analyses of the combined pool of 41 items showed that measurement precision is peaked in the mild to moderate range of cognitive impairment. Finally, simulated adaptive testing revealed that only about 10 to 12 items are necessary to achieve latent trait level estimates with reasonably small standard errors for most individuals. This suggests that these interview-based measures of cognitive deficits could be shortened without loss of measurement precision.     

Life events can trigger depressive exacerbation in the early course of schizophrenia

Previous studies have linked life events with depression in chronic schizophrenia, but those studies had methodological limitations. Using a prospective research design and examining events that were clearly independent of the patients' illnesses, the authors sought to determine whether stressful life events could trigger depressive symptoms in the early course of schizophrenia. Schizophrenia patients (n = 99) were followed for 1 year from a point of outpatient stabilization. Life event interviews were conducted every 4 weeks and symptom assessments every 2 weeks. Survival analyses showed a significantly increased risk for an exacerbation of significant depressive symptoms following an independent life event. Of interest is that an analysis of competing risk showed that the odds of psychotic exacerbation following a major independent life event were not significantly greater than the odds of depressive exacerbation. The risk of depression and of psychosis after experiencing a stressful life event is significantly increased for the first month, but the risk period can extend to 3 months.     

Is Phonological Encoding in Naming Influenced by Literacy?

We examined phonological priming in illiterate adults, using a cross-modal picture-word interference task. Participants named pictures while hearing distractor words at different Stimulus Onset Asynchronies (SOAs). Ex-illiterates and university students were also tested. We specifically assessed the ability of the three populations to use fine-grained, phonemic units in phonological encoding of spoken words. In the phoneme-related condition, auditory words shared only the first phoneme with the target name. All participants named pictures faster with phoneme-related word distractors than with unrelated word distractors. The results thus show that phonemic representations intervene in phonological output processes independently of literacy. However, the phonemic priming effect was observed at a later SOA in illiterates compared to both ex-illiterates and university students. This may be attributed to differences in speed of picture identification.     

The development of the orthographic consistency effect in speech recognition: from sublexical to lexical involvement

The influence of orthography on children's on-line auditory word recognition was studied from the end of Grade 2 to the end of Grade 4, by examining the orthographic consistency effect [Ziegler, J. C., & Ferrand, L. (1998). Orthography shapes the perception of speech: The consistency effect in auditory recognition. Psychonomic Bulletin &Review, 5, 683-689.] in auditory lexical decision and shadowing tasks. Words with rhymes that can be spelled in two different ways (inconsistent) produced longer auditory lexical decision and shadowing times and more errors than did consistent words. A similar consistency effect was also observed on pseudowords. The observation of a general consistency effect, both for words and pseudowords, in lexical decision and in shadowing suggests a widespread influence of orthography in the children's spoken word recognition system. On exactly the same material, with adult listeners we replicated the usual pattern of an orthographic consistency effect restricted to words in lexical decision [Ventura, P., Morais, J., Pattamadilok, C., & Kolinsky, R. (2004). The locus of the orthographic consistency effect in auditory word recognition. Language and Cognitive Processes, 19, 57-95; Ziegler, J. C., & Ferrand, L. (1998). Orthography shapes the perception of speech: The consistency effect in auditory recognition. Psychonomic Bulletin &Review, 5, 683-689]. A reanalysis of the lexical decision and shadowing results of Ventura et al. [Ventura, P., Morais, J., Pattamadilok, C., & Kolinsky, R. (2004). The locus of the orthographic consistency effect in auditory word recognition. Language and Cognitive Processes, 19, 57-95.] confirmed the discrepancy between the effects of orthographic consistency in child readers and adults. A further control experiment showed that orthographic consistency effects were not present in pre-readers. Results are interpreted considering the coexistence in children's reading of a mechanism of automatic access to well-specified orthographic representations of words and the persistence of grapho-phonological decoding procedures.