Tangled webs: tracing the connections between genes and cognition

The rise of molecular genetics is having a pervasive influence in a wide variety of fields, including research into neurodevelopmental disorders like dyslexia, speech and language impairments, and autism. There are many studies underway which are attempting to determine the roles of genetic factors in the aetiology of these disorders. Beyond the obvious implications for diagnosis, treatment and understanding, success in these efforts promises to shed light on the links between genes and aspects of cognition and behaviour. However, the deceptive simplicity of finding correlations between genetic and phenotypic variation has led to a common misconception that there exist straightforward linear relationships between specific genes and particular behavioural and/or cognitive outputs. The problem is exacerbated by the adoption of an abstract view of the nature of the gene, without consideration of molecular, developmental or ontogenetic frameworks. To illustrate the limitations of this perspective, I select two cases from recent research into the genetic underpinnings of neurodevelopmental disorders. First, I discuss the proposal that dyslexia can be dissected into distinct components specified by different genes. Second, I review the story of the FOXP2 gene and its role in human speech and language. In both cases, adoption of an abstract concept of the gene can lead to erroneous conclusions, which are incompatible with current knowledge of molecular and developmental systems. Genes do not specify behaviours or cognitive processes; they make regulatory factors, signalling molecules, receptors, enzymes, and so on, that interact in highly complex networks, modulated by environmental influences, in order to build and maintain the brain. I propose that it is necessary for us to fully embrace the complexity of biological systems, if we are ever to untangle the webs that link genes to cognition.     

Stimulus fading and differential reinforcement for the treatment of needle phobia in a youth with autism

Stimulus fading in the form of gradually increased exposure to a fear-evoking stimulus, often combined with differential reinforcement, has been used to treat phobias in children who are otherwise normal and in children with autism. In this investigation, we applied stimulus fading plus differential reinforcement with an adolescent with autism and diabetes whose needle phobia had prevented medical monitoring of his blood glucose levels for over 2 years. Results showed that the treatment was successful in obtaining daily blood samples for measuring glucose levels.     

Concurrent task effects on memory encoding and retrieval: Further support for an asymmetry

Several studies have demonstrated that divided attention at encoding significantly reduces memory performance, whereas divided attention at retrieval affects memory performance only minimally. However, the possibility exists that retrieval processes have shown such resilience because the concurrent tasks used have often not been very demanding. To assess this possibility, we used independent manipulations of the concurrent task during either encoding or retrieval that included stimulus-response compatibility and participant- versus experimenter-controlled pace. In addition, we manipulated the distribution of practice that the participants received with the primary and the concurrent tasks. The results replicated and extended those recently reported by Rohrer and Pashler (2003), indicating that although memory performance is negatively affected by divided attention at retrieval, especially with noncompatible stimulus-response mapping in the concurrent task, this effect was much smaller than that at encoding, in line with the asymmetry notion. Furthermore, experimenter versus participant control of the concurrent task had no effect on memory retrieval. Finally, under conditions of equal practice with both the memory and the concurrent tasks, memory retrieval was affected only to a small degree. In contrast to encoding processes, the processes involved in retrieval accuracy appear, in many cases, to be less interrupted by divided attention, although this protection requires substantial resources.     

Moving up from the segment: a comment on Aichert and Ziegler's syllable frequency and syllable structure in apraxia of speech, Brain and Language, 88, 148-159, 2004

In a recent article, explore whether apraxia of speech (AOS) can be explained by disruption of the phonetic plans for high frequency syllables. This approach is a hybrid one, combining the notion of a mental syllabary with an explanation that the impairment in AOS results from reduced access to supra-segmental phonetic plans. In this commentary, we explore Aichert and Ziegler's approach and suggest that in testing a hybrid model it is important to be cautious in identifying implications for the two source models.     

Can values moderate the attitudes of right-wing authoritarians?

This investigation explored how right-wing authoritarianism (RWA) and endorsement of egalitarian beliefs may interact to determine attitudes toward immigrants, homosexuals, and African Americans. Study 1 (N = 239) found that RWA was negatively related to evaluations of immigrants for those who weakly endorsed egalitarian beliefs. In contrast, endorsement of egalitarian beliefs was associated with positive evaluations of immigrants for both low and high RWAs. RWA did not interact with egalitarianism to determine attitudes toward homosexuals or African Americans. Study 2 analyzed data from the 1992 National Election Study and replicated these effects in a young adult (age < or = 24) sample (n = 102) using moral traditionalism as a proxy for RWA. Partial support for the hypotheses also was found in the adult (age > or = 25) sample (n = 1,257). It is concluded that when tradition and/or social norms offer unclear positions, endorsement of egalitarian beliefs influences the attitudes of authoritarians.     

Learning phonotactic constraints from brief auditory experience

Three experiments asked whether phonotactic regularities not present in English could be acquired by adult English speakers from brief listening experience. Subjects listened to consonant-vowel-consonant (CVC) syllables displaying restrictions on consonant position. Responses in a later speeded repetition task revealed rapid learning of (a) first-order regularities in which consonants were restricted to particular positions (e.g. [baep] not *[paeb]), and (b) second-order regularities in which consonant position depended on the adjacent vowel (e.g. [baep] or [pIb], not *[paeb] or *[bIp]). No evidence of learning was found for second-order regularities in which consonant position depended on speaker's voice. These results demonstrated that phonotactic constraints are rapidly learned from listening experience and that some types of contingencies (consonant-vowel) are more easily learned than others (consonant-voice).     

Emotion-modulated performance and activity in left dorsolateral prefrontal cortex

Functional MRI (fMRI) was used to examine the relationship between processing of pleasant and unpleasant stimuli and activity in prefrontal cortex. Twenty volunteers identified the colors in which pleasant, neutral, and unpleasant words were printed. Pleasant words prompted more activity bilaterally in dorsolateral prefrontal cortex (DLPFC) than did unpleasant words. In addition, pleasant words prompted more activity in left than in right DLPFC. Response speed to pleasant words was correlated with DLPFC activity. These data directly link positive affect, enhanced performance, and prefrontal activity, providing some of the first fMRI evidence supporting models of emotional valence and frontal brain asymmetry based on electroencephalography (EEG).     

Comparing Levels of Spiritual Well-being in State,Catholic and Independent Schools in Victoria,Australia

This article reports on a survey completed by Chaplains, Religious Education and Student Welfare Coordinators in State, Catholic and Independent schools in Victoria. Results from this survey support the model of spiritual well-being, which was seen to be reflected in the quality of relationships that people develop with themselves, others, the environment, and with a Transcendent Other. The staff surveyed generally reported positively on current practice and expressed high priorities for action in nurturing their students' spiritual well-being. School type contributed to significant differences in each of these four sets of relationships.     

EFFECTS OF A FIXED‐TIME SCHEDULE ON ABERRANT AND ADAPTIVE BEHAVIOR

Fixed‐time (FT) schedules of reinforcement have been used to decrease destructive behavior. However, the effects of FT schedules on acquisition and maintenance of appropriate behavior remain unclear. In this study, we present a case in which an FT schedule produced an increase in adaptive behavior and resulted in a significant decrease in destructive behavior.