A cortical circuit for voluntary laryngeal control: Implications for the evolution language

The development of voluntary laryngeal control has been argued to be a key innovation in the evolution of language. Part of the evidence for this hypothesis comes from neuroscience. For example, comparative research has shown that humans have direct cortical innervation of motor neurons controlling the larynx, whereas nonhuman primates do not. Research on cortical motor control circuits has shown that the frontal lobe cortical motor system does not work alone; it is dependent on sensory feedback control circuits. Thus, the human brain must have evolved not only the required efferent motor pathway but also the cortical circuit for controlling those efferent signals. To fill this gap, I propose a link between the evolution of laryngeal control and neuroscience research on the human dorsal auditory-motor speech stream. Specifically, I argue that the dorsal stream Spt (Sylvian parietal-temporal) circuit evolved in step with the direct cortico-laryngeal control pathway and together represented a key advance in the evolution of speech. I suggest that a cortical laryngeal control circuit may play an important role in language by providing a prosodic frame for speech planning.     

Self-relevance effects and label choice: Strong variations in label-matching performance due to non-self-relevant factors

Attention, Perception, & Psychophysics - Merely associating one’s self with a stimulus may be enough to enhance performance in a label-matching paradigm (Sui, He, & Humphreys,...     

Variation in working memory capacity and episodic memory: Examining the importance of encoding specificity

In the present study, we examined the extent to which encoding specificity influences the relation between individual differences in working memory capacity (WMC) and episodic recall. Participants performed a paired associates cued recall task in which a rhyme or a semantic judgment was made during encoding. During recall participants were presented with the cue word along with either a rhyme or semantic cue. Across both rhyme and semantic conditions, encoding and retrieval conditions either matched or mismatched. When encoding and retrieval conditions matched, high WMC individuals outperformed low WMC individuals. When encoding and retrieval conditions mismatched, high and low WMC individuals performed equivalently. Importantly, this occurred because high WMC individuals were hurt more than low WMC individuals when conditions mismatched. These results demonstrate the importance of encoding specificity in the relation between WMC and episodic recall as well as of unifying prior work that has demonstrated that high WMC individuals are hurt more in some recall conditions than are low WMC individuals.     

Extensive performance on the antisaccade task does not lead to negative transfer

Executive-control processes regulate thoughts, emotions, actions, and behaviors that are critical for everyday functioning. Recently, researchers have suggested that these processes can be flexibly modified by tasks that require executive control. Specifically, it has been argued that executive-control tasks can deplete these executive-control processes, which can in turn lead to negative transfer on subsequent task performance. Importantly, the degrees of malleability in executive-control processes and transfer to different tasks are of ongoing debate. The present study critically examined the hypothesis that executive-control processes can be exerted and whether or not this exertion would negatively transfer to performance on various subsequent tasks. Across a series of experiments, negative transfer effects from extensive performance on the antisaccade task were not found. Traditional hypothesis testing and Bayes factor computations were used to validate these findings. Collectively, the present results put in question the use of the antisaccade task to observe both near and far negative transfer from using executive-control processes.     

Depression and anxious apprehension distinguish frontocingulate cortical activity during top-down attentional control

A network consisting of left dorsolateral prefrontal cortex (LDLPFC) and dorsal anterior cingulate cortex (dACC) has been implicated in top-down attentional control. Few studies have systematically investigated how this network is altered in psychopathology, despite evidence that depression and anxiety are associated with attentional control impairments. Functional MRI and dense-array event-related brain potential (ERP) data were collected in separate sessions from 100 participants during a color-word Stroop task. Functional MRI results guided ERP source modeling to characterize the time course of activity in LDLPFC (300-440 ms) and dACC (520-680 ms). At low levels of depression, LDLPFC activity was indirectly related to Stroop interference and only via dACC activity. In contrast, at high levels of depression, dACC did not play an intervening role, and increased LDLPFC activity was directly related to decreased Stroop interference. Specific to high levels of anxious apprehension, higher dACC activity was related to more Stroop interference. Results indicate that depression and anxious apprehension modulate temporally and functionally distinct aspects of the frontocingulate network involved in top-down attention control.     

Individual differences in prejudice and associative versus rule‐based forms of transitive reasoning

Two experiments examined whether individual differences in prejudice are associated with different reasoning styles when targets and nontargets of prejudice are processed in the same context. High‐prejudice and low‐prejudice participants studied pairwise relations between four persons (one a prejudice target, three nontargets). Stereotypes were made salient by using specific ethnic names and stereotypic traits to define relations between the targets. Relations between the persons were always stereotype congruent in Experiment 1, whereas they were sometimes stereotype incongruent in Experiment 2. We examined study time, relational memory, and transitive reasoning in both experiments. The results of both experiments indicated that the high‐prejudice participants studied sets of relations presented to them faster than did the low‐prejudice participants. The high‐prejudice participants were also more likely to show impaired relational memory and reasoning about nontarget persons but no such limitations with respect to target persons. This novel evidence that prejudice might substantially impair memory and transitive reasoning processes about nontarget persons is discussed in the light of alternative theoretical frameworks in the social cognition and emotion domains. Copyright © 2011 John Wiley & Sons, Ltd.     

Information–integration category learning and the human uncertainty response

The human response to uncertainty has been well studied in tasks requiring attention and declarative memory systems. However, uncertainty monitoring and control have not been studied in multi-dimensional, information-integration categorization tasks that rely on non-declarative procedural memory. Three experiments are described that investigated the human uncertainty response in such tasks. Experiment 1 showed that following standard categorization training, uncertainty responding was similar in information-integration tasks and rule-based tasks requiring declarative memory. In Experiment 2, however, uncertainty responding in untrained information-integration tasks impaired the ability of many participants to master those tasks. Finally, Experiment 3 showed that the deficit observed in Experiment 2 was not because of the uncertainty response option per se, but rather because the uncertainty response provided participants a mechanism via which to eliminate stimuli that were inconsistent with a simple declarative response strategy. These results are considered in the light of recent models of category learning and metacognition.     

Peer relationships and adolescents’ academic and non‐academic outcomes: Same‐sex and opposite‐sex peer effects and the mediating role of school engagement

Background. The literature has documented theoretical/conceptual models delineating the facilitating role of peer relationships in academic and non‐academic outcomes. However, the mechanisms through which peer relationships link to those outcomes is an area requiring further research. Aims. The study examined the role of adolescents’ perceptions of their relationships with same‐sex and opposite‐sex peers in predicting their academic performance and general self‐esteem and the potentially mediating role of school engagement in linking these perceived peer relationships with academic and non‐academic outcomes. Sample. The sample comprised 1,436 high‐school students (670 boys, 756 girls; 711 early adolescents, 723 later adolescents). Method. Self‐report measures and objective achievement tests were used. Structural equation modelling (SEM) was performed to test the hypothesized model and its invariance across gender and age groups. Results. Perceived same‐sex peer relationships yielded positive direct and indirect links with academic performance and general self‐esteem. Perceived opposite‐sex peer relationships yielded positive direct and indirect links with general self‐esteem and an indirect positive link with academic performance, but mediation via school engagement was not as strong as that of perceived same‐sex peer relationships. These findings generalized across gender and age groups. Conclusion. Adolescents’ same‐sex and opposite‐sex peer relationships seem to positively impact their academic performance and general self‐esteem in distinct ways. It appears that school engagement plays an important role in mediating these peer relationship effects, particularly those of same‐sex peer relationships, on academic and non‐academic functioning. Implications for psycho‐educational theory, measurement, and practice are discussed.     

Emotional experience improves with age: evidence based on over 10 years of experience sampling

Recent evidence suggests that emotional well-being improves from early adulthood to old age. This study used experience-sampling to examine the developmental course of emotional experience in a representative sample of adults spanning early to very late adulthood. Participants (N = 184, Wave 1; N = 191, Wave 2; N = 178, Wave 3) reported their emotional states at five randomly selected times each day for a one week period. Using a measurement burst design, the one-week sampling procedure was repeated five and then ten years later. Cross-sectional and growth curve analyses indicate that aging is associated with more positive overall emotional well-being, with greater emotional stability and with more complexity (as evidenced by greater co-occurrence of positive and negative emotions). These findings remained robust after accounting for other variables that may be related to emotional experience (personality, verbal fluency, physical health, and demographic variables). Finally, emotional experience predicted mortality; controlling for age, sex, and ethnicity, individuals who experienced relatively more positive than negative emotions in everyday life were more likely to have survived over a 13 year period. Findings are discussed in the theoretical context of socioemotional selectivity theory.     

Neural correlates in the processing of phoneme-level complexity in vowel production

We investigated how articulatory complexity at the phoneme level is manifested neurobiologically in an overt production task. fMRI images were acquired from young Korean-speaking adults as they pronounced bisyllabic pseudowords in which we manipulated phonological complexity defined in terms of vowel duration and instability (viz., COMPLEX: /ti?i/ >> MID-COMPLEX: /tiye/ >> SIMPLE: /tii/). Increased activity in the left inferior frontal gyrus (Brodmann Areas (BA) 44 and 47), supplementary motor area and anterior insula was observed for the articulation of COMPLEX sequences relative to MID-COMPLEX; this was the case with the articulation of MID-COMPLEX relative to SIMPLE, except that the pars orbitalis (BA 47) was dominantly identified in the Broca’s area. The differentiation indicates that phonological complexity is reflected in the neural processing of distinct phonemic representations, both by recruiting brain regions associated with retrieval of phonological information from memory and via articulatory rehearsal for the production of COMPLEX vowels. In addition, the finding that increased complexity engages greater areas of the brain suggests that brain activation can be a neurobiological measure of articulo-phonological complexity, complementing, if not substituting for, biomechanical measurements of speech motor activity.