Neural substrates of the ‘low‐level’ system for speech articulation: Evidence from primary opercular syndrome

We describe a patient with progressive disorder of speech, without language impairment (opercular syndrome). Morphometric analysis confirmed asymmetric volume reduction of the precentral areas (>left). Diffusion imaging showed significant white matter changes in the left frontal lobe, with specific involvement of the left corticobulbar tract and connections between supplementary/pre‐supplementary motor areas and the frontal operculum (frontal aslant tract). We suggest that the organization of expressive language includes a ‘low level’ motor system principally distributed in the left hemisphere that shows specific susceptibility to neurodegeneration, distinct from neural systems subtending praxic, and cognitive aspects of language.     

Persistence and relapse of reinforced behavioral variability

The present study examined persistence and relapse of reinforced behavioral variability in pigeons. Pigeons emitted four‐response sequences across two keys. Sequences produced food according to a lag schedule, in which a response sequence was followed by food if it differed from a certain number of previous sequences. In Experiment 1, food was delivered for sequences that satisfied a lag schedule in both components of a multiple schedule. When reinforcement was removed for one component (i.e., extinction), levels of behavioral variability decreased for only that component. In Experiment 2, food was delivered for sequences satisfying a lag schedule in one component of a multiple schedule. In the other component, food was delivered at the same rate, but without the lag variability requirement (i.e., yoked). Following extinction, levels of behavioral variability returned to baseline for both components after response‐independent food delivery (i.e., reinstatement). In Experiment 3, one group of pigeons responded on a lag variability schedule, and the other group responded on a lag repetition schedule. For both groups, levels of behavioral variability increased when alternative reinforcement was suspended (i.e., resurgence). In each experiment, we observed some evidence for extinction‐induced response variability and for variability as an operant dimension of behavior.     

Peer Victimization and Suicidal Thoughts and Behaviors in Depressed Adolescents

Suicide is a leading cause of death among youth worldwide, and depressed adolescents are at a significantly elevated risk to report suicidal ideation, planning, and attempts. Peer victimization is a robust predictor of adolescent suicidal thoughts and behaviors (STBs), but little research has focused on why bullying leads to suicidal thoughts and behaviors. To address this empirical gap, we recruited 340 (246 female) depressed adolescents ages 13–19 (M = 15.59, SD = 1.41) within 48 h of admission for acute psychiatric treatment. At the initial assessment, participants were administered clinical interviews characterizing psychopathology, nonsuicidal self-injury, and STBs (ideation, plans, and attempts). Further, they completed questionnaires assessing 3 forms of victimization (overt, relational, and reputational), recent risky behavior engagement, and psychiatric symptom severity. Controlling for internalizing symptoms and age, overt and reputational bullying were associated with more frequent past month suicide attempts, but not suicide ideation. Past month risky behavior engagement, but not NSSI, mediated the relation between victimization and attempts. However, sex differences revealed that this effect only held for males whereas bullying was directly associated with suicide attempts among females. In contrast, overt and relational bullying were non-linearly associated with suicide plans, and these relations were not mediated by risky behaviors or NSSI. Results highlight the complex network of factors that lead victimized adolescents to engage in STBs and may inform targeted suicide prevention and intervention programs.     

Sex differences in jealousy: the (lack of) influence of researcher theoretical perspective

The sex difference in jealousy is an effect that has generated significant controversy in the academic literature (resulting in two meta-analyses that reached different conclusions on the presence or absence of the effect). In this study, we had a team of researchers from different theoretical perspectives use identical protocols to test whether the sex difference in jealousy would occur across many different samples (while testing whether mate value would moderate the effect). In our samples, we found the sex difference in jealousy to occur using both forced choice and continuous measures, this effect appeared in several different settings, and, we found that mate value moderated participant responses. The results are discussed in light of the controversy surrounding the presence of the effect.     

Retrieval-induced forgetting and unwanted thought intrusions

The act of retrieving an existing memory has been found to inhibit the recall of related memories, a phenomenon known as retrieval-induced forgetting (RIF). The purpose of the present study was to investigate the hypothesis that individuals with a strong RIF effect might be better at suppressing unwanted intrusive thoughts. In Experiment 1 the relationship between RIF and the prevalence of intrusive thoughts was investigated using a sample of 58 normal British participants, who completed three different questionnaires to measure their susceptibility to intrusive thoughts, obsessional thoughts, and impulsive thoughts. Their susceptibility to RIF was also measured, using the standard procedure introduced by Anderson, Bjork, and Bjork (1994). The results showed a significant RIF effect, and, although no significant correlations were found between RIF strength and any of the three measures of intrusive thoughts, there was some evidence to suggest a possible relationship between RIF and intrusive thoughts. In an effort to clarify these inconclusive findings, Experiment 2 investigated the relationship between RIF and intrusive thoughts in a different and more varied population sample, consisting of 90 normal members of the Greek population. Experiment 2 confirmed the RIF effect, but no significant association was found between RIF and intrusive thoughts. These findings therefore offer no support for the hypothesis that RIF assists the suppression of intrusive thoughts in normal individuals.     

Time to guide: Evidence for delayed attentional guidance in contextual cueing

Contextual cueing experiments show that, when displays are repeated, reaction times (RTs) to find a target decrease over time even when the observers are not aware of the repetition. Recent evidence suggests that this benefit in standard contextual cueing tasks is not likely to be due to an improvement in attentional guidance (Kunar, Flusberg, Horowitz, & Wolfe, 2007). Nevertheless, we ask whether guidance can help participants find the target in a repeated display, if they are given sufficient time to encode the display. In Experiment 1 we increased the display complexity so that it took participants longer to find the target. Here we found a larger effect of guidance than in a condition with shorter RTs. Experiment 2 gave participants prior exposure to the display context. The data again showed that with more time participants could implement guidance to help find the target, provided that there was something in the search stimuli locations to guide attention to. The data suggest that, although the benefit in a standard contextual cueing task is unlikely to be a result of guidance, guidance can play a role if it is given time to develop.     

Perceived burdensomeness, familism, and suicidal ideation among Mexican women: enhancing understanding of risk and protective factors

The interpersonal-psychological theory of suicide and a culturally-relevant construct, familism, was used to examine predictors of suicidal ideation among Mexican and Mexican American women in the United States. A sense of perceived burdensomeness toward others was expected to significantly predict suicidal ideation, especially among women who endorsed high levels of familism. Mexican and Mexican American outpatient women (N = 73) completed self-report measures and an interview measure of suicidal ideation. Main and interactive effects of perceived burdensomeness and familism were examined. Perceived burdensomeness, but not familism, significantly predicted suicidal ideation. The interaction hypothesis was not supported. These findings highlight perceived burdensomeness as a risk factor for suicidal behavior in Mexican and Mexican American women.     

Speech imagery is not always faster than visual imagery

One approach to the study of mental imagery is to examine the performance characteristics of different forms of mental imagery when used in various tasks. To demonstrate the utility of this functional approach, the use of speech and visual imagery processes in the serial mental rehearsal of common verbal sequences le.g., letters of the alphabet and familiar object arrays (objects found in familiar rooms) was examined in the present experiments. Rehearsal rates and self-reporte were consistent with the hypothesis that mental rehearsal efficiency is a function of the compatibility of characteristics of the rehearsal materials and rehearsal mode. While verbal sequences were rehearsed faster under speech than under visual imagery conditions, object arrays were rehearsed as fast under visual as under speech imagery conditions. In addition, evidence was found that covert verbal rehearsal is faster than overt verbal rehearsal under some circumstances.