The contribution of executive control to semantic cognition: Convergent evidence from semantic aphasia and executive dysfunction

Semantic cognition, as described by the controlled semantic cognition (CSC) framework (Rogers et al., 2015 , Neuropsychologia, 76, 220), involves two key components: activation of coherent, generalizable concepts within a heteromodal ‘hub’ in combination with modality‐specific features (spokes), and a constraining mechanism that manipulates and gates this knowledge to generate time‐ and task‐appropriate behaviour. Executive–semantic goal representations, largely supported by executive regions such as frontal and parietal cortex, are thought to allow the generation of non‐dominant aspects of knowledge when these are appropriate for the task or context. Semantic aphasia (SA) patients have executive–semantic deficits, and these are correlated with general executive impairment. If the CSC proposal is correct, patients with executive impairment should not only exhibit impaired semantic cognition, but should also show characteristics that align with those observed in SA. This possibility remains largely untested, as patients selected on the basis that they show executive impairment (i.e., with ‘dysexecutive syndrome’) have not been extensively tested on tasks tapping semantic control and have not been previously compared with SA cases. We explored conceptual processing in 12 patients showing symptoms consistent with dysexecutive syndrome (DYS) and 24 SA patients, using a range of multimodal semantic assessments which manipulated control demands. Patients with executive impairments, despite not being selected to show semantic impairments, nevertheless showed parallel patterns to SA cases. They showed strong effects of distractor strength, cues and miscues, and probe–target distance, plus minimal effects of word frequency on comprehension (unlike semantic dementia patients with degradation of conceptual knowledge). This supports a component process account of semantic cognition in which retrieval is shaped by control processes, and confirms that deficits in SA patients reflect difficulty controlling semantic retrieval.     

Psychophysics with children: Investigating the effects of attentional lapses on threshold estimates

When assessing the perceptual abilities of children, researchers tend to use psychophysical techniques designed for use with adults. However, children’s poorer attentiveness might bias the threshold estimates obtained by these methods. Here, we obtained speed discrimination threshold estimates in 6- to 7-year-old children in UK Key Stage 1 (KS1), 7- to 9-year-old children in Key Stage 2 (KS2), and adults using three psychophysical procedures: QUEST, a 1-up 2-down Levitt staircase, and Method of Constant Stimuli (MCS). We estimated inattentiveness using responses to “easy” catch trials. As expected, children had higher threshold estimates and made more errors on catch trials than adults. Lower threshold estimates were obtained from psychometric functions fit to the data in the QUEST condition than the MCS and Levitt staircases, and the threshold estimates obtained when fitting a psychometric function to the QUEST data were also lower than when using the QUEST mode. This suggests that threshold estimates cannot be compared directly across methods. Differences between the procedures did not vary significantly with age group. Simulations indicated that inattentiveness biased threshold estimates particularly when threshold estimates were computed as the QUEST mode or the average of staircase reversals. In contrast, thresholds estimated by post-hoc psychometric function fitting were less biased by attentional lapses. Our results suggest that some psychophysical methods are more robust to attentiveness, which has important implications for assessing the perception of children and clinical groups.

     

Patient preference as a predictor of outcomes in a pilot trial of person-centred counselling versus low-intensity cognitive behavioural therapy for persistent sub-threshold and mild depression

The aim of this analysis was to explore whether pre-treatment intervention preferences were related to outcomes for patients with persistent sub-threshold and mild depression who received one of two treatment types. Thirty-six patients took part in a two-arm, parallel group, pilot randomized controlled trial that compared short term (3 month and 6 month) outcomes of person-centred counselling (PCC) compared with low-intensity, CBT-based guided self-help (LICBT). Patient preferences for the two interventions were assessed at baseline assessment, and analysed as two independent linear variables (pro-PCC, pro-LICBT). Eight out of 30 interactions between baseline treatment preferences and treatment type were found to be significant at the p < .05 level. All were in the predicted direction, with patients who showed a stronger preference for a treatment achieving better outcomes in that treatment compared with the alternative. However, pro-LICBT was a stronger predictor of outcomes than pro-PCC. The findings provide preliminary support that treatment preferences should be taken into account when providing interventions for patients with persistent sub-threshold and mild depression. It is recommended that further research analyses preferences for different treatment types as independent variables, and examines preferences for format of treatment (e.g. guided self-help vs. face-to-face).     

Collaboration facilitates abstract category learning

We examined the effects of collaboration (dyads vs. individuals) and category structure (coherent vs. incoherent) on learning and transfer. Working in dyads or individually, participants classified examples from either an abstract coherent category, the features of which are not fixed but relate in a meaningful way, or an incoherent category, the features of which do not relate meaningfully. All participants were then tested individually. We hypothesized that dyads would benefit more from classifying the coherent category structure because past work has shown that collaboration is more beneficial for tasks that build on shared prior knowledge and provide opportunities for explanation and abstraction. Results showed that dyads improved more than individuals during the classification task regardless of category coherence, but learning in a dyad improved inference-test performance only for participants who learned coherent categories. Although participants in the coherent categories performed better on a transfer test, there was no effect of collaboration.     

Motivated attention to fear-related stimuli: Evidence for the enhanced processing of fear in the late positive potential

Differences in the processing of emotions like fear and sadness have important implications for our understanding of many psychological phenomena (e.g., attentional biases, psychopathology). The late positive potential (LPP) is an established event-related potential that reflects motivated attention to emotional stimuli at the neural level with excellent temporal resolution, but has been infrequently used to study differences across emotions. Drawing on functional theories of emotion suggesting that the quick processing of fear-inducing stimuli increases chances of survival, we hypothesized that fear-inducing pictures would produce larger LPP amplitudes compared to other emotions (happy and sad) in the early time windows of the LPP (e.g., 400–700, 700–1000 ms). The results supported our hypothesis, offering new, albeit preliminary, evidence of the differential processing of threat-related stimuli on the LPP.     

The Visual Spatial Learning Test: Differential impairment during the premanifest and manifest stages of Huntington's disease

Visual spatial memory was assessed using the Visual Spatial Learning Test (VSLT) in individuals with mild to moderate Huntington's disease (HD), pre‐manifest gene carriers for HD, and demographically similar controls. The VSLT has been demonstrated to be a valid, normed measure of non‐verbal memory involving minimal motoric responses. The VSLT assesses immediate and delayed memory for designs, positions of the designs, and design/position associations. The HD group was significantly impaired (p < .05) relative to both the control and Pre‐HD groups on immediate and delayed memory for the designs, positions, and design/position associations. Although there were no differences between the Pre‐HD and control groups on immediate or delayed memory for designs or positions, the Pre‐HD group was significantly impaired (p < .05) relative to the control group on immediate and delayed memory for design/position associations. The results offer novel insight into a relatively unexamined memory deficit that may occur in gene carriers for HD prior to phenoconversion. The data indicate that the VSLT may be a useful measure of visuospatial memory during the premanifest and manifest stages of HD.     

An Approach‐Inhibition Model of Employee Silence: The Joint Effects of Personal Sense of Power and Target Openness

When employees consciously withhold potentially important suggestions or concerns from those who may be able to act on that information, it can have serious implications for organizational performance. Yet there is research suggesting that, when faced with the choice of whether or not to raise an issue, employees often choose to remain silent. Our objective in this paper is to expand current theoretical understanding of why employees often remain silent and of situational factors that can lessen this tendency. Drawing on the approach‐inhibition theory of power, we argue that an employee's personal sense that he or she is lacking in power in relation to others at work is a key factor contributing to the decision to remain silent but that this effect is moderated by perceived target openness. We took a multimethod approach, testing these relationships across 3 studies: a laboratory experiment, a survey study of healthcare workers, and a survey study of employees working across a wide range of industries. Our findings suggest that, although silence is indeed rooted in the psychological experience of powerlessness, perceived target openness mitigates this relationship, encouraging employee to speak up when they would not otherwise do so.