Organization of and access to semantic memory in aphasia

Previous experiments with picture sorting and matching tasks have shown aphasics to give more deviant responses than controls when decisions require the identification of single features of concepts, whereas their responses are close to normal whenever decisions have to be based on the relative overlap of broad associative fields. The present experiment was designed to compare picture matching based on single features (property verification) with picture matching based on category membership (category verification). Fifty-five aphasics (14 amnesics, 18 Brocas, 13 Wernickes, 10 global aphasics) and 29 right-brain-damaged control patients served as subjects. Aphasics were poorer than right hemisphere controls on property as well as on category sortings, especially when the sorting criterion was not a dominant property of the object or when the object in question was not a typical member of the criterion category. Contrary to other studies, the "semantic distance" variable did not differentially affect Brocas as compared to Wernickes aphasics. Verbal labels denoting the sorting criterion and added to the picture presentation did not affect the performance of the right hemisphere controls but significantly improved that of the aphasics.     

Unvaxxed and unafraid: Unvaccinated Americans perceive less disease risk than do vaccinated Americans

Is disease risk perception accurately calibrated among the unvaccinated? People shift their attitudes to rationalize their choices, so those who choose to be unvaccinated may be motivated to feel less at risk. In three studies (total N = 1446), we asked Americans how worried they were about catching/spreading influenza and COVID-19 and whether they were vaccinated against those diseases. Unvaccinated participants felt less at risk of catching/spreading the diseases they were unvaccinated against than vaccinated participants. For instance, unvaccinated participants felt ∼24% less at risk of catching/spreading COVID-19 and had ∼28% stronger intention to engage in activities that carried a high risk of COVID-19 transmission (Study 3). Overall, those who choose to be the most vulnerable to disease feel and act the least vulnerable.     

Low Reliability of Perceptual Priming: Consequences for the Interpretation of Functional Dissociations Between Explicit and Implicit Memory

In this study, three experiments are presented that investigate the reliability of memory measures. In Experiment 1, the well-known dissociation between explicit (recall, recognition) and implicit memory (picture clarification) as a function of age in a sample of 335 persons aged between 65 and 95 was replicated. Test-retest reliability was significantly lower in implicit than in explicit measures. In Experiment 2, parallel-test reliabilities in a student sample confirmed the finding of Experiment 1. In Experiment 3, the reliability of cued recall and word stem completion was investigated. There were significant priming effects and a dissociation between explicit and implicit memory as a function of levels of processing. However, the reliability of implicit memory measures was again substantially lower than in explicit tests in all test conditions. As a consequence, differential reliabilities of direct and indirect memory tests should be considered as a possible determinant of dissociations between explicit and implicit memory as a function of experimental or quasi-experimental manipulations.     

Incidental sequence learning across the lifespan

The purpose of the present study was to investigate incidental sequence learning across the lifespan. We tested 50 children (aged 7-16), 50 young adults (aged 20-30), and 50 older adults (aged >65) with a sequence learning paradigm that involved both a task and a response sequence. After several blocks of practice, all age groups slowed down when the training sequences were removed, providing indirect evidence for sequence learning. This performance slowing was comparable between groups, indicating no age-related differences. However, when explicit sequence knowledge was considered, age effects were found. For both children and older adults with no or only little explicit knowledge, incidental sequence learning was largely reduced and statistically not significant. In contrast, young adults showed sequence learning irrespective of the amount of explicit knowledge. These results indicate that different learning processes are involved in incidental sequence learning depending on age.     

The bivalency effect: evidence for flexible adjustment of cognitive control

When bivalent stimuli (i.e., stimuli with features for two different tasks) appear occasionally, performance is slower on subsequent univalent stimuli. This "bivalency effect" reflects an adjustment of cognitive control arising from the more demanding context created by bivalent stimuli. So far, it has been investigated only on task switch trials, but not on task repetition trials. Here, we used a paradigm with predictable switches and repetitions on three tasks, with bivalent stimuli occasionally occurring on one task. In three experiments, we found a substantial bivalency effect for all trials with at least one source of conflict. However, this effect was reduced for the repetition trials sharing no features with bivalent stimuli, that is, for those without conflict. This confirms that the bivalency effect reflects an adjustment of cognitive control. The news is that this adjustment of cognitive control is sensitive to the presence of conflict, but neither to its amount nor to its source.     

Time-dependent effects of treadmill exercise on aversive memory and cyclooxygenase pathway function

Exercise induces brain function adaptations and improves learning and memory; however the time window of exercise effects has been poorly investigated. Studies demonstrate an important role for cyclooxygenase-2 (COX-2) pathway function in the mechanisms underlying memory formation. The aim of present work was to investigate the effects of treadmill exercise on aversive memory and COX-2, PGE(2) and E-prostanoid receptors contents in the rat hippocampus at different time points after exercise has ended. Adult male Wistar rats were assigned to non-exercised (sedentary) and exercised (running daily for 20min, for 2weeks) groups. The inhibitory avoidance task was used to assess aversive memory and the COX-2, PGE(2) and E-prostanoid receptors (EP1, EP2, EP3 and EP4) levels were determined 1h, 18h, 3days or 7days after the last training session of treadmill exercise. The step down latency in the inhibitory avoidance, COX-2 and EP4 receptors levels were acutely increased by exercise, with a significant positive correlation between aversive memory performance and COX-2 levels. Increased EP2 content decreased PGE(2) levels were observed 7days after the last running session. The treadmill exercise protocol facilitates inhibitory avoidance memory and induces time-dependent changes on COX-2 pathways function (COX-2, PGE(2) and EP receptors).     

The bivalency effect: adjustment of cognitive control without response set priming

The occasional occurrence of bivalent stimuli, that is, stimuli with features relevant to two tasks, slows performance on subsequent tasks with univalent stimuli, including those which have no common features with bivalent stimuli (i.e., the “bivalency effect”). We have suggested that the bivalency effect might stem from an episodic context binding arising from the occasional occurrence of bivalent stimuli. However, as the same response set is used usually for univalent and bivalent stimuli, bivalent stimulus features may be negatively primed via response features. We investigated this possibility in two experiments, in which one group of participants used the same response keys for all tasks and another group used separate response keys. The results showed a comparable bivalency effect in both groups. Thus, it rather results from episodic context binding than from response set priming.     

Imams in Flanders: A Research Note

This paper presents the results of an exploratory, mixed-method study on imams in Flanders. The research question was mainly who are they?, in an attempt to draw the first picture of their socio-demographic background, ethnicity, functions, and expectations with respect to their position in Flanders, or in Belgium more broadly speaking. The first three sections give context information about Muslims, Islam, and mosques in Belgium and Flanders. In the next sections, the research design and the results are presented. This presentation focuses on four issues: imams as immigrants; their tasks and workload; their job situation and attitude towards official recognition and payment; and finally their ambiguous attitudes towards government initiatives. We give also some reflections in dialogue with research on imams in other Western European countries. The conclusion discusses the challenges for imams and the government to become real partners within the further integration process of the Muslim community in Flanders and Belgium.     

Dealing with laughter and ridicule in adolescence: relations with bullying and emotional responses

We investigated the fear of being laughed at (gelotophobia), the joy in being laughed at (gelotophilia), and the joy in laughing at others (katagelasticism) in adolescent students (N = 324, 13–15 years). Gelotophobia was associated primarily with the victim and katagelasticism with the bully-role (self- and peer reports). Gelotophobia correlated with laughing at oneself if experiencing an embarrassing situation. Gelotophilia increased with the propensity to laugh if observing or experiencing embarrassment; katagelasticism increased with laughing if observing something embarrassing in another person. Imagining potentially embarrassing situations was associated with greater feelings of anxiety, shame, sadness, and embarrassment; gelotophilia with joy and cheerfulness. The study breaks the ground for a better understanding on how adolescent students deal with laughter and ridicule.     

Temporal characteristics of overt attentional behavior during category learning

Many theories of category learning incorporate mechanisms for selective attention, typically implemented as attention weights that change on a trial-by-trial basis. This is because there is relatively little data on within-trial changes in attention. We used eye tracking and mouse tracking as fine-grained measures of attention in three complex visual categorization tasks to investigate temporal patterns in overt attentional behavior within individual categorization decisions. In Experiments 1 and 2, we recorded participants’ eye movements while they performed three different categorization tasks. We extended previous research by demonstrating that not only are participants less likely to fixate irrelevant features, but also, when they do, these fixations are shorter than fixations to relevant features. We also found that participants’ fixation patterns show increasingly consistent temporal patterns. Participants were faster, although no more accurate, when their fixation sequences followed a consistent temporal structure. In Experiment 3, we replicated these findings in a task where participants used mouse movements to uncover features. Overall, we showed that there are important temporal regularities in information sampling during category learning that cannot be accounted for by existing models. These can be used to supplement extant models for richer predictions of how information is attended to during the buildup to a categorization decision.