Timing the “magical number seven”: Presentation rate and regularity affect verbal working memory performance

The informative value of time and temporal structure often remains neglected in cognitive assessments. However, next to information about stimulus identity we can exploit temporal ordering principles, such as regularity, periodicity, or grouping to generate predictions about the timing of future events. Such predictions may improve cognitive performance by optimising adaptation to dynamic stimuli. Here, we investigated the influence of temporal structure on verbal working memory by assessing immediate recall performance for aurally presented digit sequences (forward digit span) as a function of standard (1000 ms stimulus-onset-asynchronies, SOAs), short (700 ms), long (1300 ms) and mixed (700–1300 ms) stimulus timing during the presentation phase. Participant's digit spans were lower for short and mixed SOA presentation relative to standard SOAs. This confirms an impact of temporal structure on the classic “magical number seven,” suggesting that working memory performance can in part be regulated through the systematic application of temporal ordering principles.     

Transport and mobility decisions of consumers with disabilities

People with disabilities are the world's largest minority stakeholder group, and they continue to face significant challenges in every aspect of their lives. This study explored the transport and mobility decisions of consumers with disabilities (CWDs) in the context of Nigeria, one of the world's largest developing countries, using the conservation of resources theory and the intersection of travel decisions, disability and country context regarding consumer behaviour. A total of 32 individuals with varying disabilities were interviewed. A thematic analysis of qualitative data revealed that CWDs make travel decisions based on their ability, as well as the availability, accessibility, affordability and reliability of different modes of transport. This study presents a conceptual framework illustrating the transport and mobility decisions of CWDs and highlights practical implications for various stakeholders.     

Personality traits,money attitudes and consumer decision-making styles as predictors of investment products choice in South Africa

This study examines how personality traits and money attitudes influence consumers' decision-making styles when purchasing investment products in South Africa. A sample of 269 South Africans completed the research questionnaire, which assessed their extraversion, conscientiousness, openness, money power/prestige, money retention/time, money quality, info-mising, extending, and tax-free investment purchase decision. Also, confirmatory factor analysis and structural equation modelling approaches were used to analyze the survey data. The results suggest that personality traits and money attitudes significantly impact consumer decision-making regarding tax-free investment products. However, the relationships between extraversion and money power/prestige and between info-mising decision styles and tax-tree investment purchase decisions were found to be negative. Cluster analysis revealed three distinct segments based on the characteristics of respondents and their drive for investment: strong conscientiousness investors, status-driven investors, and introverted investors. Marketing professionals and investment firms can use the study findings on consumer traits and money attitudes to improve marketing effectiveness in an organisation. Practically, extensive information processing has a fundamental bearing on investment decision-making in emerging markets. Extraversion and conscientiousness personality traits and money attitudes must be taken into consideration by investment products marketers and practitioners in marketing practice.     

Causal Attributions for Poorly Performing Projects: Their Effect on Project Continuation Decisions

This study examined the escalation problem within an attribution theory framework. Students read a case scenario containing causal attribution information that described a poorly performing project under their supervision. They made estimates of its future success, as well as a decision whether to continue it. Perceived stability of causality had the primary effect on expectancy of success. A project whose performance downturn was attributed to a stable cause had a lower expectancy. Locus of causality had a smaller but still significant effect. Project downturns attributed to internal causes had a lower expectancy. Expectancy of success was significantly correlated with project continuation decisions. Discrepancies between these results and those reported by Staw and Ross (1978) are accounted for in terms of Weiner's (1985, 1986) attributional analysis.     

Expectations about stimulus structure in implicit learning

In two experiments, artificial grammar learning was used to create learning tasks of identical symbolic complexity that differed in terms of the instructions and the appearance of the stimuli. In Experiment 1, the stimuli were letter strings that appeared in either upper- or lowercase; however, letter case was irrelevant to the learning task. Participants were unable to take into account the instruction to ignore letter case. In Experiment 2, the stimuli were sequences of cities that corresponded to the routes of a traveling salesman. It was assumed that participants would adopt the expectation that the salesman would prefer short journeys. When the structure of the stimuli was inconsistent with this expectation, performance on the learning task was inhibited. The results suggest that there are circumstances in which explicit expectations about the structure of a set of stimuli can affect implicit learning of the stimuli.     

Changes in the neuropsychological correlates of clinical dimensions between the acute and stable phase of schizophrenia

This study was designed to investigate whether the neuropsychological correlates of the symptom dimensions of schizophrenia vary with the clinical state in patients followed from the acute to stable the phase of the illness. Fifteen patients were assessed for symptoms (SAPS-SANS) and undergone a complete neuropsychological assessment at two sessions. The first session (S1) was carried out within six days after admission, i.e., acute phase and the second (S2) at least two month after hospitalization, i.e., stable phase. The data were analyzed using stepwise regression models in which neuropsychological scores were in entered to predict each dimensional score. This analysis was applied on the S1 and S2 data as well as on the S2-S1 difference to assess the neuropsychological predictors of clinical changes. Generally, the results replicate the previous associations between neuropsychological and dimensional measures found in stable patients. In addition, this study shows if each dimension appears to rely on a key structure, symptom variations seems to involve changes in the spread of the dysfunction and/or changes in the connectivity between the key and other regions. The results also suggest that functional changes related to some symptoms dimensions occur to compensate for the dysfunction associated with other symptoms.     

The paradox of quetiapine in obsessive-compulsive disorder

Schizophrenia and obsessive-compulsive disorder (OCD) have historical, clinical, and epidemiological links. The clinical use of atypical neuroleptics (ie, dual serotonin-dopamine antagonists) to treat both conditions sheds a new light on them. We report the first two cases of obsessive-compulsive symptoms (OCS) induced by quetiapine in schizophrenia patients. A case of successful augmentation by quetiapine in refractory OCD is also presented. A review of the literature on OCS induced by atypical neuroleptics follows. This paradoxically induced OCD symptomology in schizophrenia patients administered atypical neuroleptics is discussed from new pathophysiological and clinical perspectives. The discussion emphasizes the prognostic implications of OCS in schizophrenia and available therapies for this comorbidity.     

Intra-basolateral amygdala infusions of AP-5 impair or enhance retention of inhibitory avoidance depending on training conditions

Previous evidence has suggested that N-methyl-D-aspartate receptors (NMDARs) in the basolateral amygdala (BLA) are critically involved in the acquisition of aversively based learning tasks. However, the role of NMDARs in the BLA in the consolidation of memory of aversive training has not been well elucidated. In the present study, the NMDAR antagonist AP-5 (1 or 3 microg) was infused into the BLA of male Sprague-Dawley rats immediately before, immediately after, or 6h after training on an inhibitory avoidance task with either a high footshock (HFS; only high dose of AP-5 given) or a low footshock (LFS; both doses of AP-5 given). The 48 h retention of animals given AP-5 (3 microg) immediately before or after HFS training was significantly impaired compared to that of vehicle-controls. In contrast, the retention of rats given AP-5 (3 microg) immediately after LFS training was significantly enhanced compared to that of vehicle-controls. AP-5 (3 microg) infusions administered 6h after training with either an HFS or LFS did not affect retention. These findings suggest that the NMDARs in the BLA are involved in both the acquisition and consolidation of aversive memory. In addition, the AP-5-induced enhancement of memory obtained with LFS training suggests that NMDARs in the BLA are involved in other mechanisms influencing synaptic transmission, in addition to their well-established role in neuroplasticity.     

ERP study of pre-attentive auditory processing in treatment-refractory schizophrenia

Event-related potential (ERP) studies have demonstrated impaired auditory sensory processing in patients with schizophrenia, as reflected in abnormal mismatch negativity (MMN). We sought to extend this finding by evaluating MMN in 13 treatment-refractory patients with schizophrenia, and 14 age- and gender-matched healthy controls. Subjects responded to infrequent visual stimulation while ignoring binaurally presented auditory tones. The amplitude and topographical pattern of the MMN were analyzed. The control group presented the expected reduction in the amplitude of the MMN from frontal to central and parietal locations. In comparison, the MMN amplitude was not reduced in the treatment-refractory patients, and was largest at the central-posterior electrode location. In addition, patients displayed larger negativities at left frontal, and left- and right-temporal electrode locations than the control subjects. These findings are consistent with pre-attentive abnormalities in treatment-refractory patients with schizophrenia.     

Preservation of autobiographical memory in a case of pure progressive amnesia

G.D., a 79 year-old female, presents with a severe and slowly progressive amnesia although she remains entirely independent in daily life and is perfectly well spatially oriented. Her amnesia is relatively isolated and her deficit does not embrace other cognitive domains. G.D. underwent extensive neuropsychological evaluation including language, executive functions, perceptual, and memory tests. Based on clinical observation, the purpose of this study was to determine whether there was a dissociation between her autobiographical and semantic memory. Results point out a severely degraded semantic knowledge of famous public events and persons while autobiographical memory of personally experienced and relevant information remains intact. Results from this study and from previous studies seem to suggest that relative sparing of hippocampal structures may be related to the preservation of autobiographical memory.