Reactivation and Consolidation of Memory During Sleep

ABSTRACT— Recent research has shown compellingly that sleep supports the consolidation of declarative memories for events and facts. During consolidation, memories are stabilized against future interference and undergo qualitative changes with regard to their "explicitness" and underlying neural representation. In this article, we argue that declarative memory consolidation during sleep is based on covert reactivations of newly encoded memory traces in the hippocampus. During slow-wave sleep (SWS), the prominent slow oscillations act to synchronize the repeated reactivation of the newly encoded representations in hippocampal networks with the generation of spindle activity in the thalamus, supporting changes in neocortical networks that contribute to long-term memory storage. In this view, sleep plays an active role in the consolidation of memories, in which the neuronal reactivation of newly acquired memories is critical for the redistribution and integration of these memories into the network of pre-existing long-term memories.     

Criterion‐Related Validity of Dutch Police‐Selection Measures and Differences Between Ethnic Groups

This study investigated the criterion‐related validity of cognitive ability as well as non‐cognitive ability measures and differences between ethnic majority (N=2365) and minority applicants (N=682) in Dutch police officer selection. Findings confirmed the relatively low predictive validity of cognitive ability generally found for police jobs. Previous research reported no differential prediction. The present study, however, found small but systematic evidence for differences in validity for the ethnic majority and minority group of both cognitive and non‐cognitive measures. For the minority group, training performance appeared to be mainly predicted by the cognitive ability test. For the majority group, cognitive ability showed very little predictive power. Non‐cognitive ability variables appeared to be somewhat more predictive in this group.     

Examination performance in lecture-discussion and personalized instruction courses

Students enrolled in a Psychology of Learning course were assigned to either a lecture section, one of two similar personalized instruction sections, or a fourth section that rotated across all three teaching procedures. All students took identical midterms and a final examination. After correcting test performance for differences in the cumulative grade point average of students in the four sections, examination performance of students in the personalized sections was found to be superior to that of students in the lecture section. An analysis of class section examination performance by item type revealed that students in the lecture section scored lower on all item types, but the greatest differences occurred on items that required written responses (essay and fill-in items) rather than recognition responses (multiple choice items). A gross analysis of student performance in the class rotated across the instructional procedures suggests that personalized instruction had its greatest impact on students with "average" to "poor" academic records.     

Sleep enhances explicit recollection in recognition memory

Recognition memory is considered to be supported by two different memory processes, i.e., the explicit recollection of information about a previous event and an implicit process of recognition based on an acontextual sense of familiarity. Both types of memory supposedly rely on distinct memory systems. Sleep is known to enhance the consolidation of memories, with the different sleep stages affecting different types of memory. In the present study, we used the process-dissociation procedure to compare the effects of sleep on estimates of explicit (recollection) and implicit (familiarity) memory formation on a word-list discrimination task. Subjects studied two lists of words before a 3-h retention interval of sleep or wakefulness, and recognition was tested afterward. The retention intervals were positioned either in the early night when sleep is dominated by slow-wave sleep (SWS), or in the late night, when sleep is dominated by REM sleep. Sleep enhanced explicit recognition memory, as compared with wakefulness (P < 0.05), whereas familiarity was not affected by sleep. Moreover, explicit recognition was particularly enhanced after sleep in the early-night retention interval, and especially when the words were presented with the same contextual features as during learning, i.e., in the same font (P < 0.05). The data indicate that in a task that allows separating the contribution of explicit and implicit memory, sleep particularly supports explicit memory formation. The mechanism of this effect appears to be linked to SWS.     

Treatment of menopause-related mood disturbances

More than 1.7 million American women are expected to reach menopause each year. Recent Canadian statistics show that a 50-year-old woman can now expect to live until her mid-80s, which implies living at least one-third of her life after menopause. The menopausal transition is typically marked by intense hormonal fluctuations, accompanied by vasomotor symptoms (eg, hot flashes, night sweats), sleeps disturbance, and changes in sexual function, as well as increased risk for osteoporosis, cardiovascular disease, and cognitive decline. More importantly, recent studies have demonstrated a significant association between menopausal transition and a higher risk for developing depression. In the post-Women's Health Initiative Study era, physicians and patients are questioning the safety and efficacy of long-term hormone therapy use. This article reviews the current literature on the benefits and risks of using hormone therapy for the treatment of menopause-related mood disturbances and alternate strategies currently available for the management of menopause-related problems, including antidepressants, complementary and alternative medicine, and selective estrogen receptor modulators.     

Stimulus control acquired by components of two color-form compound stimuli

Four pigeons were trained to respond on one of two keys in the presence of one color-form display, and on the other key when a second color-form display was present. Both responses were maintained on a 2-min variable-internal schedule of reinforcement. Subsequently, stimulus control acquired by components of the compound stimuli was determined by brief test probes in which the colors and forms separately, and in novel combinations, appeared on the display screen. When either color component was present, both choice of response key and response rate were like responding to the training compound display containing that color. When the forms were presented separate from the colors, generally low and comparable rates of responding occurred on both keys.     

The effect of cultural orientation and leadership style on self‐ versus other‐oriented organizational citizenship behaviour in Turkey and the Netherlands

This paper investigated the effects of a paternalistic and empowering leadership style on organizational citizenship behaviour (OCB) in an experimental design using 100 Turkish and 100 Dutch students who held part‐time jobs. Confirming our expectations, a paternalistic leadership style had a more positive effect on job dedication and organizational support in Turkey than in the Netherlands. Contradicting our expectations, an empowering leadership style did not have a more positive effect on any of the OCB dimensions in the Netherlands than it did in Turkey. However, in the Netherlands an empowering leadership style had a stronger effect on interpersonal facilitation, job dedication, and organizational support than a paternalistic leadership style. Paternalistic and empowering leadership styles both had positive effects on OCB dimensions in Turkey. As expected, collectivism moderated the relationship between paternalistic leadership style and other oriented OCB (i.e., interpersonal facilitation). Specifically, people who had more collectivistic tendencies were more positively influenced by a paternalistic leader than people who had low collectivistic tendencies in both countries. However, individualism did not have any moderating effects on the relationship between empowering leadership style and self‐oriented OCB (i.e., job dedication). Our findings are relevant for understanding the effects of leadership styles and cultural orientations on self‐ versus other‐oriented OCB in Turkey and the Netherlands.     

Academic performance differences among ethnic groups: do the daily use and management of time offer explanations?

This explorative study describes time use and time management behaviour of ethnic minority and ethnic majority students as possible explanations for the poorer study results of ethnic minority students compared to those of majority students. We used a diary approach in a small sample to examine students’ daily time use in both a lecture week and an exam week. Time management behaviour was measured in a questionnaire, as were demographic variables. The sample consisted of 48 full-time first-year university students of Business Administration of which 24 students belonged to a non-Western ethnic minority group. Student pairs (ethnic majority vs. non-Western ethnic minority) were fully matched by gender, socio-economic status, living situation and type of secondary education. Results showed that ethnic majority students earned higher grades compared to ethnic minority students. As regards time management behaviour, ethnic majority students appeared to have a stronger preference for organisation (e.g., leaving a clear study space at the end of a study day) than ethnic minority students. No differences between ethnic groups were revealed in setting goals and priorities (e.g., setting deadlines) and mechanics of time management (e.g., making to-do lists). Daily time use also appeared to be the same for both ethnic groups.     

Relating the Spherical representation of vocational interests to the HEXACO personality model

The present study extends previous research on interests–personality relations by comparing recent models of vocational interests (using the Personal Globe Inventory; PGI, Tracey, 2002) and personality (using the HEXACO-PI-R; Ashton, Lee, & de Vries, 2014) with each other. First, the structure of the Spherical representation was adequately replicated in a Dutch sample (N = 656). Second, in so far as comparisons were possible, the relations between interests and personality were found to be congruent with previous findings. Third, Prestige interests, the defining feature of the Spherical representation, were related, albeit weakly, to Openness to Experience and to Extraversion. Last of all, Honesty–Humility and Openness to Experience were related to profile elevation in interest scores. All results were obtained for normative and ipsatized scales, revealing several meaningful differences in interests–personality relations depending on the type of interest scoring procedure.