The university participant pool is a key resource for behavioral research, and data quality is believed to vary over the course of the academic semester. This crowdsourced project examined time of semester variation in 10 known effects, 10 individual differences, and 3 data quality indicators over the course of the academic semester in 20 participant pools (N = 2,696) and with an online sample (N = 737). Weak time of semester effects were observed on data quality indicators, participant sex, and a few individual differences-conscientiousness, mood, and stress. However, there was little evidence for time of semester qualifying experimental or correlational effects. The generality of this evidence is unknown because only a subset of the tested effects demonstrated evidence for the original result in the whole sample. Mean characteristics of pool samples change slightly during the semester, but these data suggest that those changes are mostly irrelevant for detecting effects. Word count = 151Keywords: social psychology; cognitive psychology; replication; participant pool; individual differences; sampling effects; situational effects 4 Many Labs 3: Evaluating participant pool quality across the academic semester via replication University participant pools provide access to participants for a great deal of published behavioral research. The typical participant pool consists of undergraduates enrolled in introductory psychology courses that require students to complete some number of experiments over the course of the academic semester. Common variations might include using other courses to recruit participants or making study participation an option for extra credit rather than a pedagogical requirement. Research-intensive universities often have a highly organized participant pool with a participant management system for signing up for studies and assigning credit. Smaller or teaching-oriented institutions often have more informal participant pools that are organized ad hoc each semester or for an individual class.To avoid selection bias based on study content, most participant pools have procedures to avoid disclosing the content or purpose of individual studies during the sign-up process.However, students are usually free to choose the time during the semester that they sign up to complete the studies. This may introduce a selection bias in which data collection on different dates occurs with different kinds of participants, or in different situational circumstances (e.g., the carefree semester beginning versus the exam-stressed semester end).If participant characteristics differ across time during the academic semester, then the results of studies may be moderated by the time at which data collection occurs. Indeed, among behavioral researchers there are widespread intuitions, superstitions, and anecdotes about the "best" time to collect data in order to minimize error and maximize power. It is common, for example, to hear stories of an effect being obtained in the first part of the semester that then "d...

Many Labs 3 is a crowdsourced project that systematically evaluated time-of-semester effects across many participant pools. See the Wiki for a table of contents of files and to download the manuscript.

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the use of cognitive words in narratives of negative events and the association with the meaning-making process were examined. Cognitive word use, a past predictor of beneficial outcomes from the expressive writing intervention, was related to the process of meaning making in Study 1. this finding was true for memories that lacked psychological closure. in Study 2, we replicated the finding that cognitive word use is related to the meaning-making process using an alternative measure of meaning making. however, cognitive word use was not found to be related to the outcome of meaning making. the extent to which participants were engaged in meaning-making was negatively related to narrative coherence. these results suggest that the meaning-making process may be a precursor to achieving narrative coherence. Additionally, participants randomly assigned to expressive writing instructions engaged in the meaning-making process to a greater extent than participants asked to simply describe their negative event, suggesting that expressive writing encourages the meaning-making process.

Trait self-control is related to a number of positive outcomes, including mental health, interpersonal success, academic success and health-related behaviours. This study sought to explore the relationships between self-control, reports of mental and physical health symptoms and coping styles. The results revealed that higher self-control was related to fewer mental and physical health symptoms and less avoidance coping. There was not a significant relationship between self-control and problem-focused or emotion-focused coping styles. Further, the relationships between self-control and mental and physical health outcomes were partially mediated by avoidance coping style. Specifically, the data suggest lower self-control is associated with unhealthy coping strategies (avoidance coping), which in turn are associated with worse mental health outcomes and greater reports of physical health symptoms. Thus lower trait self-control can serve as an indicator, suggesting circumstances in which individuals' tendencies to engage in unhealthy coping strategies are increased. These findings add to a growing body of literature underscoring the importance of trait self-control.

To qualify for a diagnosis of posttraumatic stress disorder (PTSD), the Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV) requires that individuals report experiencing dominant emotions of fear, helplessness, and horror during the trauma (Criterion A2). Despite this stipulation, traumatic events can elicit a myriad of emotions other than fear, such as anger, guilt or shame, sadness, and numbing. The present study examined which emotional reactions to a stressful event in a college student sample are associated with the highest levels of PTSD symptoms. Our results suggest mixed support for the DSM-IV criteria. Although, participants who experienced a dominant emotion of fear reported relatively high PTSD symptomatology, participants who experience danger, disgust-related emotions, and sadness reported PTSD symptoms of equivalent severity. Additionally, participants reported dominant emotions of sadness and other emotions (including disgust, guilt, and shame) more frequently than they reported fear. These results question the specifics of diagnostic Criterion A2 and may have diagnostic and treatment implications.

Summary Poor sleep quality has been demonstrated to diminish cognitive performance, impair psychosocial functioning and alter the perception of stress. At present, however, there is little understanding of how sleep quality affects emotion processing. The aim of the present study was to determine the extent to which sleep quality, measured through the Pittsburg Sleep Quality Index, influences affective symptoms as well as the interaction between stress and performance on an emotional memory test and sustained attention task. To that end, 154 undergraduate students (mean age: 21.27 years, standard deviation = 4.03) completed a series of measures, including the Pittsburg Sleep Quality Index, the Sustained Attention to Response Task, an emotion picture recognition task and affective symptom questionnaires following either a control or physical stress manipulation, the cold pressor test. As sleep quality and psychosocial functioning differ among chronotypes, we also included chronotype and time of day as variables of interest to ensure that the effects of sleep quality on the emotional and non‐emotional tasks were not attributed to these related factors. We found that poor sleep quality is related to greater depressive symptoms, anxiety and mood disturbances. While an overall relationship between global Pittsburg Sleep Quality Index score and emotion and attention measures was not supported, poor sleep quality, as an independent component, was associated with better memory for negative stimuli and a deficit in sustained attention to non‐emotional stimuli. Importantly, these effects were not sensitive to stress, chronotype or time of day. Combined, these results suggest that individuals with poor sleep quality show an increase in affective symptomatology as well as a negative cognitive bias with a concomitant decrease in sustained attention to non‐emotional stimuli.

Stressful or traumatic events have been shown to impair cognitive functioning on laboratory-based tasks due to stress-related intrusive thoughts and avoidance. However, research on the effects of stress on everyday cognitive functioning has been lacking. A sample of 909 undergraduates completed measures of perceived stress, PTSD symptoms, and everyday cognitive failures. The results revealed that both perceived stress and PTSD symptoms uniquely predicted cognitive failures, even after controlling for a number of potentially confounding variables. Additionally, there was a significant interaction. Participants with low scores on both measures of stress reported the fewest occurrences of everyday cognitive failures. In contrast, participants with elevated scores on either measure of stress reported higher levels of cognitive failures. These results suggest that there are unique negative effects of perceived stress and PTSD symptoms on everyday cognitive functioning and sharpen our understanding of the relationship between stress and cognition.