Transcranial direct current stimulation (tDCS) over parietal cortex improves associative memory.

Associative memory plays a key role in everyday functioning, but it declines with normal ageing as well as due to various pathological states and conditions, thus impairing quality of life. Associative memory enhancement via neurostimulation over frontal areas resulted in limited success, while posterior stimulation sites seemed to be more promising. We hypothesized that anodal transcranial direct current stimulation (tDCS) of parietal areas would lead to higher performance in associative memory due to high connectivity between posterior parietal cortex (PPC) and hippocampus. Forty-two healthy adults participated in two sham-controlled cross-over experiments. Anodal electrode (20 min, 1.5 mA) was placed over P3 in Experiment 1 and over P4 in Experiment 2. During tDCS participants played a simple computer game. After each stimulation session, participants completed parallel forms of an associative memory task (Experiment 1: face-word memory; Experiment 2: object-location memory) and a control task (verbal fluency). In both experiments, associative memory was improved after anodal stimulation compared to sham stimulation, while no differences were observed in the control task. Additionally, memory performance was higher in the second than in the first trial, but the increase in performance between the two trials did not differ between stimulation conditions. It can be concluded that a single-session anodal tDCS over posterior parietal cortex can improve associative memory performance. The specificity, robustness, and reproducibility of the effect suggest that PPC is a promising target for brain stimulation aiming to enhance memory functions.

Does distance from the equator predict self-control? Lessons from the Human Penguin Project.

We comment on the proposition "that lower temperatures and especially greater seasonal variation in temperature call for individuals and societies to adopt … a greater degree of self-control" (Van Lange et al., sect. 3, para. 4) for which we cannot find empirical support in a large data set with data-driven analyses. After providing greater nuance in our theoretical review, we suggest that Van Lange et al. revisit their model with an eye toward the social determinants of self-control.

Data from the Human Penguin Project, a cross-national dataset testing social thermoregulation principles.

In the Human Penguin Project (N = 1755), 15 research groups from 12 countries collected body temperature, demographic variables, social network indices, seven widely-used psychological scales and two newly developed questionnaires (the Social Thermoregulation and Risk Avoidance Questionnaire (STRAQ-1) and the Kama Muta Frequency Scale (KAMF)). They were collected to investigate the relationship between environmental factors (e.g., geographical, climate etc.) and human behaviors, which is a long-standing inquiry in the scientific community. More specifically, the present project was designed to test principles surrounding the idea of social thermoregulation, which posits that social networks help people to regulate their core body temperature. The results showed that all scales in the current project have sufficient to good psychometrical properties. Unlike previous crowdsourced projects, this dataset includes not only the cleaned raw data but also all the validation of questionnaires in 9 different languages, thus providing a valuable resource for psychological scientists who are interested in cross-national, environment-human interaction studies.

Cross-cultural consistency and relativity in the enjoyment of thinking versus doing.

Which is more enjoyable: trying to think enjoyable thoughts or doing everyday solitary activities? Wilson et al. (2014) found that American participants much preferred solitary everyday activities, such as reading or watching TV, to thinking for pleasure. To see whether this preference generalized outside of the United States, we replicated the study with 2,557 participants from 12 sites in 11 countries. The results were consistent in every country: Participants randomly assigned to do something reported significantly greater enjoyment than did participants randomly assigned to think for pleasure. Although we found systematic differences by country in how much participants enjoyed thinking for pleasure, we used a series of nested structural equation models to show that these differences were fully accounted for by country-level variation in 5 individual differences, 4 of which were positively correlated with thinking for pleasure (need for cognition, openness to experience, meditation experience, and initial positive affect) and 1 of which was negatively correlated (reported phone usage). (PsycINFO Database Record (c) 2019 APA, all rights reserved).