Letters in 2018

Pryor et al. show that people conform to social norms, even when they understand that the norms have been determined arbitrarily and do not reflect people’s actual preferences. Prominent, rationality-based explanations of norm effects cannot explain these results.

Michelmann and colleagues investigated how humans search for information in episodic memory. Using MEG, the authors show fast, forward-directed memory replay, with speed changing flexibly depending on the task.

A new study by Keynan and colleagues provides evidence that training in amygdala self-regulation via EEG neurofeedback (‘electrical fingerprint’) results in neurobehavioural markers of stress resilience in a cohort of individuals undergoing military training.

Randomly informing people that they had a high or low genetic risk of obesity changed their gene-related physiology and subjective experience in a manner consistent with the perceived risk, regardless of their actual genetic risk of obesity.

Analysing the results from four major sports leagues and a multiplayer online game reveals that prior shared success as a team significantly improves the odds of winning beyond what is explained by the skill of individual players.

A century after being predicted by theory, the authors detect and quantify the genomic signature of assortative mating in ~400,000 contemporary human genomes, and report new genetic evidence for assortative mating on height and educational attainment.

When searching for rewards in complex, unfamiliar environments, it is often impossible to explore all options. Wu et al. show how a combination of generalization and optimistic sampling guides efficient human exploration in complex environments.

Bentz et al. estimate the phylogenetic signals of environmental factors and population size on more than 6,000 phylogenetic trees of 46 language families and find that environment influences the evolution of language families beyond neutral drift.

Kahn et al. show that learners capitalize on higher-order topological properties when they learn a probabilistic motor sequence based on a network traversal.

Analyses of transactions in a new monetary system (Sardex community currency) reveal that transaction cycles increase in prevalence over time and that economic activity within these cycles is higher compared to linear transactions through the network.

Reputational concerns reinforce the instinct to cooperate in social situations. McAuliffe et al. find that cooperative habits can be overturned in one-shot anonymous interactions, when people learn that defection will not damage their self-interest.

Having too many choices can lead to choice overload. Reutskaja et al. find that brain activity in striatum and anterior cingulate reflects subjects’ engagement in decision making as a function of choice set size and can serve as an indicator of choice overload.

A five-arm trial with 228,000 participants found that a single mailed letter increased absolute influenza vaccination rates in individuals ≥66 years of age by about 1%. The framing of the letter made no significant difference to the outcome.

Despite being a major cultural group, Arabs are relatively neglected in cultural psychology. Going beyond the prevailing East versus West paradigm, this paper suggests that a unique form of interdependence that is self-assertive typifies Arab culture.

Analyses of data from 211 independent, randomized controlled trials (N = 16,198,595) show that second-order normative beliefs—community members’ belief that saving energy helps the environment—play a critical role in promoting energy conservation.

Siegel et al. describe an asymmetric Bayesian updating mechanism for moral impression formation, which shows that beliefs about badly behaved agents are more uncertain and therefore more flexible than beliefs about well-behaved agents.

Gerlach and colleagues harness the power of big data to address the question of whether individuals can be reliably classified into personality types and how many types exist. The authors identify four different personality types, which surface across data sets.

Thomas and colleagues show that toddlers preferred a puppet that had won a conflict against another puppet—but only when it won without using force. This suggests that toddlers consider social status when making social evaluations.

In a compound climate change dilemma that allows some to earn a pre-game advantage, advantaged participants act prosocially later to maintain a public good, but the disadvantaged act antisocially, creating conflict that reduces cooperative success.

People differ in how they cope with task complexity and time constraints. Eldar et al. use magnetoencephalography to show that these differences can be explained by the temporal organization of a neural information integration process.