The Structure of Temperament and Personality Traits: A Developmental Perspective

In this chapter, we articulate a developmental perspective on personality traits from early childhood through adulthood. In the first section, we address two topics that are fundamental in defining the most important traits at each point in the life span: the relationship between temperament and personality and the methods used to ascertain the structure of traits in the temperament and personality research traditions. We argue in this section that temperament and personality are different ways of describing the same basic traits, with temperament research primarily focused on early-emerging individual differences and personality research focused on individual differences that appear later in childhood and continue into adulthood. In the second section, we describe the current status of the most prominent models of temperament, as well as the most widely-accepted personality trait model, the Big Five. In the third section, we articulate a structural model that integrates contemporary findings on temperament and personality traits from early childhood through adulthood. We use the Big Five trait structure, along with the trait of activity level, to organize this taxonomy. In the fourth section, we discuss the current research on the psychological and biological processes that underlie individual differences in the Big Five traits in childhood and adulthood. In the final sections, we offer concluding thoughts on the nature of personality trait development and suggestions for future research. This is an exciting time in the study of personality in part because of the marked progress in uncovering the basic structure of traits across the lifespan.

Working memory and attention in choice.

We study the role of attention and working memory in choices where options are presented sequentially rather than simultaneously. We build a model where a costly attention effort is chosen, which can vary over time. Evidence is accumulated proportionally to this effort and the utility of the reward. Crucially, the evidence accumulated decays over time. Optimal attention allocation maximizes expected utility from final choice; the optimal solution takes the decay into account, so attention is preferentially devoted to later times; but convexity of the flow attention cost prevents it from being concentrated near the end. We test this model with a choice experiment where participants observe sequentially two options. In our data the option presented first is, everything else being equal, significantly less likely to be chosen. This recency effect has a natural explanation with appropriate parameter values in our model of leaky evidence accumulation, where the decline is stronger for the option observed first. Analysis of choice, response time and brain imaging data provide support for the model. Working memory plays an essential role. The recency bias is stronger for participants with weaker performance in working memory tasks. Also activity in parietal areas, coding the stored value in working, declines over time as predicted

Gender Differences in Personality across the Ten Aspects of the Big Five

This paper investigates gender differences in personality traits, both at the level of the Big Five and at the sublevel of two aspects within each Big Five domain. Replicating previous findings, women reported higher Big Five Extraversion, Agreeableness, and Neuroticism scores than men. However, more extensive gender differences were found at the level of the aspects, with significant gender differences appearing in both aspects of every Big Five trait. For Extraversion, Openness, and Conscientiousness, the gender differences were found to diverge at the aspect level, rendering them either small or undetectable at the Big Five level. These findings clarify the nature of gender differences in personality and highlight the utility of measuring personality at the aspect level

Imagination as a facet of Openness/Intellect: A new scale differentiating experiential simulation and conceptual innovation

30 pagesPrevious research has investigated the nature of imagination as a construct related to multiple forms of higher-order cognition. Despite the emergence of various conceptualizations of imagination, few attempts have been made to explore the structure of imagination as a trait in the context of existing hierarchically-nested personality dimensions. We present a scale for measuring trait imagination that distinguishes between experiential simulation and conceptual innovation, aligned with the two major subfactors (aspects) of the Big Five dimension Openness/Intellect. Across two large samples, we provide evidence of a consistent factor structure distinguishing experiential, conceptual, and general descriptions of imagination, as well as validity as measures of facets of Openness and Intellect. Our findings provide a measure of major forms of imagination in line with mainstream models of the hierarchical structure of personality

Personality Is Reflected in the Brain's Intrinsic Functional Architecture

Personality describes persistent human behavioral responses to broad classes of environmental stimuli. Investigating how personality traits are reflected in the brain's functional architecture is challenging, in part due to the difficulty of designing appropriate task probes. Resting-state functional connectivity (RSFC) can detect intrinsic activation patterns without relying on any specific task. Here we use RSFC to investigate the neural correlates of the five-factor personality domains. Based on seed regions placed within two cognitive and affective ‘hubs’ in the brain—the anterior cingulate and precuneus—each domain of personality predicted RSFC with a unique pattern of brain regions. These patterns corresponded with functional subdivisions responsible for cognitive and affective processing such as motivation, empathy and future-oriented thinking. Neuroticism and Extraversion, the two most widely studied of the five constructs, predicted connectivity between seed regions and the dorsomedial prefrontal cortex and lateral paralimbic regions, respectively. These areas are associated with emotional regulation, self-evaluation and reward, consistent with the trait qualities. Personality traits were mostly associated with functional connections that were inconsistently present across participants. This suggests that although a fundamental, core functional architecture is preserved across individuals, variable connections outside of that core encompass the inter-individual differences in personality that motivate diverse responses

Developing a Personality Model for Speech-based Conversational Agents Using the Psycholexical Approach

We present the first systematic analysis of personality dimensions developed specifically to describe the personality of speech-based conversational agents. Following the psycholexical approach from psychology, we first report on a new multi-method approach to collect potentially descriptive adjectives from 1) a free description task in an online survey (228 unique descriptors), 2) an interaction task in the lab (176 unique descriptors), and 3) a text analysis of 30,000 online reviews of conversational agents (Alexa, Google Assistant, Cortana) (383 unique descriptors). We aggregate the results into a set of 349 adjectives, which are then rated by 744 people in an online survey. A factor analysis reveals that the commonly used Big Five model for human personality does not adequately describe agent personality. As an initial step to developing a personality model, we propose alternative dimensions and discuss implications for the design of agent personalities, personality-aware personalisation, and future research.Comment: 14 pages, 2 figures, 3 tables, CHI'2

Male-Mediated Gene Flow in Patrilocal Primates

BACKGROUND: Many group-living species display strong sex biases in dispersal tendencies. However, gene flow mediated by apparently philopatric sex may still occur and potentially alters population structure. In our closest living evolutionary relatives, dispersal of adult males seems to be precluded by high levels of territoriality between males of different groups in chimpanzees, and has only been observed once in bonobos. Still, male-mediated gene flow might occur through rare events such as extra-group matings leading to extra-group paternity (EGP) and female secondary dispersal with offspring, but the extent of this gene flow has not yet been assessed. METHODOLOGY/PRINCIPAL FINDINGS: Using autosomal microsatellite genotyping of samples from multiple groups of wild western chimpanzees (Pan troglodytes verus) and bonobos (Pan paniscus), we found low genetic differentiation among groups for both males and females. Characterization of Y-chromosome microsatellites revealed levels of genetic differentiation between groups in bonobos almost as high as those reported previously in eastern chimpanzees, but lower levels of differentiation in western chimpanzees. By using simulations to evaluate the patterns of Y-chromosomal variation expected under realistic assumptions of group size, mutation rate and reproductive skew, we demonstrate that the observed presence of multiple and highly divergent Y-haplotypes within western chimpanzee and bonobo groups is best explained by successful male-mediated gene flow. CONCLUSIONS/SIGNIFICANCE: The similarity of inferred rates of male-mediated gene flow and published rates of EGP in western chimpanzees suggests this is the most likely mechanism of male-mediated gene flow in this subspecies. In bonobos more data are needed to refine the estimated rate of gene flow. Our findings suggest that dispersal patterns in these closely related species, and particularly for the chimpanzee subspecies, are more variable than previously appreciated. This is consistent with growing recognition of extensive behavioral variation in chimpanzees and bonobos

Genome sequencing and population genomic analyses provide insights into the adaptive landscape of silver birch

Silver birch (Betula pendula) is a pioneer boreal tree that can be induced to flower within 1 year. Its rapid life cycle, small (440-Mb) genome, and advanced germplasm resources make birch an attractive model for forest biotechnology. We assembled and chromosomally anchored the nuclear genome of an inbred B. pendula individual. Gene duplicates from the paleohexaploid event were enriched for transcriptional regulation, whereas tandem duplicates were overrepresented by environmental responses. Population resequencing of 80 individuals showed effective population size crashes at major points of climatic upheaval. Selective sweeps were enriched among polyploid duplicates encoding key developmental and physiological triggering functions, suggesting that local adaptation has tuned the timing of and cross-talk between fundamental plant processes. Variation around the tightly-linked light response genes PHYC and FRS10 correlated with latitude and longitude and temperature, and with precipitation for PHYC. Similar associations characterized the growth-promoting cytokinin response regulator ARR1, and the wood development genes KAK and MED5A.Peer reviewe