Showing papers by "Jüri Allik published in 2012"

Meta-analysis of genome-wide association studies for personality

Abstract: Personality can be thought of as a set of characteristics that influence people's thoughts, feelings and behavior across a variety of settings. Variation in personality is predictive of many outcomes in life, including mental health. Here we report on a meta-analysis of genome-wide association (GWA) data for personality in 10 discovery samples (17 375 adults) and five in silico replication samples (3294 adults). All participants were of European ancestry. Personality scores for Neuroticism, Extraversion, Openness to Experience, Agreeableness and Conscientiousness were based on the NEO Five-Factor Inventory. Genotype data of similar to 2.4M single-nucleotide polymorphisms (SNPs; directly typed and imputed using HapMap data) were available. In the discovery samples, classical association analyses were performed under an additive model followed by meta-analysis using the weighted inverse variance method. Results showed genome-wide significance for Openness to Experience near the RASA1 gene on 5q14.3 (rs1477268 and rs2032794, P = 2.8 x 10(-8) and 3.1 x 10(-8)) and for Conscientiousness in the brain-expressed KATNAL2 gene on 18q21.1 (rs2576037, P = 4.9 x 10(-8)). We further conducted a gene-based test that confirmed the association of KATNAL2 to Conscientiousness. In silico replication did not, however, show significant associations of the top SNPs with Openness and Conscientiousness, although the direction of effect of the KATNAL2 SNP on Conscientiousness was consistent in all replication samples. Larger scale GWA studies and alternative approaches are required for confirmation of KATNAL2 as a novel gene affecting Conscientiousness. Molecular Psychiatry (2012) 17, 337-349; doi: 10.1038/mp.2010.128; published online 21 December 2010

Stereotypes of age differences in personality traits: universal and accurate?

Abstract: Age trajectories for personality traits are known to be similar across cultures. To address whether stereotypes of age groups reflect these age-related changes in personality, we asked participants in 26 countries (N = 3,323) to rate typical adolescents, adults, and old persons in their own country. Raters across nations tended to share similar beliefs about different age groups; adolescents were seen as impulsive, rebellious, undisciplined, preferring excitement and novelty, whereas old people were consistently considered lower on impulsivity, activity, antagonism, and Openness. These consensual age group stereotypes correlated strongly with published age differences on the five major dimensions of personality and most of 30 specific traits, using as criteria of accuracy both self-reports and observer ratings, different survey methodologies, and data from up to 50 nations. However, personal stereotypes were considerably less accurate, and consensual stereotypes tended to exaggerate differences across age groups.

Factors affecting bibliometric indicators of scientific quality

Abstract: The High Quality Science Index (HQSI) was constructed on the basis of the release of the Essential Science Indicators (Thomson Reuters) for the period from January 1, 2002 to August 31, 2012. The HQSI was computed for a country or territory as a sum of normalised scores of the mean impact (citations per paper) and the percentage of papers that reach the top-1% citation ranking. Expectedly, countries or territories that are producing larger Gross National Income per capita and allocate higher percentage of the produced economic wealth for the research and development (R&D) were more likely to achieve prominence in the scientific publications. The size of the country and its population were not important factors to excel in scientific research. Since economic and socio-demographic factors only partly predicted the quality of science in a given country or territory, there is considerable space for historical and science policy factors that could affect the quality of science in a given country. Several countries being in almost identical starting positions twenty years ago have developed on completely different trajectories dependent on policies and decisions made by their policy makers. Possibilities of how to improve reliability of measures of scientific quality have been discussed.

Links between self-reported and laboratory behavioral impulsivity.

Abstract: Havik, M., Jakobson, A., Tamm, M., Paaver, M., Konstabel, K., Uusberg, A., Allik, J., Oopik, V. & Kreegipuu, K. (2012). Links between self-reported and laboratory behavioral impulsivity. Scandinavian Journal of Psychology 53, 216–223. A major problem in the research considering impulsivity is the lack of mutual understanding on how to measure and define impulsivity. Our study examined the relationship between self-reported impulsivity, behavioral excitatory and inhibitory processes and time perception. Impulsivity – fast, premature, thoughtless or disinhibited behavior – was assessed in 58 normal, healthy participants (30 men, mean age 21.9 years). Self-reported impulsivity as measured by Adaptive and Maladaptive Impulsivity Scale (AMIS) and behavioral excitatory and inhibitory processes as measured by Stop Signal Task were not directly related. Time perception, measured by the retrospective Time Estimation Task, was related to both. The length of the perceived time interval was positively correlated to AMIS Disinhibition subscale and negatively to several Stop Signal Task parameters. The longer subjects perceived the duration to last, the higher was their score on Disinhibition scale and the faster were their reactive responses in the Stop Signal Task. In summary our findings support the idea of cognitive tempo as a possible mechanism underlying impulsive behavior.

Relationship Between Linguistic Antonyms in Momentary and Retrospective Ratings of Happiness and Sadness

Abstract: Momentary ratings of affective states with a pair of strict antonyms ("happy" vs. "sad") were studied with an experience- sampling method in a group of 110 participants during 14 consecutive days at 7 randomly determined occasions per day. Before and after the experimental session participants also retrospectively rated how happy or sad they had been during the previous 2 weeks. Multilevel analysis showed that, at the level of single measurement trials, the momentary ratings of happiness and sadness were moderately negatively correlated (r = -.32, p < .001). A between-subject correlation of the two antonyms, however, was in a positive direction (r = .13, p = .123). Participants experienced mixed feelings during a considerable number of measurement trials, whereas the tendency to feel mixed emotions was predicted by all Big Five personality traits except Agreeableness. A configural frequency analysis (CFA) demonstrated that, although there was no strict bipolarity between momentary ratings of happiness and sadness, they were nevertheless used in an exclusive manner in many occasions.

Personality and Culture Cross-Cultural Psychology at the Next Crossroads

Abstract: A review of nearly three decades of cross-cultural research shows that this domain still has to address several issues regarding the biases of data collection and sampling methods, the lack of clear and consensual definitions of constructs and variables, and measurement invariance issues that seriously limit the comparability of results across cultures. Indeed, a large majority of the existing studies are still based on the anthropological model, which compares two cultures and mainly uses convenience samples of university students. This paper stresses the need to incorporate a larger variety of regions and cultures in the research designs, the necessity to theorize and identify a larger set of variables in order to describe a human environment, and the importance of overcoming methodological weaknesses to improve the comparability of measurement results. Cross-cultural psychology is at the next crossroads in it’s development, and researchers can certainly make major contributions to this domain if they c...

Person-Fit to the Five Factor Model of Personality

Abstract: The Five Factor Model (FFM), a valid model of interindividual differences in the personality of a group of people, reportedly does not always provide a good fit for the individuals of that group. In addition to intraindividual variation across a considerable period of time, meaningful intraindividual variation can be observed within a single test administration. Two person-fit indices showed that the FFM is an adequate model for 95% of the 1,765 target-judge pairs in four different countries (Belgium, the Czech Republic, Estonia, and Germany): the double-entry intraclass correlation (ICCDE), which indicated that the 30 NEO PI-R scores on scales measuring the same personality trait are more similar and certainly less different than scores measuring different traits, and the individual contribution to the extracted eigenvalues (Zeig). The individual response pattern to the personality questionnaire characterized by the ICCDE and Zeig strongly determined the percentage of explained variance for the group-level factor structure of interindividual differences and the mean self-ob- server profile agreement. We demonstrate that, if the percentage of variance explained by the first five principal components is high enough, the FFM also provides an adequate fit at the individual level for most people.

Visibility versus accountability in pooling local motion signals into global motion direction.

Abstract: The human observer is surprisingly inaccurate in discriminating proportions between two spatially overlapping sets of randomly distributed elements moving in opposite directions. It was shown that observers took into account an equivalent of 74 % of all moving elements when the task was to estimate their relative number, but only an equivalent of 21 % of the same elements when the task was to discriminate between opposite directions. It was concluded that, in the motion direction discrimination task, a large proportion of the signal from all of the elements was inaccessible to the observers, whereas the majority of the signal was accessible in a numerosity task. This type of perceptual limitation belongs to the attentional blindness category, where a strong sensory signal cannot be noticed when processing is diverted by parallel events. In addition, we found no evidence for the common-fate principle, as the ability to discriminate numerical proportions remained the same, irrespective of whether all estimated elements were moving coherently in one direction or unpredictably in opposite directions.

A new approach for assessment of mental architecture: repeated tagging.

Abstract: A new approach to the study of a relatively neglected property of mental architecture—whether and when the already-processed elements are separated from the to-be-processed elements—is proposed. The process of numerical proportion discrimination between two sets of elements defined either by color or by orientation can be described as sampling with or without replacement (characterized by binomial or hypergeometric probability distributions respectively) depending on the possibility to tag an element once or repeatedly. All empirical psychometric functions were approximated by a theoretical model showing that the ability to keep track of the already tagged elements is not an inflexible part of the mental architecture but rather an individually variable strategy which also depends on conspicuity of perceptual attributes. Strong evidence is provided that in a considerable number of trials, observers tagged the same element repeatedly which can only be done serially at two separate time moments.

Cross-Cultural Psychology at the Next Crossroads

Abstract: A review of nearly three decades of cross-cultural research shows that this domain still has to address several issues regarding the biases of data collection and sampling methods, the lack of clear and consensual definitions of constructs and variables, and mea- surement invariance issues that seriously limit the comparability of results across cultures. Indeed, a large majority of the existing studies are still based on the anthropological model, which compares two cultures and mainly uses convenience samples of university students. This paper stresses the need to incorporate a larger variety of regions and cultures in the research designs, the necessity to theorize and identify a larger set of variables in order to describe a human environment, and the importance of overcoming methodological weaknesses to improve the comparability of measurement results. Cross-cultural psychology is at the next crossroads in it's development, and re- searchers can certainly make major contributions to this domain if they can address these weaknesses and challenges.