Something we all learned and have known at some point, but which we often forget when extrapolating from group-based research statistics/parameters to individuals.
Lack of group-to-individual generalizability is a threat to human subjects research. Article link in PNAS.
Aaron J. Fishera, John D. Medaglia and Bertus F. Jeronimus
Only for ergodic processes will inferences based on group-level data generalize to individual experience or behavior. Because human social and psychological processes typically have an in-dividually variable and time-varying nature, they are unlikely to be ergodic. In this paper, six studies with a repeated-measure design were used for symmetric comparisons of interindividual and intraindividual variation. Our results delineate the potential scope and impact of nonergodic data in human subjects research. Analyses across six samples (with 87–94 participants and an equal number of assessments per participant) showed some degree of agreement in central tendency estimates (mean) between groups and individuals across constructs and data collection paradigms. However, the variance around the expected value was two to four times larger within individuals than within groups. This suggests that literatures in social and medical sciences may overestimate the accuracy of aggregated statistical estimates. This observation could have serious consequences for how we understand the con-sistency between group and individual correlations, and the gen-eralizability of conclusions between domains. Researchers should explicitly test for equivalence of processes at the individual and group level across the social and medical sciences.
The current study quantified the degree to which group data are able to describe individual participants. We utilized in-tensive repeated-measures data—data that have been col-lected many times, across many individuals—to compare the distributions of bivariate correlations calculated within subjects vs. those calculated between subjects. Because the vast ma-jority of social and medical science research aggregates across subjects, we aimed to assess how closely such aggregations reflect their constituent individuals. We provide evidence that conclusions drawn from aggregated data may be worryingly imprecise. Specifically, the variance in individuals is up to four times larger than in groups. These data call for a focus on idi-ography and open science that may substantially alter best-practice guidelines in the medical and behavioral sciences.
How Much Does Education Improve Intelligence? A Meta-Analysis. Psychological Science 1 –12. Article link.
Stuart J. Ritchie and Elliot M. Tucker-Drob
Intelligence test scores and educational duration are positively correlated. This correlation could be interpreted in two ways: Students with greater propensity for intelligence go on to complete more education, or a longer education increases intelligence. We meta-analyzed three categories of quasiexperimental studies of educational effects on intelligence: those estimating education-intelligence associations after controlling for earlier intelligence, those using compulsory schooling policy changes as instrumental variables, and those using regression-discontinuity designs on school-entry age cutoffs. Across 142 effect sizes from 42 data sets involving over 600,000 participants, we found consistent evidence for beneficial effects of education on cognitive abilities of approximately 1 to 5 IQ points for an additional year of education. Moderator analyses indicated that the effects persisted across the life span and were present on all broad categories of cognitive ability studied. Education appears to be the most consistent, robust, and durable method yet to be identified for raising intelligence.
The results reported here indicate strong, consistent evidence for effects of education on intelligence. Although the effects—on the order of a few IQ points for a year of education—might be considered small, at the societal level they are potentially of great conse-quence. A crucial next step will be to uncover the mechanisms of these educational effects on intelligence in order to inform educational policy and practice.
Mental rotation and fluid intelligence: A brain potential analysis Intelligence 69 (2018) 146–157. Article link.
Vincenzo Varrialea, Maurits W. van der Molenb, Vilfredo De Pascalis
The current study examined the relation between mental rotation and fluid intelligence using performance measures augmented with brain potential indices. Participants took a Raven's Progressive Matrices Test and performed on a mental rotation task presenting upright and rotated letter stimuli (60°, 120° or 180°) in normal and mirror image requiring a response execution or inhibition depending on instructions. The performance results showed that the linear slope relating performance accuracy, but not speed, to the angular rotation of the stimuli was related to individual differences in fluid intelligence. For upright stimuli, P3 amplitude recorded at frontal and central areas was positively associated with fluid intelligence scores. The mental rotation process was related to a negative shift of the brain potential recorded over the parietal cortex. The linear function relating the amplitude of the rotation-related negativity to rotation angle was associated with fluid intelligence. The slope was more pronounced for high- relative to low-ability participants suggesting that the former flexibly adjust their expenditure of mental effort to the mental rotation demands while the latter ones are less proficient in doing so.
An interesting list and logically based taxonomy in need of empirical validation.
Why Is Working Memory Performance Unstable? A Review of 21 Factors
Rachael N. Blasiman, Christopher A. Wasa
Europe's Journal of Psychology, 2018, Vol. 14(1), 188–231, doi:10.5964/ejop.v14i1.1472
In this paper, we systematically reviewed twenty-one factors that have been shown to either vary with or influence performance on working memory (WM) tasks. Specifically, we review previous work on the influence of intelligence, gender, age, personality, mental illnesses/ medical conditions, dieting, craving, stress/anxiety, emotion/motivation, stereotype threat, temperature, mindfulness training, practice, bilingualism, musical training, altitude/hypoxia, sleep, exercise, diet, psychoactive substances, and brain stimulation on WM performance. In addition to a review of the literature, we suggest several frameworks for classifying these factors, identify shared mechanisms between several variables, and suggest areas requiring further investigation. This review critically examines the breadth of research investigating WM while synthesizing the results across related subfields in psychology.
Visualization, inductive reasoning, and memory span as components of fluid intelligence: Implications for technology education. Article link.
Jeffrey Buckleya, Niall Seerya, Donal Cantyc, Lena Gumaelius
International Journal of Educational Research, 90 (2018) 64–77
The philosophy and epistemology of technology education are relatively unique as the subject largely focusses on acquiring task specific relevant knowledge rather than having an explicit epistemological discipline boundary. Additionally, there is a paucity of intelligence research in technology education. To support research on learning in technology education, this paper describes two studies which aimed to identify cognitive factors which are components of fluid intelligence. The results identify that a synthesis of visualization, short-term memory span and inductive reasoning can account for approximately 28% to 43% of the variance in fluid intelligence. A theoretical rationale for the importance of these factors in technology education is provided with a discussion for their future consideration in cognitive interventions.
Keywords: Emotional intelligence, Training Meta-analysis
A B S T R A C T
Human resource practitioners place value on selecting and training a more emotionally in-telligent workforce. Despite this, research has yet to systematically investigate whether emo-tional intelligence can in fact be trained. This study addresses this question by conducting a meta-analysis to assess the effect of training on emotional intelligence, and whether effects are mod-erated by substantive and methodological moderators. We identified a total of 58 published and unpublished studies that included an emotional intelligence training program using either a pre-post or treatment-control design. We calculated Cohen's d to estimate the effect of formal training on emotional intelligence scores. The results showed a moderate positive effect for training, regardless of design. Effect sizes were larger for published studies than dissertations. Effect sizes were relatively robust over gender of participants, and type of EI measure (ability v. mix-edmodel). Further, our effect sizes are in line with other meta-analytic studies of competency-based training programs. Implications for practice and future research on EI training are discussed.