Donnerstag, 28. Februar 2013

Gender Differences in Personality : A Meta-Analysis

Gender Differences in Personality : A Meta-Analysis
A Feingold, 1994


Four meta-analyses were conducted to examine gender differences in personality in the literature (1958-1992) and in normative data for well-known personality inventories (1940-1992). Males were found to be more assertive and had slightly higher self-esteem than females. Females were higher than males in extraversion, anxiety, trust, and, especially, tender-mindedness (e.g., nurturance). There were no noteworthy sex differences in social anxiety, impulsiveness, activity, ideas (e.g., reflectiveness), locus of control, and orderliness. Gender differences in personality traits were generally constant across ages, years of data collection, educational levels, and nations.

Sonntag, 24. Februar 2013

The Adolescent Brain

The Adolescent Brain
B J Casey et al., 2008


Adolescence is a developmental period characterized by suboptimal decisions and actions that are associated with an increased incidence of unintentional injuries, violence, substance abuse, unintended pregnancy, and sexually transmitted diseases. Traditional neurobiological and cognitive explanations for adolescent behavior have failed to account for the nonlinear changes in behavior observed during adolescence, relative to both childhood and adulthood. This review provides a biologically plausible model of the neural mechanisms underlying these nonlinear changes in behavior. We provide evidence from recent human brain imaging and animal studies that there is a heightened responsiveness to incentives and socioemotional contexts during this time, when impulse control is still relatively immature. These findings suggest differential development of bottom-up limbic systems, implicated in incentive and emotional processing, to top-down control systems during adolescence as compared to childhood and adulthood. This developmental pattern may be exacerbated in those adolescents prone to emotional reactivity, increasing the likelihood of poor outcomes.

Approach and Avoidance Temperament as Basic Dimensions of Personality:

Approach and Avoidance Temperament as Basic Dimensions of Personality
E J Elliot and T M Trash, 2010

"A central premise of our work on approach and avoidance temperament is that these constructs not only represent basic elements of personality, but that they represent the core dispositions on which other dispositions rest. The premise was supported by our Study 4 results showing that approach and avoidance temperament could account for the shared variance among the other popular basic constructs, but that the other popular basic constructs could not serve this same role. These data are promising, but we hasten to ad that more research is needed, using additional methodical approaches (e.g., Markon, Krueger, & Watson, 2005), participants from different cultures (e.g., Tsai, Levenson, & McCoy, 2006), and additional dimensional candidates (e.g., Zuckerman, 1991) before any empathetic statements on this issue are warranted."

Samstag, 23. Februar 2013

On Being Eager and Uninhibited: Narcissism and Approach–Avoidance Motivation

On Being Eager and Uninhibited: Narcissism and Approach–Avoidance Motivation
J D Foster and R F Trimm, 2008


This article demonstrates the validity and utility of conceptualizing narcissistic personality in terms of relative approach–avoidance motivation. Across three studies (N = 1,319), narcissism predicted high approach and low avoidance motivation. That is, narcissists reported being strongly motivated to approach desirable outcomes but only weakly motivated to avoid negative outcomes. Relative approach–avoidance motivation was shown to be useful in terms of explaining behavioral tendencies associated with narcissism (i.e., functional and dysfunctional impulsivity) and distinguishing different “flavors” of narcissism (i.e., overt and covert narcissism). Discussion focuses on how approach–avoidance motivation may be used to explain prior findings in the narcissism literature and generate novel future hypotheses.

Cognitive and Sensory Declines in Old Age: Gauging the Evidence for a Common Cause

Cognitive and Sensory Declines in Old Age: Gauging the Evidence for a Common Cause
U Lindenberger et al., 2009


Resource accounts of behavioral aging postulate that age-associated impairments within and across intellectual and sensory domains reflect, in part, a common set of senescent alterations in the neurochemistry and neuroanatomy of the aging brain. Hence, these accounts predict sizeable correlations of between-person differences in rates of decline, both within and across intellectual and sensory domains. The authors examined reliability-adjusted variances and covariances in longitudinal change for 8 cognitive measures and for close visual acuity, distant visual acuity, and hearing in 516 participants in the Berlin Aging Study (ages 70 to 103 years at 1st measurement). Up to 6 longitudinal measurements were distributed over up to 13 years. Individual differences in rates of cognitive decline were highly correlated, with a single factor accounting for 60% of the variance in cognitive change. This amount increased to 65% when controlling for age at first measurement, distance to death, and risk of dementia. Contrary to expectations, the correlations between cognitive and sensory declines were only moderate in size, underscoring the need to delineate both domain-general and function-specific mechanisms of behavioral senescence.

Mittwoch, 20. Februar 2013

Automatic inattention to attractive alternatives: the evolved psychology of relationship maintenance

Automatic inattention to attractive alternatives: the evolved psychology of relationship maintenance
Jon K. Maner et al., 2008


There can be important reproductive benefits to maintaining a long-term romantic relationship. As a result, humans may possess evolved psychological mechanisms designed to help them maintain their commitment to a long-term mate, particularly when faced with attractive alternative relationship partners. The current study identifies a relationship maintenance process that involves being inattentive to alternative relationship partners. Experimentally eliciting thoughts and feelings of romantic love — an emotion thought to have evolved for the purpose of relationship maintenance —reduced attention to alternative partners at an early, automatic stage of visual perception. Consistent with evolutionary models of mate selection, this reduction in attention was observed only for opposite sex targets displaying high levels of physical attractiveness. This research illustrates the utility of integrating evolutionary models of mating with theory and method from cognitive science.

Age differences in personality across the adult life span

Age differences in personality across the adult life span: parallels in five cultures
McCrae RR et al., 1999


Both cross-sectional and longitudinal studies in the United States have shown consistent changes between college age and middle adulthood. There appear to be declines in 3 of the 5 major factors of personality--Neuroticism, Extraversion, and Openness--and increases in Agreeableness and Conscientiousness. To examine cross-cultural generalizability of these findings, translations of the Revised NEO Personality Inventory were administered to samples in Germany, Italy, Portugal, Croatia, and South Korea (N = 7,363). Similar patterns of age differences were seen in each country, for both men and women. Common trends were also seen for the more specific traits that define the major factors. Because these nations differ substantially in culture and recent history, results suggest the hypothesis that these are universal maturational changes in adult personality.

[see also:
Age Differences in Personality Traits From 10 to 65: Big Five Domains and Facets in a Large Cross-Sectional Sample, C J Soto et al., 2011; this paper visualizes the age trends]

Donnerstag, 14. Februar 2013

Are moral virtues attractive?

Sexual selection for moral virtues
Geoffrey F. Miller, 2007

A few points of the paper:

"Research shows that many particular moral virtues are sexually attractive and relationship-stabilizing; these include: [kindness, empathy, niceness, honesty, heroism]; Most of these moral virtue preferences are stronger when seeking a serious long-term partner than a short-term lover."

"All else being equal, virtues should be favored in mate choice. They should be highly valued aspects of potential mates that individuals are motivated not just to judge passively by observation, but to probe actively..."

"One might object that intelligence is not really a moral virtue; it just happens to predict a wide range of specific moral behaviors. Yet, what is a moral virtue if not an individual differences dimension that predicts a wide range of specific moral behaviors? Moral virtues are socially attributed traits that carry predictive information about morally relevant behaviors. If kindness is a moral virtue because it predicts specific prosocial behaviors, and is valued as such, then intelligence must also be a moral virtue, along with being an academic, economic, and epistemological virtue. Another reason for accepting the quasi-moral status of intelligence is the recent convergence between virtue ethics and “virtue epistemology,” the study of cognitive and intellectual virtues (Axtell 2000; Brady and Pritchard 2003; DePaul and Zagzebski 2003). Traditional epistemology tried to evaluate the truth of particular conceptual systems through consistency and coherence criteria. By contrast, for the virtue epistemologist, true beliefs arise from acts of intellectual virtue, those typical of intelligent, rational, cognitively complex agents (Zagzebski 1996) who show impartiality, epistemic responsibility, and intellectual courage (Code 1987; Kvanvig 1992; Montmarquet 1993). For example, Aristotle named intuition, wisdom, prudence, and science as intellectual virtues. In virtue epistemology as in virtue ethics, the favored level of description is the whole individual as a cognitive/moral agent, not the isolated belief or moral act. This naturally leads to an emphasis on individual differences in epistemological virtue, differences that intelligence researchers have already succeeded in measuring with unparalleled reliability and validity for over a century ( Jensen 1998). Thus, intelligence is a sexually attractive, quasimoral trait at the intersection of virtue epistemology and virtue ethics."

Montag, 11. Februar 2013

Birth-Cohort Effects in the Association Between Personality and Fertility:

Birth-Cohort Effects in the Association Between Personality and Fertility
Markus Jokela, 2012


The present study investigated whether associations between individuals’ personality traits and whether they have children have been modified by birth-cohort effects in the 20th-century United States. Participants were from the Midlife Development in the United States study (n = 6,259) and the Wisconsin Longitudinal Study (n = 3,994) and were born between 1914 and 1974. Data on personality traits of the Five Factor model and fertility history were collected in adulthood. Higher levels of openness to experience in both sexes and higher levels of conscientiousness in women were associated with lower fertility, and these associations strengthened linearly as birth cohorts became younger. In the total sample, high extraversion, low neuroticism, and women’s high agreeableness were associated with high fertility rate, but there were no systematic cohort effects. The fertility decisions of people with certain personality traits may be influenced by prevailing societal and cultural circumstances.
[It would be interesting to know how strong these correlations and cohort effects are. ]

Sonntag, 10. Februar 2013

Reading men's faces: women's mate attractiveness judgments track men's testosterone and interest in infants

Reading men's faces: women's mate attractiveness judgments track men's testosterone and interest in infants
James R. Roney et al., 2006

This study investigated whether women track possible cues of paternal and genetic quality in men's faces and then map perception of those cues onto mate attractiveness judgments. Men's testosterone concentrations served as a proxy for genetic quality given evidence that this hormone signals immunocompetence, and men's scores on an interest in infants test were chosen as prima facie markers of paternal quality. Women's perceptions of facial photographs of these men were in fact sensitive to these two variables: men's scores on the interest in infants test significantly predicted women's ratings of the photos for how much the men like children, and men's testosterone concentrations significantly predicted women's ratings of the men's faces for masculinity. Furthermore, men's actual and perceived affinity for children predicted women's long-term mate attractiveness judgments, while men's testosterone and perceived masculinity predicted women's short-term mate attractiveness judgments. These results suggest that women can detect facial cues of men's hormone concentrations and affinity for children, and that women use perception of these cues to form mate attractiveness judgments.

Production and appreciation of humor as sexually selected traits:

Production and appreciation of humor as sexually selected traits
Eric R. Bressler et al., 2006


Both men and women prefer someone with a "good sense of humor" as a relationship partner. However, two recent studies have shown that men are not attracted to funny women, suggesting the sexes use the phrase good sense of humor differently. To investigate this question, we measured the importance participants placed on a partner’s production of humor vs. receptivity to their own humor. Men emphasized the importance of their partners’ receptivity to their own humor, whereas women valued humor production and receptivity equally. In a second task, participants chose whether they preferred a person who only produced humor or a person who only appreciated their own humor for several types of relationships. Women preferred those who produced humor for all types of relationships, whereas men preferred those who were receptive to their own humor, particularly for sexual relationships. Our results suggest that sexual selection may have operated on men’s and women’s preferences during humorous interaction in dramatically different ways.

The ideal romantic partner personality:

The ideal romantic partner personality
Figueredo et al., 2006,%20Sefcek,%20%26%20Jones%202006.pdf


Most contemporary social psychological studies on inter-personal attraction have independently explored the competing concepts of similarity and complementarity. Incorporating evolutionary principles associated with assortative mating, two studies were conducted that examined individual difference preferences using the five-factor model (FFM) of human personality as assessed by the NEO-FFI. The first study ( N = 104) examined the degree to which individuals showed an absolute or relative preference in an ‘‘ideal romantic partner’’ when compared to self-rated personality. The second study ( N = 161) extended this by incorporating personality ratings for self, ‘‘ideal’’ romantic partner, and ‘‘actual’’ romantic partner, and perceptions of mate value for each. Overall, findings supported both evolutionary and social psychological theories of inter-personal attraction and support both relative and absolute preferences in romantic partners. Individuals sought mates that were matches of themselves to some degree (a concept that we termed aspirational positive assortative mating) but also sought mates that were somewhat higher in Conscientiousness, Extraversion, Agreeableness, and Mate Value, but lower in Neuroticism than themselves.

Samstag, 9. Februar 2013

The Third Demographic Transition:

Immigration and Ethnic Change in Low-Fertility Countries: A Third Demographic Transition
David Coleman, 2006

Publications of David Coleman:

Smart Fraction Theory:

"The ability value (intelligence, knowledge and the intelligent use of knowledge) of the smart fraction (95th percentile, comparable to an IQ 125 or higher in within-country norms) is more important for country differences in wealth, nations’ intellectual excellence (in STEM fields: patents, Nobel Prices in science, scientists, high technology exports) and political attributes of societies (government effectiveness, democracy, rule of law and political liberty) than the average ability or the ability level of a non-smart fraction (5th percentile, comparable to an IQ 75 or lower in within-country norms). But the cognitive ability level of the non-smart fraction is more important for country differences in HIV, AIDS and homicide. Wealth differences between countries could be completely explained through differences in high intellectual achievement in STEM fields, which itself largely depends on differences in smart fractions ability. The smart fraction is essentially relevant for beneficial societal development."

H. Rindermann et al., The impact of smart fractions, cognitive ability of politicians and average competence of peoples on social development, 2009

Dienstag, 5. Februar 2013

Age Differences in Sensation Seeking and Impulsivity:

Age Differences in Sensation Seeking and Impulsivity as Indexed by Behavior and Self-Report: Evidence for a Dual Systems Model
Laurence Steinberg et al., 2008


It has been hypothesized that sensation seeking and impulsivity, which are often conflated, in fact develop along different timetables and have different neural underpinnings, and that the difference in their timetables helps account for heightened risk taking during adolescence. In order to test these propositions, the authors examined age differences in sensation seeking and impulsivity in a socioeconomically and ethnically diverse sample of 935 individuals between the ages of 10 and 30, using self-report and behavioral measures of each construct. Consistent with the authors’ predictions, age differences in sensation seeking, which are linked to pubertal maturation, follow a curvilinear pattern, with sensation seeking increasing between 10 and 15 and declining or remaining stable thereafter. In contrast, age differences in impulsivity, which are unrelated to puberty, follow a linear pattern, with impulsivity declining steadily from age 10 on. Heightened vulnerability to risk taking in middle adolescence may be due to the combination of relatively higher inclinations to seek excitement and relatively immature capacities for self-control that are typical of this period of development.

[Poor impulse control and an intense need for excitement are also two key symptoms of psychopathy.]

Score gains on g-loaded tests: No g

Score gains on g-loaded tests: No g
Jan de Nijenhuis et al., 2006


IQ scores provide the best general predictor of success in education, job training, and work. However, there are many ways in which IQ scores can be increased, for instance by means of retesting or participation in learning potential training programs. What is the nature of these score gains? Jensen [Jensen, A.R. (1998a). The g factor: The science of mental ability. London: Praeger] argued that the effects of cognitive interventions on abilities can be explained in terms of Carroll's three-stratum hierarchical factor model. We tested his hypothesis using test–retest data from various Dutch, British, and American IQ test batteries combined into a meta-analysis and learning potential data from South Africa using Raven's Progressive Matrices. The meta-analysis of 64 testretest studies using IQ batteries (total N=26,990) yielded a correlation between g loadings and score gains of 1.00, meaning there is no g saturation in score gains. The learning potential study showed that: (1) the correlation between score gains and the g loadedness of item scores is .39, (2) the g loadedness of item scores decreases after a mediated intervention training, and (3) low g participants increased their scores more than high-g participants. So, our results support Jensen's hypothesis. The generalizability of test scores resides predominantly in the g component, while the test-specific ability component and the narrow ability component are virtually non-generalizable. As the score gains are not related to g, the generalizable g component decreases and, as it is not unlikely that the training itself is not g-loaded, it is easy to understand why the score gains did not generalize to scores on other cognitive tests and to g-loaded external criteria. 

The rise and fall of the Flynn Effect

"From the present perspective, the Flynn Effect (the secular rise in IQ) is not a Jensen Effect (because it does not occur on g)."
J. P. Rushton & Arthur R. Jensen, 2009

The rise and fall of the Flynn effect as a reason to expect a narrowing of the Black-White IQ-gap: J. Philippe Rushton, Arthur R. Jensen; 2009

see also:
Secular gains in IQ not related to the g factor and inbreeding depression - unlike Black - White differences: A reply to Flynn; J.P. Rushton; 1999

Montag, 4. Februar 2013

Jensen's critical thoughts on IQ-tests:

>If there's anything on which my judgment has changed significantly since 1969, it is the scientific value of typical IQ tests. Psychological tests are limited by the fact that they do not provide absolute scales, that is, those that have a true zero point and equal intervals throughout their range. As is well known in the physical sciences, the mathematical, and not just statistical, analysis of data is much greater with measurements based on absolute, or ratio-property scales. These are virtually absent in the psychological measurement. There's no doubt, however, that IQ tests and many other conventional psychological tests have real practical value. They are unquestionably valid predictors of certain kinds of performance in education and employment, and can be most useful in education selection, and in hiring and promotion decision.<

Intelligence, Race and Genetics - Conversations with Arthur R. Jensen, Frank Miele  (2002)

g and job performance:

g has greater predictive validity for job performance of all kinds than any particular aptitude, although the prediction of job performance in any particular occupation can be significantly improved by taking certain special aptitudes into account, in addition to g. Certain aptitudes are completely irrelevant to success in certain jobs, but there is practically no job for which g is wholly irrelevant. Jobs differ in their g demands just as tests do, and highly g-loaded tests, such as standard intelligence tests and scholastic aptitude tests, are the best predictors of performance in g-demanding jobs. These are the jobs that cannot be routinized and require thinking, judgment, planning, assimilating new information, and making decisions on the basis of complex and changing conditions. Such demands are most typically found in highly skilled technical and professional occupations and in high-level managerial and executive positions. Persons who are low in g, therefore, are virtually excluded from such jobs. The educational requirements for many such highly g-demanding jobs usually screen out persons of below-average intelligence, because secondary and higher education are themselves quite g-demanding.

Arthur Jensen, Straight Talk About Mental Tests, 1981

[g is the technical term for general intelligence. Howard Gardner is a very prominent member of the anti-g-lobby. It would be very interesting to deeply analyze this anti-g-lobby (especially the motivations of Howard Gardner and others, why they are ignoring the facts, etc.). ... Sometimes it seems as if the 20th century was the century of the "anti-movements".]

Hominid Brain Evolution:

Hominid Brain Evolution - Testing Climatic, Ecological, and Social Competition Models
Drew H. Bailey, David C. Geary; 2009,%20Human%20Nature%5D.pdf


Hypotheses regarding the selective pressures driving the threefold increase in the size of the hominid brain since Homo habilis include climatic conditions, ecological demands, and social competition. We provide a multivariate analysis that enables the simultaneous assessment of variables representing each of these potential selective forces. Data were collated for latitude, prevalence of harmful parasites, mean annual temperature, and variation in annual temperature for the location of 175 hominid crania dating from 1.9 million to 10 thousand years ago. We also included a proxy for population density and two indexes of paleoclimatic variability for the time at which each cranium was discovered. Results revealed independent contributions of population density, variation in paleoclimate, and temperature variation to the prediction of change in hominid cranial capacity (CC). Although the effects of paleoclimatic variability and temperature variation provide support for climatic hypotheses, the proxy for population density predicted more unique variance in CC than all other variables. The pattern suggests multiple pressures drove hominid brain evolution and that the core selective force was social competition.

[see also: Ecological dominance, social competition, and coalitionary arms races: Why humans evolved extraordinary intelligence; Mark V. Flinn et al.; 2005 or papers of Robin Dunbar on "the social brain hypothesis" or papers of R.D. Alexander on Human Evolution.]

Sonntag, 3. Februar 2013

Vocabulary and Intelligence:

>[The] concepts represented by some words are too complex, abstract, or subtle for some people to infer from any context or to fully understand even when the word is fully defined. A person may look up the definition in the dictionary and might even memorize it verbatim; but unless the meaning of the word is grasped at a deeper, nonverbal conceptual level, it does not become a part of his functional vocabulary. It is remarkable how hard it is to retain such words - the memorized definition soon fades beyond retrieval. And even if the memorized definition is provided again, the person's lack of conceptual grasp of the word's meaning is shown by his inability to express the meaning adequately in words other than those of the memorized definition. There is a very high correlation between the subtlety with which people understand the meaning of words, and the sheer number of different words whose meaning they can recognize in any sense. Thus, vocabulary or word knowledge is a good indicator of g, provided, of course, that the test words are not too narrowly selected from specialized areas of learning.<

Arthur Jensen, Straight Talk About Mental Tests, 1981

Working memory and intelligence are highly related constructs, but why?

Working memory and intelligence are highly related constructs, but why?
Roberto Colom et al., 2008


Working memory and the general factor of intelligence (g) are highly related constructs. However, we still don't know why. Some models support the central role of simple short-term storage, whereas others appeal to executive functions like the control of attention. Nevertheless, the available empirical evidence does not suffice to get an answer, presumably because relevant measures are frequently considered in isolation. To overcome this problem, here we consider concurrently simple short-term storage, mental speed, updating, and the control of attention along with working memory and intelligence measures, across three separate studies. Several diverse measures are administered to a total of 661 participants. The findings are consistent with the view that simple short-term storage largely accounts for the relationship between working memory and intelligence. Mental speed, updating, and the control of attention are not consistently related to working memory, and they are not genuinely associated with intelligence once the short-term storage component is removed.

Working memory is (almost) perfectly predicted by g

Working memory is (almost) perfectly predicted by g
Roberto Colom et al., 2004

"The central factor in the human-abilities model is g, not fluid intelligence, spatial visualization, spatial relations, or perceptual speed, while the central factor in the theories of human information processing is WM (Jensen, 1998; Lohman, 2000). An adequate representation of psychometric g requires a number and variety of tests (Jensen & Weng, 1994) . The only two studies relating WM with g are the ones performed by Ackerman et al. (2002) and Sueb et al. (2002). The former study found a correlation of .70 between WM and g, while the later study found a correlation of .38 between spatial WM and g, and of .58 between verbal-quantitative WM and g. However, these two studies did not test the predictive power of g over WM and against other first-order latent factors. CFA models are informative with respect to the predictive power of g over WM. Considering the three reported studies in the present article, the loading of g over the WM latent factor averages .96. Therefore, WM is (almost) perfectly predicted by g (92% of explained variance)."

Samstag, 2. Februar 2013

Astrology Beliefs among Undergraduate Students:

Astrology Beliefs among Undergraduate Students
Hannah Sugarman et al., 2011

A survey of the science knowledge and attitudes toward science of nearly 10000 undergraduates at a large public university over a 20-year period included several questions addressing student beliefs in astrology and other forms of pseudoscience. The results from our data reveal that a large majority of students (78%) [!] considered astrology “very” or “sort of” scientific. Only 52% [!!] of science majors said that astrology is “not at all” scientific. We find that students’ science literacy, as defined by the National Science Foundation in its surveys of the general public, does not strongly correlate with an understanding that astrology is pseudoscientific, and therefore belief in astrology is likely not a valid indicator of scientific illiteracy.

Breadth and Altitude of Intellect:

>The American psychologist Edward L. Thorndike (1874-1949) described two aspects of intellect: breadth and altitude.
Breadth is measured by how many different things a person knows that are relatively easy to know; that is they are not highly complex, abstruse, esoteric, or profound. There are many words, for excample, that are known by about 50 percent of the general population. Therefore they are fairly common and simple words. The number of such words that a person knows is an indication of his mental breadth. The same goes for items of general information. There are great individual differences in the "breadth of intellect" as so measured.
Altitude is measured by the most difficult and complex problems a person can solve, or the most difficult words in a vocabulary test or the most difficult general information questions he can get right. A test item's difficulty is indexed by the percentage of the standardization population that fails the item. So items can be ranked in difficulty, from very difficult items that are failed by more than 99 percent of the population to very easy items that are failed by fewer than 1 percent. The average of the most difficult items in several types of tests that a person can pass is an indication of that person's alititude. There are great individual differences in "altitude of intellect" just as in "breadth of intellect".
But the really interesting fact discovered by Thorndike is that measures of individual differences in breadth and altitude are allmost perfectly correlated. That is, these two seemingly different aspects of mental ability are both indices of one and the same general ability, or g. People who know rare or difficult things or can solve very complex problems also generally know a lot more than do most people of the rather ordinary kinds of words and facts that many people know. Persons with poor reasoning and problem-solving ability also possess much less common knowledge about the world around them. Brighter persons automatically pick up more information from any experience afforded by their environment.
I recall once interviewing a young man who tested out as borderline retarded, in the range of IQ 75, to get some idea of his fund of general information. I decided to begin by trying to find out how much he knéw about whatever topic he claimed to have the greatest interest in and to know the most about. It was baseball. He frequently went to baseball games with his father or watched them on television, and found them very exciting. Yet when I questioned him about baseball, I discovered that he didn't know for sure how many players are on a team, couldn't name all the positions on the team, and had only vague and at times incorrect notions of the rules of the game. He knew the names of three or four players on the local team but didn't know any of the world's most famous players or even the names of any of the Big League teams. When I probed other topics in which he claimed an interest - automobiles and gardening - I found that he possessed even less information about these than about baseball. It was evident that his quite low score on the General Information subtest of the Wechsler Adult Intelligence Scale, on which I had tested him, gave an accurate assessment of his level of general knowledge of the world around him. On the other hand, just out of curiosity, I later put the same baseball questions to a learned professor who, I happend to know, had no interest in any sport whatever. He even had positive disdain for spectator sports and claimed never to have seen a baseball game in his life. Yet he had no trouble answering the several baseball questions I asked him, and could name three Big League teams and several famous baseball players. Interestingly, he was quite surprised to discover that he knew anything at all about baseball and seemed puzzled as to where he could have learned facts about something he cared nothing about. But conversations with him revealed that he knew a great deal about a great many things, in science, literature, the arts, economics, politics, and world affairs. In his own field he is an acknowledged world authority.
These striking differences that are so obvious between the extremes of the IQ scale exist in smaller degrees between less extreme IQ differences. But when the differences are fairly small - less than 10 points or so - they cannot be dependably recognized by casual observation. Without very carefully designed tests we cannot reliably discriminate between the g levels of persons whose IQs are within ten or so points of each other. Within that range, the more obvious differences between persons involve their special talents, developed skills, interests, personal experiences, and educational backgrounds. The ordinarily observed differences between persons, then, are a poor basis for subjective judgments about differences in intelligence or g. In general, however, someone who knows a lot about something is more intelligent than one who doesn't know much about anything.<
Arthur Jensen, Straight Talk About Mental Tests, 1981

[Jensen wrote this book for the general public. Allthough old it seems to be a very readable, generally intelligible introduction to intelligence.]

Freitag, 1. Februar 2013

High Intelligence:

>In all, it appears that highly intelligent individuals identify and apprehend bits of social and ecological information more easily and quickly than do other people, and their perceptual systems process this information such that it is activated in short-term memory more quickly and with greater accuracy than it is for other people. Once active in short-term memory, the information is made available for conscious, explicit representation and manipulation in working memory. Central characteristics of highly intelligent people are their ability to represent more information in working memory than other people and their enhanced ability to consciously manipulate this information. The manipulation in turn is guided and constrained by... reasoning and inference-making mechanisms... . Finally gF is associated with the ability to learn new information (Ackermann, 1986, 1988). When high fluid intelligence and strong long-term memory system is combined with an interest in seeking novel experiences, the result is the aquisition of a large store of crytallized knowledge, gC, over the life span (Bates & Shieles, 2003; Cattell, 1963; Horn, 1968; Li et al., 2004).<
David C. Geary, The Origin of Mind, 2005

Storage capacity explains fluid intelligence but executice control does not:

Storage capacity explains fluid intelligence but executice control does not
Adam Chuderski et al., 2012

"The present study has supported the theories of fluid intelligence assuming that the crucial cognitive mechanism underlying fluid ability lies in storage capacity, which enables people to actively maintain distinct chunks of information and flexibly construct task-relevant bindings among them. In the two large-scale psychometric studies reported in this paper, storage capacity accounted for on average 70% of variance in fluid intelligence. On the contrary, no support has been found for the theories looking for the mechanisms responsible for intelligence in the domain of effectiveness of executive control. The measures of control were either not significantly related to fluid ability, as in the case of interference resolution and response inhibition, or fully depended on individual storage capacity, as in the case of attention control."

Faster, smarter?

Faster, smarter? Working memory capacity and perceptual speed in relation to fluid intelligence
T. Rehdick, N. Unsworth, A. Kelly, R. Engle; 2012

[This study shows no correlation between working memory capacity and perceptual  speed.]