Bias and error rates for premorbid IQ estimators: comment on Veiel and Koopman (2001)

H. O. F. Veiel and R. F. Koopman (2001) advance statistical and legal theses. They correctly point out that the usual regression formula for estimating a pre-event IQ underestimates high IQs and overestimates low IQs (due to regression to the mean). They call this a conditional bias and show it can be sizeable. The author takes issue with their claim that a new estimator they propose should be used in place of the usual formulas, because it negates this statistical bias. Their argument against the usual estimator conflates statistical bias and legal bias. Their discussion in favor of their new estimator mentions, but does not derive a general formula for, a gross loss of precision entailed by use of the new estimator. The author quantifies this loss of precision and, using Veiel and Koopman's numerical example, shows that their estimator quadruples error.     

The validity and appropriateness of methods, analyses, and conclusions in Rind et al. (1998): A rebuttal of victimological critique from Ondersma et al. (2001) and Dallam et al. (2001).

The authors respond to 2 victimological critiques of their 1998 meta-analysis on child sexual abuse (CSA). S. J. Dallam et al. (2001) claimed that B. Rind, P. Tromovitch, and R. Bauserman (1998) committed numerous methodological and statistical errors, and often miscoded and misinterpreted data. The authors show all these claims to be invalid. To the contrary, they demonstrate frequent bias in Dallam et al.'s criticisms. S. J. Ondersma et al. (2001) claimed that Rind et al.'s study is part of a backlash against psychotherapists, that its suggestions regarding CSA definitions were extrascientific, and that the moral standard is needed to understand CSA scientifically. The authors show their suggestions to have been scientific and argue that it is Ondersma et al.'s issue-framing and moral standard that are extrascientific. This reply supports the original methods, analyses, recommendations, and conclusions of Rind et al.     

Context,goal, utility,and relevance: A reply to Evans (2002) considering Oaksford (2002)

Yama (2001) argued that the matching bias effect was an amalgam of a genuine matching effect and a set size effect. However, Evans (2002) pointed out some problems with Yama's argument. One was on the matching index used in Yama (2001). The others concerned a gap between Yama's (2001) interpretation of matching bias and Evans' (1998) recent discussions that had placed emphasis on the problem of implicit negation. I reply to these claims taking Oaksford (2002) into consideration. Further, I propose a framework connecting context, goal, utility, and relevance, and including a hierarchical structure of goals. I argue that theories of reasoning can be developed and extended with the framework.     

Expanding variance and the case of historical changes in IQ means: a critique of Dickens and Flynn (2001)

The Flynn effect is the rise in mean IQ scores during the 20th century, amounting to about 0.33 IQ points per year. Many theoretical explanations have been proposed, though none are universally accepted. W. Dickens and J. R. Flynn's (2001) new approach explains the large IQ changes by means of recursive models of IQ growth. A salient feature of their models is that IQ phenotypes and their supportive environments are correlated; in addition, environmental effects can rebound on phenotypic IQ to increase or lower IQ. In this critique, the authors examine an empirical challenge to their models, which typically imply large changes in IQ variance. However, the historical rise in IQ mean level has not been accompanied by substantial variance changes, a finding inconsistent with the properties of the proposed model.     

Single versus multiple systems of category learning: Reply to Nosofsky and Kruschke (2002)

Nosofsky and Kruschke (2002) argued that the singlesystem ALCOVE model (Kruschke, 1992) can account for the dual-task category learning data reported by Waldron and Ashby (2001). In our reply, we argue that Nosofsky and Kruschke overstated the ability of ALCOVE to account for the Waldron and Ashby results. In fact, ALCOVE has difficulty with these data, and we show that the only versions of ALCOVE that actually fit the Waldron and Ashby accuracy data make incorrect predictions about other previously unreported features of that experiment. We also show that the dual-system COVIS model (Ashby, Alfonso-Reese, Turken, & Waldron, 1998) naturally predicts these results.     

Case for Non‐Biased Intelligence Testing Against Black Africans Has Not Been Made: A Comment on Rushton,Skuy, and Bons (2004)

This reply reviews the conceptual, methodological, and statistical foundations of Rushton, Skuy and Bons' article in this journal that compared Black Africans, Whites and East Indians on the Raven's Advanced Progressive Matrices, and concluded that the Raven's is an unbiased test. Through a technical re‐analysis of both the internal and external validity criteria for test bias using data reported in the Rushton et al. paper, we demonstrate that the Raven's Matrices test is in fact biased against Black Africans. We take issue with several additional elements of Rushton et al.'s study, including the use of non‐equivalent groups in test samples. We briefly review Rushton's racial‐realist research agenda and show that the assumption of test bias is central to advancing that agenda. Industrial/organizational and occupational psychologists should critically analyze and re‐evaluate the science employed in Rushton's racial‐realist research and also should better understand the ethical and social implications of accepting his reports of research findings on test bias and White–Black IQ differences as established scientific facts.     

Illusory conjunctions die hard: a reply to Prinzmetal, Diedrichsen, and Ivry (2001).

M. Donk (1999) showed that various data patterns that have been considered as evidence for the existence of illusory conjunctions may be due to errors of target-nontarget confusion, an account that challenges the mere existence of illusory conjunction. In a reply, W. Prinzmetal, J. Diedrichsen, and R. B. Ivry (2001) argued against this conclusion, claiming that some earlier findings can be explained only when one assumes that illusory conjunctions exist. The current article shows that Prinzmetal et al.'s claims cannot refute any of Donk's earlier conclusions, suggesting indeed that one can only conclude that "illusory conjunctions are an illusion."     

The theoretical diagnosis of skepticism

Radical skepticism about the external implies that no belief about the external is even prima facie justified. A theoretical reply to skepticism has four stages. First, show which theories of epistemic justification support skeptical doubts (show which theories, given other reasonable assumptions, entail skepticism). Second, show which theories undermine skeptical doubts (show which theories, given other reasonable assumptions, do not support the skeptic’s conclusion). Third, show which of the latter theories (which non-skeptical theory) is correct, and in so doing show that all of the rival theories of justification, skeptical and non-skeptical alike, are mistaken. Fourth, explain why skeptical doubts are sometimes (or sometimes merely seem) intuitive, and thereby accommodate skeptical doubts without capitulation. Michael Williams has pioneered the very idea of a theoretical reply. A theoretical diagnosis consists in just the first two stages. An adequate reply, which is correct at each stage, would rebut the skeptic entirely. Williams’ own reply, I argue, is inadequate. I offer in its place an exhaustive and accurate diagnosis of skepticism. I distinguish four kinds of skepticism and five theories of justification. I then show which theories do, and which theories do not, support which kinds of skepticism.     

A longitudinal study of sex differences in intelligence at ages 7, 11 and 16 years

This paper presents the results of a longitudinal study of sex differences in intelligence as a test of Lynn’s (1994) hypothesis that from the age of 16 years males develop higher average intelligence than females. The results show that at the ages of 7 and 11 years girls have an IQ advantage of approximately 1 IQ point, but at the age of 16 years this changes in the same boys and girls to an IQ advantage of 1.8 IQ points for boys.     

Expanding the g-nexus: Further evidence regarding the relations among national IQ, religiosity and national health outcomes

The current study seeks to better understand how religiosity and health are positioned within the g-nexus. Specifically, the degree to which differences in average IQ across nations is associated with differences in national religiosity (i.e., belief rate) and national health statistics independent of differences in national wealth is examined. Consistent with expectations, results show that, independent of national wealth and belief rate, IQ has a positive influence on national health as indicated by fertility rate, infant mortality rate, maternal mortality rate, and deaths due to HIV/AIDS, and life expectancy. Additionally, as hypothesized, IQ and belief rate interacted to influence reproductive health (i.e., fertility rate, infant- and maternal mortality). Specifically, high IQ acts as a buffer against the negative effects of belief rate; when IQ is high belief rate has no effect, but when IQ is low belief rate has a strong negative effect. The pattern of findings from this study, combined with previous research, serve to confirm that general cognitive ability (i.e., the g-factor) is an important and central node within a larger nexus of psychological and social variables. Theoretical and epidemiological implications are discussed.     

Grounding, scientific explanation, and Humean laws

It has often been argued that Humean accounts of natural law cannot account for the role played by laws in scientific explanations. Loewer (Philosophical Studies 2012) has offered a new reply to this argument on behalf of Humean accounts—a reply that distinguishes between grounding (which Loewer portrays as underwriting a kind of metaphysical explanation) and scientific explanation. I will argue that Loewer’s reply fails because it cannot accommodate the relation between metaphysical and scientific explanation. This relation also resolves a puzzle about scientific explanation that Hempel and Oppenheim (Philosophy of Science 15:135–75, 1948) encountered.     

Intelligence,gender, and assessment method affect the accuracy of self‐estimated intelligence

Self‐estimates of intelligence (SEI), which influence to what extent people engage in and how well they perform at a task, are subject to distortion. Here, the distortion effects of individual differences in intelligence (IQ), gender, and proximal (with reference to test performance) and distal (with reference to IQ score distributions) assessments of SEI were tested in a sample of 200 British adults. The results showed that (1) people with lower IQ misestimated their SEI to a greater extent than people with high IQ; (2) this effect was more pronounced in distal than proximal measures of SEI; (3) SEI means did not differ significantly across gender but the IQ‐related level of SEI distortion did; (4) this effect was greater for distal than proximal measurement; and (5) proximal SEI were on average less distorted than distal SEI scores and also correlated more closely with IQ. Overall, the findings suggest that the distal SEI assessment method resulted in greater gender‐ and IQ‐related distortions of SEI.     

Puppeteers,hypnotists, and neurosurgeons

Conclusion The objection to R-S accounts that was raised by the possibility of external agents requires the acceptance of two premises, viz., that all R-S accounts allow for puppeteers and that puppeteers necessarily make us unfree. The Metaphilosophical reply shows that to the extent that puppeteers are more problematic than determinism per se, pup-peteers may be explicitly excluded since they violate our paradigm of free will. The Metaphilosophical reply also suggests that we should not expect our mature R-S account to supply logically necessary and sufficient conditions for free will, but rather give us answers that agree with our intuitions regarding paradigms of free and unfree decisions. The Irrelevancy reply completed our reply to incompatibilists who continue to object that determinism per se destroys the R-S program. It may be debated whether my autonomy variable account is a satisfactory way to spell out the Irrelevancy reply, but I think that this type of approach suggests the way to vindicating the R-S view from an important type of objection.     

Are Shunt Revisions Associated with IQ in Congenital Hydrocephalus? A Meta -Analysis

Although it is generally acknowledged that shunt revisions are associated with reductions in cognitive functions in individuals with congenital hydrocephalus, the literature yields mixed results and is inconclusive. The current study used meta-analytic methods to empirically synthesize studies addressing the association of shunt revisions and IQ in individuals with congenital hydrocephalus. Six studies and three in-house datasets yielded 11 independent samples for meta-analysis. Groups representing lower and higher numbers of shunt revisions were coded to generate effect sizes for differences in IQ scores. Mean effect size across studies was statistically significant, but small (Hedges’ g = 0.25, p < 0.001, 95 % CI [0.08, 0.43]) with more shunt revisions associated with lower IQ scores. Results show an association of lower IQ and more shunt revisions of about 3 IQ points, a small effect, but within the error of measurement associated with IQ tests. Although clinical significance of this effect is not clear, results suggest that repeated shunt revisions because of shunt failure is associated with a reduction in cognitive functions.     

Revisiting the constraint attunement hypothesis: reply to Ericsson, Patel, and Kintsch (2000) and Simon and Gobet (2000)

This article is part of an exchange concerning the contributions of the constraint attunement hypothesis (CAH) to the understanding of expertise effects in memory recall. K. A. Ericsson, V. Patel, and W. Kintsch (2000) and H. A. Simon and F. Gobet (2000) claim that the CAH is not novel and that existing theories of this phenomenon do not have the limitations that were attributed to them. In this reply, the CAH is argued to be the only theory of expertise effects in memory recall to adopt the abstraction hierarchy as a theory of the environment, a feature that has important theoretical implications. Also, other theories focus on psychological mechanisms but have not satisfied the burden of scientific proof required of process theories. Progress can be made by integrating the complementary advantages of existing theories into a unified theory that acknowledges the equally important roles of the organism and the environment.     

“Das Ding”: Excessive Existence: Discussion of “Melancholic Psychosis”

Derek Hook’s (this issue) excellent paper provides illustrations of complex Lacanian concepts through the relatively rare presentation of Lacanian case material. His paper lends itself to reading Freud with Lacan. This reply to his paper engages such a reading to show that the idea of the over present object emphasised by Lacan is prefigured in Freud in his 1917 paper on Mourning and Melancholia. My reply to Hook affirms the additional clinical themes he introduces and indicates that these themes would be anticipated if, as Lacan argues, melancholia is seen to be underpinned by a psychotic structure. Finally, the reply argues for a resurrection of the Lacanian notion of Das Ding, as it connotes differently to objet a despite overlaps in meaning and the fact that in later Lacan the term Das Ding was dropped.     

Individual differences,aging, and IQ in two-choice tasks

The effects of aging and IQ on performance were examined in three two-choice tasks: numerosity discrimination, recognition memory, and lexical decision. The experimental data, accuracy, correct and error response times, and response time distributions, were well explained by Ratcliff’s (1978) diffusion model. The components of processing identified by the model were compared across levels of IQ (ranging from 83 to 146) and age (college students, 60–74, and 75–90 year olds). Declines in performance with age were not significantly different for low compared to high IQ subjects. IQ but not age had large effects on the quality of the evidence that was obtained from a stimulus or memory, that is, the evidence upon which decisions were based. Applying the model to individual subjects, the components of processing identified by the model for individuals correlated across tasks. In addition, the model’s predictions and the data were examined for the “worst performance rule”, the finding that age and IQ have larger effects on slower responses than faster responses.     

Skull size and intelligence, and King Robert Bruce's IQ

An estimate of someone's IQ is a potentially informative personal datum. This study examines the association between external skull measurements and IQ scores, and uses the resulting regression equation to provide an estimate of the IQ of King Robert I of Scotland (Robert Bruce, 1274–1329). Participants were 48 relatively healthy Caucasian men (age 71–76 years) resident in Scotland. Using magnetic resonance imaging data, intracranial volume estimated from external skull length and width correlated greater than .5 (p < .001) with measured intracranial area, which correlates very highly with brain volume. IQ scores estimated from the National Adult Reading Test (NART) correlated .56 (p < .001) with measured intracranial area, and .49 (p < .01) with estimated intracranial volume based on external skull width and length. The partial correlation coefficient of this latter association was .25 (p = .09) after adjustment for measured intracranial area. Thus, actual intracranial area accounts for about 74% of the variance shared by NART and estimated intracranial volume. A cast of the skull of Robert Bruce was measured and its intracranial volume estimated. A regression equation between IQ and estimated intracranial volume, based on data from the 48 subjects, estimated the IQ of Robert Bruce at about 128 (95% confidence interval 106 to  130), i.e. almost two standard deviations above the mean. NART scores show a ceiling effect, so this estimated IQ might be an underestimate. Robert Bruce's estimated high IQ is congruent with his military, political and other intellectual achievements.     

A longitudinal study of bilingual and cognitive development(1)

This paper presents the findings of a longitudinal study of IQ data collected over a 5-year period (Grades K-4) on pupils enrolled in a French immersion program (anglophone pupils receiving all instruction in French except English language arts) and pupils in the regular English program. Although year-by-year results may fail to show IQ differences between the two groups, repeated measures analysis indicates that the immersion group has a higher IQ measure over the 5-year period. However, considering Grades 1–3 only, which involved the administration of the same test, the two groups do not score differentially with respect to either overall IQ measure or specific subtest scores (classification/categorization, analogies, following of verbal directions) when scores are adjusted for initial IQ (and age) differences, thus failing initially to support studies which show positive relationships between bilingualism and cognitive functioning. However, supportive of those studies is a further analysis on the data of immersion pupils classified as “high” French achievers vs. “low” French achievers. The high French achievers obtain significantly higher IQ measures and subtest scores (analogies and following of verbal directions) than the low French achievers, even when scores are adjusted for initial IQ and age differences. These findings are interpreted in the context of Cummins' (1976) “threshold” hypothesis relating to level of competence in the second language.     

The determinants of parents' beliefs about the intelligence their children: A study from Hong Kong

One hundred and ninety‐three Hong Kong parents (mean age 42.2 years) were given a structured interview / questionnaire concerning their own and their children's self‐estimated overall and multiple intelligence. Previous research suggested that males tend to give higher overall “g” estimates to their children and themselves than do females, as well as higher scores on mathematical and spatial intelligence (Furnham, 2001). Further, studies in the West suggest that parents think their children are significantly brighter than they are and that their sons are brighter than their daughters. Estimates were lower than those found in Western populations but, even so, males rated their own mathematical and spatial intelligence higher than did females. Hong Kong Chinese parents did not think their sons were brighter than their daughters. The seven multiple intelligences factored into three clear factors for self and children, and regressions indicated that it was “academic” intelligence (verbal, mathematical, spatial) that was most “g” loaded. The child's age and the self‐rated overall IQ of both the parents were the best predictors of the child's overall estimated IQ. Less than a third of the parents had taken an IQ test or believed they measured IQ very well. Those who were more likely to be better educated, had taken an IQ test, and believed intelligence was inherited were more likely to award themselves higher overall IQ scores. Results are compared with the British studies in the same area.