DOCSLIB.ORG

A Single G Factor Is Not Necessary to Simulate Positive Correlations Between Cognitive Tests

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
A Single G Factor Is Not Necessary to Simulate Positive Correlations Between Cognitive Tests Journal of Clinical and Experimental Neuropsychology ISSN: 1380-3395 (Print) 1744-411X (Online) Journal homepage: http://www.tandfonline.com/loi/ncen20 A single g factor is not necessary to simulate positive correlations between cognitive tests Dennis J. McFarland To cite this article: Dennis J. McFarland (2012) A single g factor is not necessary to simulate positive correlations between cognitive tests, Journal of Clinical and Experimental Neuropsychology, 34:4, 378-384, DOI: 10.1080/13803395.2011.645018 To link to this article: http://dx.doi.org/10.1080/13803395.2011.645018 Published online: 20 Jan 2012. Submit your article to this journal Article views: 218 View related articles Citing articles: 2 View citing articles Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=ncen20 Download by: [Tufts University] Date: 28 September 2016, At: 08:05 JOURNAL OF CLINICAL AND EXPERIMENTAL NEUROPSYCHOLOGY 2012, 34 (4), 378–384 A single g factor is not necessary to simulate positive correlations between cognitive tests Dennis J. McFarland Laboratory of Neural Injury and Repair, Wadsworth Center, New York State Department of Health, Albany, NY, USA In the area of abilities testing, one issue of continued dissent is whether abilities are best conceptualized as man- ifestations of a single underlying general factor or as reflecting the combination of multiple traits that may be dissociable. The fact that diverse cognitive tests tend to be positively correlated has been taken as evidence for a single general ability or “g” factor. In the present study, simulations of test performance were run to evaluate the hypothesis that multiple independent abilities that affect test performance in a consistent manner will produce a positive manifold. Correlation matrices were simulated from models using either one or eight independent factors. The extent to which these factors operated in a consistent manner across tests (i.e., that a factor that facilitates performance on one test tends to facilitate performance on other tests) was manipulated by varying the mean value of the randomly selected weights. The tendency of both a single factor and eight independent factors to produce positive correlations increased as the randomly selected weights operated in a more consistent fashion. Thus the presence of a positive manifold in the correlations between diverse cognitive tests does not provide differential support for either single factor or multiple factor models of general abilities. Keywords: Abilities; Simulation; Positive manifold. Currently one of the principal arguments for the cognitive abilities may be antithetical to the mod- construct of general intelligence, or g, is the fact ular approach taken by most neuropsychologists that a matrix of correlations between diverse cog- (Anderson, 2005). There have been attempts at inte- nitive tests can be described as a positive mani- gration. For example, it has been suggested that the fold (Carroll, 1993; Molenaar, Dolan, Wicherts, & construct of psychometric intelligence is associated van der Maas, 2010; Murphy, Dzieweczynski, & with the frontal lobes (Duncan, 2005). However this Zhang, 2009; Spearman, 1904). That is, correla- view contrasts with the description of frontal lobe tions between tests of abilities tend to be positive. function as fractionated (Stuss & Levine, 2002). This positive manifold is generally thought to result Thus, the notion of a single general factor is at odds from the operation of a common factor that influ- with the view of specific dissociable abilities that is ences performance on all tests of mental abilities. common in neuropsychology. Alternative viewpoints hold that intelligence is best There have been recent attempts to explain the described as multiple independent abilities (e.g., positive manifold without recourse to g. Van der Gardner, 1983; Guilford, 1972). However, in a sur- Maas et al. (2006) suggest that the positive manifold vey of opinions, Reeve and Charles (2008) found could result from multiple independent cognitive that there seems to be a general consensus among abilities that become correlated through a process experts that g is a valid construct. of mutualism. Mutualism is described as a process The construct of a general factor accounting of positive beneficial interactions between cogni- for a large portion of the variance in tests of tive factors during development. Van der Maas I thank Loretta S. Malta for her helpful discussions and comments on this manuscript. Address correspondence to Dennis J. McFarland, Wadsworth Center, New York State Dept. of Health, P. O. Box 509, Empire State Plaza, Albany, New York 12201-0509, USA (E-mail: [email protected]). © 2012 Psychology Press, an imprint of the Taylor & Francis Group, an Informa business http://www.psypress.com/jcen http://dx.doi.org/10.1080/13803395.2011.645018 SIMULATION OF A POSITIVE MANIFOLD 379 et al. (2006) demonstrate how this might occur could be obtained from a set of uncorrelated abili- by means of simulated test scores. Bartholomew, ties with weights that were continuous rather than Deary, and Lawn (2009) discuss a bonds model binary. derived from a proposal originally suggested by The bonds model is a specific case of a more Thompson (1920) as a competing explanation for general condition in which individual differences Spearman’s (1904) observations. The bonds model affect performance in a relatively consistent man- posits multiple factors that are sampled by any ner across cognitive tasks. Given that a factor has given test score. Bartholomew (2007) showed that a relatively consistent effect across a set of tests, the Spearman (1904) and Thompson (1920) models its mean weight across tests will differ from zero. are statistically indistinguishable. In contrast, if the values of the weights associated A feature of the bonds model is that each of the with a specific ability in W had a mean of zero and independent factors (bonds) contribute to all test some standard deviation σ , then larger values of a scores in the same way; that is, because a bond has a would be expected to decrease performance on a weight of either 0 or 1, if a bond affects test scores, it given test as often as they increased performance. will always do so in a positive manner. Specifically, In this case, abilities would not operate in a consis- Bartholomew (2007) expressed this bonds model as tent manner across tests (i.e., across tests, a given ability would decrease performance as often as it t = Wa (1) improved performance). In practice, it can be dif- ficult to test this hypothesis without knowing the where t is a vector of test scores, W is a matrix of true extent to which individual differences affect coefficients that describe whether a given bond has performance. Simulation studies can fill this knowl- been sampled by a given test, and a is a vector of edge gap, because the effects of a factor or factors random values that describe individual differences on test performance can be systematically manip- in these bonds. (The notation has been changed ulated by varying the mean value of the factor but the model is identical to that discussed by weights. Bartholomew, 2007.) Thus, if sampled by test i, Sternberg (1979) describes two major approaches larger values of ai, the variable describing individ- that have emerged in the study of mental abili- ual differences, always produce larger values of ti, ties. The differential approach has primarily studied the variable representing test scores. If the proba- relationships between patterns of test scores within bility of a bond being included on the ith test is p, individuals, principally by means of factor analysis. then the mean value of the weights in W is equal The information-processing approach has primar- to p and thus varies between 0 and 1. As a result, if ily varied attributes of cognitive tasks, focusing a bond affects a test score, it is always in a positive on task attributes rather than subject attributes. manner, and thus the bonds model holds that indi- Simulations of cognitive performance have been vidual differences operate in a consistent manner employed by the information-processing approach. across tasks—that is, a bond will not have a negative Simulation has not been a favored method of the effect on performance. differential approach. However, simulation is a use- While the bonds model represents a case where ful form of modeling that has shown great utility in a positive manifold can be produced without the modeling complex and otherwise intractable prob- need to postulate a general factor, it is a highly lems in physics (Rohrlich, 1990). It well might also specific case since it assumes weighting on any prove useful in the biological and social sciences, given task of either 0 or 1. The notion that a spe- including differential psychology. cific ability has equivalent effects on all tasks that Hence, the present study used simulations to it influences is unlikely to be the case in prac- examine the general conditions whereby a positive tice. This assumption is not made in research on manifold could result from multiple uncorrelated models of abilities, which generally estimate the latent abilities. The hypothesis is that a positive weighing of each factor separately and find that manifold results when these multiple abilities oper- the resulting estimates are not equal as would ate in a relatively consistent manner across diverse be predicted by the bonds model (e.g., Tulsky & tasks. For example, we would expect an ability such Price, 2003). Furthermore, it is entirely possible as freedom from distraction to facilitate perfor- that in some cases a given ability might actually be mance on most cognitive tests. While it might be associated with poorer performance. Thus, a more more important for some cognitive tasks than oth- general model that allows for a continuum of fac- ers, in general, freedom from distraction should tor weights on different tests would have greater not have detrimental affects on test performance.
Load more

Recommended publications
  • A History of Intelligence Assessment: the Unfinished Tapestry
    From Contemporary Intellectual Assessment: Theories, Tests, and Issues, Third Edition. Edited by Dawn P. Flanagan and Patti L. Harrison. Copyright 2012 by The Guilford Press. All rights reserved. CHAPTER 1 A History of Intelligence Assessment The Unfinished Tapestry John D. Wasserman When our intelligence scales have become more accurate and the laws governing IQ changes have been more definitively established it will then be possible to say that there is nothing about an individual as important as his IQ, except possibly his morals; that the greatest educational problem is to determine the kind of education best suited to each IQ level; that the first concern of a nation should be the average IQ of its citizens, and the eugenic and dysgenic influences which are capable of raising or lowering that level; that the great test problem of democracy is how to adjust itself to the large IQ differences which can be demonstrated to exist among the members of any race or nationality group. —LEWIS M. TERMAN (1922b) This bold statement by the author of the first of intelligence and its assessment deservedly elicits Stanford–Binet intelligence scale captures much many strong feelings. of both the promise and the controversy that have Intelligence is arguably the most researched historically surrounded, and that still surround, topic in the history of psychology, and the concept the assessment of intelligence. Intelligence tests of general intelligence has been described as “one of and their applications have been associated with the most central phenomena in all of behavioral some of the very best and very worst human be- science, with broad explanatory powers” (Jensen, haviors.
    [Show full text]
  • What Grades and Achievement Tests Measure
    IZA DP No. 10356 What Grades and Achievement Tests Measure Lex Borghans Bart H.H. Golsteyn James J. Heckman John Eric Humphries November 2016 DISCUSSION PAPER SERIES Forschungsinstitut zur Zukunft der Arbeit Institute for the Study of Labor What Grades and Achievement Tests Measure Lex Borghans Maastricht University and IZA Bart H.H. Golsteyn Maastricht University and IZA James J. Heckman University of Chicago, American Bar Foundation and IZA John Eric Humphries University of Chicago Discussion Paper No. 10356 November 2016 IZA P.O. Box 7240 53072 Bonn Germany Phone: +49-228-3894-0 Fax: +49-228-3894-180 E-mail: [email protected] Any opinions expressed here are those of the author(s) and not those of IZA. Research published in this series may include views on policy, but the institute itself takes no institutional policy positions. The IZA research network is committed to the IZA Guiding Principles of Research Integrity. The Institute for the Study of Labor (IZA) in Bonn is a local and virtual international research center and a place of communication between science, politics and business. IZA is an independent nonprofit organization supported by Deutsche Post Foundation. The center is associated with the University of Bonn and offers a stimulating research environment through its international network, workshops and conferences, data service, project support, research visits and doctoral program. IZA engages in (i) original and internationally competitive research in all fields of labor economics, (ii) development of policy concepts, and (iii) dissemination of research results and concepts to the interested public. IZA Discussion Papers often represent preliminary work and are circulated to encourage discussion.
    [Show full text]
  • (BTACT) with Stop & Go Switch Task (SGST) Margie E. Lachman, Project
    Brief Test of Adult Cognition by Telephone (BTACT) with Stop & Go Switch Task (SGST) Margie E. Lachman, Project Leader Patricia A. Tun, Co-Investigator Brandeis University MIDUS II Cognitive Test Battery Manual Updated January 2011 Supported by PO1 AG20166 & RO1 AG17920 Table of Contents 1. Brief Test of Adult Cognition by Telephone form A – p. 1-10 2. Brief Test of Adult Cognition by Telephone form B – p. 11-19 3. BTACT form A answer sheet – p. 20-27 4. BTACT form B answer sheet – p. 28-35 5. Guidelines for Administering and Scoring the BTACT – p. 36-40 6. Options for Administration and Scoring of the Stop and Go Switch Task – p. 41-47 7. Information about Recording and Administering the BTACT and Stop and Go Switch Task – p. 48 8. Information about Automatic Scoring of the Stop and Go Swich Task – p. 49 9. BTACT References – p. 50 MIDUS II Cognitive Test Battery Brief Test of Adult Cognition by Telephone (BTACT) February 2012 For Website In this phone interview I will ask you to try and do some exercises that involve remembering and making judgments about words and numbers. Before we begin, I need to tell you a few things. Your participation is completely voluntary. If you prefer not to answer any question, just let me know and we will go on to the next question. The information that you give me will be confidential and used for statistical analysis only. It will be identified only by computer code and at no time will your name or other identifying information be attached to the survey results.
    [Show full text]
  • Cognition in MS: an Overview
    Cognition in MS: An Overview John DeLuca, Ph.D. Senior Vice President for Research Kessler Foundation West Orange, New Jersey, USA Professor, Department of Physical Medicine & Rehabilitation Department of Neurology Rutgers, New Jersey Medical School Newark, New Jersey, USA Disclosures • Advisory board for Biogen IDEC • Speaker, Sanofi - Genzyme • Grant funding, Biogen IDEC • Grant funding, EMD Serono • Grant funding, NMSS • Grant funding, CMSC Overview • Cognition in MS – impact on daily life – assessment – brain imaging parameters • Cognitive Rehabilitation • Exercise and Medication • Conclusions Charcot (1868) Cognitive experience of patients with MS : “a marked enfeeblement of the memory; conceptions are formed slowly …” MS - Historical • By 1960’s, medical students taught – cognitive change not characteristic of MS • Early 1970’s: cognitive impairment in about 3% • Today, cognitive impairments up to 65% in MS Cognitive Deficits in MS • Information processing speed/ efficiency • Learning and Memory • Executive functions • planning, organization, initiation • Perceptual processing Cognitive Impairment in MS 60 50 40 30 20 percent impaired 10 0 cognitive domain Chiaravalloti & DeLuca, 2008, Lancet Neurol The frequency of cognitive impairment tends to increase over MS course Adapted from Ruano et al (2017), MSJ Examine MS symptoms prior to clinical onset (or dx) Prospectively investigate potential signs of preclinical MS activity Cognitive performance of all Norwegian men born 1950-1995 who underwent conscription between 18-19yo Linked
    [Show full text]
  • Test Validity: G Versus the Specificity Doctrine
    J. SociaI Biol. Struct. 1984 7, 93-118 Test validity: g versus the specificity doctrine Arthur R. Jensen University of California, Berkeley, USA The specificity doctrine, a legacy of the positivism and radical behavorism that have dominated the history of American psychology, holds that psychometric tests measure nothing other than the specific bits of knowledge and learned skills reflected in the item content of the tests. This prevailing doctrine has influenced the interpretation of test scores and the conceptualization of test validity, as well as the practical use of tests in educational and personnel selection. Opposed to the specificity doctrine is the view that a wide variety of cognitive tests measure in common a few large factors of mental ability, most prominently general intelli- gence, or g. The commonality is not ascribable to common contents of the tests but to common brain processes. Recent massive validity evidence from the use of cognitive tests in personnel selection is consistent with the broad common- factor theory and contradicts the specificity doctrine. The practical and theoretical utility of the construct of g as a general information processing capacity also appears warranted by other lines of evidence independent of factor analysis. First, I will define the specificity doctrine, and say something about its historical roots and its effects on psychometrics and theories of human abilities. Second, I will describe the manifestations of the specificity doctrine in the applied field of mental testing and per- sonnel selection, and discuss how it has influenced prevailing notions of test validity. Third, I will review the massive research on test validity in the past decade which totally refutes the implications of the specificity doctrine for employment testing, and I will cite estimates of the monetary costs to our nation which would result from the abandonment of tests for employment selection or from the use of less than optimal selection procedures based on test results.
    [Show full text]
  • A Longitudinal Study of Great Ape Cognition: Stability, Reliability And
    A Longitudinal Study of Great Ape Cognition: Stability, Reliability and the Influence of Individual Characteristics Manuel Bohn (manuel [email protected]) Johanna Eckert (johanna [email protected]) Daniel Hanus ([email protected]) Daniel Haun ([email protected]) Department of Comparative Cultural Psychology, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103 Leipzig, Germany Abstract sample of study participants and therefore cannot test a new sample. Nevertheless, in such conditions, we can ask a more Primate cognition research allows us to reconstruct the evo- lution of human cognition. However, temporal and contex- basic question: how repeatable are the results of a study. That tual factors that induce variation in cognitive studies with great is if we test the same animals multiple times, do we get sim- apes are poorly understood. Here we report on a longitudinal ilar results? Repeatability could be seen as a pre-condition study where we repeatedly tested a comparatively large sam- ple of great apes (N = 40) with the same set of cognitive mea- for replicability. In this study, we investigate the stability of sures. We investigated the stability of group-level results, the results by repeatedly testing the same sample of great apes reliability of individual differences and the relation between on the same tasks. This will allow us to estimate how sta- cognitive performance and individual-level characteristics. We found results to be relatively stable on a group level. Some, but ble group-level performance is and thus how representative a not all, tasks showed acceptable levels of reliability. Cogni- single data collection point is for a group of great apes.
    [Show full text]
  • Cognitive Ability William T
    Forthcoming in The New Palgrave Dictionary of Economics, Steve Durlauf ed. Cognitive Ability William T. Dickens Senior Fellow The Brookings Institution ABSTRACT Modern psychological theory views cognitive ability as multidimensional while acknowledging that the many different abilities are themselves positively correlated. This positive correlation across abilities has led most psychometricians to accept the reality of a general cognitive ability that is reflected in the full scale score on major tests of cognitive ability or IQ. This entry provides an introduction to the history of cognitive testing and some of its major controversies. Evidence supporting the validity of measures of cognitive ability is presented and the nature and implications of group differences is discussed along with evidence on its malleability. Some people obviously and consistently understand new concepts quicker, solve unfamiliar problems faster, see relationships that others don’t and are more knowledgeable about a wider range of topics than others. We call such people smart, bright, quick, or intelligent. Psychologists have developed tests to measure this trait. Originally called IQ tests (for Intelligence Quotient because the measures were constructed as the ratio of mental age to chronological age multiplied by 100) that name has fallen out of favor. Instead, such tests are now often referred to as tests of cognitive ability. Although the term IQ is still sometimes used to refer to what such tests measure, none construct a ratio. History Spearman (1904) first popularized the observation that individuals who do well on one type of mental task also tend to do well on many others. For example, people who are good at recognizing patterns in sequences of abstract drawings are also good at quickly arranging pictures in order to tell a story, telling what three dimensional shapes drawn in two dimensions will look like when rotated, tend to have large vocabularies and good reading comprehension, and are quick at arithmetic.
    [Show full text]
  • Theory of Mind in Individuals with Alzheimer-Type Dementia Profiles
    Florida State University Libraries Electronic Theses, Treatises and Dissertations The Graduate School 2004 Theory of Mind Performance of Individuals with Alzheimer-Type Dementia Profiles Gina L. Youmans Follow this and additional works at the FSU Digital Library. For more information, please contact [email protected] THE FLORIDA STATE UNIVERSITY COLLEGE OF COMMUNICATION THEORY OF MIND PERFORMANCE OF INDIVIDUALS WITH ALZHEIMER-TYPE DEMENTIA PROFILES By GINA L. YOUMANS A Dissertation submitted to the Department of Communication Disorders in partial fulfillment of the requirements for the degree of Doctor of Philosophy Degree Awarded: Summer Semester, 2004 Copyright © 2004 Gina L. Youmans All Rights Reserved The members of the Committee approve the dissertation of Gina L. Youmans defended on June 15, 2004. Michelle S. Bourgeois Professor Directing Dissertation Michael E. Rashotte Outside Committee Member Howard Goldstein Committee Member Leonard L. LaPointe Committee Member Approved: Howard Goldstein, Chair, Department of Communication Disorders John K. Mayo, Dean, College of Communication The Office of Graduate Studies has verified and approved the above named committee members. ii TABLE OF CONTENTS List of Tables …………………………………………………………………………… v Abstract ………………………………………………………………………....… vii 1. LITERATURE REVIEW …………………………………………………………… 1 Theory of Mind………………………………………………………………….. 1 Theories of Theory of Mind……………………………...……………………… 4 Theory of Mind Assessment………………………………………..…………… 8 Acquired Theory of Mind Impairment in Neurogenic Populations…...…………
    [Show full text]
  • The G-Factor of International Cognitive Ability Comparisons: the Homogeneity of Results in PISA, TIMSS, PIRLS and IQ-Tests Across Nations
    European Journal of Personality Eur. J. Pers. 21: 667–706 (2007) Published online in Wiley InterScience (www.interscience.wiley.com) DOI: 10.1002/per.634 The g-Factor of International Cognitive Ability Comparisons: The Homogeneity of Results in PISA, TIMSS, PIRLS and IQ-Tests Across Nations HEINER RINDERMANN* Institute of Psychology, Otto-von-Guericke-University Magdeburg, Germany Abstract International cognitive ability and achievement comparisons stem from different research traditions. But analyses at the interindividual data level show that they share a common positive manifold. Correlations of national ability means are even higher to very high (within student assessment studies, r ¼ .60–.98; between different student assessment studies [PISA-sum with TIMSS-sum] r ¼ .82–.83; student assessment sum with intelligence tests, r ¼ .85–.86). Results of factor analyses indicate a strong g-factor of differences between nations (variance explained by the first unrotated factor: 94–95%). Causes of the high correlations are seen in the similarities of tests within studies, in the similarities of the cognitive demands for tasks from different tests, and in the common developmental factors at the individual and national levels including known environmental and unknown genetic influences. Copyright # 2007 John Wiley & Sons, Ltd. Key words: intelligence; knowledge; education; student assessment; educational achievement; OECD; IEA INTRODUCTION The past century of empirical research on cognitive abilities has convincingly demonstrated their relevance for both individuals and societies across a wide variety of criteria. For individuals, both IQ (Schmidt & Hunter, 2004) and literacy (OECD, 2000) have been linked with job performance, longevity (Gottfredson & Deary, 2004; OECD, 2000), and low criminality (Herrnstein & Murray, 1994).
    [Show full text]
  • The G-Factor of International Cognitive Ability Comparisons: the Homogeneity of Results in PISA, TIMSS, PIRLS and IQ-Tests Across Nations’ by Heiner Rindermann
    European Journal of Personality Eur. J. Pers. 21: 707–765 (2007) Published online in Wiley InterScience (www.interscience.wiley.com) DOI: 10.1002/per.648 Discussion on ’The g-Factor of International Cognitive Ability Comparisons: The Homogeneity of Results in PISA, TIMSS, PIRLS and IQ-Tests Across Nations’ by Heiner Rindermann OPEN PEER COMMENTARY Geographical Distribution of Mental Abilities and Its Moral Consequences JU¨ RI ALLIK Department of Psychology, University of Tartu, Estonia [email protected] Abstract Rindermann’s study provides the most comprehensive evidence so far that national scores of school assessment have systematic differences and the geographical distribution of these differences almost perfectly repeat the distribution of the mean national scores of intelligence. It is argued that without comparison with the random effects of statistical aggregation it is impossible to decide whether additional factors are needed to explain the strong association between national scores of school assessment and intelligence tests. The ignorance about real differences in mental abilities may become a source of social injustice because this does not allow natural inequalities to be arranged such that they are to the greatest benefit of the least advantageous. Copyright # 2007 John Wiley & Sons, Ltd. Rindermann (this issue) provides the most comprehensive evidence so far that national scores of school assessment have systematic differences and the geographical distribution of these differences almost perfectly repeat the distribution of the mean national scores of intelligence. By analogy with many previous controversial discoveries, it is predictable that the first most typical reaction would be denial. Indeed, many critics are not able to tolerate the idea that the mean level of intelligence could systematically vary across countries and world regions.
    [Show full text]
  • Intelligence: Foundations and Issues in Assessment
    Canadian Psychology © 2009 Canadian Psychological Association 2009, Vol. 50, No. 3, 183–195 0708-5591/09/$12.00 DOI: 10.1037/a0016641 Intelligence: Foundations and Issues in Assessment Linda Gottfredson Donald H. Saklofske University of Delaware University of Calgary There is no more central topic in psychology than intelligence and intelligence testing. With a history as long as psychology itself, intelligence is the most studied and likely the best understood construct in psychology, albeit still with many “unknowns.” The psychometric sophistication employed in creating intelligence tests is at the highest level. The authors provide an overview of the history, theory, and assessment of intelligence. Five questions are proposed and discussed that focus on key areas of confusion or misunderstanding associated with the measurement and assessment of intelligence. Keywords: intelligence, intelligence testing, intelligence tests To understand how we are like all others, some others, and no tory psychologists; now tests have become objects of the attention for others, to paraphrase Kluckhohn and Murray (1948), has led to the many workers whose primary interest is in education, social service, search for those key individual differences factors that can be medicine, industrial management and many other fields in which applied operationally defined and measured. Individual differences char- psychology promises valuable returns. (Whipple, 1914, p. v) acteristics attributed as the causes or underlying basis of human behaviour include intelligence, personality, and conative factors. The Army Alpha and Beta tests used extensively for screening Here, the view is that school achievement, job success, or longev- U.S. military recruits during World War I further demonstrated the ity is, in turn, related to these latent traits.
    [Show full text]
  • Dementia Revealed: What Primary Care Needs to Know
    Dementia Revealed What Primary Care Needs to Know A Primer for General Practice Prepared in partnership by NHS England and Hardwick CCG with the support of the Department of Health and the Royal College of General Practitioners Dr Elizabeth Barrett, Shires Health Care – Hardwick CCG Professor Alistair Burns, NHS England July 2014 Dementia Revealed What Primary Care Needs to Know Version 2: November 2014 2 CONTENTS Introduction to the first edition ................................................................................... 5 Introduction to the second edition ............................................................................. 6 What can people with dementia and their carers expect? ........................................ 8 Prevention of dementia ............................................................................................. 8 What is ‘normal’? ...................................................................................................... 8 The syndrome of dementia ........................................................................................ 9 Identification and diagnosis of dementia ................................................................... 9 Types of dementia ................................................................................................... 11 Assessing cognition................................................................................................. 13 Activities of daily living (ADLS) ..............................................................................
    [Show full text]