An Investigation of Similarities in Parent.- Child Test Scores for Evidence of Hereditary Components
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DOCUMENT RESUME ED 027 060 PS 001 391 By-Stafford, Richard E. An Investigation of Similarities in Parent.- Child Test Scores for Evidence of HereditaryComponents. Prnceton Univ., N.J. Dept. of Psychology. Spons Agency-Edward R. Johnstone Training and Research Center, Bordentown,N.J.; National Science Foundation, Washington, D.C. Report No-RBUL-63-11 Pub Date Apr 63 Note-150p. EDRS Price MF-$0.75 FIC-$7.60 Descriptors-Adolescents, Arithmetic, Association (Psychological), Auditory Discrimination,Concept Formation, *Correlation, Fathers, *Heredity, Mothers) *Parent Child Relationship, Parents,Personality Development, *Psychological Characteristics, Psychological Patterns, Psychological Studies,Psychological Tests, Spelling, Symbolic Learning, Vocabulary Identi fiers-Dichotomic Analysis This study on psychological traits examines three hypotheses:(1) there is a similarity between parents and their children unexplained by asimilarity between the parents, (2) this similarity may be explained byhereditary components, and (3) these hereditary components are of the discrete or segregated typeof inheritance. There were 104 families selected.Included in the study were the fathers, the mothers, and 58 teenage sons, and 72 teenage daughters. They were giveneight psychological tests. In the 58 tests of the first hypothesis, word association wasthe only variable which did not show significant similarity between parent andchild. In regard to the last part of the hypothesis, English vocabulary and height werethe only factors which showed a significant correlation between father and mother.The second hypothesis was accepted becausespatial visualization and reasoning ability showed aunidiue family correlation pattern. In the third. hypothesis, only perceptualspeed and musical aptitude clearly fulfilled the requirement that the best fits to theautosomal genetic model were approximately same percentages for thefather-son distribution of scores as they werefor the mother-daughter scores. Inductive reasoning showed a possibility of having an underlying dichotomy, but noneof the remaining variables showed anyevidenceofunderlyingdithotomyforbothfather-sonand mother-daughter distribution.s (DO) 4 U. S. DEPARTMENTOF HEALTH, EDUCATION & WELFARE OFFICE OF EDUCATION THE THIS DOCUMENT HAS BEEN REPRODUCEDEXACTLY AS RECEIVED FROM PERSON OR ORGANIZATION ORIGINATING IT.POINTS OF VIEW OR OPINIONS. RECEIVED STATED DO NOT NECESSARILY. REPRESENT OFFICIALOFFICEOE gDUCABON POSITION OR POlIOL APR16 1968 An Investigation of Similarities in Parent-Child Test Scores for Evidence of Hereditary Components Prepared by RICHARD E. STAFFORD April 1963 Educational Testing Service Research Bulletin (RB-63-11) and ONR Technical Report Project on: "Mathematical Techniques in Psychology" Principal Investigator: HAROLD GULLIKSEN Prepared in connection with research done under Office of Naval Research Contract Nonr 1858-(15), Project Designation NR 150-088, and National Science Foundation Grant G-22889 Psychology Department, Princeton University Princeton, New Jersey Reproduction, translation, publication, use and disposal in whole or in part by or for the United Slates Government is permitted. AN INVESTIGATION OFSIMILARITIES IN PARENT-CHILD TESTSCORES FOR EVIDENCE OFHEREDITARY COMPONENTS by Richard E. Stafford - A DISSERTATION PRESENTED TO THE FACULTY OF PRINCETONUNIVERSITY IN CANDIDACY FOR THEDEGREE OF DOCTOR OFPHILOSOPHY RECOMMENDED FOR ACCEPTANCEBY THE DEPARTMENT OF PSYCHOLOGY April 1963 AN INVESTIGATION OF SIMILARITIESIN PARENT-CHILD TEST SC01-03S FOR EVIDENCE OFHEREDITARY COMPONENTS Abstract The general hypothesis ofthis study states that certainpsychological traits which have their scoresdistributed continuously may actuallyhave an underlying genetic dichotomywhich is masked by various othereffects. To be (1) more precise,three specific hypotheses statefor each variable that: there is a similarity betweenparents and their childrenunexplained by similarity between the parents;(2) this similarity may be explained by hereditary components, and(3) these hereditary components are of the discrete or segregated type ofinheritance. The population, consistina of104 fathers and mothers and their teenage sons or daughters, wasgiven eight psychologicaltests: Symbol Comparison, Word Association, MentalArithmetic, Pitch Discrimination,Letter Concepts, Spelling, Identical Blocks, andEnglish Vocabulary. Self-reports of height and weight were also obtained. These data were analyzed bothby correlational methods and dichotomic analysis. The latter is a new method designedfor this study. Parent-child correlations have previouslybeen inadequate for investi- gating the presence of hereditarycomponents in mental tests,because it is impossible to assess the degree towhich the correlations are due toenviron- mental effects. However, the transmission of atrait determined by a gene located on the X chromosome resultsin a unique pattern of familycorrelation coefficients. Dichotomic analysis is essentially an arbitraryquartering of a bivariate distribution ofparent-chlld scores by a successive series of artificial divisions in the continuous distributions.The frequencies observed by these arbitrary quarteringsmay be compared tothe theoretical expected genetic frequencies by a series ofchi-square goodness-of-fit tests. Should a "good fit" be found at one of the artificial divisionsin the bivariate distribution of the father-son scores,and at approximately the same artificial division in the bivariate distributionof the mother- daughter scores, then an underlying dichotomy would be assumed. To test the first hypothesis stated above, correlations betweenfamily members for each variable in the study were obtained from standard scores which partialed out the age differences in the raw scores.From these correlations, it was observed that there was only one variable, word asso- ciation, which did not show a significant similarity between at least one of the parents and one of their offspring. Two of the variables, English vocabulary and height, showed a highly significant correlation between fathers and mothers which negated the second part of the firsthypothesis. The second hypothesis was accepted because two variables,spatial visualization as measured by the Identical Blocks Test and a general reasoning ability as measured by the Mental Arithmetic Test, showed aunique family correlation pattern which indicated that they have a sex-linked recessive hereditary component. Although the two tests have some variance in common, inspection of the mothers' and sons' test scoressuggested that each test has an independent hereditary unit on the X chromosome. To test the third hypothesis, each variable was subjected to dichotomic analysis. Only the Symbol Comparison Test oI perceptual speed and the Pitch Discrimination Test, a measureof musical aptitude, gaveclear evidence of the genetic model wasapproxi- fulfilling the requirementthat the best fit to of mately the samehypothesized dichotomy forthe father-son distribution distribution of scores. The Letter scores as it wasfor the mother-daughter of having an Concepts Test of inductivereasoning showed a possibility variables showed any evidence underlying dichotomy,but none of the remaining and mother-daughter distri- of an underlyingdichotomy for both father-son butions. ACKNOWLEDGEMENTS It is not possible to conduct astudy of this size without thehelp of a great manypeople. Space does not allow me to thankall of these people individually, but I do wish tomention a few who have made thisstudy possible. First, I would like to express mydeep appreciation to the membersof my dissertation committee: Dr. Harold Gulliksen, Chairman,for his overall suggestions and criticismsthroughout the study, and especiallyfor his faith in my attempt to chart a newinterdisciplinary area; Dr, Bruce Eberhartfor his helpful suggestions andcriticisms, especially in the theoryof genetics; and Dr. Charles P. Smith for manysuggestions on the organization of this dissertation and for his constantencouragement. I wish to thank Mr. JohnsonO'Connor whose early conjectures onthe possibilities of genetic transmissionof mental traits planted theinitial seed for this study, and also Dr.Herluf H. Strandskov whose teachingsin human genetics nurtured my early vagueformulations. A number of school officials gavefreely of their time and facilities to make possible the testing ofthe families. With profound thanks, I have listed them individually inAppendix Al- but I would like tomention here, especially, the New Jersey SchoolDevelopment Council. I should also like to acknowledge gratefully thecooperation of the many parents andtheir sons and daughters who participated assubjects in this study. With warm appreciation I wishto thank Mrs. Sally Matlack ofEducational Testing Service and through herthe many ETS staff members who gave generous help in the construction andprinting of the test battery andinvaluable suggestions in the editing,typing, proofing and printing of thisdissertation. iv Many persons at ThePennsylvania State University havehelped in this specifically to study. A large vote of thanks isextended to them all, and Dr. Martin L. Zeigler,Director of Student AffairsResearch, for making staff and time available. I am gratefully indebted tohis staff members who labored long in checkingcalculations, constructing graphs,and typing the preliminary drafts ofthis dissertation. I would also like to thank Dr. Donald Ford, Director ofthe Division of Counseling,who counseled me over thosedifficult and discouraging