Fusté Escolano, Adela

Ruiz Rodríguez, José

Diposit Digital de la Universitat de Barcelona

INDIVIDUAL DIFFERENCES IN HEMISPHERICITY:ASSESSMENT OF “THE HEMISPHERIC MODE INDICATOR”Ruiz, J. & Fusté, A.Department of Personality, Assessment and Psychological TreatmentUNIVERSITY OF BARCELONAMETHOD  &  PSYCHOMETRIC ANALYSIS5th EUROPEAN CONFERENCE ON PSYCHOLOGICAL ASSESSMENT . University of Patras, GREECE  (1999) PURPOSEMALES32%FEMALES68%• To analyse the psychometric properties(internal consistency, temporal reliabilityand validity indices) of a Spanish versionof the Hemispheric Mode Indicator.• To verify the existence of individualdifferences in lateralized cognitivestrategies of information processing bysex and handedness.SUBJECTS     The sample consisted of 325 Spanish undergraduate students (215 females and 110 males) recruited from the campus of the University of Barcelona (UB) and the Politechnics University of Catalonia (UPC). Their ages ranged from 18 to 46 years, with a mean of 21.19 years (Std. Dev.=3.34) for females, and a mean of 22.16 years (Std. Dev.=4.62) for males. To verify differences in cognitive strategies of information processing, associated by some researches (e.g. Coren, 1995) to the hemispheric asymmetry as a function of handedness and sex, subjects weresubdivided by sex into four categories of manual lateralization (Consistent Right-Hander (CR), Mixed Right-Hander (MR), Mixed Left-Hander (ML) and Consistent Left-Hander ( CL). The indices of manuallateralization was computed as suggested by Coren (1993). Ambilateral subjects were included into mixed left-hander category (ML).CONSISTENT RIGHT-HANDERS (CR)MIXED RIGHT-HANDERS  (MR)CONSISTENT LEFT-HANDERS (CL)MIXED LEFT-HANDERS  (ML) RELIABILITY INDICESTESTS - RETEST RELIABILITYFACTOR ANALYSISINTERNAL CONSISTENCYOF    H M IN=325 Reliability ResultsNº ITEMS 32Mean 3.17Std. Dev. 17.77Cronbach’s   0.81Estandardized   0.81SPLIT-HALF RELIABILITY INDICESOF THE “HEMISPHERIC  MODE INDICATOR”N=325 FIRST HALF SECOND HALFItems Half 1-2 Odds EvensNº Items 16 16Mean 2.64 0.54Std. Dev. 9.80 9.38Cronbach’s  0.70 0.66rx,y  half  1-2 =  0.72Spearman-Brown Reliability Index =  0.83Guttman Reliability Index =  0.83063TEMPORAL STABILITY OF  H M IComparativeStudyLieberman(1986)Hartman &Hylton (1997)PresentdataN 47 70 140Retest Interval 2 months 6 months 3 monthsTest-Retest 0.90 0.74 0.89•Bogen, J.E. & Bogen, G.M. (1983). Hemispheric specialization and cerebral duality. TheBehavioral and Brain Sciences, 6 (3), 517-520.• Coren, S. (1993). The Lateral Preference Inventory for measurement of handedness, footedness, eyedness and earedness. Bull. Psychon. Soc., 31(1), 1-3. Coren, S. (1995). Differences in divergent thinking as a function of handedness and sex. Am. J. Psychol., 108 (3), 311-325.• Hartman,S. & Hylton, J. (1997) Estimates validity and reliability for the Hemispheric Mode Indicator. Perceptual and Motor Skills, 85, 1355-1364• Lieberman, M.G. (1986). The Hemispheric Mode Indicator (HMI). Technical notes. Barrintong, IL: Excel, Inc.• McCarthy, B. (1993). Hemispheric Mode Indicator (HMI). Barrintong, IL: Excel, Inc.• Merckelbach, H. Muris, P., Pool, K., De Jong, P. & Schouten, E. (1996). Reliability and validity of a paper-and-pencil Test MeasuringHemisphere Preference. European Journal of Personality, 10, 221-231.• Ruiz, J., Tous, J.M. & Fusté, A. (1998). Individual differences in lateralized cognitive strategies: “The Human Information Processing Survey”.9th. European Conference on Personality. University of Surrey. Guilford, United Kingdom.• Taggart, W. & Torrance, P. (1984). Human Information Processing Survey. Scholastic Testing Service, Inc.Bensenville, Illinois.• Torrance, E. & Reynolds, C. (1980) Preliminary norms-technical manual for Your Style of Learning and Thinking. Athens, C.A. Univ. of GeorgiaThe “Hemispheric Mode Indicator” (HMI) (Lieberman, 1986; McCarthy, 1993) is a self-report measure designed to assess hemisphericity. Hemisphericity refers to the idea that people tend to rely, at least sometimes and in some situations, upon a preferred mode of cognitive processing, which is linked to differential involvement of the cerebral hemispheres (Bogen & Bogen, 1983).FACTOR ANALYSIS OF HMI (N=313)FEATURES  OF THECORRELATION  MATRIXRESULTSDeterminantKMOBartlett Test of Sphericity% OFF-Diagonal elem.>0.090.00044370.832319.9791 (Sign=.00000)10.3% (102)FACTOR  EXTRACTIONROTATION METHODFact. with Eigenvalues > 1Cum  Pct  of  VarResiduals  > 0.05Criteria Factors (Scree Test)Cum Pct of VarPrincipal ComponentsVarimax955.3%226 (45%)4(36.2%)As the HMI returns a single score for each subject, Hartman & Hylton(1997) consider that hemisphericity should be treated as unidimensional. So,in spite of preliminary exploratory principal components analyses indicatethat the factor structure of this instrument’s items actually ismultidimensional, they focus on correlations of all items with the underlyingfirst component (structure coefficients). Their hypothesis is: ”if structurecoefficients associated whit a principal component are relatively high andinteritem correlations relatively low, low item redundancy and strong, multi-item support for the underlying construct are suggested” To verify this pointwe have examined the factor structure of the Spanish version of HMI.The analysis of the interaction “sex by handedness” in relation to preferred lateralized cognitive strategies yields significant differences among the several groups, such as is shown in the above graph.Correlation of each item of  H M Iwith fist principal component and with over-all scoreHartman & Hylton (1997)(N=525)Present data(N=313)ItemPrincipalComp.Over-allScore ItemPrincipalComp.Over-allScore1131825153025222312124816101961713281432731261292042927.62.60-.60.58.57.56.55.54.53.51.50.49.47.47.47.45.41.40.39.39.38.36.28.25.22.22.21-.19.14.13.09-.06.45.48-.51.48.41.48.43.43.42.40.47.42.42.36.40.32.39.34.31.37.34.30.23.22.19.18.21-.17.11.14.08-.053019524202131112315106252282183213147426172816122731929.68.65.63.63.60.60.58.58.57.57.56.52.51.48.45.42.41-.39.37.36.34.32.27.27.17.17.17.13.08-.07-.04-.001.59.53.56.53.52.48.47.49.45.48.43.42.44.38.38.36.35-.34.32.34.27.27.25.27.20.13.13.14.12-.06-.04.009Average% Var..3418.2.28 Average% Var..3619.60.31There are significant differences between sexes in each one of the several groups of handedness: CR (p=0.042), MR (p=0.048), ML (p=0.017), with the exception of CL. Moreover of differences shown, itis worth noting differences among mixed left-handed (ML) males and the other groups of females: ML-CR (p=0.011), ML-MR (p=0.002), ML-ML (p=0.017), ML-CL (p=0.002). According to thetendency shown in Graph-1, females of all groups of manual lateralization always score significantly greater than males in HMI. Likewise, significant differences were found between consistent left-handed (CL) females and consistent right-handed (CR) males (p=0.014), and between mixed right-handed (MR) females and consistent right-handed males (p=0.004). This general tendency of women toscore higher than men in a right mode of cognitive processing confirms results of a previous work in which hemisphericity was assessed through the Human Information Processing Survey (Ruiz et al, 1998).CONCLUSIONS Psychometric analysis of the Spanish version ofthe HMI results in very good indices of reliability, and in acceptable convergentvalidity indices. This results are agree with Lierberman and Hartman & Hylton’s findings. Factor analysis suggests the multidimensional structure of the HMI. Accordingto Hartman & Hylton (1997) the structure coefficients and item/overall scorecorrelations make clear that items 9, 18 and 29 should be reworded or discarded.With regard to individual differences in lateralized cognitive strategies ofinformation processing assessed by HMI, in relation to sex and handedness, it isworth noting the general tendency of women to score higher than men in anholistic mode in all groups of manual lateralization. The most significant contrastwith analytic mode is show with regard to the group of mixed left-handed males.DISTRIBUTION OF THE SAMPLE BY SEX AND HANDEDNESSSEX/HAND. CR MR ML CL N RATIOFEMALES 141 49 8 17 215 66%MALES 67 27 8 8 110 34%N 208 76 16 25 325 100%RATIO 64% 23% 5% 8% 100%DESCRIPTIVES OF HMI SCORES BY SEX AND HANDEDNESSSEX/HAND. CR MR ML CL TOTALFEMALES Mean=4.11Std. Dev.=17.928.1816.008.8714.5410.4718.895.7217.50MALES -1.2118.71-0.2313.87-12.1219.553.8722.47-1.4017.73TOTAL 2.4118.125.2615.73-1.6219.868.3619.873.3317.87MALES32%FEMALES68%MALES50%FEMALES50%MALES36%FEMALES64%To test if the HMI scores are different between males and females an ANOVA Between Groups was performed with HMI scores as dependent variable and sex and handedness as independent variables. All variables comply with Homocedasticity Test (p>0.05). Significant differences were found between sexes in HMI scores. As we can see in the Graph 1, women score higher than men in right hemispheric preference (F(7,315) =2.76 p=0.008). FEMALESMALESHMI SCORES BY SEX AND HANDEDNESSHANDEDNESSHMI SCORES-15-10-5051015CR MR ML CLFemales Males5,72-1,4-2-10123456The HMI scores are normally distributed (Kolmogorov-Smirnov d=0.02280, p= n.s.).Graph - 1HMI ScoresINTRODUCTIONThe HMI is comprised of 32 pairs of words or phrases, one of each pair reflecting right-brain functions and the other left-brain functions. Subjects are instructed tochoose “a lot” or “somewhat” with respect to one or other pole of the pairs. Scores can range from -64 to +64, with lower values indicating relative left-hemisphericpreference and higher values indicating relative right-hemispheric preference. Information of both reliability and validity indices of the HMI is limited. Only twostudies, developed by Lieberman (1986) and Hartman & Hylton (1997), have reported indices of internal consistency, test-retest reliability and concurrent validity.The correlation coeficients resulting of such analyses show a very acceptable psychometric properties of the Hemispheric Mode Indicator.See correlations of each item of HMI with first principal component inthe attached table. Structure coefficients and item/overall scorecorrelations are ranked by absolute value of structure coefficients. Tocompute item-overall score correlations, item of interest was excluded.VALIDITY INDICESCorrelations in bold type are either negative or notstatistically significant at p<0.05 level.Convergent validity was calculatedby the product-moment correlationbetween the HMI and other muchbetter known measures of hemis-phericity: HIPS (Taggart, et al., 1984),SOLAT (Torrance, et al., 1980) andHPT (Merckelbach, et al., 1996).CONVERGENTVALIDITYCRITERIA XYSOLAT (N=230)HIPS     (N=319)HPT      (N=319)0.64*0.61*0.61** Significant at p<0.001To verify if HMI discriminate thecognitive strategies of informationprocessing identified with left(Analytic) and right (Holistic)hemispheres, we have analyzed theHMI scores of two groups ofsubjects (N=136) classified likevery analytic (N=47) or veryholistic (N=87) through theHemisphere Preference Test (HPT)These results reveal very acceptable indices of validity.Average Inter-Item Correlation = 0.12(t = -9.392  p=0.00000)Hartman & Hylton (1997) report Alphacoefficients of 0.78 and 0.84 for different samples.

Individual differences in hemisphericity: assessment of "The hemispheric mode indicator"

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