Structural Analysis of the Facets and Domains of the Zuckerman–Kuhlman–Aluja Personality Questionnaire (ZKA–PQ) and the NEO PI–R

Aluja, Kuhlman, and Zuckerman (2010) developed an instrument for American and Spanish populations (Zuckerman–Kuhlman–Aluja Personality Questionnaire [ZKA–PQ]) that includes 4 facets for each 5 basic traits of Zuckerman's psychobiological personality model. This new instrument is intended to improve the previous measure based on the same personality model, the Zuckerman–Kuhlman Personality Questionnaire (ZKPQ), by including the narrower traits (facets) defining the factors. This article explores the convergent and discriminant validity of the new instrument relative to the NEO PI–R in a sample from the Spanish general population. A series of exploratory factor analyses comparing both instruments was conducted. Results showed good convergent and discriminant validity between both instruments, although the ZKA–PQ had a slightly better structure than the NEO PI–R. The results support the validity of the ZKA–PQ factor domains and the facets composing them. The new instrument might be useful in both applied and research settings.

Those studies showed good convergent and discriminant validity between the NEO PI-R from the Five-factor model (FFM; Costa & McCrae, 1992) and the ZKPQ from the Zuckerman's Alternative Five model (Zuckerman, 1991) with the exception of the fifth factor in both (Activity and Openness). However, the NEO PI-R format has some advantages over the ZKPQ in practical settings. For instance, personality disorders are best predicted when facets instead of general domains are used as independent variables and facet-level analyses contribute to increased specificity and discrimination between personality disorders (Aluja, García, Cuevas, & García, 2007a;Dyce & O'Connor, 1998). The inclusion of facets is also relevant because they are being used to generate equations to diagnose personality disorders from a dimensional approach (Costa & Widiger, 2002). However, the absence of facets in the ZKPQ precludes the possibility of developing useful equations based on the Zuckerman's Alternative Five, although they have shown a similar (even slightly better) prediction of personality disorders compared to Big Five traits (Aluja, García, Cuevas, & García, 2007b). Beyond the research on personality disorders, some studies have demonstrated that facets can be more useful than general factors in predicting some behaviors (Paunonen, Haddock, Forsterling, & Keinonen, 2003), or developmental trajectories (Morizot & Le Blanc, 2003). In general, personality profiles for clinical, educational, or organizational purposes are enriched more by using many facets rather than broad general factors (Westen, 1995). An additional advantage of the new Zuckerman-Kuhlman-Aluja Personality Questionnaire (ZKA-PQ; Aluja, Kuhlman, & Zuckerman, 2010) is that it uses a Likert-type answer format that increases the variability of the scores, leading to finer population norms and statistical information compared to the dichotomous answer format of the ZKPQ. 156 STRUCTURAL ANALYSIS OF THE ZKA-PQ AND THE NEO PI-R 157 Zuckerman (1991Zuckerman ( , 2005 has largely focused on the psychobiological basis of personality traits. From this standpoint, individual differences on personality domains, especially on the impulsive-sensation seeking trait, are strongly accounted for by genetic and psychobiological variables. For instance, it is well replicated that low levels of monoamine-oxidase (MAO) are associated with high sensation-seeking scores (Zuckerman, 1991(Zuckerman, , 1994(Zuckerman, , 2005. Thus, Zuckerman has created a broad psychobiological model where differences on the five domains are linked to the role of neurotransmitters (mainly dopamine, norepinephrine, and serotonin), enzymes (e.g., MAO and Catechol-OMethyltransferase), and gonadal hormones (e.g., testosterone and cortisol; Aluja & Torrubia, 2004;Zuckerman, 1991Zuckerman, , 2005. In general, Zuckerman's psychobiological model has stimulated many studies about the psychobiological basis of human personality (for reviews, see Roberti, 2004;Stelmack, 2004;Zuckerman, 1991Zuckerman, , 2005. Assuming that facets might also improve the validity of a personality measure in research settings, a new instrument including facets for the Zuckerman's Alternative Five would help to extend the usefulness of this model in the psychobiological research field. Aluja et al. (2010) designed a new psychometric instrument, the ZKA-PQ, based on Zuckerman's psychobiological personality model and including facets. The ZKA-PQ measures the same five factors as the ZKPQ: Sensation Seeking, Neuroticism, Aggressiveness, Activity, and Extraversion. Although greatly similar to the ZKPQ constructs, the Sensation Seeking (SS), Neuroticism (NE), Aggressiveness (AG), and Extraversion (EX) domains have been slightly changed compared to the original ZKPQ (Impulsive-Sensation Seeking, Neuroticism-Anxiety, Aggression-Hostility, and Sociability, respectively), so the names have been modified to represent the broader nature of the constructs provided by a summing of the facets within each factor.
As a new instrument, a predictive and construct validation process is required to support the usefulness of the ZKA-PQ in practical and research settings (American Psychological Association, American Educational Research Association, & National Council on Measurement in Education, 1999). As a first step, information about the relationships between the ZKA-PQ and other established personality measures should be gathered. Both the ZKA-PQ and the NEO PI-R are based on facets within factors and both postulate five-factor models, although some of the factors appear different. Convergent (Aluja et al., 2010), but the NEO-FFI-R does not assess facets. This study was designed to compare the psychometric properties of both the ZKA-PQ and the NEO PI-R in a new sample of subjects from a general population with a similar sex and age distribution. We are mainly concerned with exploring the similarities and differences in the psychometric properties, comparing the fit of both instruments to the expected theoretical structures through exploratory factor analysis, and testing the convergent validity of the ZKA-PQ and the NEO PI-R at the domain and facet levels.

METHOD Participants
Both the ZKA-PQ and the NEO PI-R were given to a sample of 654 persons (317 men, 337 women) with a mean age of 44.9 years (SD = 17.15). The sample was distributed among the following age ranges: 18-30, 20.6%; 31-40, 19.8%; 41-50, 20.8%; 51-60, 20.1%; and older than 60, 18.7%. In regard to education level, 22.9% of the sample had completed primary or secondary studies, 21.3% completed high school, 13% had some university studies, and the remaining 42.8% had finished a university degree. Because 22.9% of the sample had less than a high school education, the Flesch-Kincaid reading grade level of the ZKA-PQ was computed. For the Spanish version of the ZKA-PQ, the number of words is 1,951 in 200 sentences. The approximate average number of syllables in the Spanish version of the ZKA-PQ is 16 per sentence, totaling 4,000 syllables. With these data, the Flesch-Kincaid grade level formula gives a value close to 8, corresponding to a typical age of 13 to 14 years. Most of the sample had enough years of education to understand the ZKA-PQ. In this way, a similar index was developed specifically for Spanish texts; the Fernandez-Huerta's index gave a score of 70 for the ZKA-PQ corresponding to a level of fairly easy.

Instruments
The ZKA-PQ is composed of 200 items with a 4-point Likerttype response format ranging from 1 (disagree strongly) to 4 (agree strongly). It measures five domains and 20 facets as explained earlier. Alpha reliabilities for the five factors varied between .85 and .92 for the Spanish sample, and between .88 and .93 for the U.S. sample (Aluja et al., 2010). The average alpha for the 20 facets of the ZKA-PQ in the Spanish validation sample was .75 with a minimum and a maximum of .65 and .90, respectively.
The NEO PI-R) is a well-known measure of the FFM personality domains: Neuroticism (N), Extraversion (E), Openness to Experience (O), Agreeableness (A), and Conscientiousness (C), and their 30 facets (six facets for each of the five factors; see McCrae & Costa, 1990, for a description of the N, E, and O facets, and Costa, McCrae, & Dye, 1991, for a description of the A and C facets). The 240 items of the questionnaire are answered on a 5-point Likert-type scale ranging from 0 (strongly disagree) to 4 (strongly agree). The Spanish version of the NEO PI-R (Costa & McCrae, 1999) has good psychometric properties, similar to those of the original U.S. version Aluja, García, García, & Seisdedos, 2005;Blanch, Aluja, Solé, Gallart, & Dolcet, 2009). The reliability coefficients for the five NEO PI-R domains were in the range of .83 to .90 reported for the Neuroticism and Openness to Experience factors, respectively (Costa & McCrae, 1999). 158 GARCÍA ET AL.

Procedure
University psychology students from the Autonomous University of Madrid were trained in the theory and instruments from the Zuckerman model and the FFM. As a regular exercise, they had to administer both instruments, preferably individually, to 10 persons with the following characteristics: one male and one female with an age between 18 and 30 years, one male and one female with an age between 31 and 40 years, one male and one female with an age between 41 and 50 years, one male and one female with an age between 51 and 60 years, and one male and one female elder than 60 years. To increase the motivation, students had to complete several activities related to the profiles obtained and, as it has been told before, scores on the domains of the ZKA-PQ and NEO PI-R as well as a minimal explanation of the scores obtained were returned to participants.

Analysis
Statistical analyses were used to compare both instruments adding evidence about the convergent and discriminant validities of the new instrument in relation to the NEO PI-R. First, descriptive analysis and exploratory factor analysis were conducted separately for ZKA-PQ and NEO PI-R. Second, facets of both instruments were factor analyzed conjointly. All exploratory factor analyses included in this study were performed following the principal axis extraction and Varimax rotation methods.

RESULTS
Tables 1 and 2 show the descriptive statistics for the ZKA-PQ and the NEO PI-R, respectively, in this sample. As can be seen, facets and domains of both instruments show a normal distribution because the skewness and kurtosis values are within the -1 to +1 range. In regard to the internal consistency, only 5out 20 facets of the ZKA-PQ showed alpha indexes lower than .70, and the five factors had alpha values around .90. For the NEO PI-R, most of the facets had alphas lower than .70 (26 out of 30), although the five factors had reliability coefficients higher than .80. Table 3 shows the correlations between factors from both instruments. As can be seen, Sensation Seeking correlated positively with Extraversion and Openness to Experience and negatively with Conscientiousness. Those values are congruent with previous evidence from Spanish studies about the relationships between these traits (Aluja, Garcia, & Garcia, 2003;García, Aluja, García, & Cuevas, 2005). Sensation Seeking had a negative relationship with Conscientiousness, reflecting the role of sensation seeking in antisocial behavior Zuckerman, 1999). Aggressiveness and Agreeableness correlated negatively as in Zuckerman et al. (1993). Activity is mainly related with Conscientiousness  although in Zuckerman et al. (1993) it was mainly associated with Extraversion. Both Neuroticism and Extraversion correlated highly with the similarly labeled scales of the NEO PI-R.
Correlations between facets from ZKA-PQ and NEO PI-R are shown in Table 4. As expected from the factor correlations in Table 3, Aggressiveness facets correlated negatively with Agreeableness facets, especially with A4 (compliance), and positively with N2 (anger-hostility). Activity facets correlated highly with the activity facet of the Extraversion factor from NEO PI-R and with NEO facets of Conscientiousness. It is notable that all Ac- tivity facets correlated highly with achievement striving (C4). Extraversion facets from ZKA-PQ are strongly correlated with the Extraversion facets from NEO PI-R, the largest correlations observed for warmth (E1) and positive emotions (E6). They were also correlated with two Agreeableness facets (trust and altruism). It should be noted that EX1 (positive emotions) had high negative correlations with almost all Neuroticism facets, especially with depression and vulnerability. Neuroticism facets from the ZKA-PQ are strongly related with the facets of the same factor from the NEO PI-R, with the exception of N5 (impulsivity), which had correlations lower with Neuroticism and relatively higher with ZKA Aggression facets. The ZKA Neuroticism facets did correlate highly with other traits, with the exception of low self-esteem, which correlated negatively with assertiveness (E3), positive emotions (E6), competence (C1), and self-discipline (C5). Finally, no general pattern of relationships was found between the Sensation Seeking facets and NEO PI-R, except for the high relationship between the excitement seeking facet of the NEO PI-R (E5) and three of the four ZKA facets. ZKA experience seeking (SS2) correlated with all NEO Openness facets, and boredom susceptibility/impulsivity (SS4) correlated with three of the six facets of NEO Conscientiousness. As a final commentary, most of the correlations between nonrelated factor facets reported  of five factors because the lowest value was obtained for the fifth component (the average squared partial correlations were 0.0336, 0.0252, and 0.0293 for the fourth, fifth, and sixth factors, respectively). The five factors accounted for 57.98% of the variance. All facets loaded most highly on their appropriate factors, and no secondary loading was larger than ±.40. The structure of the ZKA-PQ found in this sample is close to that observed in the original study (Aluja et al., 2010).
On the NEO PI-R, the MAP method also supports the extraction of five factors because the lowest value was obtained for the fifth component (the average squared partial correlations were 0.0129, 0.0122, and 0.0126 for the fourth, fifth, and sixth factors, respectively). Those five factors accounted for 47.33% of the variance, 10% less than the variance explained by the factor solution for the facets of the ZKA-PQ. All but four facets (E3, E5, A3, A6) loaded most highly on their postulated factor, with only four secondary loadings larger than ±.40. The reported structure is quite similar to other Spanish studies using the NEO PI-R .
The next factor analysis included all facets from the ZKA-PQ and NEO PI-R (Table 7). No factor sum scores were included. The five factors accounted for 48.17% of the variance. All theoretical groups of four facets from the ZKA-PQ loaded on the corresponding factor only, except for AG3 (anger), AG4 (hostility), SS4 (boredom susceptibility/impulsivity), and EX3 (exhibitionism). The first two also load on the first factor formed by the facets of Neuroticism of both instruments, whereas the third and fourth ones load on the second factor mainly composed of the Aggressiveness (ZKA-PQ) and, in negative, Agreeableness (NEO PI-R) facets. The assertiveness (E3), and angry-hostility (N2) facets from the NEO PI-R also load on this second factor. The last one (N2) has been previously linked to the Agreeableness factor of the NEO PI-R . The impulsivity facet (N5) from the NEO PI-R, and boredom susceptibility/impulsivity (SS4) from the ZKA-PQ also load on this second factor. Considering that this factor is composed of Aggressiveness, Impulsivity and Agreeableness facets, this factor shows the convergence of both models in regard to the description and prediction of antisocial behavior (Costa & Widiger, 2002;Zuckerman, 1999).
The third factor includes the Sensation Seeking facets of the ZKA-PQ as well as the Openness facets of the NEO PI-R, with the largest loading on SS2 (experience seeking; .808). The fourth factor is defined by the ZKA-PQ Extraversion facets as well as a combination of facets from the Extraversion and Agreeableness factors of the NEO PI-R. Finally, the fifth factor included the Activity facets from the ZKA-PQ, all Conscientiousness facets, excluding C6 (deliberation), which has no strong loading on any factor, and the facet of activity (E4) from the NEO PI-R. In fact, E4 presents a much larger loading on this factor than on the Extraversion one. This result might have been a function of the inclusion of more facets related to the Activity construct in the construction of the ZKA-PQ.

DISCUSSION
The purpose of this article was to investigate the structure of the new instrument based on the Zuckerman's psychobiological personality model (ZKA-PQ) and its relationships with the FFM as measured by the NEO PI-R. The structure of the ZKA-PQ was robust and somewhat better than the NEO PI-R structure.  Because the NEO PI-R has more secondary loadings (4) compared with the ZKA-PQ (0), this suggests a better factor structure validity of the ZKA-PQ. Another explanation might be that the ZKA-PQ assesses constructs more narrowly than the NEO PI-R. For instance, Aggressiveness is formed by four facets closely linked to the aggressiveness concept (physical aggression, verbal aggression, anger and hostility), whereas the Agreeableness factor includes other content beyond aggression as suspiciousness, modesty, or sensitivity to others. Most relationships between ZKA-PQ and the NEO factors are similar to relationships previously reported with ZKPQ factors. Correlation and factor analyses show that Neuroticism and Extraversion facets and factors from both instruments were defined by the same constructs with few differences. Agreeableness is negatively and strongly related with Aggressiveness. On the other hand, Activity is positively related with Conscientiousness rather than Extraversion. Sensation Seeking presents a more diverse pattern but some relationships observed are supported by previous evidence with the ZKPQ (Aluja et al., 2003;García et al., 2005). The Extraversion factor does not present a simple structure when both instruments were analyzed conjointly. In the fivefactor solution, Extraversion is formed by three of the four facets of the ZKA-PQ, and three of the six NEO Extraversion facets plus two NEO Agreeableness facets. The absence of the other E facets raises questions about the content facet validity of Extraversion, particularly in the NEO. Excitement seeking (E5) is more closely related to Sensation Seeking in the ZKA than to Extraversion in the NEO. Activity in the NEO is more clearly related to NEO Conscientiousness and Activity facets in the ZKA. The absence of more than one facet sampling sensation (excitement) seeking and activity factors in the construction of the NEO reflects the initial presumptions of the authors regarding primary and secondary traits. The assertiveness facet has a larger loading on the Aggressiveness-Agreeableness factor than on the Extraversion one, questioning the real nature of the NEO PI-R Assertiveness scale. Those doubts are reinforced by previous evidence suggesting a significant relationship between this facet and antisocial personality disorder in U.S. (Dyce & O'Connor, 1998) and, especially, Spanish (Aluja, Cuevas, García, & García, 2007b) populations. The Openness to Experience factor of the FFM is not represented in Zuckerman's Alternative Five personality model (Zuckerman et al., 1993). However, low but consistent relationships between Openness and Sensation Seeking have been previously reported (Aluja et al., 2003;García et al., 2005). Looking at the correlations between facets, it can be seen that just one facet, experience seeking (EX2), correlates with all Openness facets. This facet is defined by preference for new or unpredictable situations, which matches very well with the Openness to Experience construct (Costa & McCrae, 1992, 1999. However, the lack of correlations with the other three Sensation Seeking facets suggests that the preference for risk activities (SS1: thrill and adventure seeking), the searching for pleasure through risky hedonic pursuits like sex or drugs (SS3: disinhibition), or impulsivity (SS4: boredom susceptibility/impulsivity) are not core aspects of the Openness to Experience construct. This pattern replicates the findings reported in a different sample by Aluja et al. (2003). Results in this study can be used to derive further hypotheses based on previous findings from both personality models. For instance, it is well known that the FFM has been successfully used on behavioral prediction in many contexts. For instance, Conscientiousness has been described as a good predictor of job performance (Hurtz & Donovan, 2000), so considering the links between this trait and Zuckerman's Activity, it should be hypothesized that the latter will be a good predictor of job performance as well. In fact, the combination of both traits might help us look into the reasons for such prediction in depth. For instance, results of this study suggest that the ability to predict job success could be linked to the energy devoted to work activities because the work energy facet (AC4) of Activity has the strongest relationship with Conscientiousness facets. The consistent relationship found between Conscientiousness and compulsivity (Costa & Widiger, 2002;Dyce & O'Connor, 1998) supports these findings.
Considering the strong psychobiological foundation of Zuckerman's model (Stelmack, 2004;Zuckerman, 2005) and the relationships with the NEO PI-R depicted in this article, Zuckerman's model could be used as a useful framework to explore the psychobiological basis of the FFM, originally developed as a descriptive taxonomy of personality. For instance, Sensation Seeking has been linked to differences in some neurotransmitters, such as dopamine, serotonin, and norepinephrine, and hormones, such as testosterone and cortisol Aluja, García, Blanch, & Fibla, 2011;Aluja & Torrubia, 2004;Zuckerman, 2005), as well as differences on the enzymes regulating the levels of neurotransmitters, like MAO-B (Roberti, 2004;Zuckerman & Kuhlman, 2000). Therefore, the results of this study might help to select the optimum psychological assessment instruments in psychobiological personality research from either or both models.
This article presents evidence favoring the facet internal reliability and structural validity of the ZKA-PQ compared to the NEO PI-R. However, these comparisons are based on a Spanish population and might not hold for others. The convergent and discriminant validity of the new instrument should be compared to instruments derived from other personality models, particularly those with a strong psychobiological foundation, such as Cloninger's, Eysenck's and Gray's models. The validity of the ZKA-PQ in practical and research settings should be tested with special emphasis on the prediction of personality disorders as well as the relationships with behavioral and biological variables.
In summary, the ZKA-PQ and the NEO PI-R have good convergent and discriminant validity on at least four of the major factors, replicating previous evidence about the relationships between basic factors of both models. This good convergent validity is reported for both factors and facets. Focusing on the ZKA-PQ facets, exploratory factor analysis supported their construct validity because ZKA-PQ facets grouped in the factor expected theoretically with no secondary loadings at all. In fact, this instrument shows a slightly better content validity and facet-factor structure than NEO PI-R. The ZKA-PQ has also shown the ability to add useful information about specific facet and factor personality variables in the NEO PI-R such as Assertiveness and Openness to Experience. Finally, this article demonstrates the great possibilities for both models to be combined to increase our knowledge about basic personality structure. STRUCTURAL ANALYSIS OF THE ZKA-PQ AND THE NEO PI-R 163