• -

  Socio-demographic and Sexual History Questionnaire, which was used to collect information regarding the participants’ age, education level, sexual orientation, relationship status, age at first intercourse, and number of sexual partners.

• -

  Sexual Excitation/Sexual Inhibition Inventory for Women (SESII-W; Graham et al., 2006), consisting of 36 items rated on a four-point Likert scale: 1=strongly disagree; 2=disagree; 3=agree; and 4=strongly agree. The characteristics of this questionnaire have been described in the Introduction.

• -

  Spanish version of the Sexual Sensation Seeking Scale (SSSS; Kalichman, 2011) of Sierra et al. (2013). The scale was composed of 10 items assessing sexual sensation seeking with a Likert scale from 1 (not at all like me) to 4 (very much like me). Higher scores indicated greater sensation seeking. The authors reported appropriate reliability, with Cronbach's alpha values greater than .75. In this study the reliability was .76 and .78 in Sample 1 and Sample 2, respectively.

• -

  Spanish short version of the Sexual Opinion Survey (Fisher, White, Byrne, & Kelley, 1988) of Vallejo-Medina, Granados, and Sierra (2014) in which the six items that assess erotophilia are rated on a seven-point Likert scale ranging from 1 (strongly disagree) to 7 (strongly agree). Its internal consistency reliability is .74, and it has excellent validity indicators. In this study, Cronbach's alpha values of .72 in Sample 1 and .74 in Sample 2 were obtained.

As recommended by Muñiz, Elosua, and Hambleton (2013), a forward-translation of the items was made from English into Spanish. This translation was executed by two experts in sexuality research with high English proficiency and knowledge in psychometrics and in the construction of questionnaires. This initial translation was then revised by a bilingual psychologist, expert in sexuality. Once the translation was executed, the original version and the Spanish version were sent to a panel of five experts in psychological assessment and sexuality research to assess understanding and the conceptual equivalence degree of each item. When there was not at least 85% agreement in regards to the content comprehension or equivalence of an item, it was changed as suggested by the experts. This occurred in the case of 19 items. The Spanish scale was then given to 10 women university students and 10 women from the Spanish general population to test whether the items were clearly expressed and understandable. After modifying one of the items, the final version of the scale was obtained.

From January to April 2013, the final Spanish version of the SESII-W was administered by well-trained evaluators to university students and general population in southern Spain. Participation was voluntary, and the anonymity and confidentiality of answers was guaranteed. Students were evaluated collectively in a classroom and the general population both individually (shopping malls, parks, stations, etc.) and collectively (community centers and associations). Both evaluations were always carried out in the presence of an evaluator in case doubts arose. Everyone who decided to contribute to the study, read and signed an informed consent. After answering the scales, participants returned them in a sealed envelope to the evaluators. The estimated time to complete the questionnaires was 15minutes.

The test-retest reliability was carried out with university students in their respective classrooms at three different times in the presence of an evaluator. In the first session, each participant was given three copies of the SESII-W, along with the informed consent form. All documents had the same code, as well as the exact date of the second and third administrations (at 4 and 8 weeks, respectively) that had to be administered in a group in class. After answering the scales, students put them in a sealed envelope and delivered them to the evaluator. Unlike the university population, data collection for the test-retest reliability in the general population was performed individually at the three established time intervals. This study was approved by the Ethics Committee on Human Research of the University of Granada.

CFA of Sample 1 was used to test the factorial solution in Graham et al. (2006), which consisted of eight primary factors and two higher-order factors. Items with a low load were then eliminated, and an alternative model was proposed. Following the recommendations on scale validation (Neukrug & Fawcett, 2014) and generalization of models (Delgado-Rico, Carretero-Dios, & Ruch, 2012), the selection of items was carried out, based on the adjusted model in the sample of university students. Subsequently, this same model was applied to a sample of subjects from the general population. Sample 1 was used with university students for being more homogeneous in terms of socio-demographic characteristics (age, education level, etc.). The factorial structure was put to test in Sample 2 with similar characteristics to the ones in the Graham et al. (2006) study. The factorial analyses were performed with M-plus version 7.3 (Muthén & Muthén, 2004/2008) using polychoric correlations with a WLSMV estimator because of the ordinal nature of the items. Items with loads lower than .40 and a high error variance were eliminated. The goodness of fit of the models was evaluated by estimating the χ2/degree freedom (χ2/df), Root Mean Square Error (RMSEA), Comparative Fit Index (CFI), and the Tucker-Lewis Index (TLI).

Table 3 shows the analysis of the items in the Spanish version of SESII-W (i.e., means, standard deviations, corrected item-total correlations, and Cronbach's alpha if the items were deleted) clustered into the factors derived by means of CFA. The results show the mean around the theoretical midpoint of the scale (i.e., 2.00; a minimum value is 1.72 and a maximum value is 3.23 in Sample 1, and a minimum is 1.74 and a maximum is 3.42 in Sample 2) and standard deviations very close to 1.00. The corrected item-total correlations were equal/greater than .30 (Nunnally & Bernstein, 1995), except for items 1 and 25 in Sample 1, and item 15 in Sample 2.

As for the reliability of the scales, we examined both their internal consistency (Cronbach's alpha; Table 3), and the 4-week (Time 1 to Time 2) and 8-week (Time 1 to Time 3) test-retest reliabilities. Table 4 shows the correlations between Time 1 to Time 2 and Time 1 to Time 3.

As reflected in the results from both samples, erotophilia and sexual sensation seeking positively correlated with SE and its sub-factors, and negatively with SI and its sub-factors, except for Concerns about Sexual Function. In general, the correlations between age at first sexual intercourse and number of sexual partners with different SESII-W factors showed the direction expected. There was no relationship between age at first sexual intercourse and Arousability, Smell, Partner Characteristics and Setting in Sample 1, and Smell and Partner Characteristics in Sample 2. Regarding the number of sexual partners, no relationship was found with Smell and Concerns about Sexual Function in Sample 1 (Table 5).

After translating and linguistically adapting the SESII-W, we tested the model of eight factors grouped into two higher-order dimensions of Sexual Excitation (SE) and Sexual Inhibition (SI) as proposed in the original study (Graham et al., 2006). A CFA for a population of university students resulted in a version of the scale consisting of 33 items, divided into eight factors: four for SE (Arousability, Sexual Power Dynamics, Smell, and Partner Characteristics) and four for SI (Setting, Relationship Importance, Arousal Contingency, and Concerns about Sexual Function). A second CFA for women from the general population also showed good fit indices. This factorial structure fit the DCM (Bancroft, 1999; Bancroft et al., 2009), which was the theoretical model on which the SESII-W is based. Previous studies recommend the use of eight sub-factors for they provide more information about the different manifestations of sexual excitation and inhibition in women and because the fit of the model worsened by including higher order factors (Bloemendaal & Laan, 2015; Graham et al., 2006; Velten et al., 2016). According to the results of this work, the use of the two-factor structure is recommended because it is simpler and shows a good fit and better indicators of reliability and external validity, as well as eight factors if more specific information about the sexual excitation and sexual inhibition in women is required.

Although the factor structure of this study is very similar to the original one, it should be noted that the sub-factor Setting, which belonged to SE in the original, is part of SI in the adaptation. The items in Setting evaluate the ability to become sexually excited/inhibited in anticipation of possible external threats that can affect sexual response (Janssen & Bancroft, 2007). Sexual inhibition is thus expected to increase in the presence of a perceived external threat (Bancroft & Janssen, 2000). Moreover, one of the most important mechanisms of sexual inhibition in women is social pressure (Bancroft et al., 2009; Graham et al., 2006), which is part of the content of these items. According to Bancroft (1999), the possibility of the existence of different types of sexual inhibition due to a lack of understanding of the nature and specificity of this response should be left open; especially in women. Therefore, we propose to further study sexual inhibition in women.

In accordance with the DCM, sexual excitation and sexual inhibition are relatively independent. As in the original version, its adaptation for the German population (Velten et al., 2016) and the present study, the correlations between the excitation and inhibition factors were low or nonexistent in both samples. This confirms the relative independence between sexual excitation and sexual inhibition (Bancroft et al., 2009). Furthermore, the present study revealed positive correlations between the SE sub-factors Arousability, Smell, and Partner Characteristics, with the SI sub-factor, Concerns about Sexual Function in Sample 1 and Partner Characteristics with Concerns about Sexual Function in Sample 2 (similar to Velten et al., 2016). Almost in all cases, the items Arousability, Smell, and Partner Characteristics, refer to the excitation produced by another person. This is not incompatible with a certain inhibition stemming from concern about one's own sexual functioning, which can be derived, among other things, from performance anxiety (Dove & Wiederman, 2000), high expectations (Sánchez-Fuentes, Salinas, & Sierra, 2016) or high sexual perfectionism (Stoeber & Harvey, 2016).

Overall, the reliability of the Spanish version of the SESII-W was adequate. Both the two higher-order factors as well as the eight sub-factors showed satisfactory internal consistency, except for Sexual Power Dynamics in Sample 1 and Concerns about Sexual Function in Sample 2. Items 5, 25, and 26 in Sexual Power Dynamics evaluate the potential impact of the use of physical force or domination in a sexual situation (Graham et al., 2006). All of the women in Sample 1 were born in the nineties, a decade in Spain in which there was a generational change in behaviors and attitudes (Fernández-Llebrez González & Camas-García, 2012). In recent years, young people have become more progressive and increasingly in favor of a more equal relationship between men and women (García-Cueto et al., 2015). This is particularly true of women, especially those with a higher education level (Ajenjo-Cosp & García-Román, 2014). As for the low reliability of Concerns about Sexual Function in Sample 2, this may be due to the higher mean age of this group. This factor may involve a better understanding of the body, of desire, of the couple and an increased acceptance of sexuality (Beckman, Waern, Gustafson, & Skoog, 2008). Consequently, these items may not represent them faithfully. Low reliability in factor Concerns about Sexual Function is consistent with the results obtained in the original study (Graham et al., 2006) and in Dutch (Bloemendaal & Laan, 2015) and German (Velten et al., 2016) adaptations. Both in this study and in the original (Graham et al., 2006), sexual excitation factors showed higher reliability values than those of sexual inhibition.

To obtain evidence of external validity, the SESII-W scores were correlated with sexual sensation seeking, erotophilia, age at first sexual intercourse, and number of sexual partners. The effect of age was controlled in the general population sample (Sample 2), since its effect on sexual excitation and sexual inhibition has been demonstrated (Bancroft et al., 2009; Velten et al., 2016), as well as on sexual difficulties in women (e.g., Hunter, Nakagawa, Van Den Eeden, Kuppermann, & Huang, 2016; Sierra et al., 2014). Correlations between SESII-W scores and the aforementioned variables revealed adequate evidence of validity of its measures, following the expected direction according to the hypotheses. Similarly to what happens in the original study (Graham et al., 2006) and Bloemendaal and Laan (2015) and Velten et al. (2016) adaptations, the lowest correlations are obtained between the sub-factor Concerns about Sexual Function, sexual sensation seeking and erotophilia. As hypothesized, higher scores for SE were related to a younger age of sexual debut, whereas the opposite occurred in the case of SI scores. These results are in line with other studies (Granados & Sierra, 2016; Piña-López & Rivero-Icedo, 2009), in which participants indicated sexual excitation as a factor that predisposed an early initiation of sexual intercourse. On the other hand, in both samples, SE was positively associated with the number of sexual partners. These results are consistent with previous studies, where sexual excitation is a predisposing factor for having sex with a higher number of sexual partners (see Granados & Sierra, 2016). Thus, sexual excitation positively predicted sex with multiple partners in a sample of university women (Piña-López & Rivero-Icedo, 2009), and a higher number of sexual partners was associated with higher SE in women from the general population (Nguyen et al., 2012).

In short, the Spanish version of the SESII-W has adequate psychometric guarantees and is a reliable and useful instrument for the assessment of sexual excitation in Spanish women, both in research and clinical practice. This scale provides a global score of SE and SI, as well as each of its sub-factors, and permits the interpretation of various components of sexual excitation and sexual inhibition. However, this study also had certain limitations. Although the participants were women with different sociodemographic characteristics, the sample was incidental, which does not allow the generalization of the results to the general Spanish population. In addition, all participants were heterosexual. Likewise, a measure of sexual functioning like the Female Sexual Function Index (FSFI; Rosen et al., 2000), that would allow to know the prediction capacity and to bring validity clues on the Spanish version SESII-W, was not included. Another aspect to consider is the limited privacy of participants while answering the scales in class or in centers, as well as the possible social desirability that may be present. It is recommended to consider these aspects in future studies. Future research should expand the study of SI in women. The scale should also be improved to include more items in the sub-factor Smell. The review of those factors with lower reliability is suggested in future studies. Additionally, it would be necessary to apply the scale to a sample of non-heterosexual women, a clinical population, and also females at sexual risk.

This research was funded by the Spanish Ministry of Education, Culture and Sports through grant AP2010-4843 for the training of university teachers awarded to the first author.