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ORIGINAL RESEARCH Implicit and Explicit Associations with Erotic Stimuli in Sexually Functional and Dysfunctional Men Jacques van Lankveld, PhD,* Ingrid Odekerken, MSc,* Lydia Kok-Verhoeven, MSc,* Susan van Hooren, PhD,* Peter de Vries, PhD,† Anja van den Hout, PhD,‡ and Peter Verboon, PhD* *Faculty of Psychology and Educational Sciences, Open University of the Netherlands, Heerlen, The Netherlands; † Department of Urology, Atrium Medical Center, Heerlen, The Netherlands; ‡Department of Medical Psychology, Atrium Medical Center, Heerlen, The Netherlands DOI: 10.1111/jsm.12930

ABSTRACT

Introduction. Although conceptual models of sexual functioning have suggested a major role for implicit cognitive processing in sexual functioning, this has thus far, only been investigated in women. Aim. The aim of this study was to investigate the role of implicit cognition in sexual functioning in men. Methods. Men with (N = 29) and without sexual dysfunction (N = 31) were compared. Main Outcome Measures. Participants performed two single-target implicit association tests (ST-IAT), measuring the implicit association of visual erotic stimuli with attributes representing, respectively, valence (‘liking’) and motivation (‘wanting’). Participants also rated the erotic pictures that were shown in the ST-IAT on the dimensions of valence, attractiveness, and sexual excitement to assess their explicit associations with these erotic stimuli. Participants completed the International Index of Erectile Functioning for a continuous measure of sexual functioning. Results. Unexpectedly, compared with sexually functional men, sexually dysfunctional men were found to show stronger implicit associations of erotic stimuli with positive valence than with negative valence. Level of sexual functioning, however, was not predicted by explicit nor implicit associations. Level of sexual distress was predicted by explicit valence ratings, with positive ratings predicting higher levels of sexual distress. Conclusions. Men with and without sexual dysfunction differed significantly with regard to implicit liking. Research recommendations and implications are discussed. van Lankveld J, Odekerken I, Kok-Verhoeven L, van Hooren S, de Vries P, van den Hout A, and Verboon P. Implicit and explicit associations with erotic stimuli in sexually functional and dysfunctional men. J Sex Med 2015;12:1791–1804. Key Words. Erectile Dysfunction; Implicit Cognition; Dual-Process Model; Implicit Association Test; Sexual Dysfunction

Introduction

T

heoretic models of sexual dysfunction have proposed cognitive processes as important determinants of sexual arousal that can explain the dysfunctional genital response to erotic stimulation of—otherwise—physically healthy men [1,2]. Importantly, cognitive processing occurs at differ-

© 2015 International Society for Sexual Medicine

ent levels of awareness and regulatory control. Sigmund Freud was one of the first theoreticians who suggested that sexual dysfunction is governed by cognitive-emotional mechanisms that largely operate outside of the individual’s conscious awareness and volitional control [3]. Probably only a limited part of the cognitive process is accessible for the individual in conscious awareness [4,5]. J Sex Med 2015;12:1791–1804

1792 Whereas early cognitive theory of sexual dysfunction (e.g., [1]) featured a central role for conscious dysfunctional cognizing, later models (e.g., [2]) have stressed, once more, that automatic cognitive processing occurring outside of awareness may also be involved in causing low sexual arousal. In the following paragraphs, we will briefly describe the recent models and the empiric support they received as the background against which our present study was developed. In his model of sexual dysfunction, Barlow [1] proposed that cognitive interference at the conscious level is a major cause of dysfunctional erectile performance. He postulated that sexually dysfunctional men, compared with men without erectile problems, tend to be more preoccupied with thoughts about dysfunctional erectile performance, that they focus their attention less on the available erotic stimuli, and expect low personal efficacy in becoming sexually aroused. Subsequent dysfunctional sexual performance is experienced as a confirmation of the preceding expectations, thus reinforcing the vicious circle, and may result in chronic sexual dysfunction. Studies using selfreport measures of thought content have provided ample support for the involvement of conscious negative cognition in erectile dysfunction. Nobre, Pinto-Gouveia and Gomes [6] found that men who suffered from sexual dysfunction were characterized by a strong performance-oriented (“macho”) ideal role model, when asked to which extent they endorsed statements such as “a real man is always ready for sex and must be capable of satisfying any woman.” Moreover, sexually dysfunctional men were found to harbor more negative sexual self-schemas [7], characterized by internal and stable attributions of failure and personal incompetence [8–10]. Although these studies strongly suggest the involvement of specific negative conscious cognitions in the etiology of sexual dysfunction, the cross-sectional design of these studies cannot eliminate the possibility that the negative content of conscious thought is an effect rather than a cause of sexual dysfunction. More than a decade after Barlow introduced his model, Janssen and colleagues [2] introduced flawed automatic cognition as an additional determinant of sexual arousal problems in their information-processing model of sexual responding. A central proposition in this model is that erotic stimuli can evoke both sexual and nonsexual meaning, and that this evaluation of stimuli as sexual vs. nonsexual crucially determines, respectively, the activation or inhibition of sexual arousal. J Sex Med 2015;12:1791–1804

van Lankveld et al. Sexual meaning will initiate and maintain the physiologic sexual response as well as the subjective experience of sexual arousal, whereas nonsexual meaning serves to inhibit sexual arousal. The model proposes that the evaluation of stimuli as either sexual or nonsexual occurs both at conscious and deliberate, and at unconscious and automatic levels of processing. The model also postulates that erotic stimuli, even when they are not consciously perceived, may automatically initiate the efferent physiologic process that underlies the genital response. Empiric support for Janssen et al.’s model with regard to the involvement of unconscious control over the genital response was provided by experimental research in men and women using a subliminal priming paradigm [11– 13]. In this paradigm, trials consist of two stimuli that are subsequently presented. The first stimulus is the “prime,” and the second is the target. The reaction time (RT) of a key press, following target stimulus onset, with which the respondent categorizes the target stimuli as, for instance, sexual or nonsexual, is used as dependent variable. The priming stimulus can be erotic or nonerotic. Although priming stimuli were made inaccessible to conscious cognitive elaboration by backward masking and very brief presentation duration, identification of sexual targets was, nevertheless, found to be enhanced after presentation of erotic primes, compared with neutral prime stimuli. These findings were interpreted as evidence that sexual representations in memory can be activated automatically and below the threshold of conscious awareness [14]. How can (conscious or unconscious) negative cognition impair erectile performance? A cognitive processing-capacity model of sexual arousal might explain why the harboring of certain thought content hinders the deployment and maintenance of the genital sexual response [15– 17]. The capacity of the brain to simultaneously process bits of information is considered to be fundamentally limited [18,19]. The sharing of processing capacity with nonerotic thought content diminishes the capacity that is required for the processing of erotic stimuli. Several experimental studies using a double-task paradigm have provided support for the processing-capacity model by demonstrating that the genital response during erotic stimulation becomes progressively lower when a concurrent cognitive task captures increasingly more processing capacity. This was demonstrated for sexual arousal responses in both men and women [20–25], although some other studies

Implicit and Explicit Cognitions in Male Sexual Dysfunction suggested, in contrast, that cognitive distraction facilitated erectile responses [26,27]. Although the information-processing model of sexual responding of Janssen et al. [2] postulates the involvement of both conscious and unconscious processing in the control of efferent sexual responses, it does not articulate the mechanism in which conscious and unconscious processes might interact to facilitate vs. hinder sexual arousal, and the contextual determinants of such interaction. A possible account of this interaction mechanism is offered by dual-process theories, in which a crucial role is attributed to working memory capacity to determine the relative impact of cognitions operating at different levels of awareness [5,28–30]. Essentially, these models postulate that the constraints that are imposed on the functioning of the working memory by contextual factors, including—among others—fatigue, stimulus degradation, and alcohol intoxication, suppress the regulatory function of conscious, deliberate cognizing, as this is dependent upon the availability of sufficient processing resources. Limited working memory thus clears the way for unconscious, automatic cognitive processing that operates in a fast and parallel mode, independent of working memory capacity. In this manner, a dual-process framework might be able to reconcile the thus far disparate psychologic models of sexual functioning, that propose, respectively, conscious cognitive interference [1], conscious and unconscious information-processing [2], and cognitive processing capacity [15,17] as determinants of sexual responding. The individual has—by definition—no direct access to his or her own unconscious (implicit) cognitive processing. Its presence and impact can, however, be inferred from investigations using indirect cognitive measures, demonstrating that unconscious and automatic processing is implicitly involved in behavioral control. Incorporating such implicit cognitive mechanisms in addition to explicit and conscious cognition has been found to increase the explanatory power of psychologic models in several other areas of psychopathology, including affective disorders, alcohol-related disorder, and eating disorder (see [31], for a review). To warrant further investigation of dual-process explanations of sexual functioning and sexual dysfunction, it is crucial that sexually dysfunctional individuals should be demonstrated to differ regarding their implicit sexual cognitions from individuals whose sexual functioning is uncom-

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promised, as well as the conditions under which they differ. The differential involvement of implicit cognition has already been demonstrated in men and women with heterosexual vs. homosexual orientation (e.g., [32–34]). With regard to sexual functioning, however, the empiric evidence is thus limited to the study of female sexual responding. In two studies implicit associations of women with sexual disorders have been compared with those in sexually healthy women [35,36]. Women with sexual pain disorder and lifelong vaginismus showed enhanced automatic sex-disgust associations using two single-target implicit association tasks, assessing the strength of the implicit associations of vaginal penetration stimuli with, respectively, disgust and threat [35]. Both groups of dysfunctional women differed significantly from healthy women. In another study, women with acquired hypoactive sexual desire disorder (HSDD) were compared with sexually functional women. Women with HSDD exhibited less positive (but not more negative) implicit associations with sexual stimuli than healthy women, using a single-target implicit association task to assess the strength of the implicit associations of vaginal penetration stimuli with liking (“positive” vs. “negative” valence) [36]. Whether implicit associations cause sexual dysfunction or change as a result of it, cannot be inferred from these studies, because of their observational design. Thus far, the involvement of implicit associations with sexual stimuli in sexual functioning has not been investigated in men. The aim of the present study was to investigate the presence of differences between men with and without sexual dysfunction regarding their implicit associations with erotic stimuli, and to investigate the relative strength of the association of implicit and explicit cognitions with their self-reported sexual functioning. Following the studies of Borg et al. [35] and Brauer et al. [36] that showed differences between symptomatic and healthy women, we used singletarget implicit association tests (ST-IAT) [37] in our study. The ST-IAT is a modified version of the original implicit association test (IAT) [38], using only sexual stimuli to represent the target category. In the original IAT, two target categories are contrasted (e.g., men vs. women; animate vs. inanimate; political right-wing vs. left-wing, etc.). These categories form naturally occurring or intuitively correct opposites. However, sexual stimuli do not have an intuitively or intrinsically opposing category. Both the ST-IAT [37] and the IAT J Sex Med 2015;12:1791–1804

1794 [39,40] were found to possess good psychometric characteristics. Another relevant distinction should be introduced at this point. A relatively strong (automatic) association of sexual stimuli with positive valence may be a prerequisite for satisfactory sexual functioning. However, this automatic “liking” of sexual stimuli might be insufficient, and another dimension, a relatively strong automatic tendency to approach sex might also be necessary for adequate sexual functioning. This is analogous to the distinction between hedonic value of and craving reactions to psychotropic drug-related stimuli [41,42], and in line with recent findings of the differential effects of implicit “liking” and “wanting” associations with food stimuli in disordered eating behavior [43]. Based on these notions, we have used two versions of the ST-IAT that measure the implicit associations of sexual stimuli with, respectively, valence (“liking”) and desire (“wanting”). Whether wanting and liking associations are differentially involved in sexual dysfunction cannot be inferred from previous research; this is the first study, to our knowledge, of the involvement of implicit wanting associations in sexual dysfunction. The investigation of cognitive determinants of sexual functioning should be positioned within a more comprehensive biopsychosocial theoretic framework. Several biologic factors have been shown to underpin the functionality of the sexual response system, including hormonal [44], vascular [45], and neurologic systems [46], and when the individual suffers from impairments of these systems, sexual functioning can be compromised [47]. Next to more abrupt impairments because of disease and its pharmacologic treatment [48–50], including lower urinary tract symptoms (see [51]) and prostatic hyperplasia (see [52]), the functioning of several of these biologic systems has been shown to decrease during the individual’s lifetime and is therefore significantly associated with age [53,54]. In addition, age differences have been found in studies of implicit associations involved in emotion (e.g., [55]) that are implied in sexual functioning, including anger [56]. As a secondary research aim, age will be exploratively investigated as a moderating factor. In sum, we aim to investigate differences between sexually functional and dysfunctional men regarding the implicit and explicit associations of erotic stimuli with liking and wanting. We also want to investigate the association of implicit and explicit sexual cognition with self-reported level of sexual functioning and sexual distress. Specifically, J Sex Med 2015;12:1791–1804

van Lankveld et al. we test the hypotheses that (i) sexually dysfunctional men will show weaker liking and wanting associations with erotic stimuli than functional men, as well as lower explicit positive evaluations of erotic stimuli; (ii) positive implicit associations of erotic stimuli with liking and wanting will be associated with higher self-reported level of sexual functioning and sexual distress; and (iii) positive explicit ratings of erotic stimuli will be associated with higher self-reported level of sexual functioning and sexual distress. Furthermore, in an exploratory analysis, we will investigate whether these associations are qualified by age. Method

Participants Participants in the study were heterosexual men who visited an outpatient urology clinic for various urologic complaints, either with or without sexual complaints. Participants were required to have thorough mastery of the Dutch language. This was deemed necessary to be able to answer all relevant questions in the study and to perform the computer tasks. Clinically relevant psychopathology, based on questionnaire responses in the screening phase of participation in the study (Hospital Anxiety and Depression Scale [HADS] total score > 15; [57]), was used as exclusion criterion. None of the tested participants were excluded. Recruitment took place in a period of 10 weeks. Of approximately 400 patients who met the inclusion criteria, 60 male patients (15%) participated. A substantial proportion of urologic patients who suffer from sexual dysfunction do not self-present its existence during their consultation with the urologist [58]. Allocation to the functional or dysfunctional subgroup was therefore based on patient self-assignment, regardless of whether or not they had reported sexual dysfunction to their urologist. For this purpose, they responded to the question “Do you currently experience any problem with your sexual functioning?” that was included in the questionnaire on demographic characteristics and medical history. Demographic and medical characteristics of the study sample and subgroups are shown in Table 1. Ethical clearance for the study was obtained from the hospital’s institutional review board. Instruments Sexual Functioning International Index of Erectile Functioning (IIEF). The IIEF [59] is a 15-item self-report questionnaire for assessing male sexual function-

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Implicit and Explicit Cognitions in Male Sexual Dysfunction Table 1 Demographic, medical, sexual, and psychologic functioning characteristics of sexually functional and dysfunctional participants

Demographics Age (years) Steady relationship Length of current sexual relationship (years) Education level (highest achieved) Elementary—lower secondary Higher secondary—professional College—university Medical condition (multiple answers possible) Lower urinary tract symptoms Prostate disease Erectile dysfunction Kidney stones Hematuria Phimosis Sterilization request Penile deformity Sexual functioning (IIEF) Erectile functioning Orgasmic functioning Sexual desire Satisfaction with intercourse Global sexual satisfaction IIEF total score Sexual distress (SDS) Total SDS Score Help or sexual problem Psychological functioning (HADS) Depression Anxiety

Sexually functional men (N = 31)

Sexually dysfunctional men (N = 29)

Total (N = 60)

M (SD)

M (SD)

M (SD)

%

59.0 (15.9)

%

63.0 (11.3) 84

30.8 (18.9)

60.9 (11.3) 93

32.4 (16.4) 16 52 32

%

88 31.6 (17.5)

38 48 14

27 50 23 29 24 22 10 8 6 6 2

19.2 (11.1)c 6.2 (3.9)b 6.3 (1.8) 7.3 (5.3)a 7.2 (2.4)b 46.1 (21.8)c

9.0 (7.1)c 3.4 (3.4)b 5.5 (2.5) 3.9 (4.6)a 4.9 (2.5)b 26.8 (17.0)c

9.1 (9.1)c

22.7 (13.3)c 69c

3.7 (2.7) 5.0 (2.8)

5.1 (3.7) 5.8 (3.6)

14.3 (10.6) 4.9 (3.9) 5.9 (2.2) 5.6 (5.2) 6.1 (2.7) 36.7 (21.8) 15.7 (13.1) 13c

40 4.4 (3.3) 5.4 (3.2)

a P < 0.05; bP < 0.01; cP < 0.001. HADS = Hospital Anxiety and Depression Scale; IIEF = International Index of Erectile Functioning; SD = standard deviation; SDS, Sexual Distress Scale.

ing in five areas: erectile function, orgasmic function, sexual desire, intercourse satisfaction, and overall sexual satisfaction. Subscale scores are summated to form a global index of sexual functioning (IIEF total score). Participants provided answers on a six-item scale, with higher scores indicating better sexual functioning. In a psychometric study, the internal consistency of the IIEF was found to be excellent (Cronbach’s α between 0.92 and 0.96), and test–retest reliability was high (r = 0.84 [59]). In the present study, the internal consistency was found to be ranging from satisfactory for the overall sexual satisfaction subscale (Cronbach’s α = 0.75) to excellent for the erectile function subscale (α = 0.95). Sexual Distress Scale (SDS). The SDS is comprised of the 12 items of the Female Sexual Distress Scale [60]. The wording of the items is gender neutral, and the aspects of sexual distress that are described

in them pertain to both female and male sexual problems. The FSDS has successfully been used in male samples [61]. The version of the FSDS we used was validated in Dutch female samples [62]. It is organized in a single scale and was found to have good psychometric properties with Cronbach’s α = 0.93. In the present study, the internal consistency was found to be excellent, with Cronbach’s α = 0.97.

Implicit Associations with Sexual Stimuli ST-IAT. The ST-IAT is a computerized RT test for measuring the strength of the implicit associations of a single-target category (erotic stimuli) with, respectively, liking and wanting. It is a modified version of the IAT [38] with similar reliability characteristics [63]. In accordance with standard IAT practice (e.g., [39]) the “erotic” target in both the liking and the wanting ST-IATs was represented using four pictures of heterosexual interacJ Sex Med 2015;12:1791–1804

1796 Table 2

van Lankveld et al. Sequence of trial blocks in the sex-liking ST-IAT

Block

Number of trials

Function

Items assigned to left-key response

Items assigned to right-key response

1 2 3 4 5

16 12 36 12 36

Attribute practice Practice Test Practice Test

Positive Positive Positive Positive Positive

Negative Negative Negative Negative Negative

(8) (4) + erotic (4) (12) + erotic (12) (4) (12)

(8) (4) (12) (4) + erotic (4) (12) + erotic (12)

Note. For half the subjects, the positions of blocks 2 and 3 are switched with those of blocks 4 and 5, respectively. ST-IAT = single-target implicit association test.

Table 3

Sequence of trial blocks in the sex-wanting ST-IAT

Block

Number of trials

Function

Items assigned to left-key response

Items assigned to right-key response

1 2 3 4 5

16 12 36 12 36

Attribute practice Practice Test Practice Test

I I I I I

I I I I I

want want want want want

(8) (4) + erotic (4) (12) + erotic (12) (4) (12)

don’t don’t don’t don’t don’t

want want want want want

(8) (4) (12) (4) + erotic (4) (12) + erotic (12)

Note. For half the subjects, the positions of blocks 2 and 3 are switched with those of blocks 4 and 5, respectively. ST-IAT = single-target implicit association test.

tion [35], selected1 from the International Affective Picture System (IAPS) [64]. Each picture depicted a female and a male actor engaging in explicit sexual activity, without showing full close-up shots of the genitals. Female breasts were fully visible. The male actors’ penis was not visible. Participants were instructed to assign the words and pictures appearing in the center of a laptop computer screen to one of two categories, using the “z” and “m” keyboard keys. The attribute categories for the liking ST-IAT were “positive” (represented by the words humor, health, gift, and peace) and “negative” (represented by the words hatred, war, disease, and pain). The labels of the attribute categories (“positive” and “negative”) were continuously shown in the upper left and right corners of the screen. Upon a correct response, the next stimulus was presented. Following an incorrect response, error feedback was given using a red X that replaced the stimulus and remained on the screen until the correct response was given. Tables 2 and 3 displays the setup of the ST-IAT procedure. To familiarize participants with the procedure, the ST-IAT started with a practice run with the attribute stimuli only. Next, there were two blocks of 48 trials, each starting with a practice block of 12 trials in which both erotic pictures and positive and negative attribute 1

Selected erotic pictures were IAPS-numbers 4658, 4659, 4664, and 4680.

J Sex Med 2015;12:1791–1804

words were randomly presented, followed by a test block of 36 trials. Within both practice and test blocks, the numbers of key presses on both response keys were unequal. Within the erotic– positive test block, participants made 24 key presses on the right key, and 12 presses on the left key. In the erotic–negative test block, this was reversed, with 12 right-key and 24 left-key presses being made. The same target and attribute stimuli were used in the practice and test trials [39]. In one block erotic pictures and positive words were mapped on the same response key (“sex-positive” combination), whereas in the other block, erotic pictures and negative words shared the same response key (“sex-negative” combination). The order of presentation of sex-positive and sexnegative blocks was counterbalanced across participants. Because performance is assumed to be faster when the association between the target and the attribute is congruent with the participant’s representational network than when this association is incongruent, one of both combinations (sex-positive or sex-negative) is expected to yield briefer RTs. The attribute categories for the wanting ST-IAT were “I want” (represented by the words humor, health, gift, and peace) and “I do not want” (represented by the words hatred, war, disease, and pain). The labels of the attribute categories (“I want” and “I do not want”) were continuously shown in the upper left and right corners of the screen. The same erotic pictures were used

Implicit and Explicit Cognitions in Male Sexual Dysfunction as in the liking ST-IAT. The next stimulus was presented irrespective of the selected response key, to emphasize the more personalized nature of this ST-IAT version [65]. The order of performance of the liking and wanting ST-IATs was fixed, with the liking ST-IAT used as the first task.

Explicit Associations with Sexual Stimuli Explicit Evaluation Scale of Erotic Stimuli (EEES). To index explicit cognitive associations with sexual stimuli, the same erotic pictures that were used in both ST-IATs were presented on a computer screen and participants evaluated each picture on three dimensions, using 5-point Likert scales (valence [very positive to very negative], attractiveness [not at all to very attractive], and sexual excitement [not at all to very exciting]). Per participant mean rating scores across the four ST-IAT pictures were calculated for, respectively, “EEES-valence,” “EEES-attractiveness,” and “EEES-excitement.” The EEES item scores were entered in a principal components analysis using varimax rotation. A single-factor solution was found, explaining 89.1% of the variance, with factor loadings ranging from 0.832 to 0.951. In further analyses, a sum score was used to index explicit cognitive ratings. Psychopathology HADS. The HADS was used to assess the exclusion criterion of the severity of depression and anxiety symptoms. It is a 14-item self-report questionnaire, specifically used in hospital and outpatient clinic settings [66]. It is organized in two subscales for the domains of, respectively, anxiety and depression. High scores represent higher levels of anxiety and depression. The HADS has been found to possess satisfactory to high internal consistency in Dutch samples, with Cronbach’s α ranging from 0.71 to 0.90 [57]. In the present study, the internal consistency was found to be satisfactory for the anxiety subscale (Cronbach’s α = 0.77) and almost satisfactory for the depression subscale (Cronbach’s α = 0.69). Procedure All participants visited an outpatient urology clinic for clinical evaluation and treatment. Consecutive patients of one of the authors (PdV, urologist), who met the inclusion and exclusion criteria, were invited by their urologist for participation in the study within a time period of 10 weeks. If patients were interested, they were given an information leaflet and an informed consent form. Those who

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wanted to give their consent immediately were allowed to participate in the testing directly following their visit to the urologist. After signing the informed consent form, participants were escorted to a quiet space and received further instructions. However, all invited participants were allowed to postpone their decision to participate; those who gave their consent at a later moment were scheduled for testing in a follow-up visit to the hospital. First, the ST-IAT tasks were performed. Subsequently, participants completed the online questionnaires (demographic questions, explicit ratings of the ST-IAT erotic pictures, IIEF, and HADS).

Statistic Analysis To index the implicit associations of erotic stimuli with liking and wanting, the optimalized D600 computation algorithm of Greenwald, Nosek and Banaji [67] was employed. Only test trial data were used to calculate the D600 ST-IAT index. In this measure, RTs below 400 ms were discarded and RTs above 2,500 ms were replaced with this value (2,500) before calculation of the mean RTs. RTs from error trials were replaced with the mean RT of correct responses in the same block in which the error occurred plus a 600-ms penalty. The D600 index score was calculated as the difference score between the mean RTs to the sex-positive and sexnegative combination blocks (sex-positive minus sex-negative), divided by the standard deviation calculated across all blocks with exception of the attribute practice block. Lower D600 index scores indicate that erotic stimuli are more strongly associated with liking and wanting. Using d = 0.65 as a conservative mean effect size estimate of IAT differences, based on group comparison studies [39], we required 60 participants to obtain 80% statistic power of an independentsamples t-test, using P < 0.05. Analyses were performed using SPSS Version 21 (SPSS Inc., Chicago, IL, USA). In a preliminary analysis, the self-categorization by participants into, respectively, sexually functional and dysfunctional subgroups was checked using multivariate analysis of variance (MANOVA) with IIEF subscale scores, the total IIEF score and the SDS scale as dependent variables. The potentially confounding impact of age was examined, using multivariate analysis of covariance (MANCOVA). Data were examined to check the assumptions for statistic analyses. To test hypothesis 1, a MANOVA was performed with ST-IAT liking and wanting indices and EEES sum scores as dependent variables, and sexual function status (sexually J Sex Med 2015;12:1791–1804

1798 functional vs. dysfunctional) as between-subjects factor. Hierarchic logistic regression analysis was used to explore the moderation by age of the association of sexual function status with implicit liking, implicit wanting, and explicit cognition. To test hypothesis 2, hierarchic linear regression analyses were performed with ST-IAT liking and wanting indices as independent variables, and respectively sexual functioning (IIEF total score) and sexual distress (SDS total score) as dependent variables. To test hypothesis 3, linear regression analyses were performed with EEES sum score as independent variable and, respectively, level of sexual functioning (IIEF total score) and sexual distress (SDS total score) as dependent variables. In exploratory hierarchic linear analyses, the moderation effect of age on the association of ST-IAT liking and wanting indices and EEES, on the one hand, and sexual function status and sexual functioning level on the other hand, was investigated. For this purpose, the logistic and linear regression analyses were repeated, adding standardized age score and the interaction of age with ST-IAT liking and wanting indices and EEES as predictors to the models in a subsequent step. Effect sizes and their 95% confidence intervals (CIs) were calculated [68]. Results

Preliminary Analyses Of 60 included participants, 29 explicitly selfreported suffering from a sexual problem; 31 explicitly reported satisfactory sexual functioning and absence of sexual problems. To check the selfcategorization of participants as, respectively, sexually functional and dysfunctional, a MANOVA was performed with IIEF subscale scores, IIEF total score, and SDS scores as dependent variables, and sexual function status (sexually functional vs. dysfunctional) as between-subjects factor. A main effect of sexual function status was found (F(6.53) = 5.9, P < 0.001, partial η2 = 0.40 [95% CI: 0.17–0.48]). Post hoc univariate tests showed that sexually dysfunctional participants had lower scores, indicating lower sexual functioning, on erectile functioning (F(1.58) = 17.8, P < 0.001, partial η2 = 0.24, [95% CI: 0.09–0.37]), orgasmic functioning (F(1.58) = 8.4, P < 0.01, partial η2 = 0.13, [95% CI: 0.02–0.26]), intercourse satisfaction (F(1.58) = 7.0, P < 0.05, partial η2 = 0.11, [95% CI: 0.01–0.24]), global sexual satisfaction (F(1.58) = 12.5, P < 0.001, partial η2 = 0.18, [95% CI: 0.05–0.31]), IIEF total score (F(1.58) = 14.5, J Sex Med 2015;12:1791–1804

van Lankveld et al. Table 4 Bivariate correlations between implicit and explicit associations of erotic stimuli with valence and motivation

D600 liking D600 wanting EEES

D600 liking

D600 wanting

EEES valence

— 0.308* −0.228

— −0.354**

—

*P < 0.05 (two-tailed); **P < 0.01 (two-tailed). EEES = Explicit Evaluation Scale of Erotic Stimuli.

P < 0.001, partial η2 = 0.20, [95% CI: 0.07–0.34]), and higher sexual distress (SDS total score, F(1.58) = 21.5, P < 0.001, partial η2 = 0.27, [95% CI: 0.12–0.41]), whereas both groups did not differ with regard to their level of sexual desire (P > 0.05). These findings were considered to support the adequacy of the participants’ self-categorization. Age was not significantly different in both groups ([M = 63.0 years vs. M = 59.0 years], t = 1.1, degrees of freedom = 54, P = 0.257). To investigate the impact of age on sexual functioning, the previous analysis was repeated as MANCOVA, with age entered as covariate. The main effect of sexual function status was replicated (F(6.52) = 5.6, P < 0.001, partial η2 = 0.39), and a main effect of age was found (F(6.52) = 3.6, P = 0.004, partial η2 = 0.30). Higher age was found to be correlated with lower sexual function on all IIEF subscales (−0.50 < r < −0.33, Ps < 0.01), except for overall sexual satisfaction, and sexual distress (both Ps > 0.05). The bivariate correlations of the implicit associations of erotic stimuli with liking and wanting, and the explicit ratings of erotic stimuli are shown in Table 4. To check the effect of presentation order of the two ST-IAT combinations on the ST-IAT index, a hierarchic logistic regression analysis was performed with sexual function status (sexually functional vs. dysfunctional) as dependent variable. In the first step, ST-IAT liking was entered; in the second step presentation order, and the interaction term of presentation order with ST-IAT liking were entered as predictor variables. A test of the model after the first step against a constant-only model was significant, with model χ2(1) = 3.97, P = 0.046. ST-IAT liking made a significant contribution to prediction, B = −0.965, P = 0.057, 95% CI: 0.14–1.03. After the second step, the regression model was no longer significant, model χ2(3) = 4.00, P = 0.26. Using ST-IAT wanting as predictor variable, the regression model was not

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Implicit and Explicit Cognitions in Male Sexual Dysfunction Table 5 Implicit and explicit cognitions in sexually functional and sexually dysfunctional men; the interaction with presentation order of the sex-positive and sex-negative combination blocks of the ST-IAT D600 liking

Sexual dysfunction No Yes ST-IAT order 1† 2‡ Sexual dysfunction No/ST-IAT order 1 2 Yes/ST-IAT order 1 2

D600 wanting

EEES sum score

M

SD

M

SD

M

SD

−0.151* −0.435*

0.537 0.566

−0.242 −0.360

0.518 0.610

10.85 10.91

2.79 2.68

−0.189 −0.402

0.537 0.584

−0.239 −0.368

0.588 0.535

11.13 10.60

2.70 2.75

−0.068 −0.252

0.457 0.624

−0.134 −0.374

0.545 0.468

10.84 10.88

2.83 2.85

−0.326 −0.552

0.601 0.521

−0.359 −0.362

0.630 0.611

11.47 10.32

2.60 2.73

→ sex-negative; ‡sex-negative → sex-positive; *P < 0.05. SD = standard deviation; ST-IAT = single-target implicit association test.

†Sex-positive

significant at either step. Presentation order was not used as a factor in further analyses.

Implicit and Explicit Associations with Erotic Stimuli of Sexually Functional and Dysfunctional Men Descriptive statistics of implicit and explicit scores as a function of sexual function status and presentation order are shown in Table 5. Mean ST-IAT index scores were negative in both groups, indicating a stronger implicit association of erotic stimuli with positive valence than with negative valence for men in both groups. A MANOVA was performed with ST-IAT liking and wanting scores and EEES sum scores as dependent variables and sexual function status as fixed factor. Upon visual inspection of the boxplots of the distributions of the ST-IAT liking and wanting scores, five univariate outliers were identified, two sexually functional and three sexually dysfunctional participants. One univariate outlier among the EEES sum scores was found of a sexually functional participant. No multivariate outliers were detected. After deletion of the outliers, 54 cases were left for analysis. A significant multivariate effect was found, F(3.50) = 3.9, P = 0.014, partial η2 = 0.19. Follow-up testing revealed a significant effect of ST-IAT liking (F(1.52) = 11.4, P = 0.001, partial η2 = 0.18), whereas the effects of ST-IAT wanting (F(1.52) = 0.9, P = 0.34, partial η2 = 0.02) and the explicit ratings (F(1.52) = 0.1, P = 0.81, partial η2 = 0.00) were not significant. Compared with sexually functional participants, sexually dysfunctional participants had more negative ST-IAT index scores, indicating a stronger automatic association with positive valence.

Associations of Implicit and Explicit Cognitions with Sexual Functioning and Sexual Distress A series of hierarchic linear regression analyses were performed with, respectively, level of sexual functioning (IIEF total score) and sexual distress scores (SDS) as dependent variables, and with ST-IAT liking and wanting indices, and EEES sum scores as independent variables. For each analysis, the assumptions of normality, linearity and collinearity, and the presence of outliers were evaluated. If a significant model was revealed, the analyses were repeated for an exploratory investigation of the potential moderation by age of the association of the predictor variables with sexual functioning. Standardized age scores and the interaction terms of age with the implicit and explicit cognition variables were entered as predictor variables in the second step. A linear regression analysis was performed between level of sexual functioning as dependent variable and ST-IAT liking and wanting scores as predictors. The regression model was not significant compared with a constant-only model, R2 = 0.02, F(2, 57) = 0.68, P = 0.51 (see Table 6). A linear regression analysis was performed with level of sexual functioning as dependent variable and EEES sum score as predictor. The regression model was not significant compared against a constant-only model, R2 = 0.03, F(1, 57) = 1.95, P = 0.17 (see also Table 6). A linear regression analysis was performed with level of sexual distress as dependent variable and ST-IAT liking and wanting index scores as predictor variables. The regression model was found to be significant against a constant-only model, J Sex Med 2015;12:1791–1804

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van Lankveld et al.

Table 6 Hierarchic linear regressions of implicit liking, implicit wanting, and explicit ratings of erotic stimuli on sexual functioning level† Predictor Variables

B

SE

β

t

Step 1 R = 0.02, F(2, 57) = 0.68, P = 0.51 (IV = implicit liking, implicit wanting) Constant 36.837 3.370 10.931 ST-IAT liking 5.276 5.301 0.137 0.995 ST-IAT wanting −4.737 5.324 −0.122 −0.890 Step 1 R2 = 0.03, F(1, 57) = 1.95, P = 0.17 (IV = explicit ratings of erotic stimuli) Constant 20.188 12.493 0.182 1.616 EEES 1.543 1.106 1.395

P

95% CI

0.000 0.324 0.377

30.089 −5.338 −15.397

43.586 15.891 5.923

0.112 0.169

−4.830 −0.672

45.206 3.757

2

Note. †IIEF total score. EEES = Explicit Evaluation Scale of Erotic Stimuli; CI, confidence interval; IIEF = International Index of Erectile Functioning SE = standard error; ST-IAT = singletarget implicit association test.

R2 = 0.10, F(2, 57) = 3.25, P = 0.046 (see Table 7). However, both ST-IAT liking, β = −0.197, P = 0.140, 95% CI: −10.724–1.553, and ST-IAT wanting, β = −0.198, P = 0.139, 95% CI: −10.787– 1.542, did not contribute significantly as predictor. A linear regression analysis was performed between level of sexual distress as dependent variable and EEES sum scores as predictor. The regression model was significant, R2 = 0.08, F(1, 58) = 4.90, P = 0.031 (see Table 7). 95% CI were calculated to verify the significance of the regression coefficient. Positive ratings of erotic stimuli were associated with higher levels of sexual distress, β = 0.279, P = 0.031, 95% CI: 0.129–2.573.

Exploratory Analysis of Moderation by Age of the Associations of Implicit and Explicit Cognitions with Sexual Function Status, Level of Sexual Functioning, and Level of Sexual Distress A hierarchic logistic regression analysis was performed with sexual function status (sexually functional vs. dysfunctional) as dependent variable. In

the first step, ST-IAT liking was entered; in the second step, age and the interaction term of age with ST-IAT liking were added. As expected, a test of the model in the first step against a constantonly model proved significant, model χ2(1) = 3.97, P = 0.046. However, adding age and the interaction term of age with ST-IAT liking in the second step did not increase predictive value, step χ2(2) = 2.63, P = 0.27. Table 8 presents the results of the regression analyses. A hierarchic linear regression analysis was performed with level of sexual distress as dependent variable and EEES sum score as predictor in the first step, and age and the interaction terms of age with EEES sum score in the second step. As expected, a test of the model in the first step against a constant-only model proved significant, R2 = 0.08, F(1.56) = 4.90, P = 0.031. However, adding age and the interaction terms of age with EEES sum score to the model did not increase the proportion of explained variance, R2 change = 0.03, F(2.56) = 0.87, P = 0.43 (see Table 7).

Table 7 Hierarchic linear regression of implicit liking, implicit wanting, and explicit ratings of erotic stimuli on sexual distress level† Predictor variable

B

SE

β

t

Step 1 R = 0.10, F(2.57) = 3.25, P = 0.046 (IV = implicit liking, implicit wanting) Constant 12.944 1.949 6.642 ST-IAT liking −4.586 3.065 −0.197 −1.496 ST-IAT wanting −4.622 3.078 −0.198 −1.502 Step 1 R2 = 0.08, F(1, 58) = 4.90, P = 0.031 (IV = explicit ratings of erotic stimuli) Constant 0.947 6.844 0.138 EEES 1.351 0.611 0.279 2.213 Step 2 R2change = 0.03, F(2.56) = 0.87, P = 0.43 ST-IAT liking 1.864 2.200 0.718 0.397 Age −0.364 0.264 1.892 0.169 Age × ST-IAT liking −0.581 0.453 1.649 0.199 Constant 1.384 1.258 1.210 0.271

P

95% CI

0.000 0.140 0.139

9.041 −10.724 −10.787

16.846 1.553 1.542

0.890 0.031

−12.753 0.129

14.647 2.573

6.451 0.695 0.559 3.991

0.086 0.414 0.230

481.150 1.167 1.358

2

Note. †SDS total score. EEES = Explicit Evaluation Scale of Erotic Stimuli; CI, confidence interval; SDS = Sexual Distress Scale; SE = standard error; ST-IAT = single-target implicit association test.

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Implicit and Explicit Cognitions in Male Sexual Dysfunction Table 8

Hierarchic logistic regression of ST-IAT liking and age on sexual function status†

Predictor variable

B

SE

Step 1 R2 = 0.09 (Nagelkerke). Model χ2 (1) = 3.97, P = 0.046 ST-IAT liking −0.965 0.508 Constant −0.350 0.307 2 2 Step 2 R = 0.16(Nagelkerke). Step χ (2) = 2.63, P = 0.27 ST-IAT liking 1.864 2.200 Age −0.364 0.264 Age × ST-IAT liking −0.581 0.453 Constant 1.384 1.258

Wald χ2

P

Exp(B)

95% CI

3.610 1.299

0.057 0.254

0.381

0.141

1.03

0.718 1.892 1.649 1.210

0.397 0.169 0.199 0.271

6.451 0.695 0.559 3.991

0.086 0.414 0.230

481.150 1.167 1.358

Note. †Sexually functional vs. sexually dysfunctional EEES = Explicit Evaluation Scale of Erotic Stimuli; CI, confidence interval; SDS = Sexual Distress Scale; SE = standard error; ST-IAT = single-target implicit association test.

Discussion

This is the first study in which both implicit and explicit cognitions were investigated in men with self-identified sexual problems and in sexually well-functioning men. Both groups were found to show positive implicit, automatic associations of erotic stimuli with valence. Compared with sexually functional men, sexually dysfunctional men were found to harbor stronger implicit associations of erotic stimuli with positive valence. In a linear regression analysis, using sexual functioning as a continuous variable, however, ST-IAT liking and wanting scores were found to be neither significant predictors, nor explicit cognitions. Explicit cognition, however, was found to significantly predict level of sexual distress, which is an important aspect of sexual dysfunction. Because no direct comparison with previous studies among men using indirect measurement of implicit cognition is possible, we will discuss this finding against the background of similar work in female samples. In previous studies using single-target IATs in women stronger automatic sex-disgust associations were found in women with sexual pain disorders compared with healthy women [35]. In women with HSDD weaker associations of erotic pictures with positive valence were found compared with healthy women [36]. Although the reference categories are partly different, the observed association in sexually dysfunctional women of erotic stimuli with negative valence is in the opposite direction of the findings in the present study among sexually dysfunctional men. More in line with the present finding, in a study using a modified pictorial Affective Simon Task to measure implicit cognitions, women reporting superficial dyspareunia displayed more positive rather than negative automatic associations with sexual stimuli [69]. The

present finding in men, and the discrepancy between findings in the current and previous studies using the same and similar methodology, cannot readily be explained, but may indicate method-specific sources of error, including the number of stimuli used to represent target and attribute categories. Other possible explanations might be found in differences regarding the indirect measurement methodology, including the use of full body pictures in the present study as compared with close-up shots of the genital area, and providing or not providing error feedback following predetermined “incorrect” responses. However, as it may represent a true gender difference attempts to replicate the current findings are warranted, including the use of samples containing both genders. The implicit associations of erotic stimuli with wanting (implicit motivation) were not found to differ between both sexual function status groups. The absence of any effect of ST-IAT wanting may have been due to the current experimental setup. Although the order of the sex-positive and sexnegative combination blocks within both ST-IAT versions was counterbalanced, the order of the liking and wanting ST-IAT tasks itself was fixed, with the liking ST-IAT being presented first, followed by the wanting ST-IAT. Moreover, the set of erotic stimuli was similar in both ST-IAT versions. To test whether this aspect of the experimental configuration introduced order effects, a pairedsample t-test comparing both ST-IAT indexes was performed, but order proved not significant, t(59) = 0.13, P = 0.90. Typically, IAT effects are strongest in the early phases of task performance. Although both ST-IAT indices were not significantly different, suggesting the absence of an order effect, this does not preclude the possibility that the wanting ST-IAT in the present study may still have suffered from this effect, and might have been J Sex Med 2015;12:1791–1804

1802 reduced by an order effect. This could imply that participants may have gained increasingly stronger volitional or conscious control of their key press responses during the learning process, thus decreasing the implicit nature of the task. Even though the interpretation of the direction of the observed difference between sexual function status groups on the liking ST-IAT remains difficult, the mere demonstration of differential responding of sexually healthy and dysfunctional men with respect to their implicit associations with erotic stimuli can be considered to lend support to a dual-process model of sexual functioning. Implicit liking and wanting, nor explicit positive ratings of erotic stimuli were found to be significant predictors of level of sexual functioning. The regression models of the prediction of sexual distress (SDS total score) by ST-IAT liking and wanting yielded ambiguous results. Although the regression model with both implicit index scores was significant, the individual contribution of ST-IAT liking and wanting was not significant. When ST-IAT liking and wanting were entered as predictors of sexual distress in separate analyses both were found to be significant, suggesting a power problem. In a future replication of this study, a larger sample size is recommended. On the other hand, sexual distress was significantly predicted by participant’s explicit ratings of the erotic pictures; positive ratings were associated with higher levels of sexual distress. Our pattern of findings was unexpected and was, moreover, dissimilar between the different operationalizations of sexual dysfunction. Selfreported sexual function status was associated with implicit, but not with explicit liking of erotic pictures, nor with implicit wanting. Continuously measured sexual functioning was neither associated with explicit cognitions, nor with implicit liking and wanting. A possible explanation of these disparate findings may start with the recognition that the accessibility of particular associations is highly context dependent. The pattern of associations that was observed in this laboratory setting might be different in the natural context, where dysfunctional sexual responding is experienced [70,71]. Moreover, the type of associations that was measured in the present study might not be critically involved in sexual (dys)functioning in men. One may conjecture that, for instance, failure–success associations might have evidenced a difference between both studied groups, with lower functioning men displaying stronger sex– failure associations than higher functioning men. J Sex Med 2015;12:1791–1804

van Lankveld et al. In addition to the dual-process account as described in the Introduction section, acknowledgment of the multicomponent nature of sexual functioning, including the distinction between genital and cognitive/affective responses to erotic stimuli, might tentatively provide explanations for this pattern of findings. Measurements of genital and subjective sexual arousal have repeatedly been found to be dissociated, as evidenced in a recent meta-analysis [72], although more so in women than in men. Self-reports of erectile and orgasmic performance, and of sexual intercourse satisfaction (IIEF) are different aspects of the response to erotic stimulation, which has been found to be associated with dysfunctional explicit cognition in previous research [7,9,10]. On the other hand, the implicit valence of erotic stimuli may be more reflected in self-reports of sexual distress and the self-attribution of sexual dysfunction. Some limitations of the present study should be discussed. The self-selection that is typical for research into sexuality [73] may also have biased the present study sample that was found to have relatively low levels of anxiety and depression (HADS). Although age in our sample varied, it was not found to differ between sexual function status subgroups. This may have been due to the recruitment of participants in the outpatient urology clinic, which is predominantly visited by older age groups of men with various urologic complaints. This might have obscured the linear relationship of age with prevalence of erectile dysfunction that has been found in other, nonmedical populations (see [53]). In future studies, more representative samples should be investigated to examine if the present findings also hold true in men of younger age and with lower mental health. This is, to our knowledge, the first study in which implicit associations of erotic stimuli with valence and wanting were compared in men with and without sexual dysfunction. Differences were revealed between men with and without sexual dysfunction with regard to their implicit liking of erotic stimuli. Corresponding Author: Jacques van Lankveld, PhD, Faculty of Psychology and Educational Sciences, Open University of the Netherlands, Valkenburgerweg 177, 6401 DL Heerlen, The Netherlands. Tel: 31 45 5762695; E-mail: [email protected] Conflict of Interest: The authors report no conflicts of interest.

Implicit and Explicit Cognitions in Male Sexual Dysfunction Statement of Authorship

Category 1 (a) Conception and Design Jacques van Lankveld; Ingrid Odekerken; Lydia Kok-Verhoeven; Susan van Hooren; Perter de Vries; Anja van den Hout; Perter Verboon (b) Acquisition of Data Ingrid Odekerken; Lydia Kok-Verhoeven; Perter de Vries (c) Analysis and Interpretation of Data Jacques van Lankveld; Perter Verboon

Category 2 (a) Drafting the Article Jacques van Lankveld (b) Revising It for Intellectual Content Jacques van Lankveld; Ingrid Odekerken; Lydia Kok-Verhoeven; Susan van Hooren; Perter de Vries; Anja van den Hout; Perter Verboon

Category 3 (a) Final Approval of the Completed Article Jacques van Lankveld; Ingrid Odekerken; Lydia Kok-Verhoeven; Susan van Hooren; Perter de Vries; Anja van den Hout; Perter Verboon

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