Priming the sexual system: implicit versus explicit activation

Journal of Sex Research, May, 2003 by Mark Spiering, Walter Everaerd, Erick Janssen

The development of a full-blown emotional response can be understood as the result of two independent processes (LeDoux, 1996, 2000). The core of the emotional system involves a mechanism for computing the affective significance of stimuli (cf. Zajonc, 1984). This mechanism operates automatically, outside of conscious awareness, and depends on implicit memory. Studies have found that autonomic responses can be directly activated through this mechanism and these responses are part of the precursers for the conscious emotional experience. Subjective experience is the outcome of the second process, involving the conscious elaboration of emotional information, and is dependent on explicit or declarative memory.

Empirical support for this model stems mostly from negative emotions, in particular fear (e.g., Bechera et al., 1995; LeDoux, 1996; Morris, Ohman, & Dolan, 1998). However, there is growing evidence that these pathways are also relevant to positive emotions (e.g., Adolphs, Tranel, & Damasio, 1998; Hamann, Ely, Grafton, & Kilts, 1999; Morris et al., 1996; Whalen et al., 1998). Sex can be thought of as among the emotions (Everaerd, 1988; Geer, Lapour, & Jackson, 1993), and the sexual emotions can be taken as prototypical in the domain of positive emotions. The studies presented in this paper are an attempt to investigate the contribution of implicit versus explicit central activation of sexual response.

Erotic situations may elicit a great variety of emotional responses. In addition to sexual excitement, other emotions can be experienced: for example, those connected with a tendency to approach the partner, desires, and expectations (Janssen & Everaerd, 1993). We do not know to what degree a preference for sexual stimuli is determined at birth; what we do know is that we are born with a sensitivity to what we call sexual stimuli. This sensitivity develops and becomes prominent around puberty and, although attenuated, remains manifest into old age (Everaerd, Laan, & Spiering, 2000).

Sexual arousal is activated in response to a relevant stimulus. In the production of a sexual response, stimuli that are ascribed sexual meaning by the brain are transformed into specific efferent messages. Relevant stimuli activate approach behavior; that is, they may function as an incentive (Agmo, 1999; Everaerd, Laan, Both, & Spiering, 2001). The subjective experience of sexual arousal ultimately depends on the individual's awareness and definition of the response as sexual (Everaerd, 1993). The physiological component of sexual response, however, seems connected with implicit memory and can be activated automatically (Bancroft, 1989; Everaerd, Laan, & Spiering, 2000; Geer et al., 1993; Janssen & Everaerd, 1993).

This theoretical view is supported by a number of phenomena, including a frequently observed discordance between subjective and physiological sexual response. Genital response can occur without a concurrent subjective sexual experience. This can be interpreted to involve an automatic activation of physiological responses with a concomitant conscious appraisal of the stimulus or stimulus situation as nonsexual (Everaerd & Laan, 1994; Janssen & Everaerd, 1993). An extreme example of response discordance can be found in studies with hypogonadal men. Because of low androgen (testosterone) levels, sexual appetite in these men is absent. Erections in response to erotic films, however, are largely intact (Bancroft, 1989, 1995). This suggests a strong link between visual sexual stimuli and genital responses that does not depend on the presence of sexual desire.

Janssen, Everaerd, Spiering, and Janssen (2000) first proposed a conceptual model in which sexual arousal is viewed as dependent on the interaction between automatic and attentional processes. In this model, different levels of cognitive processing can differentially affect subjective and physiological components of sexual arousal: Physiological sexual arousal can be activated automatically, after which strategic or attentional processes may lead to the subjective experience of sexual arousal. To test this model, Janssen et al. (2000) conducted two studies using a priming paradigm.

Priming involves a change in the ability to identify a stimulus as a consequence of a prior encounter with a related stimulus. This type of paradigm can be used to study the independent contributions of implicit and explicit processes (Schacter & Badgaiyan, 2001; Schacter & Buckner, 1998). An accepted operational definition of implicit processes is evidence for indirect effects of a stimulus in the absence of direct effects (e.g., Greenwald, Klinger, & Schuh, 1995): in other words, when priming stimuli produce a response without being consciously elaborated. In the studies of Janssen et al., sexual stimuli were presented subliminally. Pictures (instead of words) were used because they might produce stronger connections with sexual memory (Carr, McCaulley, Sperber, & Parmelee, 1982; De Houwer & Hermans, 1994; but for the contrary see Van Den Hout, De Jong, & Kindt, 2000).