A new study published in Biological Psychology suggests that people who frequently watch pornography or engage in other solitary sexual activities may react differently to sexual cues. Even though they still find erotic images pleasant, their bodies show weaker signs of arousal when something signals that sexual content is coming. This pattern supports the idea that some people may use pornography more often because they do not get as much reward from it as others do—not because they are more sensitive to sexual cues, as some past theories have suggested.
With the widespread availability and rising consumption of pornography around the world, researchers Johannes B. Finke and Tim Klucken from the University of Siegen sought to examine whether the underlying mechanisms of habitual pornography use align with those seen in addiction. One key question was whether frequent engagement with visual sexual content reflects an increased sensitivity to sexual cues—or the opposite: a reduced ability to experience pleasure from them, prompting repeated use to compensate.
“Visual sexual stimuli (e.g., pornographic images, video clips) are often considered to be special (in comparison to auditory stimuli, verbal materials, etc.), as humans are known to be largely visually oriented, especially in terms of sexual attraction,” explained Finke, a senior researcher specializing in the intersection of biological and clinical psychology.
“However, it has long been debated whether they are intrinsically rewarding (such as food or pleasant touch) and can thus act as primary reinforcers in a learning context. This question is notoriously difficult to investigate because we all carry an individual as well as cultural history of learning. Nevertheless, to tap into this issue, we compared effects of conditioning with visual versus auditory sexual stimuli on psychophysiological markers of emotion as well as self-report.”
“In addition, we were interested in the relationship between sexual conditioning and trait aspects of sexual motivation (particularly solitary sexual desire), because the interplay of these factors has been implicated in the development of problematic pornography use, which presumably represents an addiction-like behavior that is on the rise in Western societies,” Finke continued.
“Importantly, there are several different theories of addiction, and it is unclear which best explains this kind of mental health problem. For instance, it is conceivable that people consume higher amounts of porn simply because they experience a ‘reward deficiency’—that is, they have a blunted sensitivity to sexual rewards, so they need a higher ‘dosage.’ Alternatively, they could acquire addictive behaviors because of heightened sensitivity to cues that predict sexual rewards. This model of addiction has been termed ‘incentive sensitization’ and has been effective in explaining the development and symptomatology of certain substance use disorders, which cannot be accounted for solely in terms of tolerance.”
The study involved 62 heterosexual adults, most of them women, who each completed two lab sessions held one week apart. In each session, participants took part in a conditioning task—a type of learning experiment designed to test how people react to cues that predict emotionally powerful outcomes, such as sexual or disturbing stimuli. In one session, the “reward” was visual—erotic images. In the other session, it was auditory—sexual sounds.
During the task, participants were repeatedly shown abstract visual patterns on a screen. These patterns acted as cues. Some of them were followed by a sexual stimulus half the time, either an erotic image or sound depending on the session. Other patterns were followed by unpleasant or disturbing material, such as an aversive sound or image. One pattern was never followed by anything and served as a neutral control.
To track participants’ emotional and physiological reactions during the learning process, the researchers used three main measures: pupil dilation (to detect arousal and attention), acoustic startle responses (to gauge emotional valence), and skin conductance (to measure autonomic nervous system activity). Participants also rated how pleasant, arousing, and expected each stimulus was.
Participants also completed the Trait Sexual Motivation Questionnaire, which assesses how frequently and intensely people engage in solitary sexual behaviors, such as masturbation or pornography use. This allowed the researchers to examine how differences in sexual motivation related to learning patterns and cue reactivity.
Across the board, participants showed signs of having learned the associations between neutral cues and sexual or aversive outcomes. Visual cues that predicted sexual images triggered pupil dilation and reduced startle reflexes, while cues predicting unpleasant outcomes had the opposite effects. These patterns were consistent regardless of whether the rewards were visual or auditory, confirming that both types of sexual stimuli can reinforce learning.
However, when the researchers looked at how individual differences in solitary sexual desire shaped responses, a more nuanced picture emerged. People with higher scores on solitary sexuality showed smaller pupil dilation responses to cues that predicted visual sexual stimuli. They also demonstrated less increase in pupil dilation over repeated trials. This suggests diminished anticipatory arousal and slower learning—rather than heightened craving or increased sensitivity to reward.
Interestingly, this effect was specific to visual sexual stimuli. People with high solitary sexual desire did not show a comparable reduction in response to auditory sexual stimuli. Nor did they differ significantly in their physiological reactions to cues predicting aversive outcomes, suggesting that the effect was not simply due to a general difference in emotional reactivity.
Despite reduced physiological arousal, these individuals rated the erotic images as more pleasant than others did. This dissociation between subjective “liking” and physiological “wanting” hints at a decoupling between how enjoyable a stimulus is perceived to be and how strongly the body anticipates it.
“Viewing visual sexual stimuli seems to be rewarding in itself, at least to a certain degree,” Finke told PsyPost. “But people who show a problematic use of pornography are (perhaps somewhat counterintuitively) less likely to be influenced—that is, reinforced—by sexual stimuli. They experience visual (yet not auditory) sexual stimuli as well as cues that predict them as less arousing than individuals with lower levels of solitary sexuality. The latter finding was somewhat surprising, since the few existing studies rather suggested an account in terms of ‘incentive sensitization.’”
“Still, despite the reduced arousal and attention to these stimuli, they rate erotic pictures as more pleasant. Notably, however, we still do not know whether this is a predisposition (e.g., based on genetics) or an acquired condition—that is, a result of a long history of exposure and consumption.”
To further explore the learning process, the researchers fitted computational models to the pupil dilation data. The models showed that individuals with higher solitary sexual desire had lower learning rates in response to prediction errors—moments when a reward was expected but did not occur. This suggests they may be less flexible in updating expectations based on changing information, particularly when dealing with uncertain outcomes.
Startle reflex data supported this idea. Participants with higher solitary sexual desire exhibited enhanced habituation to cues predicting sexual images, meaning their emotional responses faded more quickly over time. This again aligns with the idea that frequent consumers of visual sexual content may require more intense or novel stimulation to maintain the same level of arousal or reward.
“Using solitary sexuality as a proxy for regular porn consumption, our data are mostly in line with the ‘reward deficiency’ model, suggesting that individuals who are relatively more prone to porn use show blunted reinforcement learning to cues that predict sexual stimuli,” Finke explained. “However, this applies only to erotic pictures (not auditory stimuli), which is consistent with the notion of at least some extent of ‘specialness’ of visual stimulation.”
However, the study does have some limitations. First, the sample included only non-clinical participants. While some may have had relatively high levels of solitary sexual desire, none had a formal diagnosis of compulsive sexual behavior. It remains unclear whether the same patterns would be observed in clinical populations with more severe symptoms. Future research should examine whether these findings hold in individuals diagnosed with compulsive sexual behavior or problematic pornography use.
It is also important to note that the study is correlational. This means it cannot determine whether reduced cue reactivity is a cause or consequence of frequent pornography consumption. Longitudinal studies or experiments that manipulate exposure to sexual content would help clarify the direction of the effect.
Looking forward, “one major objective would be to replicate the findings in a sample of patients with compulsive sexual behavior disorder,” Finke said. “Another interesting avenue for future research would be to investigate links to (a) altered reward learning in depression and (b) effects of acute stress, which is thought to often trigger relapse or acute cravings.”
The study, “Trait sexual motivation shapes cue reactivity in visual, but not auditory, sexual reward learning: Psychophysiological and computational evidence,” was published May 10, 2025.
