The internet has become an important part of our lives. We use it to access information, connect with other people, and to entertain ourselves. However, constant access to such novel information could be a driver of certain compulsive behaviours, as a recent study led by Dr Paula Banca from the University of Cambridge suggests.
The team specifically looked at individuals with compulsive sexual behaviours (CSB, best known as ‘sex addiction’) and their reaction to novel, familiar, and conditioned images. Twenty-two men who compulsively used online sexual material and 40 male healthy controls participated in this study. First, the subjects performed a novelty preference task. They were asked to choose between novel and familiar images of either undressed women (sexual images), clothed women (neutral human images), or items of furniture (neutral object images). For sexual, but not neutral images, the CSB males chose the novel image significantly more often than the controls.
In a second task, the researchers looked at cue-conditioning. Two abstract patterns were shown and repeatedly followed by either an undressed female or a grey box. The participants therefore learned to associate one pattern with a sexual image and the other pattern with a neutral image. Afterwards, the subjects chose between one of the conditioned patterns and a novel abstract image. Choice of the sexual or neutral conditioned image was more likely to lead to winning money than the novel ones. Healthy volunteers chose both of these conditioned images similarly often. In contrast, the CSB males chose the sexual conditioned image significantly more often than the neutral one, although both images had the same likelihood of winning.
Strikingly, the behavioural results also correlated with findings from brain imaging. A subset of twenty participants from each group completed a functional MRI task. Their neural activity was assessed while they saw repeated images of an undressed women, a pound coin, and a grey box. The researchers wanted to see how much activity changed over time in the dorsal cingulate cortex, a brain region involved in responding to new events and anticipating rewards. For repeated sexual but not monetary images, CSB males showed a much stronger habituation (reduction) of dorsal cingulate responses than healthy controls. These findings might reflect that CSB males are more used to seeing explicit sexual images and therefore these stimuli use their novelty value more quickly. This idea is further supported by the behavioural findings. The degree of habituation correlated with the participants’ enhanced preference for novel sexual stimuli: greater dorsal cingulate habituation was associated with greater novelty-preference.
These findings give us important insights into cognitive mechanisms of CSB. Novelty-seeking and cue-conditioning are two possible drivers of these compulsive behaviours. We spoke to Dr Paula Banca about the importance of the study:
“Although there is no formal definition of this condition yet, CSB is relatively common and is associated with significant distress, feelings of shame, and psychosocial dysfunction. Therefore, further research is extremely important to understand the similarities and differences between CSB and other psychiatric disorders, particularly impulse-control disorders and addictions, and to help with classification efforts as well as with the development of improved prevention and treatment approaches.”
It is not clear whether compulsive sexual behaviours should be regarded as behavioural addictions, such as gambling disorder. Dr Valerie Voon, the senior author of the study, said in an interview with Cambridge TV:
“The way we thought about pathological gambling behaviours and other addictions 10, 20 years ago, was very much on a moralistic level, of blaming the person and associating a value judgment with it. I think as we start to understand more of these behaviours, we can start to think of them on a biological level. There may be other factors, that we need to address, that might be underlying these behaviours. We need to take away the moral tone associated with it.”
Written by Julia Gottwald.