Recently published studies Mapping the human brain The study sheds light on the neural mechanisms of associative learning related to Internet use behavior, focusing specifically on online games and pornography. The study found that in healthy men, pornographic stimuli were more strongly associated with reward responses in the brain compared to money and gaming stimuli.
Appetitive conditioning – the process by which neutral stimuli become associated with rewards – has been extensively studied for traditional rewards such as money and food, but there is limited research into how it works with Internet-related stimuli.
Appetitive conditioning is a learning process in which a neutral stimulus becomes associated with a rewarding unconditioned stimulus, leading to a conditioned response such as increased pleasure or arousal. For example, when a neutral sound (conditioned stimulus) is repeatedly paired with food (unconditioned stimulus), the sound alone elicits salivation (the conditioned response).
Pornography and gaming are the two most common activities associated with Internet addiction, but the neural mechanisms underlying their conditioning process are not well understood. Previous studies have shown that certain brain regions, such as the orbitofrontal cortex, anterior cingulate cortex, insular cortex, amygdala, nucleus accumbens, and thalamus, are involved in reward processing.
However, it remains unclear how these areas respond to Internet-related rewards compared to traditional areas. In their new study, the researchers aimed to fill this gap by investigating how the brain learns to associate rewards with these stimuli in healthy, non-pathological conditions.
The study involved 31 healthy, right-handed men between the ages of 19 and 38, specially selected to control for sex differences in reward processing. Before the main experiment, participants were asked to choose their preferred images from three categories: pornographic pictures, game screenshots, and pictures of money. This personalized selection process ensured that the stimuli were truly rewarding for each participant.
The experimental procedure was carried out inside the MRI scanner using a classical conditioning paradigm, in which a geometric figure (conditioned stimulus, CS) is repeatedly paired with a selected reward picture (unconditioned stimulus, UCS).
Four types of CS were used: one for each type of reward (porn, game, money) and one control. Over 68 trials, the CS+ (the conditioned stimulus-reward pairing) was followed by a UCS 62.5% of the time, while the control CS- was not followed by a reward. This setup allowed the researchers to observe how the brain associates a neutral stimulus with a rewarding outcome.
To measure responses, the researchers employed three different methods: Subjective ratings were collected to measure the pleasantness and arousal of each CS before and after the conditioning process. Skin conductance responses (SCRs) were recorded to measure physiological arousal by tracking changes in sweat gland activity, providing an objective measure of the participants’ autonomic nervous system responses. Finally, functional MRI (fMRI) scans were used to record brain activity, allowing the researchers to observe how different brain regions responded to the stimuli and map the neural correlates of reward processing.
The study revealed significant differences in how participants responded to the different stimuli: in subjective assessments, after the conditioning process, all three CS+ (porn, money, and games) were rated as more pleasant and stimulating than the control CS-.
In particular, pornographic stimuli were rated as significantly more arousing than game stimuli, indicating a stronger emotional response to pornography.SCR data supported these findings, showing higher physiological arousal levels during presentation of the CS+ for pornography, money, and game compared to controls, indicating successful conditioning.
The fMRI results provided further insight into the brain’s response to these stimuli. Anticipation of pornographic rewards increased activity in key brain regions associated with reward processing, including the bilateral nucleus accumbens, right medial orbitofrontal cortex, and right ventral anterior cingulate cortex. These findings suggest that pornographic stimuli have strong reward value and can significantly activate the brain’s reward circuits.
On the other hand, despite increased subjective valuation and SCR, the money stimuli did not elicit significant brain activity compared to the control group, indicating a weaker neural response.Similarly, despite subjective valuation and SCR data indicating successful conditioning, the game stimuli did not significantly activate reward-related brain regions in fMRI scans.
Findings suggest that pornographic stimuli have a higher reward value and stronger conditioning effects than monetary and gaming stimuli. This is evidenced by the pronounced neural activity observed during anticipation of pornographic rewards, as well as increased subjective evaluations and physiological responses. These results are consistent with previous studies showing that pornography may be highly addictive because of its strong emotional and arousal properties.
In contrast, the weaker neural responses to monetary and game stimuli, despite successful conditioning on subjective and physiological measures, suggest that these rewards may be less effective at activating the brain’s reward system in non-pathological users. This highlights the complexity of reward processing and suggests that different types of rewards may act on distinct neural mechanisms.
the study, “Appetitive conditioning with pornographic stimuli induces stronger activation of reward regions than with money or game-related stimuli” was written by Kseniya Krikova, Sanja Klein, Miriam Kampa, Bertram Walter, Rudolf Stark, and Tim Klucken.
