Comment: Study demonstrating habituation (declining dopamine response) to the same sexual stimuli (film), and an increase in sexual arousal (increased dopamine) when exposed to a novel sexual stimuli. The study also measured reaction time to a tone, which became faster with each viewing of the same film. This is an example of the Coolidge effect at work – more dopamine when presented with a novel sexual possibility. Novelty is what makes Internet porn different from porn of the past.

Arch Sex Behav.

1999 Dec;28(6):539-52.

Koukounas E, Over R.

Source – School of Psychology, Deakin University, Burwood, Victoria, Australia.


A secondary-task probe (tone) was presented intermittently while men viewed erotic film segments across a session involving 18 trials with the same film segment (habituation), then 2 trials with different film segments (novelty) and 2 trials with reinstatement of the original segment (dishabituation). Reaction time to the tone (an index of the extent processing resources were being committed to the erotic stimulus) shifted during the session in parallel with changes that occurred in penile tumescence and subjective sexual arousal. The decrease in sexual arousal over the first 18 trials in the session was accompanied by a progressively faster reaction to the tone, novel stimulation led to recovery of sexual arousal and a slower reaction to the tone, and on trials 21 and 22 sexual arousal and reaction time levels were above the values that prevailed immediately prior to novel stimulation.Results are discussed with reference to the relationship between habituation and attention.