Viewing pornography causes straight men with negative personalities to have a more sexist attitude towards women, with hostility towards women linked with sexual arousal.
A team of researchers found that disagreeable men - characterised by a higher levels of antagonism, coldness, hostility, suspiciousness, disagreeability, unfriendliness and self-interest - had more negative attitudes towards women, including hostility, negative prejudices and stereotypes.
Gert Hald and Theis Lange, of the University of Copenhagen, and Neil Malamuth, University of California, were looking to establish how viewing pornography affects attitudes towards women.
They asked 200 Danish adults about their past pornography consumption and assessed their personality for their agreeableness.
The participants were then exposed to hardcore pornography in a laboratory and evaluated how it affected a variety of sexist attitudes.
There was no association between sexist attitudes and porn consumption among women, they found.
Sexism brought on by arousal
However, findings initially showed that men who had increased porn consumption had more negative attitudes towards women.
After comparing the results with the test for agreeableness, the researchers found personality had a direct influence on how sexist the participant's attitudes were.
Men with low levels of agreeableness displayed increased hostile sexist attitudes after being exposed to hardcore porn in the laboratory, which was brought about by increases in sexual arousal to the pornographic material.
For men with high levels or moderate levels of agreeableness, exposure to hardcore porn had no influence on their attitudes to women.
Lead author Hald said: "The study is important because it may help nuance the view of effects of porn and enable us to better understand for whom adverse effects of porn are most likely and the mechanisms by which such effects occur. This could be used in prevention, education, or clinical interventions.
"The study shows the importance of individual differences in research on pornography and underscores that effects of pornography on attitudes may not be the same for everyone".