Their survey revealed the younger the first viewing occurred, the more likely a male was to want power over women.
While if they were older, they were more likely to be sexually promiscuous.
Of the 330 undergraduates surveyed, with a median age of 20, the average age they first saw pornography was 13.
The youngest was only five, while the oldest was 26.
The unpublished findings were presented at a convention in Washington.
Lead researcher Alyssa Bischmann and her team asked the men, the vast majority of whom were heterosexual and white, when they first saw porn and whether it was intentional, accidental or forced.
They were then asked 46 questions which measured how they conformed to one of two behavioural traits - seeking power over women or sexually promiscuous behaviour and living a playboy lifestyle.
They found those who saw porn young were most likely to agree with statements that asserted male dominance, such as "things tend to be better when men are in charge".
The researchers were surprised to find that seeing porn later in life was associated with a playboy lifestyle, such as preferring to frequently change sexual partners.
Researcher Christina Richardson said this could be because those who were exposed to porn early often did not enjoy sex in real life.
"These men often have a lot of performance anxiety with women in real life. Sexual experiences don't go as planned or the way they do in pornography," she said.
Alternatively "those who see porn later, enjoy sex in real life more and therefore might be more likely to live a playboy lifestyle".
The research, which was presented at the American Psychological Association's annual convention, did not take into account how much porn the men watched, the type of porn or other demographic factors, such as their socio-economic background.
It could also have been other personality traits that determined when the males were exposed to porn.
Peter Saddington, sex therapist at relationship support provider Relate, said: "Pornography can and does have an impact on many young men's attitudes to sex.
"The result can be that young men develop sexist attitudes and are essentially sexually deskilled."
Either way, Ms Richardson says porn "is not the healthiest thing for men".
She added that young men needed "better role models to develop more healthy beliefs about masculinity".