People are more likely to be unfaithful to their partners in the year before they reach ‘milestone birthdays’, a new study suggests.
Researchers from the University of New York and the University of California found that people who are 29, 39, 49, or 59 are more likely to be unfaithful than they would be at other ages. These people were named “9-enders”.
Adam Alter and Hal Hershfield co-authored the study. They primarily used data from a dating website which caters to those already in a relationship. They found 950,000 male members of the site were 9-enders. This was 18 per cent more than a random sample would produce, they said.
While the focus of the study was on men due to their belief that an affair is “one of the canonical indicators” of a mid-life crisis, a similar pattern was found among female members. However, the difference was not as stark.
The finding was part of a larger study which focused on people making big lifestyle changes as they approach a new decade in their lives. It was published in the academic journal Proceedings of the National Academy of Sciences of the United States of America.
The report said that “certain numerical ages inspire greater self-reflection than others”. It also found that 9-enders are more likely to sign up for a marathon than people of other ages.
Last year, Australian researchers published a study which suggested that a person’s potential for infidelity could be genetic.