Danny's first girlfriend was dark-haired, short, and caring, though their relationship was marred with bouts of jealousy, screaming matches, and fights over his independence. In his second relationship, only months later, Danny's new girlfriend was light-haired, tall, and commanding, though she always found a way to suggest he wouldn't do well if he continued his education, or asked for a promotion at work, as he couldn't possibly be as intelligent as she. Wanting something different, Danny spent years alone before meeting his third girlfriend, who was incredibly beautiful, kind, and loving ⁠— that is, until the night Danny found her active online dating profile through a friend, two years into their relationship. 

What do these women have in common? Does Danny have a 'type' or has he simply had a string of bad luck with partners who left him feeling terribly devalued?

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According to research recently published in the Proceedings of the National Academy of Sciences, when it comes to romantic partners, there is a “significant degree of unique similarity between an individual’s past and current partners” that cannot be explained by other factors accounted for, including the inclination to date someone similar to oneself.

Researchers from the University of Toronto used data from a 9-year longitudinal study in Germany to compare the personalities of the current and past partners of 332 people. The study participants, which ranged in age, had their own personality assessed as related to the ‘Big 5’ personality traits (agreeableness, conscientiousness, extraversion, neuroticism, and openness to experience), and were asked to rate, on a 5-point scale, how much they identified or disagreed with statements including: "I am usually modest and reserved," "I am interested in many different kinds of things" and "I make plans and carry them out."

Indeed, the researchers found that the way current and past partners described themselves was incredibly similar, thus suggesting that we tend to have a “type”.

The exception to this, however, was people who reported being higher in extraversion or openness to experience, who had less of a partnered personality pattern, suggesting they would be less likely to fall into a pattern or have a ‘type’.

Because the researchers examined self-reported measures by both partners, they were able to account for a number of biases that might otherwise exist if only one partner was assessing the personality of his or her current or past partners, suggesting the scientific finding of 'types' endured more rigorous study.

While this research might suggest that Danny's future is bleak, contrarily, it could help him, or others who have had problematic relationship patterns in the past, better think through what personality traits they’d do better with, and seek out something different instead.  

Park, Y., & MacDonald, G. (2019). Consistency between individuals' past and current romantic partners' own reports of their personalities. Proceedings of the National Academy of Sciences, 201902937.