Researchers looked at data from the 2022 Romantic Love Survey, the largest cross-cultural study of people experiencing romantic love, spanning 33 countries. For the new study, the team wanted to focus on new romantic relationships, and so they selected a subset of these 18-25-year-olds who had been together for less than two years.

From here, they attempted to measure variables in the relationships, and gain insight into their romantic behaviors. Variables looked at included intensity of love, obsessive thinking (or how much they thought about their partner), their commitment levels, how many times they had been in love, and how often they were having sex. Analyzing the data, the team claims to have found four distinct phenotypes of romantic lovers: mild, moderate, libidinous, and intense.

Of these, the moderate romantic lovers were the most common, making up 40.9 percent of the total. 

“These lovers exhibit relatively low intensity and relatively low obsessive thinking, relatively high commitment, and relatively moderate frequency of sex,” Adam Bode, PhD student at ANU and lead author on the study, explained in a statement. “The lower-end-of-the-spectrum scores characterize these lovers as fairly stock-standard, and interestingly, they are also the most likely to be male.”

Mild romantic lovers, making up 20 percent of the participants, tended to have fallen in love the most number of times.

“They are most notably characterized by the lowest scores on all four primary variables,” the team explains in the study. “They have fallen in love the greatest number of times, have the shortest length of time in love, were the least likely to have fallen in love before commencement of their romantic relationship (19.75 percent), fell in love the longest length of time after having started a romantic relationship, and had the lowest proportion whose partner is ‘definitely’ in love with them (25.31 percent).”

Libidinous romantic lovers, making up the smallest group at 9.6 percent, were mainly distinguished by the sheer number of times they have sex, with an average of 10 times per week.

“Among other characteristics, they also had the highest proportion wanting to travel, spending more money than usual and smoking more cigarettes than usual,” Bode added.

This group had the lowest self-reported levels of anxiety and depression, and the highest levels of energy.

The final group was intense romantic lovers, making up 29 percent of those studied, and were dubbed by the researchers as the “head-over-heels” type.

“These lovers scored the highest intensity, highest obsessive thinking, highest commitment, and relatively high frequency of sex,” Bode said.

“These folk are your ‘crazy in love’ types. They had the highest proportion who fell in love before their romantic relationship even began and are the only group with more females (at 60 percent) than males. Some other notable characteristics of the intense lovers are that they scored the highest on agreeableness, conscientiousness and enjoying work, but had the lowest proportion engaging in risky driving, drinking more coffee and alcohol, and taking more drugs than usual.”

The team believes that there is more to be learned about these distinct groups, and that they may indicate that romantic love is still subject to evolutionary selection, with the different groups representing different strategies for mate choice and pair bonding. However, they caution that the study was conducted on primarily young students who spoke English fluently, meaning their results may not be very generalizable. Nevertheless, it is interesting that these four distinct groups could be identified.

“The bottom line is that we don’t all love the same, with some people having sex up to 20 times per week when they fall in love,” Bode added. “How we fall in love is associated with a range of other interesting behaviors.”

The study is published in Personality and Individual Differences.