The title of this post takes something for granted: that single women are drawn to men who are already married or attached. Psychologists have a name for one version of it, the "wedding ring effect". It comes from animal research on mate-choice copying, where a female is more likely to choose a male once other females have chosen him. A handful of studies have tested whether women do the same. Their answer is less tidy than the title.
The wedding ring test in Sweden
Two researchers at Göteborg University set up a series of live, face-to-face meetings between men and women to test the wedding ring effect directly. The women did not find men who signalled an engagement, or who seemed to have a partner, more attractive. They did not rate them higher in socioeconomic status either. Signs of an engagement also made no difference to whether the women said they would be open to a short-term or a long-term relationship with the man. The authors wrote that their results cast doubt on simple theories of mate-choice copying in people (Uller and Johansson, 2003).
That study used real meetings between people, and it found no pull towards the man who was taken.
When the woman beside him matters
Other studies changed the question. Instead of asking whether a ring makes a man more attractive, they asked whether seeing him with a woman does.
In a Durham study, women rated men presented either alone or with a female date. The results suggested a narrow rule: women copied only when the woman beside him was physically attractive. Further analysis pointed to experience as well, measured by the women's reported number of past sexual partners (Waynforth, 2007). A Liverpool study using video clips of the female partners found the same thing. Her attractiveness was the main cue, ahead of her personality or behaviour (Vakirtzis and Roberts, 2012).
A past or two, but not five
At James Cook University in Australia, 123 female university students rated photos of men shown alone or next to silhouettes of one, two or five women, each matched to a written relationship history. Men with one or two previous partners were rated as more desirable than men with none. Men with five were rated as less desirable. Younger women in the sample copied more than older ones (Anderson and Surbey, 2014).
What single women did differently
The study closest to this title compared single women with women already in a couple. Researchers at Southwest University in Chongqing found that both groups copied, but in different ways. Single women mostly marked a man down after seeing another woman reject him. Women in couples mostly marked a man up after seeing another woman accept him. Single women also copied less when the man and the other woman were in a committed relationship than when the pairing was temporary (Deng and Zheng, 2015).
Put plainly, in that study a committed relationship made single women less swayed by a man's partner, not more.
The study that did find a lean towards attached men
At the University of Padua, 208 women rated men described as either single or attached. Women who already had partners favoured the attached men at the low-fertility points of their monthly cycle, and switched to single men, if those men were masculine, when the chance of conceiving was high (Bressan and Stranieri, 2008). The lean towards attached men was reported in women who were partnered themselves, so it says nothing direct about single women.
What the research cannot tell you
Every study above measured how women rated men, or how open they said they would be to a relationship. None of them followed women who actually began a relationship with a married man, and none asked such women why. So the honest answer to the title is that the evidence does not show single women, as a group, preferring married men. The one live test found no such preference. Where a partner did change how a man was seen, it depended on details: how attractive she was, how many past partners he had, whether other women accepted or rejected him, or, for women already in couples, the point in their cycle. None of these studies showed single women favouring a man simply because he was married.
The other kind of date
This site is about the fruit. In Malaysia demand for dates peaks before and during Ramadan, and weddings, for hantaran, are another peak. Every date sold here is imported, because Malaysia has no commercial date-growing trade. The older version of this page linked to Kurma Bam Shah Alam, and that link stays.
For retail or wholesale prices, the about page covers retail and wholesale supply, delivery across Malaysia and quotes, and the contact page gives the WhatsApp number. More articles are on the blog.