The negative social consequences of living as an unmarried couple have diminished over time. Why, then, does anyone bother to tie the knot?

There are plenty of good reasons, of course: reducing your shared tax burden, placating traditionalist in-laws, shedding an awful maiden name, throwing a disgustingly expensive party, or even — possibly — love. But a marriage begins with a wedding and a wedding takes place on a set date: how do we decide when we should get married?

We humans often like to flatter ourselves that we are the masters of our own destiny, and that we make important life decisions based on clear thinking and reason. But our attitudes are shaped by all manner of unconscious processes, and when it comes to matters of the heart we’re perhaps more likely than not to be swayed by outside influences.

A team of psychologists based at Texas Christian University have investigated one such influence. Charles Lord and his colleagues brought 120 unmarried and student-aged men and women to their lab to take part in a study of weight perception. The volunteers were shown images of objects belonging to a specific category, such as fruit. Their task was to rank the three objects — say, a banana, an orange, and a lemon — in weight order, from heaviest to lightest. The volunteers ranked objects from multiple categories, including vehicles, clothing, and electronic devices.

If you’re now asking yourself what a study about estimating the weights of cellphones and spanners and sports cars has to do with marriage, that’s precisely the point. The cunning psychologists had designed the task to throw their volunteers off the scent — to conceal the most important part of the experiment.

Next, the volunteers were split into two groups. One half of the volunteers, the control group, judged only inanimate objects; the other half were also asked to rank a set of smiling baby photos. Now the researchers had a group of people who had been exposed to images of cute infants, and another who hadn’t.

The volunteers then began what they thought was a second task: a questionnaire about their future life plans. Among a long list of filler questions was the one question the psychologists were interested in: at what age would you like to get married?

In general, women wanted to get married at a younger age than men: about six years in the future to men’s seven and a half. But, after viewing baby photos, women desired to get married at a younger age: around 5.5 years in the future for women who saw the babies, compared to 6.7 years in the future for women who hadn’t seen the babies.

Estimating the weight of three babies made young women want to get married more than a year sooner!

What about men? Men who saw the babies wanted to get married later, although the difference between men who saw and who didn’t see babies was not statistically significant (we can’t be confident the difference would emerge again if we were to repeat the study).

A further interesting result was that men and women agreed on how long they would want to wait to marry if they hadn’t seen the baby photos. It was only among those who were shown the baby photos that the difference between men and women emerged.

This study can’t tell us whether the effect is long lasting. A few weeks, days, or even hours after seeing the baby photos, would the women have returned to their baseline desire for marriage? We don’t know.

And is the effect cumulative? If a woman’s social media accounts are a non-stop torrent of other people’s baby photos, does her desire for imminent marriage sky-rocket? Again, we don’t know.

A follow-up study, for which volunteers were recruited on the internet, produced similar results to the first. This suggests that the effect is not confined to the students of a church-affiliated Texan university, who may be more positive about the idea of marriage than the general population.

Still, I wonder if the effect is really about children. What would happen if people were to be exposed to images of smiling adults? Both smiling babies and smiling adults probably make us feel more social, and maybe when women are made to feel more social they are more positive about earlier marriage. It could even be a mood effect: baby pictures make us happy, but so do pictures of cute animals. Do kitten and puppy pictures make men or women more eager to marry?

The only way to be sure if the baby effect is really about babies is to focus in on what makes baby images unique compared to other images. Until then, any men who are not so keen to wed might want to consider steering their girlfriends away from images featuring cute babies. Easier said than done when we’re careering toward an annual celebration of the most famous baby in history. Merry Christmas, everyone!
I don't think this study proves anything, per se. However, I do think it is likely that seeing cute infants, and other people with infants would influence many women to have a family.