Thread by @datepsych

Did the invention of Tinder result in an increase of casual sexual activity?

Evidence from 1.3 million college students between 2012 and 2016. 🧵

Online dating is now one of the top ways people form relationships. About 39% of relationships began on apps as of 2019.

However, rather than a relationship formation tool we often associate apps with casual sexual activity in popular culture.

Researchers examined a very large sample (1.3M) of college students between 2012 and 2016 using the National College Health Assessment (NCHA) survey to estimate a relationship between Tinder use and sexual activity.

Greek-affiliated fraternity/sorority members saw a small increase in total and monthly sexual partners over the last month, by about 6.3% and 3.4%.

Or, about .11 and .07 standard deviations.

Greek fraternity/sorority students were also more likely to contact an STD or unplanned pregnancy following the Tinder rollout - but only by 0.2%.

This effect was concentrated in the top 25% of men: 4.3% of the increase in sexual partners (of the 6.3% total).

In other words, the top 25% of men saw an increase in sexual partners of 4.3%.

The bottom 75% saw an increase in sexual partners of 2%.

Tinder may have helped the top 25% of men twice as much!

At the same time, it also helped them remarkably little.

A 4.3% increase in sexual partners is almost nothing.

This is contrary to the belief that Tinder has had a large role in facilitating casual sex.

It is more consistent with past research on dating apps that has found people primarily do not use them for casual sex:

mdpi.com/1660-4601/17/1…

It's also contrary to the popular narrative that Tinder has funneled easy access to casual sex into the grasp of the top tier of men.

Or, the belief that the top 20% is having 80% of the sex.

The average number of yearly sexual partners for people in the top 25% was 2.

The median number was 1.

For 30 days, 1 was the value for both the median and the top 25%.

The effect was similarly small for non-Greek students (not in a fraternity or sorority).

I also see people say that Tinder use has disrupted relationship formation.

That people are forgoing relationships for "situationships" and casual sex.

But we we don't see a decline in relationships associated with the advent of Tinder either:

This can also be seen in the nationally representative GSS data. Relationship rates have not declined:

datepsychology.com/how-have-relat…

The effect of Tinder on sexual outcomes for women was also the same (or smaller but not statistically significant) as it was for men.

Contrary to some claims that Tinder has resulted in more sex for women, but less sex for men.

A few statistical comments beyond this point:

When we correlate changes in behavior following an event, it is sometimes described as a "quasi-causal" methodology.

The idea being that you can compare before/after an event to see if the event had an effect.

Ultimately it is still a correlation however, so be cautious in interpreting "causal" this way.

Without assignment to groups it strictly can't be known if your variable had a casual effect.

A word can be said about statistical significance and effects sizes as well:

When you have a large sample, almost any change at all will be statistically significant.

Even if the change is very small, not "clinically/practically" significant, or not meaningful.

Here we see what is effectively less than one additional yearly sexual partner on average following the Tinder rollout - so a pretty good example of "statistically significant, but not meaningful."

You should always look at effect sizes.

You could also interpret this from seeing the size of the increase in standard deviations, which correspond to the Cohen's d effect size conventions: very small at .11 or .07

This is what it would look like:

What are the take home points for this?

Maybe two big ones:

1. There is surprisingly little difference in sexual activity between the top 25% of men and the top 50%.

2. The Tinder rollout was only very weakly associated with more sex.

Even among college students, who we tend to think of as highly sexually active - and even for the Greek frat/soror students we tend to think of as the most popular and sexually active!

Why could this be - certainly the most attractive men could have more sex?

People likely underestimate the general trend (especially for handsome men) of forming monogamous relationships.

Rather than pursuing high levels of promiscuity, more common is entering a relationship.

Indeed - we see a large majority of sex occurs in relationships with a committed partner in representative data:

datepsychology.com/how-many-sexua…

A common trajectory for handsome men on dating apps: they find a relationship easily, but are taken off of the sexual market as they enter into that relationship.

Thus, keeping absolute partner count lower than it might have been had they pursued a promiscuous strategy.

This is the paper:

papers.ssrn.com/sol3/papers.cf…