Selfiecity is a new research project that looks at Instagram data from five cities around the world. Here's a look at the average age of selfie takes in New York City. Hint: It's actually the oldest of the five cities investigated.

Sao Paulo's average age skews much younger: 22.3 for females and 25 for males.

Mechanical Turk workers were asked to estimate the age of the photo subjects. This was compared against computer software that also estimated age. Interestingly, the computers typically assigned an older average than its Mechanical Turk counterparts.

According to this study, women take 80 percent of the selfies in Moscow. This is the biggest gender imbalance of all the cities.

Berlin is about even with NYC in terms of average age of selfie-takers.

The median ages and genders per city. This proves that yes, selfies really are a youth thing.

Selfiecity also looked at visual cues like angle of head tilt. Sao Paulo women were the most expressive with body position and tilt.

A visualization showing #selfie (yellow) and #me (blue).

The study also looked at the facial expressions as a gauge of emotion. NYC is a moderately smiley city.

Perhaps not surprisingly, more women than men tend to smile in their selfies.

Moscow appears to be the grimmest of the cities.

While Bangkok is the happiest, judging by those who smile in their selfies.