Sex sells on Instagram

We've all heard the phrase 'sex sells', when applied to advertising. It turns out that it may be true in the social media space as well. A new article by Sophia Gaenssle (Erasmus University Rotterdam), published in the journal Kyklos (open access) provides some support for this.

Gaenssle collected data over a six-month period from Heepsy (a social media influencer marketing tool) on the top 500 influencers across five categories: (1) fashion and beauty, (2) fitness and sports, (3) music, (4) photo and arts, and (5) food and vegan. The data included the average price for a sponsored post on Instagram by each influencer, and the number of such posts each influencer posted. That allowed Gaenssle to estimate social media income for each influencer (or, at least, their income from sponsored content). The data also included the 12 most recent posts from each account, which Gaenssle used to create measures of the extent of body exposure (at the extreme, nudity) for each account. Specifically:

If a picture shows 50% or more naked skin (excluding portrait pictures), the body exposure is coded as 1. If there is less nudity in the picture, it is coded as 0. To account for the degree of suggestiveness, if 50% or more focus lie on “dressed” primary sexual characteristics (breasts, bottom, genitals), this is also coded as 1... pictures. The percentage of body exposure pictures is calculated for every account...

Basically, the body exposure measure is a proportion (out of 12) of the 12 posts that included some degree of nakedness. Based on the pictures in the appendix to the paper, it doesn't take a whole lot for a picture to be coded as body exposure. However, interestingly:

The average body exposure is 37%—so less than half of the pictures on the accounts are on average nude pictures. But there are accounts with 0 and accounts with 100% body exposure.

Given that two of the five categories are 'photo and arts' and 'food and vegan', I guess that shouldn't come as a surprise. Indeed, body exposure are lowest in those two categories, as shown in the final column of Table 7 in the paper:

Gaenssle also determines the gender distribution of content for each account (i.e. whether the account predominantly features males or females in its posts). As they explain:

I coded five different variables: (1) female (clearly female features, one or more women); (2) male (clearly male features, one or more men); (3) mixed (clearly male and female, if more than one person in the picture); (4) ambivalent (sexual characteristics recognizable, but not clearly attributable to a man or a woman, e.g., transvestite or similar); and (5) no identification (no characteristics visible)... it is possible to implement a proxy—the degree of female or male pictures of every account.

This distribution is also shown in Table 7 above. It is important to note that this isn't the gender of the account holder. It is really picking up the gender distribution of their posted pictures. Gaenssle doesn't really distinguish this point in the paper, but it is important in terms of interpretation. [*]

Gaenssle then analyses the relationship between gender distribution and four measures: (1) body exposure; (2) posting frequency; (3) price per picture; and (4) average advertising revenue (which is essentially posting frequency multiplied by the average price per picture). I'm only going to focus here on the first and last of those measures. In relation to body exposure, they find that:

...accounts with focus on female contents have significantly higher body exposure than accounts with focus on male contents (p-value = 0.0000). As such, women appear to show more nudity (mean men = 1.25 pics out of 12, mean women 4.3 pics out of 12).

If you've spent much time on Instagram, that finding probably wouldn't shock you. And neither would this:

Although female accounts achieve lower prices per picture, their revenue is significantly higher. The difference in posting frequency compensates for the price difference, so that women ultimately achieve higher ad revenues (p-value = 0.0238), (mean men = 22,654.02 USD per week, mean women 26,209.39 USD per week).

I guess I was surprised that the results were so close. However, bear in mind that this isn't comparing earnings for male influencers with female influencers. It is based on the gender shown in the pictures on each account.

The important question, though, is: does body exposure increase income for these influencers? On that point, Gaenssle finds that:

...body exposure has a significant positive effect on income in all four models... one increase in body exposure (one more picture coded as nude) increases the advertising revenue by 3.9%.

That result is certainly consistent with the idea that 'sex sells'. Gaenssle then digs a bit further, showing that across the five categories:

Except for Music, the trend is “accounts with higher degree of nudity can achieve higher levels of income.”... Only within the category Fitness, the effects are so strong that significant distinctions can be observed. Here, nudity is specifically beneficial.

Then looking at the effect of gender distribution of pictures by category, Gaenssle finds that the effects of body exposure on income are largest for fitness and photo accounts that show predominantly male images. However, those results are possibly stretching the data a little too far, and the confidence intervals on those results are quite wide (such that there aren't statistically significant differences by gender across categories).

So, overall the results suggest that sex sells on Instagram. Of course, Gaenssle isn't demonstrating a causal relationship here, simply that accounts that exhibit more body exposure have higher average earnings. It could be that there is some other factor that is driving both body exposure and earnings. For example, there is evidence that extroverted people earn more on average than introverted people (see here, for example). Extroverts may be more willing to have higher body exposure on their Instagram account. Gaenssle doesn't account for the confounding effect of extroversion (or other personality traits) on their results, so can't claim that body exposure causes higher earnings. Nevertheless, the results are interesting and worth further exploration.

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[*] Of course, Instagram accounts generally do feature pictures of the account holder, but this isn't universally the case.