Which Types of Images Drive Sales of Porn DVDs?

The porn industry releases approximately 11,000 adult movies on DVD each year. What determines which porn movies will prove successful versus those that will be lost in the greater clutter? William F. McKibbin, Michael N. Pham, and Todd K. Shackelford tackled this exact issue in a forthcoming paper in Behavioral Ecology. They proposed, not surprisingly, that the images found on the DVD covers would be an important determinant of a movie’s eventual sales rank (a manifestation of the ubiquitous effect of packaging). More specifically, they had two raters (one man and one woman) code the images found on the front and back covers of DVDs, as well as the images contained within screenshots, into one of three categories: (1) two or more men interacting sexually with one woman (polyandrous depiction); (2) two or more women with one man (polygynous depiction); (3) two or more women with two or more men. See here for one of my earlier Psychology Today articles wherein I discussed the relationship between polyandrous images and men’s increased sperm motility. Also, see the 2002 article in Evolution and Human Behavior by Nicholas Pound on the greater incidence of polyandrous scenes in pornographic movies.

Returning to the study by McKibbin et al., they obtained a random sample of 166 movies from Adult DVD Empire (out of 49,493 possible films that were generated based on their search criteria). The online retail site provides sales ranks for each DVD in increments of 5,000 (the more granular data could not be shared as it was proprietary) so the researchers assigned more precise numerical values as follows: 1 corresponds to sales that fall within the 1-5,000 range; 2 corresponds to sales that fall within the 5,001-10,000 range, and so on. The raters then coded the frequency of each of the latter three times of images (interrater reliability was quite high ranging from 0.81 to 0.95 across the three image types) across the sampled DVDs. The authors theorized that only polyandrous depictions (one woman with multiple men) would be correlated with sales ranks (i.e., the popularity of a porn movie), as such images serve as a visual excitatory cue of sperm competition.

Here are some of the key findings:

(1) The correlations between the frequency of each of the three image types and sales ranks were calculated. The sole significant correlation was between the frequency of polyandrous images (two or more men with one woman) and sales rank (r = -0.23; p < .01).

(2) A multiple regression was conducted using sales ranks as the dependent variable, and the frequency of the three types of images, a DVD’s age (as measured by its release date) and its price, as the independent variables. Only the polyandrous images and the age of DVDs yielded significant effects.

Bottom line: While polygyny is the most common human mating arrangement found throughout cultural settings and time periods, visual imagery associated with polyandrous sexual scenes are particularly exciting to the male brain. Pornographers, who are in the business of turning a profit, are more than happy to oblige by offering imagery that caters to this evolutionary trigger.

For some of my other Psychology Today articles on pornography, see here, here, and here. If you are interested in a discussion of the evolutionary roots of pornography, please check out my books The Evolutionary Bases of Consumption, and The Consuming Instinct: What Juicy Burgers, Ferraris, Pornography, and Gift Giving Reveal About Human Nature (see here for my TEDx talk on The Consuming Instinct, and here for my upcoming TEDx talk on May 25th). If you are in Montreal, drop by!

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Source for Image:

http://bit.ly/Xh9LLW