Saturday, April 19, 2014

The novelty effect: a factor in mate choice


 
Series of facial images from clean-shaven to full beard (Janif et al., 2014)


For the past thirty years, the tendency has been to study sexual attractiveness from the observer's standpoint, i.e., we choose mates on the basis of what's good for us. We therefore unconsciously look for cues that tell us how healthy or fertile a potential mate may be. But what about the standpoint of the person being observed? If you want to be noticed on the mate market, it's in your interest to manipulate any mental algorithm that will make you noticeable, including algorithms that have nothing to do with mating and exist only to keep track of unusual things in the observer's surroundings. If you're more brightly colored or more novel in appearance, you will stand out and thus increase your chances of finding a mate.

We see this with hair color. In one study, men were shown pictures of attractive women and asked to choose the one they most wanted to marry. One series had equal numbers of brunettes and blondes, a second series 1 brunette for every 5 blondes, and a third 1 brunette for every 11 blondes. It turned out that the scarcer the brunettes were in a series, the likelier any one brunette would be chosen (Thelen, 1983). Another study likewise found that Maxim cover girls were disproportionately light blonde or dark brown, and much less often the more usual dark blonde or light brown (Anon, 2008). This novelty effect may be seen in sales of home interior colors over the past half-century: preference for one color rises until satiated, then falls and yields to preference for another (Stansfield & Whitfield, 2005).

The novelty effect seems to apply not only to colors but also to other visible features. In a recent study, participants were shown a series of faces with different degrees of beardedness. A clean-shaven face was preferred to the degree that it was rare, being most appreciated when the other faces had beards. Heavy stubble and full beards were likewise preferred to the degree that they were rare (Janif et al., 2014).

The authors conclude:
 
Concordant effects of frequency-dependent preferences among men and women might reflect a domain-general effect of novelty. Frost [20] suggested the variation in female blond, brown and red hair between European populations spread, geographically, from where they first arose, via negative frequency-dependent preferences for novelty. There is some evidence that men's preferences increase for brown hair when it is rare [21] and for unfamiliar (i.e. novel) female faces [22]. (Janif et al., 2014)

 
The authors go on to suggest that the quest for novelty may drive the ups and downs of fashion trends. A new fashion will rise sharply in popularity when it is still unfamiliar to most people. As the novelty wears off, its popularity will peak and then decline, especially if it faces competition from a more recent fashion.

There are certainly limits to the novelty effect—something can be novel but also disgusting—but it seems to be more general than previously thought.
 

References

Anon. (2008). Maxim's audience prefers brunettes; distribution is bimodal. Gene Expression, July 6, 2008.  http://www.gnxp.com/blog/2008/07/maxims-audience-prefers-brunettes.php  

Frost P. (2006). European hair and eye color: a case of frequency-dependent sexual selection? Evolution & Human Behavior, 27, 85-103.

Frost, P. (2008). Sexual selection and human geographic variation, Special Issue: Proceedings of the 2nd Annual Meeting of the NorthEastern Evolutionary Psychology Society, Journal of Social, Evolutionary, and Cultural Psychology, 2(4),169-191. http://137.140.1.71/jsec/articles/volume2/issue4/NEEPSfrost.pdf  

Janif, Z.J., R.C. Brooks, and B.J. Dixson. (2014). Negative frequency-dependent preferences and variation in male facial hair, Biology Letters, 10, early view
http://rsbl.royalsocietypublishing.org/content/10/4/20130958

Little A.C., L.M. DeBruine, B.C. Jones. (2013). Sex differences in attraction to familiar and unfamiliar opposite-sex faces: men prefer novelty and women prefer familiarity, Archives of Sexual Behavior, early view

Stansfield, J., and Whitfield, T.W.A. (2005) Can future colour trends be predicted on the basis of past colour trends? An empirical investigation, Color Research & Application, 30(3), 235-242. 

Thelen, T.H. (1983). Minority type human mate preference, Social Biology, 30, 162-180.

7 comments:

Bones and Behaviours said...

Since home interior colours are unrelated to mate choice, is it possible that the novelty effect on mate choice is a spandrel? Given the novelty effect on bird song, maybe it is related to the evolution of speech.

But regarding variable visual signals of sexiness, I have two words: Philomachus pugnax.

Ben10 said...

Sorry to go back to the previous post, but I gave it some further thought. As I said before, before we can look for the inheritability of a complex behavior, in this particular case the compliance to moral norms, we should define the mechanism responsible for the behavior.
I thought about 3 mechanisms:

1)Compliance to moral norms could be the contingent result of a cognitive faculty to 'imagine the future consequences of our acts in short and long term' or said otherwise, a propensity to think ahead constantly.
Thinking ahead too much, as we all know, can inhibit impulsive and fast reactions, perhaps increasing a 'wait and see' behavior that could be the root of an apparent compliance with the norm, and the opposite looking like foolish, selfish or stupid and indeed. Non-compliance is not due by malice here.
Well, 'selfish and stupid' like 'laying your eggs in some other bird's nest'. A female bird 'thinking ahead' doing so, should think that her eggs are going to be eliminated by the rightful nest owners...until it actually worked and the owners didn't throw her eggs. This behavior could then be fixed in the form of 'parasitic behavior'. By extension in humans, non-compliance to moral norm could degenerate in a form of social parasitism.
All of this taking source originally in an inability to think ahead, which could be a cognitive capability not shared equally by everybody (slight retardation) or all human 'groups'.
If that was true, then you should see a lot more of these parasitic individuals (who do not comply to moral standards) among retarded individuals or wherever people are incapable of such cognitive projection in the future. i.e., more violence and criminality.

2) It could be the result of a gene/culture neoteny: with longer parental investment and longer childhood compliance to education that could persist in adulthood in the form of compliance to the moral norms.
Here the issue becomes the inheritability of a neotenic behavior., but the end-result could be the same as in 1). People deprived of this trait would fall into a quasi-parasitic and later criminal behavior. These individuals may also display less neotenic facial cues.

3) A direct encoding in the brain of a 'compliant' behavior, inherited as an instinct via epigenetic, or via traditional genetic, but again with the same end-result for those who do not inherit the trait. Here however, the individuals do not lack the capability to think ahead, but they nonetheless don't follow the rules.
It looks like a lot of white collar criminals and crooked politicians falls in that category: they know they gonna get caught, but they cheat anyways.
In this case however, it is fit to look for hereditary background in family with known criminal members.
It is possible that women transmit the trait of 'non-compliance' but do not express it themselves. Studies in criminology have looked at these issues. http://en.wikipedia.org/wiki/Genetics_of_aggression

Sean said...

The novelty effect factor in mate choice would interfere with species recognition. Hence introgression.

Some features can amplify or attenuate others. Dark hair frames white facial skin better than blonde. I wonder about blonde hair becoming common, not as novelty, but because it framed faces with dark skin. Could white skin have caused blonde hair to become less common?

sirtyrionlannister said...

There are two possible mechanisms to explain this effect:

a) Neurological sensory bias induced by sexual selection. Variation maintained by mutation in a polygenic trait subject to optimizing selection, where population heterozygosity is increased by novel phenotypes. Frequency-dependent mate choice can contribute to the maintenance of this variation. This preference for rare patterns could be a source of negative frequency-dependent selection that may contribute to maintaining the polymorphism in hair/eyes coloration, etc.

Extreme genetic similarity between mates can result in low reproductive success but that moderate genetic similarity can be beneficial. Indeed, extreme assortative mating among humans should be limited by mechanisms of inbreeding avoidance, as well as an opposing preference for some genetic diversity (e.g., for increased allelic diversity); and a tendency to reduce outbreeding depression.

Therefore, humans might seek an optimal but delicate balance between outbreeding (novelty) and inbreeding (koinophilia) and we should expect sexual choice to be expressed towards stimuli whose similarities to individuals within a population displaying a predominance of common features, are not too obvious.


B) Fluency may mediate the effect of novelty/rarity. Therefore novelty could be processed fluently (i.e. with greater speed and efficiency). Maybe people classify novelty patterns faster and recruit fewer neural resources to perceive novel patterns.

Peter Fros_ said...

Bones and Behaviours and Sirtyon,

I agree. The novelty effect seems to be a general psychological response and is not limited to mate choice. I don't think it's a mental algorithm to avoid inbreeding.

Ben,

You seem to be arguing on two levels:

1. How did compliance with moral norms evolve?

2. Is moral compliance a specific behavior or is it part of a more general psychological response? (e.g., future time orientation)

For #1, I suspect that compliance with moral norms evolved through increased empathy for non-kin and through increased ability to detect and enforce prevailing normative behavior. In other words, the concern we feel for immediate family has been transferred to all members of the social group. Parallel to this, there has been an increase in the tendency to detect and enforce normative behavior within the social group.

It is possible that #2 is correct, but the Swedish twin study seems to indicate otherwise. Sociopaths can plan ahead. People like Jeffrey Dahmer were not retarded; they simply felt no empathy for their victims. There are plenty of intelligent, future-oriented sociopaths.

Sean,

The combination of blonde hair with dark skin is physiologically possible, but rare. It probably conflicts with a mental algorithm that evaluates facial contrast (light skin + dark frame) positively.

Ian said...

A young woman at work has dyed her hair blue. She's good-looking to begin with, but the number of awestruck men keen to talk to her, once forming a short accidental queue (this is in England), is always funny to see.

Anonymous said...

Nice article.

In defense of beards: Beards can also hide aspects of the face that may be considered less attractive.

I'd say haircuts in general fit into this category.

Imagine walking around a suburb where everyone had bright blonde hair. Yikes that would be scary.