As most of you know already, I have a very strong interest in evolutionary psychology and I believe that taking the evolutionary approach helps a lot in explaining and understanding human behavior.
One of the theories I believe to be highly significant and useful in evolutionary psychology is “Life history theory”. This theory explains many apparent paradoxes that we encounter in our social life and gives very nice insights into understanding human behavior. Let me present this theory as briefly and comprehensively as possible.
As I mentioned in earlier posts, any organism, including humans, has two evolutionary “Macro-Goals” namely survival and successful reproduction. What is usually known in popular culture as the “principle” of evolution is “Survival of the Fittest” (sometimes mistaken for survival of the strongest).
Indeed, survival is crucial and all creatures have some sort of survival driven instincts such as “self-preservation”. If we look a little deeper in the evolutionary process, however, we will see that survival is in itself irrelevant. If we agree that evolution is a slow process of selecting genes from one generation to another, mere survival is by far not enough. If an organism survives for a long time but does not send its genes into the next generation through reproduction, eventually its genetic material will be removed from evolution.
To summarize this, mere survival is not enough for the success of an organism in the evolutionary process. An organism has to reproduce in order to be part of the long and slow evolutionary process.
At first glance, survival and reproduction are goals that go “hand in hand”. However, this is not exactly so since during its life an organism has limited resources. Putting things a bit differently, to a large extent survival and reproduction are competing for the limited resources available to an organism.
Life History Theory (introduced by McArthur & Wilson, 1967 and developed in 1975) is derived from general evolutionary theory and describes the allocation of an individual’s material and metabolically resources between short term and long term survival and reproduction. The tradeoff an organism has to deal with is whether to invest in Somatic Effort - growth and maintenance of the body and in the case of humans the mind (knowledge, skills) and Reproductive Effort – attracting a mate, deferring same sex rivals, reproduction and investment in offspring. Moreover, Reproductive Effort consists of two types of investments: Mating Effort – resources needed for attracting, retaining sexual partners and deferring same sex rivals and Parental Effort – resources needed for the increase of the offspring’s chances of survival and successful reproduction.
Again taking the evolutionary perspective, the difference between reproductive and somatic effort is, in fact, a difference between “reproduction now” and “reproduction later”, since somatic effort, even if it leads to higher survival rate or longer life span, has no evolutionary benefit in itself.
Keeping in mind that there is a tradeoff between reproduction and somatic effort (survival), organisms vary on how much of their limited resources are allocated to one or another. Organisms that allocate a lot of effort to reproduction at the expense of somatic effort are considered to follow a “Fast” Life History Strategy. Organisms that allocate a lot of effort to somatic investment at the expense of reproduction are considered to follow a “Slow” Life History Strategy.
To better understand this, consider the following example. Cats tend to have a large number of offspring (between 3 and 6 depending on the age of the mother) twice a year and each generation of cubs receives about 2 months of parental investment from the female and virtually no investment from the male. Cats develop sexually rapidly (a female can have cubs at the age of 10 – 12 months), have relatively short lives, exhibit high infant mortality, are generally of small size, and show very little group cohesion. Cats are a very good example of “Fast” Life History Strategy.
At the other end of the spectrum are, for example, elephants which have a small number of offspring (one or two), have a large gestation period of two years, exhibit slow sexual development, have a low level of infant mortality, live longer, are, in general, of large size and show high group cohesion. Elephants are a very good example of “Slow” Life History Strategy.
Humans as specie have a “slow” life history strategy. This is due to the large amount of time and resources needed for a person to reach reproductive age.
However, there is a lot of variation within our species, some people tend to have more children, to have the first child at a younger age and offer less parental investment, while others tend to have fewer children, have the first child at an older age and offer higher parental investment. A very salient example of this within specie variation is the comparison between India and Europe.
A legitimate question regarding this variance is “what causes it?” The fundaments of Life history theory suggest that life history strategy is an evolutionary adaptation to the environment; thus both the between and within species variation can be explained by differences in environments that different individuals have developed and currently live in.
The two broad types of Life History strategies are evolutionary adaptations to the environment in which a species has evolved. Species that have a “fast” life history strategy evolved under unstable and unpredictable conditions. These conditions lead to a strategy focusing on having more offspring (offspring quantity). For example in an environment which has numerous threats which lead to a high mortality rate within a population the normal adaptation would be to adopt a faster life history strategy because somatic investment will not have evolutionary pay-offs since an organism would die before getting to reproduce.
Species that have a “slow” life history strategy evolved under stable and predictable conditions, which lead to a strategy focusing on the survival of offspring (offspring quality).
In humans, variation in the type of life history strategies adopted can be attributed to both environmental factors such as high infantile mortality, short life expectancy due to poor living conditions etc. and to genetic inherited traits.
As I mentioned earlier, the difference between “fast” and “slow” life history strategy resides in the allocation of resources between reproductive effort and somatic effort (survival). There are also differences in how reproductive effort is distributed between its two (sub)components which are mating effort (acquiring mating partners) and parental effort (investing in the children).
In the case of a “slow” life history strategy, there is a larger parental effort and a smaller mating effort. On the other hand, in a “fast” life history there is an emphasis on mating effort and a relative neglect on parental effort.
Life history strategy is a complex trait and, as far as I know, there is no unique scale or took to measure it to its full complexity. There are, however, three proxies that work quite well.
First there is parental investment received by a person. This parental investment consists of maternal and paternal investment to which it can be added “nepotistic” investment which is the investment received by a person from family members other than the parents. People who have received a low level of parental investment (during childhood) tend to adopt a “fast” life history strategy, whereas people who have received a large level of parental investment tend to adopt a “slow” life history strategy.
Second there is childhood socio-economic status. In essence it measures to what extent a person grew up in a relatively rich or poor family. People who have grown up in relatively poor conditions tend to adopt a “fast” life history strategy, whereas people who grown up in relatively rich conditions tend to adopt a “slow” life history strategy.
Third, there is Socio-Sexual Orientation. This measures the extent to which a person has long or short term mating goals. In other words if a person is more inclined to have short term romantic relationships or long term ones. Socio-Sexual orientation should not be mistaken for “sex drive”. It does not take into account the number of sexual intercourse instances; rather it looks at the number of sexual partners a person has. People with a more restricted socio-sexual orientation (fewer partners and more serious relationships) tend to adopt a “slow” life history strategy, whereas people with a more unrestricted socio-sexual orientation tend to adopt a “fast” life history strategy.
When it comes to Socio-Sexual Orientation there is a significant gender difference, namely that on average men are more unrestricted than women. However, this is not to say that men are unrestricted and women are restricted because there is very large within gender variation. Putting it a bit differently, there are women who are more unrestricted than the average of men and there are men more restricted than the average of women.
Which one of these proxies is better to measure one’s type of life history strategy I can’t say. What I can say is that all of them capture a significant part of the complex trait Life History Strategy, but none captures the entire trait. Also, from my own experience with research in this area there are some correlations between the proxies, but none of them is very high, meaning that each of them captures some related but distinct aspects of life history strategy.
To summarize, life history strategy captures the tradeoff between allocating resources for somatic investment and reproductive effort. People with a “fast” life history strategy allocate more resources to reproductive effort than to somatic investment. People with a “slow” life history strategy allocate more resources to somatic investment than to reproductive effort.
When it comes to reproductive effort, people with a “fast” life history strategy allocate more resources to mating effort (getting mating partners) and less to parental investment. People with a “slow” life history strategy allocate more resources to parental investment and less to mating effort (getting mating partners).
As I mentioned in the beginning of this post, I believe that Life History Theory has many significant implications in practice and it helps explain some apparent paradoxes in social life. Let me explain a bit more.
As you may know, I am Romanian and Romania is not a very rich country. Despite (or in fact because of) this the number of status brand automobiles (such as BMW, Mercedes, Bentley etc.) per capita is significantly larger than in more richer countries in the West of Europe such as The Netherlands (where I life now), France, Germany etc.
Another interesting fact about my home-country is that in 2009 when the country was hit by a severe recession (-7% of GDP) the sales for Ferrari cars actually increased compared to 2008 when the economy was doing well.
These facts are more or less the same for all emerging economies in the East of Europe and Africa, South-East Asia etc. At least from my experience when crossing the former “iron curtain” (the border between western democratic countries in Europe and Eastern former communist countries) there is a clear difference in the type of cars that are seen on the roads. In the west there are significantly fewer expensive status cars, whereas in the east their proportion is huge.
Of course, there are more causes for this difference, but one of them is related to Life History Theory. In more poor and uncertain environments many people are more on the side of a “fast” life history strategy and it is only natural for them to invest more in “mating effort” which includes enhancing one’s status through conspicuous consumption.
I have heard a sad but interesting story about a very poor family who somehow got to be presented on TV before a major Christian holyday. In brief, they were so poor that they couldn’t get a decent meal for that holyday. After the story being presented on TV, a rich man gave that family about 800 Euros (which is a lot of money) to have a decent celebration of the holyday. What that family did with the money… well they bought an iPhone…
Apparently this type of behavior is really stupid and I don’t argue with that. However, this behavior is natural. Simply people with a “fast” life history strategy invest a lot of their often few resources in their status. Unfortunately, buying iPhones or BMWs does not get someone out of poverty.
Another difference between “fast” and “slow” life history strategy is the attitude towards risk. In general all people are risk averse, but again there is variance within our specie on how risk averse or risk seeking we are. People with a more “fast” life history strategy are more willing to take risks especially when they feel a potential threat to their life or well-being (in other words, environmental threats such as recessions, wars, natural disasters etc.). On the other hand, people with a more “slow” life history strategy are more risk averse and avoid taking risks even when there are environmental threats.
This difference in attitude towards risk explains why the people with very limited possibilities are the ones that gamble their last pennies and are likely to get loans with very risky costs.
Before continuing with the argument, I have to say that having a “fast” life history strategy is not wrong neither is having a “slow” life history strategy. Each of them is an adaptation to the environment. Even if some consider that having a “fast” life history strategy is wrong, people who are more “fast” than “slow” in life history strategy are not to be blamed for their behavior. They do what is natural for them to do.
In my opinion the “fast” life history strategy contributes to what I call “Self-enforcing poverty”. If people in very poor societies have many children, then the next generation will be at best as poor as their parents were.
Even if there is an influx of money in societies dominated by “fast” life history strategy, this money will be spent on increasing status which can lead to a runaway conspicuous consumption race. Unfortunately status products will not make people less poor, nor will they give them more opportunities for future development.
In fighting poverty, one crucial aspect is to understand which the sources are of a “fast” or “slow” life history strategy. To a certain extent, life history strategy is inherited through genes, thus very little can be done in this area. At the same time, there is a component inherited through nurture and there things can be improved. Moreover, in stable predictable environments the differences between “fast” and “slow” life history strategies are very small, but things change when the environment is unpredictable and offers cues of life threats such as high infantile mortality, high incidence of diseases, wars etc.
Environments can be changed… and controlled.
Note: This post is documented from:
Griskevicius, V., Tybur, J.M., Delton, A.W., Robertson, T. E. (2011). The Influence of Mortality and Socioeconomic Status on Risk and Delayed Rewards: A Life History Theory Approach. Journal of Personality and Social Psychology, 100(6), 1015–1026.
Figueredo, A. J., Vasquez, G., Brumbach, B. H., Sefcek, J. A., Kirsner, B. R., Jacobs, J. W. (2005). The K-factor: Individual differences in life history strategy. Personality and Individual Differences, 39(8), 1349–1360.
Figueredo, A. J., Vasquez, G., Brumbach, B. H, Schneider, S.M. R. (2010). The heritability of life history strategy: The k‐factor, covitality, and personality. Biodemography and Social Biology, 51(3-4), 121-143.
Simpson, J.A., & Gangestad, S. W. (1992). Sociosexuality and Romantic Partner Choice. Journal of Personality, 60(1), 31–51.
Simpson, J.A., & Gangestad, S. W. (1992). Sociosexuality and Romantic Partner Choice. Journal of Personality, 60(1), 31–51.