There are broadly two types of heterosexual mating strategies that humans pursue: short-term and the long-term mating strategy.
Short-term mating strategy means forming brief relationships with multiple partners while a long-term mating strategy means forming an enduring relationship, typically with one partner.
Now, the kind of mating strategy an individual will pursue depends on numerous factors. It has been observed that the presence or absence of a father in a child’s early life is one strong factor that influences the type of mating strategy that he or she is likely to adopt later in life.
Individuals growing up in fatherless homes during the first 5-7 years of life are likely to adopt a short-term mating strategy marked by early sexual maturation, early sexual initiation, and frequent partner switching. Resources sought from brief sexual liaisons are opportunistically attained and immediately extracted.
On the other hand, individuals who have a reliably investing father during the first 5-7 years of life are likely to pursue a long-term mating strategy, marked by a delay of sexual maturation, later onset of sexual activity, and a search for securely attached long-term adult relationships.
Breaking it down
Children that grow up in fatherless homes develop the expectations that parental resources will not be reliably or predictably provided and that adult relationships are bound to be non-enduring and transitory.
As a result, they pursue the strategy with a high reproductive rate designed to produce a large number of children, with low levels of investment in each.
It’s likely that our ancestors who adopted this strategy in times when resources were scarce out-reproduced those who didn’t. After all, when you got little or no resources to invest in the offspring, greater reproductive success can only be attained by reproducing more.
Conversely, children that grow up in homes with reliably investing fathers develop a different set of expectations about the availability of resources and adult relationships. Relationship partners are seen as reliable and relationships are expected to be enduring.
As a result, they pursue the strategy with a low reproductive rate designed to produce a few children, with high levels of investment in each.
It’s likely that our ancestors who adopted this strategy in times when they had sufficient resources to invest in their offspring out-reproduced those who didn’t. In this case, greater reproductive success could be attained by investing more in a few offspring as opposed to investing little in a larger number of offspring.
Berlin post-World War 1
It’s likely that something similar to what we’ve been discussing so far happened in Berlin, Germany after World War 1, albeit on a much larger, societal scale.
The war rendered nearly 2 million children fatherless and the German economy was crippled by hyperinflation. In other words, a whole generation was raised without fathers and enough resources.
As predicted by evolutionary psychology, this generation grew up to pursue a short-term sexual strategy with drugs, prostitution, strip clubs, and sex clubs being rampant in the city to the point that it was at the time dubbed ‘a centre of hedonism’ and ‘the sex capital of Europe.’