Meanings of Words, Psychology

How Evolutionary Biologists Define Care in Terms of the Parental Investment Theory

parental investment

Parental Investment Theory

Parental investment was defined by evolutionary biologists as a form of sexual selection in which parents expend resources such as time and energy in their offspring at a cost to themselves. English biologist Ronald Fisher introduced parental investment theory for the first time in 1930. According to the theory, parents are naturally selected to maximise the difference between the benefits and the costs, and parental care will tend to exist when the benefits are substantially greater than the costs. The theory was expounded upon by Robert L.Trivers in 1972, and further by evolutionary biologist David Barash in his 1981 book Whisperings Within .

One example of the theory in action in the animal world can be found in the results of a study of King penguins which showed that the number of breeding experiences affected the length of time a male penguin was able to remain with an egg. He asserted that experienced parents are better at replenishing their own reserves. Male penguins have been known to sacrifice their own potential survival to ensure the survival of their young.

Parental Investment in the Human World

Biologically speaking, in the human world, reproductive costs are higher for women than for men. Women produce very few eggs in comparison to the number of sperm males are able to produce. Also, while females can only give birth once for each nine-month pregnancy, men can inseminate many women who may be pregnant simultaneously. Females are also biologically equipped to feed newborn infants after they are born. Globally, the number of women who are the sole caretakers of their children throughout their lifetimes is steadily increasing. It is estimated that between one fourth and one third of all families in the world are headed by single mothers.

Humans are an altricial, rather than a precocial, species, which means that human offspring require parental assistance for a longer period of time. The higher parental investment of humans evolved as the result of the development of the larger human brain. In other artricial species, males spend more time caring for offspring than those of precocial species, which mature more quickly. Rather than pregnancy, gestation, childbirth and breastfeeding, male paternal investment has historically been demonstrated in the form of financial support, teaching, and protection.

However, the increasing financial costs associated with parenthood, coupled with a lack of social support that reflect that reality, is one of the major reasons for the decrease in male parental investment. Another reason lies in the legal systems in place in many countries that continue to devalue fatherhood by preventing divorced fathers from participating fully in their children’s lives. Current research indicates that the lack of parental investment by fathers has a number of negative effects on children’s healthy development.

The Rising Cost of Parenthood

The amount of financial parental investment has grown steadily over the years as the cost of living has increased. In 2014, it was estimated that the cost of raising a child in the U.S. had risen to $245,000. Factors such as housing, food, transportation, clothing, health care, elementary through high school education, child care and various other expenses are included in this estimate. However, it doesn’t include the cost of college, an expense which continues to rise in many countries.

In the U.K., the cost of raising a child for 21 years is estimated at £229,251, which is a 63% increase since 2003. Childcare and education costs represent the majority of the expense. In Australia, as of 2015, the cost of raising a single child is a little over $400,000, an increase of 50% since 2007. While the costs of raising children have risen 50%, household incomes have risen only 25% within the same period of time. In China, the cost was estimated at 499,200 yuan, which is the equivalent of 76,028.61 U.S. dollars, 52,359.50 British Pounds or 69,613.72 Euros. However, the cost of housing in China has increased by 20% during the last four years.

Partially due to the increased cost of raising a child, in some countries such as Russia, Estonia, Hungary and the Ukraine, population growth rates are now negative. In developed European countries and North America as well as Japan, Australia and New Zealand, population growth is at less than 1%. Population growth in less developed countries in Africa, Asia, and Latin America remain higher in comparison.

Despite the rising costs of raising children, people all over the world continue to be willing to make whatever personal sacrifices are necessary to be able to experience the joys of parenthood and family life.

parental investment

Previous ArticleNext Article