Natural selection makes some relatives selfish, others altruistic

Mar 02, 2011

(PhysOrg.com) -- Cain and Abel certainly displayed it and the three daughters of King Lear proved the point too - families contain a mixture of the selfish and those who put themselves out to help others.

Previous research has shown that these traits - selfishness and altruism - can be passed down through families. A new study from the University of Reading shows how determines the frequencies of selfishness and altruism in successive generations.

Studies in behavior genetics show that around 40% of the willingness to help others is inherited. Those who do not help others help themselves, and anti-social behavior is inherited too. Depending on the genotypes of their parents, children may all be , all altruistic or a mixture of both.

The Reading study, based on , suggests that the numbers of altruistic and selfish individuals in society are controlled by a law of diminishing returns. If there are only one or two altruists in a family, and their actions help others in the family sufficiently compared to the cost of the , then genes for altruism will do better than genes for selfishness, resulting in more altruists in the family tree. So eventually all individuals in the population may be altruistic. Alternatively, when there are many altruists natural selection may ensure that altruistic are less likely to be passed on.

This is because the extra altruists may not bring enough extra benefits to the family. For example, if someone needs shelter when injured or food when starving, the first individual to help may save their life. Latecomers may also attempt to help, but the additional benefit is less.

In other words, there are diminishing returns because there are limits to how much individuals can be helped. Altruists are selected when rare but selected against when common. The result is an evolutionary equilibrium with some individuals selfish and others altruistic.

The research was conducted by Professor Richard Sibly, of the School of Biological Studies, and Professor Robert Curnow, of the School of Mathematical and Physical Sciences.

Professor Sibly said: "Understanding how altruism evolved was of absorbing interest to Darwin and has continued to fascinate biologists ever since. Help comes in many forms, presumably with different genetic bases, for example, child rearing, provisioning during times of need, and defence of resources against competitors. Each and any of these may be subject to laws of diminishing returns. The form of the relationship between help received and number of helpers requires quantitative description. The expected mix of selfishness and can then be calculated using the new equations."

Explore further: Seeing the (UV) light: Previously undetected difference in human mutation rate unique to Europeans

Provided by University of Reading

4.5 /5 (2 votes)
add to favorites email to friend print save as pdf

Related Stories

Acting selfish? Blame your mother

Sep 02, 2010

(PhysOrg.com) -- The fact that our female ancestors dispersed more than our male ancestors can lead to conflicts within the brain that influence our social behaviour, new research reveals.

The economics of nice folks

Jun 19, 2008

A basic tenet of economics is that people always behave selfishly, or as the 18th century philosopher economist David Hume put it, "every man ought to be supposed to be a knave."

Recommended for you

Dairy farms asked to consider breeding no-horn cows

14 hours ago

Food manufacturers and restaurants are taking the dairy industry by the horns on an animal welfare issue that's long bothered activists but is little known to consumers: the painful removal of budding horn ...

Italian olive tree disease stumps EU

Mar 27, 2015

EU member states are divided on how to stop the spread of a disease affecting olive trees in Italy that could result in around a million being cut down, officials said Friday.

China starts relocating endangered porpoises: Xinhua

Mar 27, 2015

Chinese authorities on Friday began relocating the country's rare finless porpoise population in a bid to revive a species threatened by pollution, overfishing and heavy traffic in their Yangtze River habitat, ...

A long-standing mystery in membrane traffic solved

Mar 27, 2015

In 2013, James E. Rothman, Randy W. Schekman, and Thomas C. Südhof won the Nobel Prize in Physiology or Medicine for their discoveries of molecular machineries for vesicle trafficking, a major transport ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

breadhead
1 / 5 (2) Mar 05, 2011
So then it is OK that I was born with a trait of not believing in macro-evolution? This is saying that it is NOT any fault of mine? So that I am not seen as selfish, let me help by saying that Jesus Christ is the son of God, the world was created in 6, 24 hour days. Your attempts to prove otherwise are in vain. If only the writers of the article would read more than the story of Cain and Abel.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.