Group selection theory attempts a comeback

March 3, 2009 | By | 2 Replies More

Over the past few weeks, in commemoration of the 200th anniversary of Darwin’s birthday, we’ve seen many articles published on the topic of evolution. The November 20, 2008 edition of Nature contains a drawing of Darwin on the cover, and the entire issue is titled “Beyond the Origin.”  Inside this issue is an article by Marek Kohn titled “The Needs of the Many,” an article summarizing current thinking on group selection.groups-of-people

Kohn carefully sets out some definitions at the beginning of his article. For instance, he recognizes that modern evolutionary theory is based on the idea that selection “sees” individuals and acts on them through the genes they embody. Compare that to “group selection”:

The idea that evolution can choose between groups, not just the individuals that make them up–has a higher profile today than at any time since its apparent banishment from mainstream evolutionary theory. And it gets better press, too. This is in part owing to the efforts of David Sloan Wilson of Binghamton University in New York, who argues that the dismissal of group selection was a major historical error that needs to be rectified. And it does not hurt that he has been joined by Edward O. Wilson, the great naturalist and authority on social insects. They and many others have worked to reposition group selection within the broader theme of selection that acts simultaneously at multiple levels.

Buried in the dispute about the extent to which group selection occurs are numerous definitional issues such as the proper way to define “group,” “altruism,” and “selfishness.”

Kohn draws on the work of Samir Okasha in distinguishing between two versions of multilevel selection.

MLS1 focuses on how the division of a population into groups affects the frequencies of different types of individuals in the population. The classic example would be altruism: a population divided into groups may reward altruism more than an undifferentiated one would. MLS2 focuses on the frequencies of the groups themselves. The fittest groups in the MLS1 sense are those that contribute the most individuals to the next generation; the fittest groups in the MLS2 sense are those that contributed the most groups.

MLS1 is often taken as the equivalent of kin selection. MLS2 selection is the focus of much of the current controversy regarding group selection. The focus is the extent to which levels of selection

have become entwined with that of how those levels involved: how the advent of multicellularity, say, created an organism level above the level of the cell. In such major evolutionary transitions, smaller units are integrated into larger ones, be it replicating molecules into simple cells or innocence into societies. For a stable new class of entity to emerge, selfish tendencies among the constituent units had to be suppressed at the group level.

This suppression does actually happen. For example, the mitochondrial and nuclear genome have been almost entirely united.

Wilson and Wilson argue that selection between groups can sometimes be significant, and that each situation needs to be evaluated on a case-by-case basis.  They boil down their principles to three short sentences:

Selfishness beats altruism within groups.

Altruistic groups beat selfish groups.

Everything else is commentary.

Wilson and Wilson argue that group selection was rejected out of hand in the 1960s, rather than taking a close look at the evidence, yet the evidence now supports the existence of many occurrences of group selection. Other scientists are not convinced by Wilson and Wilson. They see “group selection” as simply one instance of Hamilton’s kin selection.

Undeterred, David Sloan Wilson has argued (in Darwin’s Cathedral, for example) that “our species is the primate equivalent of a beehive or a single organism.” How could that be?  Consider this explanation by Jonathan Haidt, from his 2006 book, The Happiness Hypothesis (this passage is from page 234):

David Sloan Wilson’s claim is that religious ideas and brains that responded to those ideas, co-evolved. Even if the belief in supernatural entities emerged originally for some other reason, or as an accidental byproduct in the evolution of cognition (as some scholars have claimed), groups that parlayed those beliefs into social coordination devices (for example, by linking them to emotions such a shame, fear, guilt, and love) found a cultural solution to the free rider problem and then reaped enormous benefits of trust and cooperation. If a stronger belief led to greater individual benefits, or if a group developed a way to punish or exclude those who did not share and its beliefs and practices, conditions were perfect for the co-evolution of religion and religious brains. Religion, therefore, could have pulled human beings into the group-selection loophole. By making people long ago feel and act as though they were part of one body, religion reduced the influence of individual selection (which shapes individuals to be selfish) and brought into play the force of group selection (which shapes individuals to work for the good of their group). But we didn’t make it all the way through the loophole. Human nature is a complex mix of preparations for extreme selfishness and extreme altruism. Which side of our nature we express depends on culture and context. When the opponents of evolution object that human beings are not mere apes, they are correct. We are also part bee.

[Image by Ighost, permission by www.dreamstime.com]

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Category: Evolution, Media, nature, Science

About the Author ()

Erich Vieth is an attorney focusing on consumer law litigation and appellate practice. He is also a working musician and a writer, having founded Dangerous Intersection in 2006. Erich lives in the Shaw Neighborhood of St. Louis, Missouri, where he lives half-time with his two extraordinary daughters.

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  1. Stephan says:

    I enjoy reading your articles, but lately it seems that your voice recognition software is increasingly turning them into literary puzzles. I was able to parse "all truism" and even "out her as in" as altruism, but I'm still stumped by "multicellular nerdy".

    As voice recognition software becomes more prominent, I fear we will need a new word equivalent to "Cupertino" for describing these formulations…

    • Erich Vieth says:

      Stephan: Thanks for the reminder. Things were especially trying last night when I posted this. I thought I was finished, when I noticed a crazy bit of code messing things up. Fast forward 45 min later, I had reverted to the raw dictation (I do depend on Dragon 10 for voice recognition) and tried to quickly replace everything. I clearly failed to proofread it well enough. You've inspired me to go back and tidy things up. Thank you.

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