What is Multilevel Selection?
Charles Darwin regarded his theory of natural selection as capable of explaining all aspects of design that had previously been attributed to a creator. However, one important category of traits posed a problem for him: Prosociality—defined as any trait performed by an individual that increases the fitness of others or their group as a whole.
The problem is simple to define. Natural selection favors traits that cause individuals to survive and reproduce better than other individuals in their vicinity. Based on this metric of relative fitness, prosocial traits will not be favored by natural selection.
Darwin’s solution to the problem is also simple to define. While prosocial individuals might be at a selective disadvantage compared to more self-oriented individuals within their own social group, groups of individuals who act prosocially toward each other will have a selective advantage over groups of more self-oriented individuals who cannot cohere. Darwin applied this reasoning to prosocial traits in nature, such as the suicidal sting of the honeybee, and the evolution of prosociality in our own species.
As a necessary addition to Darwin’s theory of natural selection between individuals, group-level selection deserves to be called foundational for explaining the evolution of prosocial traits in all their forms. But that’s not what happened in the history of ideas leading up to the present. Instead, there was a period of naïve acceptance of group- level adaptations, as if special conditions (group level selection) are not required. Then there was a period of rejection during the mid-20th century, followed by a revival. Today, group-level selection, or more generally multilevel selection (MLS), is one of several theoretical frameworks for explaining the evolution of prosocial traits, whose relationships with each other are still debated by the experts.
The Simple Logic of MLS
Lost in this complex history is the very simple logic of MLS, which is described in the first three paragraphs above and remains as solid today as it was for Darwin. In modern terms, Darwin’s reasoning can be summarized as follows:
1. Social interactions almost always take place among sets of individuals (groups) that are small compared to the total evolving population. Put another way, nearly all evolving populations are metapopulations—groups of groups, which are connected to each other in diverse ways
2. As a basic matter of tradeoffs, traits that enhance the relative fitness of individuals within groups typically do not enhance the fitness of the whole group, as in the classic example of altruism compared to selfishness. This is the basic problem that caused Darwin to invoke group-level selection in the first place
3. Therefore, to explain the evolution of prosocial traits in the total population, a positive fitness differential at the scale of between-group competition is required to offset the neutral or negative fitness differential between individuals within groups.
These three assumptions have the same obviousness in retrospect as the three ingredients of Darwin’s theory of natural selection (variation, selection, and replication), which caused Thomas Huxley to exclaim “how stupid of me not to have thought of that!” No theory of social evolution can ignore them, no matter what it is called (e.g., inclusive fitness, evolutionary game theory, selfish gene theory) or what perceived relationship it had to MLS theory in the past.
Our New Initiative
Now, ProSocial World is proud to coordinate an initiative1 to establish the foundational nature of MLS for understanding the evolution of prosociality in all its forms, including cultural evolution and computerized evolutionary algorithms (AI) in addition to genetic evolution. The gallery of members listed below do not agree with each other in every respect—science and scholarship always includes a zone of disagreement in addition to a zone of agreement—but they are united in their basic appreciation of MLS and the need to simplify the study and application of prosocial evolution.
We will work both as a single group and as subgroups to make progress on the following ambitious agenda:
Theory and Evidence
1) The causal claims of MLS theory
2) MLS in relation to other theories of social evolution (equivalence)
3) Theoretical models
4) Laboratory experiments
5) Field research
6) MLS and human origins
7) Cultural MLS
Biological Applications
8) Animal and Plant Breeding
9) Microbiomes
10) Pathogens and cancer
11) Adaptive management of natural systems
Cultural Applications
12) Cultural Diversity and MLS as a Cultural Universal
13) Economics and Business
14) Systems Engineering
15) Artificial Intelligence
16) Health
17) Education
18) Spirituality
19) Governing for the Whole Earth
The Future of the Initiative
Progress on this agenda will be reported in This View of Life and other outlets over the short term, in addition to academic publications, new research programs, and applications over the longer term.
This initiative can itself be regarded as a bold experiment in multilevel cultural evolution. The long history of MLS, leading up to the present confusing situation inside Ivory Tower and nearly complete ignorance of MLS outside the Ivory Tower, is a failure of cultural evolution in the past to appreciate Darwin’s insight about the problem posed by prosocial traits and its solution.
Fortunately, the parameters of multilevel cultural evolution are not fixed and can themselves evolve. By structuring our interactions accordingly, we can achieve a clarity of academic understanding and efficacy of real-world application in a matter of months and years rather than decades or not taking place at all.
How to join the Initiative
This initiative is open to anyone in a position to contribute to the academic study of MLS or its application in real-world settings. ProSocial World is also coordinating an initiative that applies MLS to economics called the New Paradigm Coalition. If you would like to consider joining either initiative, please email hello@prosocial.world