While I agree with jobermark I am very leery of the terms "complexity" and "efficiency." The latter assumes a teleology or efficiency "relative to some end." Which could be simple bacterial growth towards increasing biomass and longevity. For this, their lack of "individual" cellular complexity but over genetic "diversity" has proven unsurpassably successful.
As to "complexity," I understand this is now highly mathematized, yet in general measures something like "parts-to-whole" and "possible interactions." I assume the determination of a "part" and a "whole" is somewhat axiomatic, with things like "swarm" now admitted into an overly strict dichotomy. As usual, the closer we look the more problematic the determinations appear. Most DNA in a human body is not human DNA. It is bacterial and microbial. Nor could "our own" cells survive as a "person" without these other "parts," making each viable homo sapiens technically a trans-species "swarm."
As your question implies, this problem of defining the atonomous "individual" apart from its cooperative system raises many social issues long debated before any "altruism algorithm." Obviously, human cultures "store" cooperative behaviors that increase the number of individuals and the complexity of interactions. These appear to collapse at intervals, somewhat as cells collapse when surface area expands at a faster rate than interior volume...a good analogy for the border problems of the Roman Empire.
A problem arises when modern liberal societies attempt to define the "individual" as an irreducible, legal "whole" with inelastic "rights." As the number of such participants grows, more and more "altruism" must be imposed. Liberals appear to dread such emergent structural "cooperation," the Communism and loss of identity parodied in "The Borg." Thus a bourgeois idealogical phobia about "too much equality" or even "excess altruism." (Can you image how stunned 19th century English speakers would be to hear politicians railing against the problem of "welfare.")
Personally, I do not see a huge problem of "too much altruism" or "too much equality" in human history. But while I am sympathetic to the noble aims of the Swiss researchers and have not looked at the study, I suspect the definitional problems are far too great to resist blatant biases and Panglossian conclusions. Logicians had already demonstrated the efficacy and necessity of altruism long before the Holocaust.