How Does Evolution Help Explain Behavior?

Adaptation, ancestry, development, and culture

Level: Intermediate
Reading load: 8 core readings in 5 units
Prerequisites: The Biological Psychology foundation or equivalent familiarity with mechanism, development, and causal comparison. Some comfort with graphs and statistical comparisons is helpful. Evolutionary terminology is introduced in the guides; population genetics and specialist comparative statistics are not assumed.
Last reviewed: September 2026

Introduction

To call a behavior adaptive is to begin an explanation whose meaning still needs to be made clear. We may mean that it is useful now, that selection helped bring it into being, or that an organism adjusts to changing circumstances. Present usefulness, historical origin, and individual adjustment belong to different questions. Evolutionary reasoning becomes stronger when we give each its proper evidence.

Begin with four complementary questions about behavior, then consider a critique of explanations that attribute a feature to natural selection alongside an experiment on cuckoo–hawk resemblance. Move from an intervention within a setting to comparisons among species: shared ancestry and task comparability become central. A developmental argument then asks where new forms of behavior and their variation come from. Finally, research on how human behavior relates to local ecological conditions and a study of Fijian food taboos bring local conditions and cultural transmission into the explanation.

By the end, you should be able to specify a proposed function, compare it with alternatives, identify what an experiment or species comparison establishes, and distinguish developmental change from evolutionary history. The critique and comparative-method paper are demanding; allow several sittings. The goal is to understand their reasoning and assumptions, without needing to reproduce every statistical derivation.

Unit 1 of 5

Which evolutionary question is being asked?

Mechanism, development, current utility, and history can constrain one another without supplying interchangeable answers. Use the opening framework to identify what evidence an explanation would need. A proposed function is a question to investigate, not an answer established by naming it.

Reading
1 of 8
Tinbergen's Four Questions: An Appreciation and an Update
Bateson, P., & Laland, K. N. (2013). Tinbergen's four questions: An appreciation and an update. Trends in Ecology & Evolution, 28(12), 712–718. https://doi.org/10.1016/j.tree.2013.09.013
Major synthesis · Contemporary update · Moderate · Full work: 7 pages
Follow the distinction between a characteristic's present contribution and the processes through which it arose.
Why you’re reading it. Establish the questions that the experiments, comparisons, and cultural case will answer only in part.
A question to consider. For alarm calling, write one question about current utility and one about evolutionary history; what evidence would distinguish them?

Unit 2 of 5

What counts as evidence of adaptation?

An evolutionary explanation needs a defensible trait definition and evidence against alternatives. Compare a critique of adaptationist habits with an experiment that changes a putative signal. Ask what current receiver responses establish and what remains unresolved about historical selection.

Reading
2 of 8
The Spandrels of San Marco and the Panglossian Paradigm
Gould, S. J., & Lewontin, R. C. (1979). The spandrels of San Marco and the Panglossian paradigm: A critique of the adaptationist programme. Proceedings of the Royal Society of London. Series B. Biological Sciences, 205(1161), 581–598. https://doi.org/10.1098/rspb.1979.0086
Foundational argument · Critical reappraisal · Challenging · Full work: 18 pages
Treat the catalogue of alternatives as a demand for discriminating evidence, including evidence for constraints and by-products.
Why you’re reading it. Prepare to evaluate a functional experiment without accepting either an adaptive or a nonadaptive story by default.
A question to consider. If striped plumage resembles a predator, propose an adaptive account and an alternative, then identify an observation that would distinguish them.
Reading
3 of 8
Cuckoo–Hawk Mimicry? An Experimental Test
Davies, N. B., & Welbergen, J. A. (2008). Cuckoo–hawk mimicry? An experimental test. Proceedings of the Royal Society B: Biological Sciences, 275(1644), 1817–1822. https://doi.org/10.1098/rspb.2008.0331
Landmark empirical study · Methodological contribution · Moderate · Full work: 6 pages
Compare species controls, the barring manipulation, and responses during and after presentation.
Why you’re reading it. Apply the critique to an experimentally tractable claim about resemblance and receiver behavior.
A question to consider. Which result supports a role for barring, and what further evidence would connect that result to selection on cuckoo plumage?

Unit 3 of 5

What can comparisons across species establish?

Many species do not necessarily represent many independent evolutionary changes. First examine ancestry and statistical assumptions, then apply that reasoning to a broad comparison of cognitive tasks. Phylogeny addresses one problem; comparable measurement and competing causal explanations remain separate.

Reading
4 of 8
Phylogenies and the Comparative Method
Felsenstein, J. (1985). Phylogenies and the comparative method. The American Naturalist, 125(1), 1–15. https://doi.org/10.1086/284325
Methodological contribution · Foundational argument · Challenging · Full work: 15 pages
Translate the alternative trees into claims about how much independent evidence the observations contain.
Why you’re reading it. Prepare for the phylogenetic regression in MacLean's study while keeping it distinct from Felsenstein's particular contrast procedure.
A question to consider. If ten closely related species share both a broad diet and high task scores, what additional species or comparisons would strengthen the inference?
Reading
5 of 8
The Evolution of Self-Control
MacLean, E. L., Hare, B., Nunn, C. L., Addessi, E., Amici, F., Anderson, R. C., Aureli, F., Baker, J. M., Bania, A. E., Barnard, A. M., Boogert, N. J., Brannon, E. M., Bray, E. E., Bray, J., Brent, L. J. N., Burkart, J. M., Call, J., Cantlon, J. F., Cheke, L. G., … Zhao, Y. (2014). The evolution of self-control. Proceedings of the National Academy of Sciences, 111(20), E2140–E2148. https://doi.org/10.1073/pnas.1323533111
Landmark empirical study · Major synthesis · Challenging · Full work: 9 pages
Keep the task, inferred capacity, brain measure, and ecological explanation separate as you follow the comparisons.
Why you’re reading it. Test how much the ancestry framework resolves and where measurement and causal questions remain.
A question to consider. Would controlling shared ancestry settle whether dietary breadth caused cognitive change, or whether all species solved the task in the same way?

Unit 4 of 5

How do development and environments enter the explanation?

Selection acts on differences among organisms, so explaining where those differences arise matters. Consider how environmental responsiveness can generate or reorganize variation, and what additional evidence is required for change across generations. Similar outcomes can arise through different developmental and historical routes.

Reading
6 of 8
Developmental Plasticity and the Origin of Species Differences
West-Eberhard, M. J. (2005). Developmental plasticity and the origin of species differences. Proceedings of the National Academy of Sciences, 102(Suppl. 1), 6543–6549. https://doi.org/10.1073/pnas.0501844102
Foundational argument · Major synthesis · Challenging · Full work: 7 pages
Separate immediate developmental responses, heritable variation in those responses, and evolutionary change in their regulation.
Why you’re reading it. Add the origin of variation to the earlier questions about function and comparative history.
A question to consider. A new foraging opportunity changes behavior within a generation: what observations would distinguish repeated learning from genetic accommodation across generations?

Unit 5 of 5

How should claims about humans be tested?

Human behavior varies with local opportunities, social institutions, and learning histories. An ecological framework generates predictions about that variation; the food-taboo case asks separately about consequences and transmission. Compare the framework's interpretation with the original study's stated limits, and retain cultural history among the explanations to investigate.

Reading
7 of 8
Human Behavioral Ecology: Current Research and Future Prospects
Nettle, D., Gibson, M. A., Lawson, D. W., & Sear, R. (2013). Human behavioral ecology: Current research and future prospects. Behavioral Ecology, 24(5), 1031–1040. https://doi.org/10.1093/beheco/ars222
Major synthesis · Foundational argument · Moderate · Full work: 10 pages
Identify the model's objective and constraints, and examine when the authors propose setting mechanisms aside.
Why you’re reading it. Provide a testable adaptive framework for human variation while making its assumptions open to criticism.
A question to consider. Could two communities reach similarly beneficial food practices through different learning histories, and what would a model of present benefits leave unexplained?
Reading
8 of 8
The Evolution of Cultural Adaptations: Fijian Food Taboos Protect Against Dangerous Marine Toxins
Henrich, J., & Henrich, N. (2010). The evolution of cultural adaptations: Fijian food taboos protect against dangerous marine toxins. Proceedings of the Royal Society B: Biological Sciences, 277(1701), 3715–3724. https://doi.org/10.1098/rspb.2010.1191
Landmark empirical study · Methodological contribution · Moderate · Full work: 10 pages
Compare evidence about toxicity, recalled illness, and learning networks instead of treating them as one demonstration.
Why you’re reading it. Apply the preceding framework and revisit Gould and Lewontin's distinction between utility and origin.
A question to consider. The review describes reduced poisoning, while this paper qualifies causal attribution: what comparison would help distinguish a taboo's effect from other changes during pregnancy or breastfeeding?

Scope and omissions

This path examines evolutionary reasoning about behavior across nonhuman and human cases. It includes functional experiments, comparative cognition, developmental plasticity, human ecology, and cultural transmission. Its animal samples and three-village human case offer specific comparisons, not representative coverage of all species or human societies.

It is not a complete course in evolutionary biology, population genetics, human origins, or every approach to evolutionary psychology. Mating, kinship, cooperation, and life-history theory deserve further paths rather than being treated as the whole field. Species are not steps on a ladder of progress. Explaining a behavior's history or possible benefits does not determine whether it is desirable or what people ought to do.

Synthesis

Evolution adds history to the explanation of behavior, along with questions about function and the persistence of variation. Its strength depends on alternatives that evidence can distinguish. Present utility leaves historical origin open; shared ancestry complicates comparisons; developmental responsiveness need not imply inherited evolutionary change. Cultural transmission, too, can carry practices with quite different consequences. A plausible history becomes convincing only as these possibilities are tested.

Choose a behavioral difference. Define the behavior, population, and relevant outcome. Propose an adaptive explanation and either a nonadaptive alternative or a different adaptive history. Describe one experiment or comparative design that could distinguish them, including how you would address ancestry, measurement, and developmental experience where relevant. State what both a positive and a negative result would leave unresolved about historical origin.

Return to the food-taboo case: separate a claim about present effects from one about transmission and one about the origin of the practice. What additional evidence would each require? That separation is a way to strengthen an evolutionary explanation rather than to demand that one study answer every question.

For a closer study of information passed between individuals, continue with How Do We Learn From Other People?. To examine genetic and environmental contributions to variation within a population, follow Where Do Individual Differences Come From?.