# Evolutionary Psychology Psychology I · History of Psychology · https://tryals.app/learn/psychology-i/evolutionary-psychology ## The Mind as an Evolved Toolkit **Evolutionary Psychology** treats the mind as a product of **natural selection** shaped in the **environment of evolutionary adaptedness (EEA)**—ancestral conditions, not modern ones. Pioneers **Leda Cosmides**, **John Tooby**, and **David Buss** argued the brain is a collection of specialized mechanisms. | Trait Type | Definition | | --- | --- | | **Adaptations** | Features shaped directly by selection for survival or reproduction | | **By-products** | Features that come along for the ride without independent selection | | **Noise** | Random variation with no functional significance | **Common Pitfall:** Assuming every trait is an **adaptation**. Critics like Stephen Jay Gould warned against **spandrels** (incidental by-products). True adaptations require positive evidence, not just a plausible story. ## Evidence and Mechanisms **David Buss** conducted massive cross-cultural studies showing consistent mate preferences: women value resource-related traits more, while men value youth and fertility cues more, driven by differing reproductive investment. **Leda Cosmides** found people reason far better about logic when framed as a **social contract**, proving a specialized **cheater-detection** mechanism rather than a single general-purpose logic module. **Key Distinction:** Evolutionary psychology requires empirical evidence proving a trait was shaped BY selection FOR its current function, separating rigorous science from unverified evolutionary storytelling. ## Practice questions 7 of this lesson's 12 practice questions, with answers. The full set is in the app. ### 1. Evolutionary psychology explains the modern taste for sugar and fat by the **EEA**: the environment we adapted to. What does that explanation predict that a simple 'we like tasty things' does not? A. That the preference will disappear within a few generations of abundance B. A mismatch: preferences calibrated to scarcity misfire under abundance C. Nothing further, it is a restatement of the preference in evolutionary language D. That people in modern environments no longer prefer sugar and fat **Answer:** B. A mismatch: preferences calibrated to scarcity misfire under abundance **Why:** It predicts systematic misfiring, which is a real claim and not a restatement. A preference tuned to rare ripeness meets unlimited supply, and the appetite has no way to know the world changed. That is why obesity is framed as a mismatch rather than a failure of character. Page: https://tryals.app/practice/psychology-i/evolutionary-psychology/evolutionary-psychology-explains-the-modern-taste-for-sugar-and-fat ### 2. Select every statement that is TRUE about evolutionary psychology. A. People reason more accurately in a social-contract (cheater) framing. B. Every trait an organism has must be an adaptation. C. Calling a trait an adaptation requires evidence of selection for its function. D. The EEA refers to the modern environment we now live in. E. A trait can be universal, useful and entirely unselected - carried along by something else that was. **Answer:** A. People reason more accurately in a social-contract (cheater) framing.; C. Calling a trait an adaptation requires evidence of selection for its function.; E. A trait can be universal, useful and entirely unselected - carried along by something else that was. **Why:** The evidence requirement, by-products, and better cheater-framing reasoning are all true. Not every trait is an adaptation, and the EEA is the ancestral (not modern) environment - so those two are false. Page: https://tryals.app/practice/psychology-i/evolutionary-psychology/select-every-statement-that-is-true-about-evolutionary-psychology ### 3. People solve the Wason selection task poorly when it is stated abstractly, but solve the same logical problem easily when it is framed as checking whether anyone is drinking underage. What does this contrast support, and what does it not establish? A. It shows people cannot reason logically, only recall rules. B. It supports content-sensitive reasoning, not that it is an adaptation. C. It establishes an evolved cheater-detection module. D. It shows the abstract version is simply badly worded. **Answer:** B. It supports content-sensitive reasoning, not that it is an adaptation. **Why:** Two problems with identical logical structure produce very different performance, so whatever people are doing is not applying a content-free rule, that much is solid. The adaptationist step needs more: evidence the trait was selected *for* that function rather than being a by-product or a product of learning with permission rules. Page: https://tryals.app/practice/psychology-i/evolutionary-psychology/people-solve-the-wason-selection-task-poorly-when-it-is-stated ### 4. Human beings enjoy music, and the taste is universal across cultures. Why is that pair of facts not yet enough to establish that a taste for music is an adaptation? A. Because music is a cultural invention, and cultural traits can never be adaptations. B. Because universality is consistent with the trait being a by-product. C. Because a trait must be present in other primates before it can be called an adaptation in humans. D. Because enjoyment is subjective, and adaptations must be defined in terms of observable behaviour only. **Answer:** B. Because universality is consistent with the trait being a by-product. **Why:** Universality is weaker evidence than it looks, because a rival explanation predicts it just as well: pitch discrimination, temporal prediction and emotional response all have their own reasons for existing, none of them musical. The question is never whether a trait is useful or common, but whether variation in it affected fitness through the claimed function. Page: https://tryals.app/practice/psychology-i/evolutionary-psychology/human-beings-enjoy-music-and-the-taste-is-universal-across-cultures ### 5. Showing that a trait is useful today is enough to prove it is an evolutionary adaptation. **Answer:** False **Why:** False. Present usefulness does not establish that a trait was selected for that function - it could be a by-product or coincidentally useful. Proving adaptation requires positive evidence of ancestral selection for the function, which is the discipline's central standard. Page: https://tryals.app/practice/psychology-i/evolutionary-psychology/showing-that-a-trait-is-useful-today-is-enough-to-prove-it-is-an ### 6. Sort each trait as an adaptation, a by-product, or noise. **Answer:** - Adaptation: The heart, shaped by selection to pump blood, Sweating, shaped by selection to cool the body - By-product: The redness of blood, a side effect of hemoglobin chemistry - Noise: The exact ridge pattern of one person's navel **Why:** The heart and sweating were selected for a function (adaptations); blood's redness and the chin ride along on other traits (by-products/spandrels); a navel's exact pattern is functionless random variation (noise). The three categories differ in whether selection acted for the trait. Page: https://tryals.app/practice/psychology-i/evolutionary-psychology/sort-each-trait-as-an-adaptation-a-by-product-or-noise ### 7. Order the reasoning steps for establishing that a trait is an evolutionary adaptation. **Answer:** 1. Identify a recurrent adaptive problem faced by ancestral humans. 2. Hypothesize a mental mechanism that would solve that problem. 3. Predict a specific design feature the mechanism should show. 4. Test whether people actually show that feature. 5. Conclude it is an adaptation only if the evidence supports selection for that function. **Why:** The method runs from an ancestral problem, to a hypothesized mechanism, to a predicted design feature, to a test, and only then to the adaptation conclusion if evidence supports selection for the function. This disciplined chain is what separates evolutionary psychology from 'just-so stories'. Page: https://tryals.app/practice/psychology-i/evolutionary-psychology/order-the-reasoning-steps-for-establishing-that-a-trait-is-an