🧠 Psychology 101 for Adults

What you’ll learn

1. The Hardest Thing Anyone Ever Tried to MeasureExplain why the mind cannot be measured directly, what an operational definition is, and why every psychological finding is an inference rather than an observation.Psychology's central problem is that its subject matter is invisible: nobody has ever observed a belief, a mood, or an intention. Researchers get around this by operationalising — defining an abstract construct as a specific measurable behaviour — which means every result depends on whether the measure really captures the thing. This gap between the construct and its proxy is where most of psychology's later troubles came from, and keeping it in view is the single most useful habit a reader of psychology can have.
2. How Psychology Knows AnythingDescribe the logic of the experiment — random assignment, control, and the p-value — and state precisely what a p-value does and does not tell you.The randomised experiment is psychology's best instrument: by assigning people to conditions at random, it makes the groups equivalent in every respect except the one being manipulated, which licenses a causal claim. Results are then filtered through the p-value, which answers only one narrow question — how surprising this data would be if the effect were not real — and famously does not tell you the probability that the finding is true. Understanding that gap between what p<.05 promises and what people hear it promise is the necessary preparation for what went wrong.
3. The Paper That Broke the FieldExplain how Bem's 2011 precognition paper — using standard, accepted methods — forced psychology to confront the possibility that its methods could produce anything.In 2011 Daryl Bem published nine experiments in a top journal appearing to show that people could feel the future, using entirely conventional methods and passing normal peer review. Because the conclusion was one nobody believed but the methodology was one everybody used, the paper functioned as a reductio: if these methods could produce this result, what else had they produced? The response — a failed replication that three journals refused to publish because it was 'merely a replication' — exposed a second problem as serious as the first.
4. The AutopsyIdentify the specific practices — researcher degrees of freedom, p-hacking, HARKing, publication bias and low power — that let a well-intentioned field fill its journals with findings that were not there.The crisis was not caused by fraud but by a set of individually reasonable habits that combined into a machine for producing false positives: flexible analytic choices made after seeing the data, hypotheses invented to fit results, journals that published only successes, and samples too small to detect anything reliably. Together these guaranteed a literature of exaggerated and often illusory effects. Naming these mechanisms precisely is what made them fixable.
5. 36 PercentState the finding of the 2015 Reproducibility Project and interpret it correctly — including why a failed replication is not proof that the original was false.In 2015 the Open Science Collaboration repeated 100 psychology studies from top journals: of 97 that had originally reported significant effects, 36% replicated, and effect sizes averaged about half the originals. The rate varied sharply by subfield — around 50% in cognitive psychology against 25% in social. The number is not a verdict on any single study, because a failed replication has several innocent explanations, but as a portrait of a whole literature it is devastating and it is honest.
6. The Famous Findings That Weren'tRecount what actually happened to ego depletion, power posing, facial feedback and social priming when they were tested properly, and identify the common structural signature of a doomed finding.Four of the most widely taught findings in modern psychology — willpower as a depletable resource, power posing, the facial feedback hypothesis and social priming — were each built on a small original study, amplified by a TED talk or textbook, and then flattened by large multi-lab replications. The pattern is consistent enough to be diagnostic: a tiny sample, a delightful counterintuitive result, an enormous inference, and no independent check for years. Knowing this list matters because these findings are still being taught.
7. How a Science Fixes ItselfDescribe the concrete reforms — preregistration, registered reports, multi-lab replication and power analysis — and explain why psychology's crisis is evidence of its health rather than its failure.Psychology responded to its crisis with structural fixes rather than exhortation: preregistration timestamps the analysis plan before the data exists, registered reports get a paper accepted on its design so the result cannot decide its fate, multi-lab consortia run one protocol across dozens of sites, and sample sizes are now justified by power analysis. These reforms have spread to medicine, economics and ecology. The right conclusion from the crisis is not that psychology is uniquely bad but that it looked first and hardest.
8. What SurvivedIdentify the classes of findings that replicate robustly and explain what they have in common, so that the crisis is understood as a filter rather than a demolition.The findings that survived rigorous replication share a profile: they involve tight measurement, large or obvious effects, mechanisms that do not depend on a participant's cultural interpretation of a scenario, and decades of independent testing. Perception, memory, learning, classical and operant conditioning, anchoring, the structure of personality traits and the basic psychometrics of intelligence all hold up. The crisis removed a layer of charming, fragile results and left a smaller, harder core.
9. Perception Is Something You DoExplain that perception is an active construction from incomplete data rather than a recording, using the blind spot, illusions and change blindness as demonstrations you can run on yourself.Your visual field feels like a seamless high-resolution recording, but it is a construction: the retina delivers a small patch of sharp colour, a literal hole where the optic nerve exits, and a smear of low-detail periphery, from which the brain builds a stable world by inference. Illusions and change blindness are not glitches — they are the construction becoming briefly visible. This is among psychology's most robust territory precisely because you can verify it on yourself in seconds.
10. Learning: The Oldest Solid GroundDistinguish classical from operant conditioning, explain why both replicate so robustly, and correct the popular misreadings of Pavlov, Watson and Skinner.Conditioning is psychology's most durable body of knowledge: Pavlov's classical conditioning describes learning that one signal predicts another, while Skinner's operant conditioning describes learning that an action produces a consequence, and both hold across species with effects large enough to see in a single subject. They survive because they are measured in counts and latencies rather than ratings. The popular versions — Pavlov's bell, Little Albert, Skinner raising his daughter in a box — are largely mythology worth correcting.
11. Emotion: The Argument That Is Still LiveContrast the basic-emotions and constructed-emotion accounts, present the evidence each side marshals, and model how to hold a genuinely unresolved scientific dispute without pretending it is settled.Whether emotions are a small set of biologically given categories with universal facial signatures, or constructions assembled from general-purpose ingredients and learned concepts, is one of psychology's live disputes. Ekman's cross-cultural recognition studies and Barrett's critiques of their forced-choice methods both have real force, and the honest position is that the question is open. Learning to sit with an unresolved question — rather than picking the tidier side — is itself a skill this course is trying to teach.
12. Personality: What Is Real, and What Is a HoroscopeExplain why the Big Five emerged from data rather than theory, why the MBTI fails basic psychometric tests, and what the person–situation debate settled.The Big Five traits were not proposed by a theorist but fell out of factor analyses of how people describe each other, replicating across languages and decades, and they predict real outcomes modestly but genuinely. The Myers-Briggs, by contrast, fails on reliability and on its central claim of discrete types, and survives commercially rather than scientifically. The person–situation debate resolved into a synthesis: traits predict long-run averages, situations dominate single moments, and the argument was largely about which question was being asked.
13. The Situation, and Its Three Famous StudiesAssess the actual evidentiary status of Milgram, the Stanford Prison Experiment and Asch, and separate a robust conclusion about situations from the mythology built on top of it.The three studies everyone knows are in wildly different evidentiary shape: Asch's conformity work replicates and is routinely misremembered as showing more conformity than it found, Milgram's obedience research is real but far messier than the famous 65% suggests, and the Stanford Prison Experiment is not usable evidence at all — its guards were coached and its conclusions largely pre-written. The underlying claim that situations shape behaviour more than we expect survives; the specific dramatisations mostly do not.
14. Who Is 'People'?Explain the WEIRD sampling problem, quantify it, and show why it makes many claims about 'human nature' claims about a narrow and unusual slice of humanity.A 2008 survey of top psychology journals found 68% of participants were American and 96% came from Western industrialised countries — societies holding about 12% of the world's population. Henrich, Heine and Norenzayan showed these WEIRD populations are not merely unrepresentative but frequently outliers on the very dimensions psychology studies, including visual illusions and fairness. This is a sampling problem, not a statistical one, and no sample size can fix it.
15. Reading Psychology Like a ScientistAssemble the whole course into a practical routine for evaluating any psychological claim you encounter.The course's through-line resolves into a usable habit: for any psychological claim, ask what was actually measured, how many people it was measured on, whether the analysis was committed to in advance, whether anyone independent has repeated it, and how far the inference travels beyond the data. These five questions would have caught nearly every casualty in this course, and they are the most transferable thing psychology has produced.

Questions this course answers

Grounded in trusted sources

• Open Science Collaboration, 'Estimating the reproducibility of psychological science', Science 349 (2015)
• Simmons, Nelson & Simonsohn, 'False-Positive Psychology', Psychological Science (2011)
• Daryl J. Bem, 'Feeling the Future', Journal of Personality and Social Psychology (2011); Ritchie, Wiseman & French, PLoS ONE (2012)
• Hagger et al., Perspectives on Psychological Science (2016); Vohs et al., Psychological Science (2021) — ego depletion multi-lab replications
• Ranehill et al., 'Assessing the Robustness of Power Posing', Psychological Science (2015)
• Wagenmakers et al., Registered Replication Report on Strack, Martin & Stepper, Perspectives on Psychological Science (2016)
• Doyen, Klein, Pichon & Cleeremans, 'Behavioral Priming: It's All in the Mind, but Whose Mind?', PLoS ONE (2012)
• Klein et al., 'Many Labs' replication projects, Social Psychology (2014) and AMPPS (2018)

Every Wunder lesson is built from real, reputable sources — never invented.

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