By showing a perfect linear correlation between an object's rotation angle and the time taken to identify it, Roger Shepard's task provided objective, measurable data on an internal mental process. This was a landmark study that helped overturn Behaviorism by proving cognition could be studied scientifically.

The 'replication crisis' shows many studies fail to replicate. Researchers, biased by their desire for success, engage in 'p-hacking' and delude themselves into finding significance. Paradoxically, the most surprising and celebrated results are often the least likely to be true.

An experiment gave people two identical vanilla desserts, but one was colored brown. Participants overwhelmingly reported the brown one tasted like chocolate. This demonstrates that perception beats cognition; our eyes tell our brain to expect a certain taste, and that visual cue subjectively overrides the actual sensory input.

Daryl Bem's 2011 paper 'proving' ESP was a key trigger for psychology's replication crisis. Because it followed the field's accepted statistical practices (p-hacking) to reach an absurd conclusion, it forced a dilemma: either ESP is real, or the field's methods are fundamentally unreliable.

The 'Invisible Gorilla' experiment is impactful because its effect—inattentional blindness—is directly and viscerally experienced by the viewer. This personal shock of 'not seeing' is more powerful and convincing than studies that rely on abstract statistical analyses to prove their point.

The famous study where priming with 'elderly' words made people walk slower is now seen as an emblem of a failed research program. This area of social priming collapsed under scrutiny due to small sample sizes, a failure to replicate, and the inherent implausibility of the claimed effects.

The Milgram shock experiment, which found 65% of people would administer lethal shocks under authority, is considered top-tier. Its strength lies in its numerous variations, rigorous design, and the fact that its core findings have been replicated—a rare feat for studies from that era.

Once-popular concepts like psychological "priming" have been largely disproven through replication studies. A reliable rule for marketers is that if a psychological input is ridiculously small and barely noticeable, it is unlikely to produce a significant or repeatable behavioral change.

In Solomon Asch's famous 1951 experiment, 75% of participants knowingly gave an incorrect answer to a simple visual test after hearing others do so. This reveals that the psychological need for group conformity is powerful enough to make people contradict the evidence of their own eyes, choosing social safety over objective truth.