15 - Chapter 15: Linda: Less Is More

Chapter 15: Linda: Less Is More

Linda is thirty-one years old, single, outspoken, and very bright. She majored in philosophy. As a student, she was deeply concerned with issues of discrimination and social justice, and also participated in antinuclear demonstrations.

• “Linda” fictitious desc. of woman, followed by q’s abt wh career is most likely for her: bank teller or feminist bank teller? — desc. fits stereotype of feminist teller better than ordinary teller — but logically, bank teller more likely (cf. Venn diagr.) —in expt. people chose wrongly — shows how heuristics (representativeness) are used in judg’t, contrary to clear logic — failure of S2, triumph of S1 — even after error is explained, S1 still insists on wrong answ.
• conjunction fallacy = judge a conj’n of 2 events more prob. than one of the events (e.g. feminist bank teller)
• Tom W. and Linda — judge probability by representativeness (similarity to stereotypes) — rep’tivness + personality desc. à coherent story
• coherent story not necess. most prob., but is plausible— easy to confuse coherence, plausibility, probability
• danger to substitute plausibility probability — esp. when scenarios are desc’d, esp. when given details, making story more plausible, or more coherent, or a better story, suggesting an answer
• adding detail to scenarios makes them more persuasive, but less probable
• logic is clear if ∃no story evoked: e.g.

Which alternative is more probable?

Mark has hair.

Mark has blond hair.

Less Is More, Sometimes Even In Joint Evaluation

  

• more on the conjunction fallacy, conflict betw intuition & logic
•  joint evaluation (when viewing both sets), higher value placed on Set A, used logic correctly — but single evaluation ( when viewing only one at a time), higher value placed on Set B, used S1’s intuition — “less is more,” S1 rep’s sets as avgs, norms, so avg value of B is higher than A, broken dishes lower avg
• similar results for joint/single eval. w. sets of baseball cards, A all high value, B same high value cards plus several lower value
• problem for econ. theory, adding items shd increase value of set
• S1 takes avg of sets instead of adding — but probability is a sum-like  variable — e.g. probability (Linda is a teller) = probability (Linda is feminist teller) + probability (Linda is non-feminist teller)
•  S2 not v. alert

Speaking of Less Is More

• “They constructed a very complicated scenario and insisted on calling it highly probable. It is not—it is only a plausible story.”
• “They added a cheap gift to the expensive product, and made the whole deal less attractive. Less is more in this case.”
• “In most situations, a direct comparison makes people more careful and more logical. But not always. Sometimes intuition beats logic even when the correct answer stares you in the face.”