{"data":{"heuristics":[{"id":"hicks-law","name":"Hick's Law","statement":"Decision time increases logarithmically with the number of equally probable choices.","formula":"T = a + b·log2(n + 1)","implications":["Cost is logarithmic, not linear: going from 4 to 8 options costs far less than intuition suggests.","The law assumes equiprobable, undifferentiated options — grouping and defaults break the relationship.","Frequently misused to argue for aggressive option-cutting. The logarithm is the whole point."],"source":{"authors":"Hick, W. E.","year":1952,"title":"On the Rate of Gain of Information","venue":"Quarterly Journal of Experimental Psychology, 4(1), 11-26","doi":"10.1080/17470215208416600"}},{"id":"fitts-law","name":"Fitts's Law","statement":"Time to acquire a target is a function of distance to it and its size.","formula":"MT = a + b·log2(2D / W)","implications":["Primary actions should be large and close to the expected cursor or thumb position.","Screen edges and corners behave as infinitely deep targets on desktop.","On mobile, the thumb-reachable arc matters more than raw distance."],"source":{"authors":"Fitts, P. M.","year":1954,"title":"The Information Capacity of the Human Motor System in Controlling the Amplitude of Movement","venue":"Journal of Experimental Psychology, 47(6), 381-391","doi":"10.1037/h0055392"}},{"id":"jakobs-law","name":"Jakob's Law","statement":"Users spend most of their time on other sites, so they expect yours to work the same way.","formula":null,"implications":["Convention beats novelty for anything instrumental: navigation, checkout, forms, auth.","Reserve originality for what differentiates the product, not for how the cart works."],"source":{"authors":"Nielsen, J.","year":2000,"title":"End of Web Design","venue":"Nielsen Norman Group","url":"https://www.nngroup.com/articles/end-of-web-design/"}},{"id":"tesler-law","name":"Tesler's Law (Conservation of Complexity)","statement":"Every system has an irreducible complexity that must be borne either by the user or by the system.","formula":null,"implications":["Simplifying an interface does not remove complexity; it relocates it into the implementation.","Decide deliberately who absorbs it — usually the engineering team, once, rather than every user, repeatedly."],"source":{"authors":"Tesler, L.","year":1984,"title":"The Law of Conservation of Complexity","venue":"Attributed; discussed in Saffer, Designing for Interaction"}},{"id":"doherty-threshold","name":"Doherty Threshold","statement":"Productivity rises sharply when system response time falls below roughly 400ms, because the user’s attention is never handed off.","formula":null,"implications":["Sub-400ms interactions keep users in flow; beyond it, attention wanders and perceived quality drops.","Where real work takes longer, perceived performance can be managed with optimistic UI and progress feedback."],"source":{"authors":"Doherty, W. J., & Thadani, A. J.","year":1982,"title":"The Economic Value of Rapid Response Time","venue":"IBM Technical Report GE20-0752-0"}}],"total":5,"corpus_version":"2026-07"},"_meta":{"request_id":"req_77285a84571342e4b4d61c111f9edcea","product":"psych/heuristics","version":"1.0.0","receipt_id":null,"cost":{"quoted":0,"charged":0,"currency":"USD","display":"0.000000"},"cache":{"hit":true,"age_s":528973},"provenance":{"sourcing_class":"B","upstream":["internal:psych-corpus@2026-07"],"fetched_at":"2026-10-13T11:52:59.224Z","license":"proprietary"},"freshness":{"as_of":"2026-07","staleness_s":528973},"confidence":1}}