{"pk":29233,"title":"Testing human use of probability in a visuo-motor conjunction task","subtitle":null,"abstract":"People overestimate the conjunctive probability of independent events (Bar Hillel, 1973). We examined conjunctive per-formance in a task involving motor uncertainty and binomial sampling. Human probabilistic judgment is typically near-optimal with either of these sources of uncertainty alone. Four subjects attempted to earn rewards by reaching to circulartargets. They chose between a single smaller target and one of N larger targets. Hitting the single target always earned areward but only one on the N larger targets was rewarded: they chose between P[Smaller] and the conjunctive probability(1/N)*P[Larger] as we varied N and the sizes of the targets. The ideal observer should be indifferent when P[Smaller] =(1/N)*P[Larger]. We also asked observers to estimate the probability of hitting targets of different sizes to verify that theycould do so accurately. Remarkably, three out of four observers ignored numerosity N in their preferences.","language":"eng","license":{"name":"","short_name":"","text":null,"url":""},"keywords":[],"section":"Member Abstracts","is_remote":true,"remote_url":"https://escholarship.org/uc/item/40f5c4vc","frozenauthors":[{"first_name":"Laurence","middle_name":"","last_name":"Maloney","name_suffix":"","institution":"New York University","department":""},{"first_name":"Jinsoo","middle_name":"","last_name":"Kim","name_suffix":"","institution":"New York University","department":""},{"first_name":"Keiji","middle_name":"","last_name":"Ota","name_suffix":"","institution":"New York University","department":""}],"date_submitted":null,"date_accepted":null,"date_published":"2019-01-01T18:00:00Z","render_galley":null,"galleys":[{"label":"PDF","type":"pdf","path":"https://journalpub.escholarship.org/cognitivesciencesociety/article/29233/galley/19104/download/"}]}