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1979 vickers 1979 df the conatural of evidence eg is

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Unformatted text preview: and McClelland, 2001; od, Howposterior probabilities. In this case, for a given weight er. 1979). Vickers, 1979). df the co“natural of evidence (e.g., is analogous to in Banburismus): This problem the stopping point one-dimensional ponses and Turing’s Weight of Evidence ted quanlar responses from a pair of sensory neurons when h a pairtrue, barriers (Link, 1992; Ratcliff Brownian motion to or h is of as indicated. For of tradePr(h1|mmotion. The lower curve would ) obabilities es of a direction-selective neuron that prefers upward The weight of evidence articular and Rouder, 1998). means of the normal B distribu(3) log ron” that prefers downward motion. Here wePr(h the simplifying assumption that the make |m) surprisal” r can be equal variances ( represent the drift rates, i (where the subscript i tions ). Note that other0 forms of the distribution, including f and and bans but old and Shadlen, 2001). The panelthe particular Turing’s weight of evidenceThe psychometon the f reward reflects B is a right shows motion strength).the barrier height where constant that represents of their difference; note the linear relationship. m of base ric function describing the probability of correctly reachexclusive hypotheses in favor of h1. For two mutually accumulate/integrate over Decision Model tion-time Figure 2. ing eitherh the is“up” r(h difference between equivalently, given) antineuron is: or “down” barrier on a Pr(h trial The weight (Pr(h favor of evidence in |m) over h the accumulated |m) or, responses of a neuron that prefers h and an 1depicted P computed under thetcondition) thatyh( is)true. The thin, wavy line depicts a simulated 1 0 0 ntlities has that prefers weight of7).evidence atare motion ( d (7) total h (see Equation The curves time1t k ihich the trajectory that represents how the weight of evidence might grow on a single trial as a function of time. The dashed line depicts the expectation 0 Pr(h1)), and assuming the weight of evidence is exn motion (mean value) of this trajectory at each time point. Note that changing the constant of proportionality used to rel...
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This note was uploaded on 09/15/2011 for the course COGS 1 taught by Professor Lewis during the Spring '08 term at UCSD.

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