psyphy (version 0.1-9)

dprime.mAFC: d' for m-alternative Forced-choice

Description

Calculate the value of \(d'\) for an m-alternative forced choice paradigm

Usage

dprime.mAFC(Pc, m)

Arguments

Pc

The proportion of correct responses based on either the Hit rate or based on an unbiased observer

m

The number of alternative choices, an integer > 1.

Value

Returns the value of \(d'\)

Details

The probability of a correct response in m-alternative forced-choice, assuming independence, is based on the product of the likelihoods of the signal alternative generating the strongest response and the m - 1 noise alternatives generating responses less than this value (Green and Dai, 1991). For a Yes-No paradigm, the sensitivity is calculated more simply as $$d' = \code{qnorm}(H) - \code{qnorm}(F)$$ where \(H\) and \(F\) are the Hit and False Alarm rates, respectively.

References

Green, D. M. and Dai, H. (1991) Probability of being correct with 1 of M orthogonal signals. Perception & Psychophysics, 49, 100--101.

Green, D. M. and Swets, J. A. (1966) Signal Detection Theory and Psychophysics Robert E. Krieger Publishing Company

See Also

See Also dprime.ABX, dprime.SD, dprime.oddity

Examples

# NOT RUN {
dprime.mAFC(0.8, 4)
# }