MixedPsy (version 1.1.0)

PsySimulate: Simulate psychophysical data

Description

The function simulates data of a typical psychophysics experiment. For each simulated participant, the function returns the following information: individual slope and intercept coefficients, given the fixed and random effects parameters provided as input; summary of the simulated binomial response to a range of intensity levels between a specified range.

Usage

PsySimulate(
  fixeff = c(-7, 0.0875),
  raneff = c(2.4, -0.002, 2e-06),
  nsubjects = 8,
  ntrials = 40,
  nintervals = 9,
  xint = c(40, 120),
  constant = T
)

Value

PsySimulate returns a simulated dataset. If no input arguments are specified, the function returns a dataset with the same characteristics as simul_data.

Arguments

fixeff

array of fixed effects. First item is the intercept, second item is the slope.

raneff

array of random effects. First item is the intercept, second item is the covariance, third item is the slope.

nsubjects

number of subjects to simulate. Default is 8.

ntrials

number of trials for each stimulus level. Default is 40.

nintervals

number of stimulus levels. Default is 9.

xint

range of the stimulus interval. Default is c(40,120)

constant

logical. If set to FALSE, stimulus levels are randomly generated, uniformly distributed values within the selected interval. otherwise, the X interval is divided in intervals of constant length. Default is TRUE.

See Also

PsychShape for plotting a psychometric function given PSE and JND.

Examples

datafr.S1 <- PsySimulate(fixeff = c(0, 1), xint = c(-5,5), 
nsubject = 1, ntrials = 60, nintervals = 10, constant = FALSE)
library(ggplot2)
g <- ggplot(datafr.S1, aes(X,Longer/Total)) + geom_point()

PsychShape(pse = 0, jnd = qnorm(0.75)/1, ps.link = "probit", 
x.range = c(-5,5), addTo = g, ps.color = "red")