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ream (version 1.0-5)

dLIMF_grid: Generate Grid for PDF of the Leaky Integration Model With Flip

Description

Generate a grid of response-time values and the corresponding PDF values. For more details on the model see, for example, dLIMF.

Usage

dLIMF_grid(rt_max = 10, phi, x_res = "default", t_res = "default")

Value

list of RTs and corresponding defective PDFs at lower and upper threshold

Arguments

rt_max

maximal response time <- max(rt)

phi

parameter vector in the following order:

  1. Non-decision time (\(t_{nd}\)). Time for non-decision processes such as stimulus encoding and response execution. Total decision time t is the sum of the decision and non-decision times.

  2. Relative start (\(w\)). Sets the start point of accumulation as a ratio of the two decision thresholds. Related to the absolute start z point via equation \(z = b_l + w*(b_u - b_l)\).

  3. Stimulus strength 1 (\(\mu_1\)). Strength of the stimulus prior to \(t_0\).

  4. Stimulus strength 2 (\(\mu_2\)). Strength of the stimulus after \(t_0\).

  5. Log10-leakage (\(log_{10}(L)\)). Rate of leaky integration.

  6. Flip-time (\(t_0\)). Time when stimulus strength changes.

  7. Noise scale (\(\sigma\)). Model scaling parameter.

  8. Decision thresholds (\(b\)). Sets the location of each decision threshold. The upper threshold \(b_u\) is above 0 and the lower threshold \(b_l\) is below 0 such that \(b_u = -b_l = b\). The threshold separation \(a = 2b\).

  9. Contamination (\(g\)). Sets the strength of the contamination process. Contamination process is a uniform distribution \(f_c(t)\) where \(f_c(t) = 1/(g_u-g_l)\) if \(g_l <= t <= g_u\) and \(f_c(t) = 0\) if \(t < g_l\) or \(t > g_u\). It is combined with PDF \(f_i(t)\) to give the final combined distribution \(f_{i,c}(t) = g*f_c(t) + (1-g)*f_i(t)\), which is then output by the program. If \(g = 0\), it just outputs \(f_i(t)\).

  10. Lower bound of contamination distribution (\(g_l\)). See parameter \(g\).

  11. Upper bound of contamination distribution (\(g_u\)). See parameter \(g\).

x_res

spatial/evidence resolution

t_res

time resolution

Author

Raphael Hartmann & Matthew Murrow

References

Evans, N. J., Trueblood, J. S., & Holmes, W. R. (2019). A parameter recovery assessment of time-variant models of decision-making. Behavior Research Methods, 52(1), 193-206.

Trueblood, J. S., Heathcote, A., Evans, N. J., & Holmes, W. R. (2021). Urgency, leakage, and the relative nature of information processing in decision-making. Psychological Review, 128(1), 160-186.