Chapter 7 Appendix

7.1 Wagenmakers SDT script

Use the script below to process the data file so that the dataset structure is the same as shown in ourSDT example. A zipped folder containing the dataset fromWagenmakers et al. (2008) can be found at thislink. As shown in our script below, the data is stored in the"PropData.txt" file.

#~~~~~~~~~~~~~~~~~~~~ Wagenmakers 2008 Lexical decision task ~~~~~~~~~~~~~~~~~~~~~~~~~~~## 1) subject = participant number# 2) block = block number# 3) practice = 1 if practice block, otherwise 0# 4) cond = condition either "2" for 75% words or "1" for 75% non-words)# 5) stimulus = unique identifier of stimulus, stimuli are nested in frequency conditions# 6) freq = Code "1" means "high frequency word", code "2" means "low frequency word",#    and code "3" means "very low frequency word". Codes 4, 5, and 6 = "non-word".# 7) resp =  0 is non-word, 1 is word, -1 is not interpretable response (i.e., pushed a button,#         but not the right one and also not the one next to the right button)# 8) rt = response time in seconds# 9) censor = 1 if value is eliminated from further analysis;#       practice block, uninterpretable response, too fast response (<180 ms), too slow response (>3 sec)rm(list=ls())require(tidyverse)wagenmakers2008<-read.delim("PropData.txt",header =FALSE)names(wagenmakers2008)<-c("subject","block","practice","cond","stimulus","freq","resp","rt","censor")wagenmakers2008<- wagenmakers2008[wagenmakers2008$censor!=1,-c(3,9)]wagenmakers2008$subject<-factor(wagenmakers2008$subject)wagenmakers2008$cond<-factor(wagenmakers2008$cond,labels =c("nw","w"))wagenmakers2008$stimulus<- wagenmakers2008$freq<4wagenmakers2008$stimulus<-factor(wagenmakers2008$stimulus,labels =c("nw","w"))wagenmakers2008$resp<-factor(wagenmakers2008$resp,labels =c("NW","W"))wagenmakers2008$freq<- ((wagenmakers2008$freq-1)%%3)+1wagenmakers2008$freq<-factor(wagenmakers2008$freq,labels =c("hf","lf","vlf"))wagenmakers2008$correct<-toupper(wagenmakers2008$stimulus)==toupper(wagenmakers2008$resp)wagenmakers2008$W<-as.character(wagenmakers2008$freq)wagenmakers2008$W[wagenmakers2008$stimulus=="nw"]<-"nw"wagenmakers2008$W<-factor(wagenmakers2008$W,c("hf","lf","vlf","nw"))wagenmakers2008<-select(.data = wagenmakers2008,                          subject,                          cond,                          W,                          resp,                          rt,                          correct)%>%rename(stimulus = W)wagenmakers2008$correct<-if_else(wagenmakers2008$correct,true ="2",false ="1")save(wagenmakers2008,file ="wagenmakers2008.RData")

References

Wagenmakers, Eric-Jan, Roger Ratcliff, Pablo Gomez, and Gail McKoon. 2008.“A Diffusion Model Account of Criterion Shifts in the Lexical Decision Task.”Journal of Memory and Language 58 (1): 140–59.