This question is about signal detection theory for psychology research.
Our study used a memory task where participants were given four options: A, B, C, and "I don't know". I have multiple conditions and want to examine how memory differs between those conditions. How would you calculate sensitivity (d') and bias for such a task?
I've tried looking for some answers. There are many papers out there describing how to measure sensitivity (d') and bias within yes/no tasks and alternative forced-choice tasks. However, I can't find a paper on this type of alternative non-forced-choice task? Does anybody have some ideas and possibly have a reference on hand?
The only idea I have is just treating "I don't know" as a choice, like the others, and applying methods for 4-alternative forced-choice designs. However, this doesn't seem ideal.
