Traditional four alternative letter "E" orientation detection using staircase psychophysical method of vision measurement.

Hello Community,

I am Eswar Kurni, and I am working on developing an experimental paradigm to measure the detection of smaller-sized letter "E" orientations using the staircase technique.

I have written a MATLAB script that presents the letter "E" in a known larger size at the center of the screen with a random orientation. As the participant responds accurately, a progressively finer and smaller-sized letter "E" is displayed.

I would like to extend this experiment using a traditional four-alternative forced-choice (4AFC) method. In this version, the letter "E" will be randomly presented in one of four screen positions, while the remaining three positions will contain distractor "E" letters in different random orientations. I aim to use the same staircase method to measure orientation detection for the smaller letter "E" in this 4AFC setup.

I would appreciate your help and guidance in writing this piece of code.

I am using MATLAB 2024a with Psychtoolbox version 3.0.19.

Attached is the code I wrote for the central letter "E" staircase method.