It adds objects to the RAD for designing and conducting perceptual experiments. Theese are designed to work together, but they can also be used individually. After each trial it will write the values of the stimulus and response variables to a file. The experimenter specifies the names of the stimulus variables, and a set of values for each variable. For generation of the blocks, the user can choose between factorial design and expanded factorial design .
Factorial design means that all possible combinations of the variable values are taken.
When the experment is run, expcontrol generates a stimulus list consisting of a user specified number of blocks. The trials within each block can be randomized. Optionally, a fixed seed can be supplied to the random number generator. This is useful when a particular experiment is to be reproduced exactly. Randomization is done individually within each block.