A program to construct stimulus sequences for controlled lag recognition memory experiments

Experimental designs in recognition memory research frequently employ a continuous sequence of trials in which each stimulus item is presented on two separate occasions. Subjects are required to indicate for each item whether it is new (first presentation) or old (second presentation), and the lag between the first and second presentation is manipulated as a variable in the design. In order to take advantage of the power and efficiency of this procedure, it is necessary to construct sequences that contain the desired set of intervening lags, while leaving no unproductive gaps in the sequence. Furthermore, in order to reduce confounding due to sequential effects, it is desirable to block experimental conditions within subsections of the sequence. Thisfortran program obviates the labor involved in devising such sequences by automating the process of construction.