THE SCALLOP IN HUMAN FIXED-INTERVAL RESEARCH - A REVIEW OF PROBLEMS WITH DATA DESCRIPTION

Early research studying human performance on schedules of reinforcemen t indicated that scalloped response patterns (initial pausing followed by accelerating responding) were prevalent in fixed-interval schedule s, but later research has shown that scalloping is rare in humans, or it occurs only under limited conditions. A review of this research rev ealed several problems with the description of response patterns. Firs t, there was considerable variability in what was identified as a scal lop. Second, the prevalence of scalloping was often exaggerated by the manner in which authors summarized cumulative record data. Methods of response pattern analysis including the Mathematical Index of Curvatu re, interresponse time microanalysis, and visual inspection of cumulat ive records are discussed. A method of interval-by-interval classifica tion of response patterns in cumulative records is suggested as a tech nique to improve descriptions of fixed-interval patterning. Cumulative record data from a published study on schedule performance with infan ts are reanalyzed using the method to illustrate its application.