Duration specificity in the long-range correlation of human serial interval production

Series of repeated intervals produced by humans can be characterised as fractional Gaussian noise (fGn). The scaling factor H of fGn was determined for this task by means of the spectral maximum likelihood estimator across a continuous range of inter-response intervals (IRIs) covering 500–1624 ms. H increased with IRI in a nonlinear fashion on both the individual and the group level. A discontinuity in this increase was indicated close to 1000 ms, consistent with results from other temporal tasks. Implications for conceptions of the human timing mechanism are discussed.