Rhythmic finger tapping to cosine-wave modulated metronome sequences: Evidence of subliminal entrainment

Rhythmic finger tapping was examined during synchronization to metronome se quences whose base intervals were slightly perturbed by a cosine-wave funct ion with the period of four samples. Data were collected under perturbation levels of 1%, 3%, 5% and 7% in conjunction with base intervals of 400, 500 , and 600 ms. Statistical analysis examined the relationship between the in ter-response interval (IRI), inter-stimulus interval (ISI) and synchronizat ion error (SE). It was observed that IRI and SE entrain to the periodicity of the ISI patterns even at perturbation levels close to and below the cons cious auditory perception threshold. Furthermore, the similarity between th e IRI and ISI increased in proportion to the perturbation level. It was als o found that the relative perturbation level had more influence on the sync hronization behavior than the absolute level. Finally, the observed rhythmi c tracking data were modeled mathematically to examine the likelihood of th ree possible synchronization strategies. (C) 1998 Elsevier Science B.V. All rights reserved.