The missing fundamental phenomenon in temporal vision

Subjective flicker rates were measured for compound waveforms consisting of five harmonics without a fundamental component. It was found that observers perceived a rate at the fundamental frequency, although energy at this frequency was not included in the signals. In auditory pitch sensation this is called the missing fundamental phenomenon, and an analogous finding is known to occur in spatial vision. Moreover, observers perceived the flicker rates at the fundamental frequency even in the random-phase conditions, in which the period of the fundamental component is unclear in the real waveforms. The results indicate that the perceived flicker rates are not detected from the temporal waveforms per se. One possible mechanism for extracting such a periodicity in the signal is an auto-correlation function to the real temporal waveforms.