Stretching time : relativistic lag-induced shifts in perceived audiovisual synchrony using cluttered displays

When presented with temporally displaced audiovisual events, observers shift their point of subjective simultaneity (PSS) in the direction of this prior lag. This effect, known as temporal recalibration (TR), has been inferred previously using single audiovisual events. Here we investigate TR using an audiovisual synchrony search paradigm employing spatiotemporally cluttered visual displays. By manipulating the relative modulation frequency of the adaptor (0.72 Hz) and test (0.36, 0.72 Hz) we find that following lag-adaptation, PSS shifts preserve the relative phase-not the latency-of the adapted lag. Applying this cross-frequency design to a classic simultaneity discrimination task, we find TR is unaffected by the relative frequency of adaptor and test in terms of latency rather than phase. This dissociation implies that under conditions of low spatial certainty TR obeys a relativistic (phase-conserving) temporal scaling law, whereas high spatial certainty affords PSS shifts, which operate in absolute (latency-conserving) temporal coordinates.