Somatosensory prior entry assessed with temporal order judgments and simultaneity judgments.

Attention is central to perception, yet a clear understanding of how attention influences the latency of perception has proven surprisingly elusive. Recent research has indicated that spatially attended stimuli are perceived earlier than unattended stimuli across a range of sensory modalities-an effect termed prior entry. However, the method commonly used to measure this, the temporal order judgment (TOJ) task, has been criticized as susceptible to response bias, despite deliberate attempts to minimize such bias. A preferred alternative is the simultaneity judgment (SJ) task. We tested the prior-entry hypothesis for somatosensory stimuli using both a TOJ task (replicating an earlier experiment) and an SJ task. Prior-entry effects were found for both, though the effect was reduced in the SJ task. Additional experiments (TOJ and SJ) using visual cues established that the earlier perception of cued tactile targets does not result from intramodal sensory interactions between tactile cues and targets.