Restoration effects in auditory and visual speech

In this paper we examined the use of context to "restore" a degraded auditory signal using the standard Auditory-Only (AO) phoneme restoration paradigm and an Auditory-Visual (AV) version. The experiment was a modified replication of Trout and Poser who used the Samuel discrimination paradigm in which white noise was either superimposed (added) on a phoneme in a word or replaced it entirely. One modification was the use of a 2IFC task in which both the added and replaced versions were presented. Another modification was that we used single words rather than sentences. The key issue was whether visual speech would augment or decrement the phoneme restoration effect. Trout and Poser used a signal detection analysis and found that visual speech reduced the bias to report a stimulus as intact (added). We found that visual speech increased the phoneme restoration effect.