Subliminal Sensitization Effect

Abstract

Eight normal-hearing male observers were trained to detect brief acoustic pips during a YES-NO procedure until a consistent correct-response rate of approximately 80% was achieved. The pips were presented to one ear at an equivalent level during reference, control, and experimental conditions. During the experimental conditions, the pips were presented at 90° re an on-going 50-Hz sinusoid, which was presented ipsilaterally at four subliminal levels (−10, −20, −30, and −40 db SL). Utilizing a balanced design, four observers received the signals in the right ear and four received them in the left. Higher correct-response rates were observed when the 50-Hz sinusoid was presented at −10 and −20 dB SL than during any of the other conditions. This increase in the correct-response rate for the pips in the presence of a subliminal 50-Hz sinusoid was called the Subliminal Sensitization Effect (SSE). When the effect of level was evaluated, it was noted that the SSE broke down when the 50-Hz sinusoid was between −20 and −30 dB SL. Analyses of group differences revealed a greater SSE for the observers who received the signals in the right ear.