Can we tell what we said when we hear ourselves saying something else? - Real-time speech manipulation as a new instrument for the testing of verbal intentions and self monitoring

It is commonly assumed that speech production is initiated and guided by clear pre-verbal intentions. These intentions are moreover supposed to function as a standard of accuracy against which actual performance can be measured. Alternative positions to such a centrally governed process have been offered, but very few empirical attempts have been made to explore the issue. We aimed to remedy this by investigating the role of auditory feedback of one‘s own voice in the understanding of the meaning of self-produced speech. Participants performed a computerized Stroop test while hearing their own voice exclusively through earphones, and we covertly recorded three of their utterances. These words were then played back to the participants over the headphones while they were engaged in a different trial of the test, effectively creating a situation where the participants heard themselves saying something other than what they actually said (i.e. we exchanged what they said for something they had said earlier). The results showed that such manipulations were almost always retrospectively detected, but that a majority of the participants reported that they had experienced significant confusion as to the actual source of the manipulated feedback, and not being certain if it was produced by themselves or not. In addition, on a minority of manipulated trials, participants acted towards the manipulated feedback as if it was self-produced.