External control of the stream of consciousness: Stimulus-based effects on involuntary thought sequences.

The stream of consciousness, often seen as free and whimsical, is actually more open to external influence than previously thought. An experimental manipulation successfully triggered not just one but two involuntary thoughts in participants: they were asked to avoid subvocalizing the names of visual objects and to avoid counting the number of letters in those object names. On many trials, participants experienced both types of involuntary thoughts, which arose from distinct high-level processes (naming and counting). This is the first demonstration of inducing two involuntary thoughts into the stream of consciousness, with stimulus word length systematically affecting the results. The findings have implications for attention, imagery, and action control.

Study at a glance

Abstract

The stream of consciousness often appears whimsical and free from external control. Recent advances, however, reveal that the stream is more susceptible to external influence than previously assumed. Thoughts can be triggered by external stimuli in a manner that is involuntary, systematic, and nontrivial. Based on these advances, our experimental manipulation systematically triggered a sequence of, not one, but two involuntary thoughts. Participants were instructed to (a) not subvocalize the name of visual objects and (b) not count the number of letters comprising object names. On a substantial proportion of trials, participants experienced both kinds of involuntary thoughts. Each thought arose from distinct, high-level processes (naming versus counting). This is the first demonstration of the induction of two involuntary thoughts into the stream of consciousness. Stimulus word length influenced dependent measures systematically. Our findings are relevant to many fields associated with the study of consciousness, including attention, imagery, and action control.