Consciousness remains a scientific mystery, but contrasting conscious and unconscious processes offers clues. The olfactory system provides a unique window for this contrast due to its neuroanatomy, cognitive mechanisms, and neural dynamics like brain oscillations. This review argues that for an olfactory content to become conscious, it must engage a large-scale neural network involving broad information integration.
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.