Searching for the elements of thought: reply to Franklin, Mrazek, Broadway, and Schooler (2013).

Understanding thoughts with no perceptual basis is a complex problem, and the commentary by Franklin, Mrazek, Broadway, and Schooler (2013) highlighted some of the difficulties that can occur when theorizing about this topic. They argued that the suppression of external input during internal thought arises from the selection of internal information. However, once a process of competition has been resolved in favor of self-generated content, it is still necessary to explain the stability of that content over time. It is proposed that perceptual decoupling and the associated attenuation of external input make environmental information less likely to gain access to limited resources explaining how internal thoughts persist over time. Franklin and colleagues also claimed that perceptual decoupling is unnecessary for an internal train of thought because statements of necessity cannot be drawn from correlational evidence. However, experimentally induced internal trains of thought also compete with concurrent external information, and this mutual inhibition is easily explained by assuming perceptual decoupling is necessary for the integrity of a detailed internal train of thought. I argue that the fundamental advantage of the process-occurrence framework is to highlight that self-generated thought is an emergent property from a general-purpose cognitive architecture and that models such as these will deepen our understanding more effectively than those focused on describing specific mental states.