The Neural Basis of Idea Density During Natural Spoken Language

Idea density (ID) evolved as a quantification of propositional base structure. Besides its function as a measure of linguistic complexity, ID has also been used as an index of general linguistic ability. In order to find the neural basis for the processing of high or low ID during spontaneous speech, a sample of healthy adults was assessed using the functional resonance imaging (fMRI) technique; participants described pictures presented to them while in the scanner. Differential patterns of activation were observed for the low- and high-ID conditions, providing new insights into the processing correlates of ID.