Cognitive parameters and morning and evening types: two decades of research (1990-2009).

An important area of study has examined cognitive aspects of morningness-eveningness orientation. Optimal times of efficiency in participants classified as Morning and Evening types are of great importance for understanding their cognitive abilities. The present review covers the last two decades (1990-2009), during which the important review by Tankova, Adan, and Buela-Casal appeared, and focuses particularly on attention, memory, and executive functions.