AbstractThe aim of this research was to investigate teachers' perception of the concept of impulsivity and its relation to the concept of reflectivity. Teacher rating scales for both concepts were constructed by means of the prototype method (Study 1). It appeared that impulsivity refers to social behaviour, whereas reflectivity is more cognitive in character. A Principal Components Analysis (Study 2) showed that the item pools for impulsive and reflective behaviour account for separate components. It is concluded that impulsivity and reflectivity as perceived by teachers are not two extremes of one dimension, but refer to different behavioural domains: social and cognitive.