Published online by Cambridge University Press: 28 September 2001
The research Nevin & Grace report is impressive in its integrative power, but it also shows the current limits of operant theory: There is tremendous concentration on understanding how existing behavioral relations are modulated in rate or time allocation, but little on dealing with the origin of the behavioral relations themselves. Specifying what should count as a behavioral unit will require source principles sensitive to the composition of the units being related.