Drive theories and stimulus generalization

Careful study of the implications of Estes' theory and D X H theories relating drive to stimulus generalization reveals that highly varied predictions result from changing the specification of boundary conditions. The boundary conditions and relevant variables which must be considered in making rigorous deductions are described. These include the relative predominance of stimulus sampling probability or energizing effects of drive as compared with drive stimulus change effects, initial and final levels of drive, strengths of competing responses, and height of the threshold. Since there are difficulties in measuring these variables, clear predictions from the theories will often be impossible. (26 ref.)