STIMULUS-CONTROL .2.

The second part of my tutorial stresses the systematic importance of t wo parameters of discrimination training: (a) the magnitude of the phy sical difference between the positive and the negative stimulus (dispa rity) and (b) the magnitude of the difference between the positive sti mulus, in particular, and the background stimulation (salience). It th en examines the role these variables play in such complex phenomena as blocking and overshadowing, progressive discrimination training, and the transfer of control by fading. It concludes by considering concept formation and imitation, which are important forms of application, an d recent work on equivalence relations.