Amount of training, deprivation, and variability of chain length as determinants of response-velocity gradients in homogeneous chains

Tested J. Platt and P. Senkowski's model for the acquisition of homogeneous behavior chains in 2 experiments with a total of 66 naive male holtzman rats. Ss were given discrete-trials lever-press training with different chain lengths and deprivation levels. Results of exp. I indicated that with constant chain lengths, response-velocity gradients were of a generally inverted- shape. As training proceeded, these gradients both heightened and moved their maxima later in the chain to final positions directly related to the chain length. These results were interpreted in terms of the generalization of both the homogeneous response and an incompatible terminal response to early-chain stimuli. The generalization gradient for the terminal response was assumed to be subsequently steepened by consistent nonreinforcement of its occurrence early in the chain. Exp. Ii further supported this interpretation by showing that occasional reinforcement of shorter chains prevented movement of the gradient maximum. Both experiments indicate that velocity of initiating a chain was much more sensitive to deprivation effects than velocity of responses within a chain.