Are associative changes in acquisition and extinction negatively accelerated?

Performance to a conditioned stimulus typically shows a negatively accelerated change with Pavlovian conditioning or extinction. This is commonly attributed to negatively accelerated changes in the underlying associative learning. However, the absence of well-specified rules for mapping learning into performance makes it difficult to infer changes in the size of associative changes for stimuli occupying different points on the performance scale. This problem can be addressed by comparing responding to stimulus compounds each consisting of 2 stimuli, 1 of which is poorly conditioned and 1 of which is well conditioned, when either the former or the latter receives a specified amount of additional training. This permits comparison at a common performance level. Two magazine-approach experiments in rats and 2 autoshaping experiments in pigeons used this technique to assess the form of the associative changes in acquisition and extinction.