This is a very fine, extensive and scholarly review of operant conditioning, with a wide background and very illustrative examples and looks across the fence into, for example, Pavlovian conditioning. Its overview character could be strengthened if some details and some of the historical descriptions could be reduced, and if some recent theoretical developments could be included.
There are two directions of research that in the past 10-25 years had a major impact on conditioning and which would fit nicely into the Scholarpedia entry.
One is the work on cognitive aspects of conditioning (through representations of the crucial events, rather than through simple strengthening of links between the events), including the behavioral work by Dickinson & Balleine on goal directed incentive learning. Maybe even the earlier incentive learning work by Bindra (which views incentives in a quite different role than D&B) could be included, as it is an extension of Pavlovian conditioning meant to reach into the spheres of operant conditioning.
The other recent development is the temporal difference version of reinforcement learning by Sutton & Barto, which has led to a tremendous breakthrough in the initially quite ineffective models of reinforcement learning and is currently quite popular with neural modellers.
Author reply(Yael Niv)
Thank you for the useful suggestions. Indeed as a reviewer (before I was added as co-author..) I also thought the above two topics were lacking. We have now added mention of both -- albeit rather short discussions, as the article is already quite long. Do you find these satisfactory? Or can you point to the parts that you think should be enhanced?