What is the necessary and sufficient condition for reinforcement in the contingency situation?

Abstract
A SET OF EXPERIMENTS WAS INITIATED TO TEST PREMACK'S HYPOTHESIS THAT ANY MORE PROBABLE RESPONSE WILL REINFORCE ANY LESS PROBABLE RESPONSE. IN THE 1ST EXPERIMENT, THE MORE PROBABLE RESPONSE REINFORCED THE LESS PROBABLE RESPONSE ONLY WHEN THE CONTINGENT BEHAVIOR WAS SUPPRESSED BENEATH THE FREE-PERFORMANCE LEVEL. HYPOTHESIZING THE NECESSARY AND SUFFICIENT CONDITION FOR REINFORCEMENT TO BE THE ANIMAL'S NECESSITY OF INCREASING INSTRUMENTAL RESPONDING IF IT IS TO MAINTAIN CONTINGENT RESPONDING AT THE FREE-PERFORMANCE LEVEL, IT WAS CORRECTLY PREDICTED THAT UPON ESTABLISHING SUCH A CONDITION THE LESS PROBABLE RESPONSE WOULD REINFORCE THE MORE PROBABLE RESPONSE. THE GENERAL CONDITIONS UNDERLYING SUCH "RESPONSE SUPPRESSION" ARE DENOTED MATHEMATICALLY, AND THE SPECIFIC CONDITIONS ASSOCIATED WITH THE REINFORCEMENT EFFECT IN PREMACK'S CONFIRMATORY EXPERIMENTS ARE DERIVED AS A SPECIAL CASE OF RESPONSE SUPPRESSION. (PsycINFO Database Record (c) 2006 APA, all rights reserved)