A preliminary investigation of the consequences that define the mand and the tact.

Skinner (1957) proposed that the mand and the tact differed with respect to their unique antecedents and consequences. The present study examined the specific reinforcement characteristic of the mand, and the nonspecific reinforcement characteristic of the tact. A severely mentally impaired individual who used sign language served as subject. A concurrent-chain with latency measures and choice was used. The results showed that specific reinforcement produced stronger verbal behavior than nonspecific reinforcement, but only when response strength was measured in terms of latency and choice. These data lend support to Skinner's assertion that the mand and the tact are different operants. These results also have practical significance in that they may lead to more effective work with individuals who have speech and language impairments.