Remediation of negative side effects of an on-going response-cost system with chronic mental patients.

Response-cost procedures within a token economy with extremely regressed residents excluded many residents from access to positive reinforcement. Procedures allowing residents to "purchase eligibility" to obtain backup reinforcers through contingent payment on standing fines, combined with proportional fine payoff schedules contingent upon time without new fines, increased payment on fines, reduced incidence of new fines, and increased utilization of backup reinforcers. These modifications removed adverse side effects while retaining the benefits associated with response costs. Failures or adverse effects of elements of token systems should not occasion abandonment of token economies, but rather encourage their continual evaluation and modification.