Previous research has demonstrated that sleep significantly enhances the emergence of two- but not one-node derived relations following a 12-hour period. The present study investigated whether a brief 11-minute Progressive Muscle Relaxation (PMR) intervention would effect a similar enhancement in derived relational responding performance. Thirty-five participants were exposed to matching-to-sample training to establish stable baseline relations, from which two-node derived equivalence relations were predicted. Participants were then randomly assigned to either a PMR group or one of two control groups; Simple or Complex Discrimination task, followed by an equivalence test. In contrast to the sleep study, but in line with experimental predictions, exposure to PMR resulted in significantly more accurate responses for both one- and two-node derived relations. The immediate and significant effects on derived relational responding performance offer support for the role of brief relaxation or non-directed attention in improving cognitive performance.