Correlated changes in a range of response classes (e.g., if a preaversive stimulus simultaneously alters heart rate, respiration, blood pressure, defecation, and operant behaviour maintained by reinforcement, it may be said to produce emotional behavior). This and related terms evolved from an imprecise colloquial vocabulary, so types of emotional behaviour cannot be defined unambiguously in terms of the response classes involved. They can be defined more consistently in terms of the operations that produce them (e.g., fear, anxiety, or, with another organism present, anger, produced by primary or conditioned aversive stimuli; relief, produced by the termination of aversive stimuli; joy or hope, produced by primary or conditioned reinforcers; and sorrow, produced by the termination of reinforcers). Different observers often disagree on defining characteristics of the various cases (e.g., stimulus magnitudes, the direction of change in different responses, etc.), so the terms have not acquired technical usages within the analysis of behavior. CE AGGRESSION, FRUSTRATION, PREAVERSIVE STIMULUS.