The theory of encoding specificity principle proposed by Tulving (1974) refers to the relation between encoding and retrieval conditions for remembering an item or an event. The recall of memory is determined by a set of retrieval cues, which are encoded in the memory at the same time the material was learnt, which are used in recall for retrieval of memorized information. Hence, the effectiveness of encoding operations relies upon retrieval cues and the potency of the cues varies with encoding operations. .
Attempts to test the encoding specificity principle typically involve two learning conditions and two retrieval conditions. This allows the experimenter to show that memory depends on both the information in the memory trace stemming from the retrieval environment. The study by Kenealy (1997) provides one example of successful test of the encoding principle. By inducing different mood state at learning and at recall stages (through the use of music), the first experiment found that participants who learnt and recalled in different moods performed worse compared to participants who were in the same mood. Experiment 2 and 3 investigated the effect of observable retrieval cues on mood-state dependent retrieval. In experiment 2, the presence of observable retrieval cues overrode the state-dependent retrieval at recall. .
In experiment 3, the occurrence and the erasure of mood-state dependency were manipulated by the presence and absence of observable cues at recall. They concluded that the effectiveness of observable cues to override the deleterious effect of a change and mood state requires further investigation; cues were shown to be effective in this experiment, but it did not apply to experiment 2. The results suggests that making accessible to subject in a sad mood material that they previously encoded in a happy mood does not enable them to self-generate appropriate retrieval cues to access that same material at a later time.