[[Hermann Ebbinghaus|Ebbinghaus,]], a pioneer of research into memory, noted that associations between items aids recall of information thus the internal context of a list matters. This is because we look for any connection that helps us combine items into meaningful units. This started a lot of research into lists of to-be-remembered (tbr) words, and cues that helped them. In 1968 Tulving and Osler made participants memories a list of 24 tbr words in the absence or presence of cue words. The cue words facilitated recall when present in the input and output of memorising and recalling the words. They concluded that specific retrieval cues can aid recall if the information of their relation to the tbr words is stored at the same time as the words on the list.<ref>{{Cite journal|last=Tulving|first=Endel|last2=Osler|first2=Shirley|date=1968|title=Effectiveness of retrieval cues in memory for words.|journal=Journal of Experimental Psychology|volume=77|issue=4|pages=593–601|doi=10.1037/h0026069|pmid=5672271|issn=0022-1015}}</ref> Tulving and Thompson studied the effect of the change in context of the tbr by adding, deleting and replacing context words. This resulted in a reduction in the level of recognition performance when the context changed, even though the available information remained context. This led to the encoding specificity principle.<ref name=":0" />
