 For example, in her study of the Mozart effect, she notes that replication studies of the Mozart effect failed to find that Mozart music had a beneficial influence on spatial abilities. Rauscher, who was the first to report results supporting the Mozart effect, suggested that the later studies were not proper replications of her study (Rauscher, Shaw, and Ky 1993, 1995). She clarified that the Mozart effect applied only to a particular category of spatial abilities (spatio-temporal processes) and that the later studies operationalised the Mozart effect in terms of different spatial abilities (spatial recognition). Here, then, there was a difficulty in determining whether to interpret failed replication results as evidence against the initial results or rather as an indication that the replication studies were not proper replications. Feest claims this difficulty arose because of tacit knowledge or assumptions: assumptions about the application of the Mozart effect concept to different kinds of spatial abilities, about whether the world is such that Mozart music has an effect on such abilities and about whether the failure of Mozart to impact other kinds of spatial abilities warrants the inference that the Mozart effect does not exist. Contra Collins, however, experimental methodology enabled the explication and testing of these assumptions, thus allowing scientists to overcome the interpretive impasse.