A test of the HERA model II: Objects as stimuli

The Hierarchical Encoding/Retrieval Asymmetry (HERA) model (Nyberg, Cabeza, and Tulving, 1996; Tulving, Kapur, Craik, Moscovitch, and Houle, 1994) suggests that episodic memory involves interhemispheric interaction, while semantic memory is a unilateral phenomenon. However, most studies supporting the model have used stimuli processed preferentially by the left- hemisphere. It was hypothesized that hemispheric processing superiority might influence hemispheric interaction in tests of HERA. Using stimuli, both hemispheres are equally capable of processing pictures. Subjects performed a semantic or an episodic task. Results did not replicate those found using letter strings in an identical paradigm, suggesting that HERA might only be applicable for strongly lateralized information.