Modality-specific sensory cues as triggers of involuntary autobiographical memories: A systematic review

Involuntary autobiographical memories (IAMs) are a form of spontaneous thought processes that reflect past personal events in the absence of deliberate retrieval attempts. They are reflexively retrieved in response to cues in the ongoing environment that share overlapping features with the content of the originally encoded event. We reviewed empirical findings on how modality-specific sensory cues influence the phenomenology of IAMs. We critically compared different experimental paradigms and assessed methodological approaches to the evaluation of phenomenological characteristics of IAMs. The data suggests a dominant role of the visual modality on eliciting IAMs in terms of the number of retrieved memories, retrieval frequency, and speed and ease of retrieval. Retrieval cues associated with the olfactory modality evoke earlier, more emotionally rich, and more evocative memories, while IAMs evoked by auditory cues are more specific, more personally important, and contain more social content. We further addressed the lack of comprehensive and ecologically valid approaches, such as the heavy focus on the dominant senses of vision and audition and little attention to other senses like gustation and haptics, as well as the overlooked influence of language on mental imagery among the reviewed studies. We concluded with several recommendations for future studies.