Even though rarely thought of, all environmental spaces contain odor information. It has been proposed that the preconditions for episodic olfactory memory may not be optimal. For example, environmental olfactory information often goes unnoticed and barely evokes attention in humans and semantic activations that are a prerequisite for optimal episodic memory functioning are typically restricted. Still, it is highly likely that olfactory information will become part of a memory representation that is linked to a specific event. This implies that an event-congruent exposure of an odor carries the potential to trigger all, or parts of, a previous episode. Indeed, available evidence shows that odors may serve as powerful reminders of past experiences. This is demonstrated by studies exploring the nature of odor-evoked autobiographical memories and by controlled experimental paradigms where odors have been embedded in a learning context and later reinstated at retrieval where an increased memory recollection for the target information is often observed. These observations converge on the notion that odor memories are retained over long periods of time.

In this chapter, we will highlight olfactory cueing of memory and how odors may act as reminders of the recent and distant past.