Table 1.
Methods and results in odor-evoked memory research with implications for psychological and physiological health.
| Authors | Methods | Results |
|---|---|---|
| Studies Reporting Predominantly Psychological Effects | ||
| Arshamanian et al., 2013 [10] | Familiar odors evocative of an AM were compared with memories elicited by verbal labels for those odors during fMRI scanning. Post-scanning, odors and labels were re-assessed and participants provided subjective evaluations of their memories. | Odors elicited more emotional and positive memories, and more activity in parahippocampal, amygdala and tempopolar regions than labels. |
| Miles and Bernsten (2011) [13] | 12 familiar stimuli presented in verbal, visual and olfactory formats were compared for various qualitative dimensions of memory. | Odor-evoked memories were more positive, and more relevant to one’s life story than memories elicited by verbal or visual cues. |
| Reid et al. (2015) [32] | 12 common scents were evaluated for nostalgic evocation and associated feelings. | Higher levels of odor-evoked nostalgia elicited higher levels of positive affect, self-esteem, self and social connectedness, optimism, and life meaning. Nostalgic scents elicited 3× more positive than negative emotions, and 2× more positive emotions than in a previous study examining music-evoked nostalgia. |
| Toffolo et al. (2012) [33] | An aversive documentary was paired with an olfactory, visual or auditory cue. One week later memories for the documentary were compared. | The olfactory condition elicited more arousing, detailed and unpleasant memories of the documentary than the auditory condition. |
| Willander and Larsson (2007) [20] | 10 common scents were presented in odor-only, verbal-only, and odor + verbal format as memory cues and various experiential factors were assessed. | Odor-only cues elicited the most positive, emotional, and evocative memories. |
| Vermetten and Bremner (2003) [34] | Case reports of three individuals suffering from odor-evoked PTSD. | Odors specific to a given individual’s past trauma evoked PTSD flashbacks that were intensely negative, persisted for decades, and did not extinguish with time. |
| Studies Reporting Predominantly Physiological Effects | ||
| Masaoka et al., 2012 [35] | A self-selected perfume that evoked an AM for each participant was compared to pleasant/neutral CFs. | Odors that evoked AMs promoted deeper, slower and more relaxed breathing compared to the CFs. More evocative memories and deeper breathing was observed among individuals who scored highest in trait anxiety. |
| Matsunaga et al. (2011) [36] | A self-selected perfume that evoked an AM for each participant was compared to a pleasant unfamiliar CF. Evoked emotions and associations were evaluated using rating scales. HR, SC, and plasma IL-2 levels in response to the odors were measured. | AM fragrances elicited more positive emotion, increased feelings of comfort and happiness, and decreased anxiety compared to the CF. HR decreased, SC increased, and IL-2 decreased after smelling the AM compared to the cf. |
| Matsunaga et al. (2013) [37] | A self-selected fragrance that evoked an AM for each participant was compared to two pleasant generic CFs. Emotions and memories evoked were evaluated. Plasma TNF-α, IFN-γ and IL levels in response to the odors were measured. PET scans of neurological activity during odor exposure were assessed. | 6.5 times more feelings of nostalgia was experienced to the AM than CF. TNF-α and IFN-γ were decreased after smelling the AM. mOFC and precuneus/PCC were significantly activated during AMs, and activity in the mOFC and precuneus/PCC were negatively correlated with IFN-γ concentration. No IL changes were observed. |
| Sayette & Parrot (1999) [38] | Chronic smokers sniffed either a pleasant odor, an unpleasant odor, or a no-odor control when they experienced a cigarette craving. | Sniffing odors reduced cravings for cigarettes compared to the control condition. There was a trend for odors that evoked a memory to be the most effective at diminishing urges. |
AM = autobiographical memory; CF = control fragrance; HR = heart-rate; SC = skin conductance; PTSD = post-traumatic stress disorder; IL = interleukin; TNF = tumor necrosis factor; IFN = interferon; PCC = posterior cingulate cortex; mOFC = medial orbitofrontal cortex.