The Effect of Aging on the Dual-Route Model of Emotion Processing Applied to Memory Recognition

Objective: Emotional faces are automatically processed in the human brain through a cortical route (conscious processing based on high spatial frequencies, HSF) and a subcortical route (subliminal processing based on low spatial frequencies, LSF). How each route contributes to emotional face recognition is still debated, and little is known about this process in aging. Method: Here, 147 younger adults (YA) and 137 older adults (OA) were passively presented with neutral, happy, and angry faces, shown as (a) unfiltered, (b) filtered at LSF, and (c) hybrid (emotional LSF superimposed to the neutral HSF of the same face). In a succeeding recognition phase, the same faces and new faces were shown as unfiltered, and participants were asked whether each face had been already presented in the encoding phase. Results: Despite the better performance by YA compared with OA for neutral faces presented as unfiltered (cortical route), the performance of OA was better than that of YA for angry faces presented as hybrid and for happy faces presented at LSF and as hybrid. Conclusions: We conclude that the activity of the subcortical route during the encoding phase facilitates emotional recognition in aging. Results are discussed in accordance with the dual-route model. Key Points Question: Emotions are particularly important for our daily life, so much so that in the evolution of humans two cerebral routes have developed to simultaneously process emotional valence, one at a subliminal level and the other one at a conscious level. Findings: Younger compared with older participants revealed a better memory performance when a conscious emotional face processing was required. Nevertheless, emotional faces were better recognized by older compared with younger participants when presented filtered at low spatial frequencies, implying a higher functioning of the subliminal emotion route in aging. Importance: Subliminal processing might be strengthened in older adults, with the aim to compensate for the expected and physiological memory decline. Next Steps: Further study should be carried out to investigate whether this result is specific for face processing or can be generalized to other stimuli.