Etiology of sensory processing sensitivity: Neurobiology, genes, and evolution

Research on the biological underpinnings of sensory processing sensitivity (SPS) in humans started in recent decades, and although some discoveries have been made, much remains to be understood. Nonetheless, studies to date range from those investigating the genetic etiology of SPS, to those examining its neural basis with functional MRI, to studies of the peripheral systems altered in SPS. We begin by discussing SPS in the context of evolution. Next, we describe the possible genetic variants and neural structures that modulate high sensitivity. Then, we discuss the peripheral systems affected in SPS. Finally, we summarize the different biological aspects of SPS, and outline a theoretical concept of how the different mechanisms contribute to the physical, emotional, cognitive, and biological manifestations of the trait. We close with a discussion of future research that is needed to understand the etiology, biological and molecular mechanisms underlying SPS.