California institute of technology neurobiologists suggest that this closeness in sensitivities is optimized toward detecting subtle changes in skin tone because of varying concentrations of oxygenated hemoglobin in the blood 美國(guó)加州理工學(xué)院的神經(jīng)生物學(xué)家推測(cè),人類與靈長(zhǎng)類在此感應(yīng)度上的雷同,應(yīng)該是為了方便觀察因血液中含氧血紅素的濃度變化,而在皮膚上呈現(xiàn)的微妙起伏。