Early experience shapes amygdala sensitivity to race: an international adoption design

Abstract

In the current study, we investigated how complete infant deprivation to out-group race impacts behavioral and neural sensitivity to race. Although monkey models have successfully achieved complete face deprivation in early life, this is typically impossible in human studies. We overcame this barrier by examining youths with exclusively homogenous racial experience in early postnatal development. These were youths raised in orphanage care in either East Asia or Eastern Europe as infants and later adopted by American families. The use of international adoption bolsters confidence of infant exposure to race (e.g., to solely Asian faces or European faces). Participants completed an emotional matching task during functional MRI. Our findings show that deprivation to other-race faces in infancy disrupts recognition of emotion and results in heightened amygdala response to out-group faces. Greater early deprivation (i.e., later age of adoption) is associated with greater biases to race. These data demonstrate how early social deprivation to race shapes amygdala function later in life and provides support that early postnatal development may represent a sensitive period for race perception.

Figures

Figure 1.

a, Behavioral performance during the emotional expression matching game. Asian-adopted and European-adopted children show differential accuracy to in- and out-group faces, such that they are each more accurate at identifying emotional expressions of in-group faces than out-group faces. For descriptive purposes only, European-American children are depicted at the top of the figure in white. European-American children do not demonstrate a differential response to identifying emotional expressions of in- and out-group faces. b, Age of adoption is associated with accuracy to identifying emotional expressions of in- versus out-group faces. Greater early race deprivation is associated with greater differential performance.

Figure 2.

a, Group differences in the bilateral amygdala to Asian versus European faces during the emotional expression matching game. Asian-adopted and European-adopted youths show differential amygdala response when identifying emotional expressions of in- and out-group faces, such that each group shows heightened amygdala response to out-group faces compared with in-group faces. For descriptive purposes only, European-American children are depicted at the top of the figure. European-American children do not demonstrate differential amygdala response when identifying emotional expressions of Asian versus European faces. Note that right = left. b, Age of adoption is associated with greater amygdala differentiation when identifying the emotional expression of in- versus out-group emotional faces. Greater early race deprivation is associated with greater amygdala response to the out-group compared with in-group. Note that age and IQ are controlled for in all analyses and figures.

Figure 3.

Correlating amygdala activation to behavioral performance. Greater differential amygdala activation to Asian and European faces is related to greater differential accuracy to identifying the emotional expressions of Asian and European faces.