The one in four subjects who inherited a variation in this allele called G/G were significantly better at accurately reading the emotions of others by observing their faces than were the remaining three-quarters of subjects, who had inherited either a pair of A's or an A and a G from their parents at this site. Compared to the three-fourths with A/A or A/G variations, the G/G individuals were also less likely to startle when blasted by a loud noise, or to become stressed at the prospect of such a noise. And by their own reports, the G/G subjects were mellower and more attuned to other people than were the A/As or A/Gs. news
Effect on Parental Sensitivity
Controlling for maternal education, depression and marital discord, OXTR [F (1,152)=4.32, P=0.04, partial n2=0.03] gene was significantly associated with maternal sensitivity. Mothers with OXTR AA or AG genotypes were less sensitive than mothers with the GG genotype. The genetic difference accounts for 3% influence on variation in sensitive parenting. [Bakermans-Kranenburg MJ, van Ijzendoorn MH. Oxytocin receptor (OXTR) and serotonin transporter (5-HTT) genes associated with observed parenting. Soc Cogn Affect Neurosci. 2008 Jun;3(2):128-34.]
In another study, heart rate responses of 40 healthy females without children were measured during the presentation of three episodes of infant cry sounds. Participants with the presumably more efficient variant of the oxytonergic system gene (OXTR GG) had more pronounced physiological reactivity to repeated cry sounds, except when they showed more symptoms of depression. [Riem MM, Pieper S, Out D, Bakermans-Kranenburg MJ, van Ijzendoorn MH. Oxytocin receptor gene and depressive symptoms associated with physiological reactivity to infant crying. Soc Cogn Affect Neurosci. 2010 Apr 16.]
Yet another study ([PMID 19934046]) found that people with the G;G genotype were better able to discern the emotional state of others and to handle stress, compared to those who carry the A-allele. The study encompassed 192 participants of both sexes and mixed ethnicities. The study subjects underwent a number of tests to determine their level of empathy and stress reactivity. They found that G;G individuals performed significantly better on the behavioral measure of empathy and were 22.7% less likely to make a mistake on the "Reading the Mind in the Eyes Test" (RMET) (a behavioural measure of empathic accuracy) than A;A/A;G individuals (P = 0.005). Similarly, G;G individuals reported higher levels of dispositional empathy than A;A/A;G individuals: mean (SE) = 3.69 (0.06) and 3.53 (0.04) for G;G and A;A/A;G, respectively (P = 0.025), and were less affected by stress (as measured by their heart rates): mean (SE) = 72.1 (0.54) and 78.4 (1.19) for G;G and A;A/A;G, respectively.