Generallyspeaking, wechoosetheeyecolourthatissimilartoourselvesbutwewouldalsogoforaneyecolourthatmatchesouropposite-sexparentmorethanoursame-sexparent, asthoughweareusingtheopposite-sexparentas a kindof a blueprintforwhatitisthatwillattractus.
Andifthetwosidesmatcheachotherperfectly, ifthemirrorimageswouldfoldoverontopperfectly, thenthatpersonismorelikelytobeattractivebecauseitimplies a healthydevelopment.
Butthere's anotherinterestingfinding, whichisthatweseemtobeabletodetectbysmellorpheromone, a personwhohas a differentimmunesystemfromourselves, suchthatwhenwematewiththem, ouroffspringwillbegiven a broadenedimmunespectrum.