1\.For reviews，see R.Plomin et al.，Behavioral Genetics，6th ed.（New York：Worth Publishing，2012）；K.J.Saudino，“Behavioral Genetics and Child Temperament，”Journal of Developmental and Behavioral Pediatrics 26（2005）：214-23. 2\.J.Kagan and N.Snidman，“Early Childhood Predictors of Adult Anxiety Disorders，”Biological Psychiatry 46（1999）：1536-41；J.Kagan，Galen’s Prophecy.Temperament in Human Nature（New York：Basic Books，1994）. 3\.M.H.McManis，J.Kagan，N.C.Snidman，and S.A Woodward，“EEG Asymmetry，Power，and Temperament in Children，”Developmental Psychobiology 41（2002）：169-77. 4\.T.J.Bouchard，“Genetic Influence on Human Psychological Train：A Survey，”Current Directions in Psychological Science 13（2004）：148-51. 5\.Ruth’s lifetime batting average was.342；Williams’s，.344. 6\.I.Biederman and M.M.Shiffrar，“Sexing Day-Old Chicks：A Case Study and Expert Systems Analysis of a Difficult Perceptual-Learning Task，”Journal of Experimental Psychology：Learning，Memory，and Cognition 13（1987）：640-45. 7\.K.A.Ericsson，W.G.Chase，and S.Faloon，“Acquisition of a Memory Skill，”Science 208（1980）：1181-82.