January 6th is my mother’s birthday. As a present, I decided to showcase the first scientist I ever knew—one who I met before I was even born. Arleen Garfinkle (one day to be Arleen Miller) entered graduate school  at the University of Colorado in the fall of 1973 and graduated in 1979. During that time she developed a battery of tests designed to track a child’s numerical and logical reasoning skills, based on the theories of psychologist Jean Piaget. Once she developed the test, she gave it (and several other tests) to over 200 pairs of twins aged four through eight and