*"Descent"
The renowned cybernetic Doctor Noonien Soong built two identical positronic asteroids. Data and Lore Soong first built Lore, but when Lore's emotions turned him into a decidedly evil direction, Soong deactivated him. The next android Soong built was without the capacity to comprehend emotions, Data. Later, Soong built a chip for Data which would allow hi to experience emotions, which Data installed with mixed results. *Source: Back of card