Konrad Lorenz's research on imprinting
1. Randomly divided goose eggs, half hatched naturally, half hatched in incubator with Lorenz as first thing goslings saw
2. Tested limits of imprinting by delaying goslings' exposure to moving objects
3. Goslings imprinted on Lorenz followed him, goslings imprinted on mother followed her
4. Found critical period of around 32 hours for imprinting