I would suggest an exemplar answer to this question to be:Lorenz studied imprinting in goslings by dividing the eggs from a mother, hatching, and rearing them in different environments. Half were left with the mother goose, half were hatched in an incubator with Lorenz. He recorded the behaviour of the goslings. Harlow studied rhesus monkeys reared in a controlled environment with 2 mother surrogates present. One surrogate was wire and dispensed food, the other was cloth covered and did not dispense food. The time spent with each mother, exploration time and fear responses.