I was very much interested in pair formation in birds because this plays an important role in speciation. And… there was the question which Konrad Lorenz had raised: does a young hatchling – a bird comes out of the egg – know what its parents are like, or does it learn that by… does it even know it… to what species it belongs, so to speak, will it recognize other birds as members of their own species, or do they have to learn that while they're being raised by their parents? And Lorenz showed that the greylag goose certainly learns it by a process he… he called prägung which means imprinting, so that the freshly hatched little greylag gosling follows the first moving object that also makes certain noises, and then adopts that as its… its species figure, first as its parents’ figure and then eventually its species figure. And very often these imprinted birds will not mate with members of their own species because they are imprinted on the human species, if you [sic]… So I decided to take some simple, easily gotten aviary birds, I still did finches and I had three species with which I worked. And I had them in cages at the Museum [of Comparative Zoology] and tried to… arrange in such a way that they wouldn't see that their own species, the hatchlings, when they grew up, and then see whether they would become imprinted or not. Well, to make a long story short, without having a special assistant doing all the… all the actual work of raising them and feeding them and taking care of them, I just couldn't do it, so I abandoned the project. And I told this to [Theodosius] Dobzhansky – my friend Professor Dobzhansky at Columbia University – and he said, ‘Look here, why don't you do that with drosophila? It's much easier’. So, he said I'm going to spend next summer’ – this was the summer of 1943 – ‘I'm going to spend next summer in Cold Spring Harbor and why don't you spend the summer there, too and… and we do… we make this experiment?’ I introduce you… the drosophila technique and you do what you want to do. And so it was done and then my family joined me too. And I spent the summer there and this happened I think for another year, and then Dobzhansky no longer would come in the summer, but my family was so enchanted with Cold Spring Harbor and spending the summer there that we, from that point on until the year 1952, spent every summer in Cold Spring Harbor, I believe.