When De Niro heard that there were still a number of post-encephalitic patients at the Highlands Hospital in London, he wanted to see them and I went along with him. He had been rather sceptical of various things, in particular of how an apparently motionless and paralysed patient could suddenly respond and catch something, and... and with a quickness and a suddenness which... which astounded me and which took me by surprise. At one point he suddenly grabbed a pair of socks and threw it at a patient and the patient caught it, and that convinced him... it convinced the patient that the patient could move, and it convinced him and it convinced me, and it was a... it was a very striking, natural demonstration. He spent two days with the patients and, I think, observing them more closely than anyone had since Purdon Martin, this great neurologist who devoted his later years to observing them.

Also with a friend of mine who has Parkinson's, De Niro spent a day and a night with him. Ed had said, 'Look, you know, I'm going to eat, I need to go out, I need to go to bed'. De Niro said, 'That's okay, I'll stay with you all the while'. I don't think he said much, he never says very much, but his ability to absorb... among other things, Ed had said, in his rather explicit encyclopaedic way, 'I have...' he said, 'you talk about freezing', he said, 'I have seven sorts of freezing, let me explain’. And Bob said, 'No, I'll observe'. Amazing observer.

With Robin, I had the feeling of two very distinct stages in acting. First, a superficial stage of mimicry, and he's an incredible mimic. I saw this once when he'd come along to a ward at Bronx State Hospital, and in the car afterwards the voices of half a dozen patients were there... the voices and postures of half a dozen patients. And... but then... then he has to go to a deeper level, as he had to do with me. With De Niro, I never saw the earlier level. I... maybe it was somehow done internally, and then what... what came out was... was the final action.