Alyssa’s death haunts Theo and Robin. Her memory has a profound effect on their personalities, as they’re never able to completely abandon her. They live in the same house, eat the same food, and visit the same places as they did when she was alive. They occupy the same physical space, and it reminds them of her, suggesting that her absence so overwhelms them that they don’t want to abandon her. Theo sees his wife in his son’s behavior, so he consults his memory of Alyssa when he needs guidance. His memory of her shapes his parenting, as he’s always aspiring to be as good a parent as he thinks Alyssa was. As a result, Alyssa still plays an active role in raising Robin. Her absence is so overpowering that neither Robin nor Theo can imagine a life in which she doesn’t play a role. Their sense of loss is so deep that they try to relive their memories of her rather than come to terms with her death.

Robin’s personality changes after Currier’s experiment and then changes again when the treatment stops. Theo feels as though Robin becomes an entirely different and much happier person through the treatment, so the end of the experiment feels to Theo like a slow death for Robin’s new personality.