According to Ramachandran, when we see someone we know, a part of our brain called the fusiform gyrus identifies the face: "That looks like mom!" That message is then sent to the amygdala, the part of our brains that activates the emotions we associate with that person. In patients experiencing Capgras, Ramachandran says, the connection between visual recognition and emotional recognition is severed. Thus the patient is left with a convincing face — "That looks like mom!" — but none of the accompanying feelings about his mother.In other words, a long history of positive emotions is the real world equivalent of having soft lighting, a good photographer, and a skilled Photoshop artist working on your behalf 24/7. A man who loves his wife literally cannot see her accurately or objectively without making a serious intentional effort. The same is obviously true of women, of course, but because women are less visually oriented than men, the amygdala effect is probably less important to the marriage.
Ramachandran holds that we are so dependent on our emotional reactions to the world around us, that the emotional feeling "that's not my mother" wins out over the visual perception that it is. The compromise worked out by the brain is that your mother was somehow replaced, and this impostor is part of a malevolent scheme.
Ramachandran thinks there's good evidence for this explanation of Capgras, in part because of an odd quirk in his patient's behavior. When his mother calls him on the phone and he hears her voice, he instantly recognizes her. Yet if she walks in the room after that call, he is again convinced that she is an impostor.
Why? Ramachandran says that our visual system and auditory system have different connections to the amygdala, so while the auditory recognition triggers an emotional response in his patient, visual recognition does not.
This may also help explain why women leaving their husbands are so often prone to overrating themselves. Even if she's a mere four, but he sees her as a six and treats her like one thanks to the amygdala effect, she is going to be inclined to see herself that way too. But since the effect doesn't exist for any other men, she is likely to be disappointed with the reactions she receives to her newfound availability.