By Olivia Scheck
When a person is prone to making claims that are clearly inconsistent with facts about the world, we say that he is crazy. His brain has gone haywire, and he is no longer responsive to reason. However, when the person making a plainly unrealistic claim is otherwise rational, this simplistic explanation may seem particularly unsatisfactory. A person suffering from Capgras Delusion, for instance, may show no other signs of mental illness, and yet he insists that someone in his life (usually a close family member) has been replaced by an imposter. Similarly, the Cotard patient may seem perfectly normal, aside from his assertion that he is actually dead and rotting before your eyes. These fascinating cases of monothematic delusion have, despite their rarity, prompted a number of psychologists and philosophers to wonder, “What is the nature of delusion?”
First, though, a little background on existing theories and a brief synopsis of Gallagher’s Multiple Realities Hypothesis:
Traditionally, accounts of delusion have fallen into one of two categories: top-down or bottom-up. Top-down accounts suggest that delusions result from disturbances in high-level understanding. The philosopher and UC Berkeley professor, John Campbell, for example, invokes Wittgentein’s notion of a “framework proposition” – an axiom that is implicitly assumed and never answerable to empirical facts – to characterize delusion. On Campbell’s view, delusions arise when an erroneous belief – such as, “my mother is an imposter” – takes on this type of incontrovertible epistemological status.
On the other hand, according to bottom-up accounts, delusions are not caused by false beliefs, but rather false perceptions. The popular neurologist Vilayanur Ramachandran gives a clear and entertaining bottom-up explanation for Capgras in his TED talk, “A Journey to the Center of Your Mind.” He believes that the Capgras patient’s assertion that his mother has been replaced by an imposter is, in fact, a rational metacognitive response to a peculiar perception. Specifically, Ramachandran proposes that the Capgras patient experiences an abnormal emotional response when looking at his mother, which results from a communicative disconnect between the area of the brain associated with face recognition and the its emotional center. Responding to this lack of affective response, the patient infers that his mother has been replaced by an imposter.
Gallagher argues that neither top-down nor bottom-up explanations can, taken alone, account for all features of delusion. Keeping with the Capgras example, Gallagher points out that bottom-up models suffer from a problem of specificity: if the delusion results from damage to the connection between the subject’s fusiform gyrus and amygdala, why should he formulate the imposter theory about his mother and not others? And if the abnormal perception is simply lacking in emotional content, then why should he form the imposter theory at all? It would seem more reasonable to conclude that he had simply lost affection for his mother. This becomes particularly problematic when one tries to explain the considerably more complex claims made by people with schizophrenia.
One feature of Capgras (and other delusions) that is not easily explained by top-down accounts is the “double-bookkeeping paradox,” identified by Louis Sass. This is the observation that although delusional patients insistently espouse false beliefs, they often do not exhibit behavior that is consistent with them. For instance, Gallagher points out that although many Capgras patients resolutely declare that a loved one has been replaced by an imposter, they do not generally exhibit concern for the displaced loved one. For these reasons, he suggests that neither bottom-up nor top-down accounts offers a satisfactory characterization of delusion.
So, Gallagher (forthcoming) proposes an alternative description, which incorporates both top-down and bottom-up components and emphasizes the influence of bodily and social factors. On this view, “in the spirit of embodied, situated and phenomenological views of cognition,” the delusional subject “does not live in the one unified world of meaning that is defined objectively (in a view from nowhere), but inmultiple realities, sub-universes or finite provinces of meaning.” He likens the experience of these realities to being “in-the-world” of a book, movie, or video game, but says that “unlike other multiple realities…[delusional ones] may be ‘firmly sustained…’”
Conceiving of delusional states in this way, Gallagher argues, allows us to account for previously unexplained aspects of delusion. For instance, it has been noted that some delusional patients actually find it strange when others express agreement with their delusional claims. This may be because they see themselves as responding to a distinct reality. And a similar explanation may obtain for the double-bookkeeping paradox.
Still, the Multiple Realities Hypothesis is not yet well-developed, and it’s possible that top-down or bottom-up models – either individually or in tandem – could be modified to account for Gallagher’s objections. I raised some of these issues in our conversation last week:
You seem to suggest that the crucial difference between the experience of having a delusion and, for instance, the experience of seeing a movie is that in the delusional case you’re persistently and completely suspending disbelief, whereas in the movie case you’re able to return to objective reality. Is that a fair characterization?
“I think it may differ from one case to another. I think there probably are cases of delusion where that type of description is right – it’s a delusion that you’re so caught up in that you can’t step outside of it. And I think some real serious cases of schizophrenia can go that way. But then I think there are others, where it’s something that you can retreat from – not that you can necessarily get a perspective on it, although that might be true too, you might feel like it feels weird or something to be in such a delusion, or vice versa, maybe it feels weird to come back to reality.”
So it’s not a binary thing; it’s a spectrum?
“It can be [binary] too, I think, though. Because there are cases, right, where there are just areas where the delusional rules, and then that seems to be embedded in a much larger, kind of normal reality….maybe Capgras is like that.”
Do you think that the multiple realities explanation needs to be invoked for cases in which a delusion has a clear causal basis – for instance if a delusion were induced by TMS simulation?
“I’m still interested in what the content of the delusion is, and can you explain the content just simply by TMS. So if you’re going to try to figure out why a person is having a delusion about this particular thing, then wouldn’t you have to bring in other factors, rather than just the kind of mechanical causal thing that gets it started. And I would think so – yes.
…The content to me is really a big puzzle – I mean, why it should take this form…So if you just think of it narrowly in terms of something just going wrong in the brain, if it’s a specific area of the brain, is it so specific an area of the brain that it just has an effect on your relationship, say, to this person? That seems, at least on some of the explanations that I’ve been reading, that seems unlikely….In Capgras, they’re saying ‘well there’s a kind of disconnect between the kind of emotional centers…but you know if there is that kind of disconnect, then how can it be so specific that it only affects my relationship with this person, rather than all of these people.”
So do you take “content” to mean something more specific than, for instance, if you were activating a part of the brain that’s associated with face recognition and the subject experienced the sensation of recognizing a face. Certainly there are studies that show that people have the same reactions to TMS stimulation on particular areas of the brain. In these cases wouldn’t the content be explained?
“So let’s say there’s a TMS on the face recognition area and suddenly I see a face, somehow or other. I would describe that as a hallucination. It’s a brief kind of thing that doesn’t involve any kind of intricate sort of [belief]…What would be the subject’s report, if you asked them, you know, ‘What do you believe about what your experience is right now?’ And I suppose that the subject would say – I’m guessing the subject would say – ‘Well, I think I’m in an experiment and you're stimulating my brain in some way, and I’m seeing a face.’ That doesn’t strike me as a delusion; that strikes me as ‘oh, he knows what’s going on.’ He’s not delusional…”
A paper published inNature(Quiroga et al., 2005) reported that a particular neuron (in the brain of a patient undergoing surgery of intractable epileptic seizures) responded consistently and exclusively to pictures of Jennifer Aniston. Does the fact that, in this case, a particular neuron was associated with a high-level concept undermine your claim about the necessity of social factors in explanations of delusion?
“No, I don’t think so…unless it’s just a traumatic effect on, you know, this particular neuron that’s been tuned to Jennifer Aniston…”
Do you think it’s possible that there could be “belief pill,” which would, upon ingestion, instantiate a particular belief in all of us?
“I think I could take a pill and I could end up with a different belief…I could take some kind of drug and start to have weird beliefs delusions and so forth, but, again, what the content of the beliefs and delusions would be is not in the pill. And the question is, is it in the neurons? And I would say, well, on a very narrow conception of what’s going on, you’d start pointing to the neurons, but, you know, how did those neurons get shaped and tuned? And you have to really go outside of that to see the system working as a whole in order to really understand what’s going on with this person.”
Is it possible to use neuroimaging techniques to get at the kind of embodied account of delusion that you’re suggesting?
“I don’t know….In terms of studying the brain of course part of the issue is just the limitations of technology. So if you say, for example that cognition – cognitive experience – really is fundamentally intersubjective in some fashion…and tied to embodiment in various ways. But the only way to test anything is by putting a single person in the scanner, lying on their back…then you really can’t get at all the things you need to get at. Maybe when the new technologies come along and we can all wear helmets and just kind of interact with one another in normal circumstances then we’ll get a much better picture of things. But until that happens, it’s hard to figure out, how do you get the body and the environment and all that stuff that we’re talking about – the social environment especially – into the scanner.”
What draws you to this topic?
“Well, for me, sometimes it’s the very specific questions about, you know, what is the nature of agency? You know, how do we explain action and intention and those types of things? And well, let’s take a look at how they go wrong in these types of pathology and that might help us understand better. Or, more generally, you know, what is the mind? And let’s take a look here, and see how that works. So at least for the philosopher – philosophers are interested in bringing whatever we can learn from the clinic over into the theoretical realm of how we talk about the mind. And I think for scientists it might be a different thing in a way – scientists like to think of the next experiment, how can we put that experiment together?”
This is a philosophical approach to answering a psychiatric question, but do you also think it has implications for other areas of philosophy? For instance, does showing that people can experience alternate realities suggest that to some extent aspects of objective reality are just shared beliefs about the world, and does this suggest that our ideas about the world are more constructed than we normally think of them as being?
“I think so – yes. I mean I think that part of the reason that philosophers – I’m a philosopher by the way, not a psychiatrist – part of the reason why philosophers like to look over there at what the psychiatrists are doing and into the clinic and so forth is because the pathologies do throw some light on our normal everyday kind of behaviors. So I think one of the big questions underneath all of this is, you know, how do we actually think about the mind – what is the mind?…And everybody agrees, it’s not a Cartesian substance, but then there’s a huge amount of talk among a lot of philosophers about beliefs and desires and mental states, and then there’s a huge amount of talk about brain states. And then the discussion gets going then about “brain states, mental states, brain states, mental states,” forgetting everything else, like the environment, like my bodily, emotional life that has to enter into it. So I think to the extent that we can find various pathologies – whether psychopathologies or neuropathologies – [in which] all that – the body, the environment, the life – breaks down, it allows us to sort of see some things going on, perhaps, that give us a different perception of what the mind is and what mental life is like.”