Inception for Dummies

If you haven't watched Inception yet, don't read this post. It's great and I don't want to spoil it for you. So stop. You didn't though, did you, you're still reading this right now. Well, I warned you.

Inception as everyone knows is about people who can hack into other people's dreams to access their subconcious. The plot concerns their attempts to achieve, well, inception - putting an idea into someone's mind, which makes what they usually do, stealing secret ideas, seem easy by comparison.

The problem is that it's easy to plant an idea, but the victim always knows that it's an external imposition - they don't really believe it. Leonardo DiCaprio comes up with the plan of going into the victim's subconcious's subconcious, and planting an emotional idea about his father, in order to lead him to conclude, on his own, that he should break up his father's business empire. I'm not sure what Freud would have thought of this plan.

Could you actually do this? Well. Hacking into people's dreams is high fantasy: we have absolutely no idea how you'd do that, and in the movie the only explanation we get is that it involves fancy machines and unspecified drugs. It's safe to say no-one will be gatecrashing your dream party any time soon.

But here's one way to achieve the same kind of effect, inspired by two recent papers: this one that I wrote about in my last post, finding that electrical stimulation of the hippocampus produces temporary amnesia, and this one covered at Neurophilosophy, finding that stimulating a mouse's lateral amygdala at the same time as playing it a noise makes it fear that noise.

Simple fear conditioning happens in the amygdala, not the hippocampus (although conditioned fear to some partiuclarly complex stimuli, like places, does.) So assuming you were a neurosurgeon with a desire to do some inception and no ethical scruples whatsoever, here's what you might decide to do.

Knock your victim out with a sedative. Keep them unconscious while you implant electrodes in their hippocampus and their amygdala. Wake them up, but make sure that you constantly stimulate their hippocampus to disrupt it, from the moment they awake. This will leave them fully aware, but will mean they'll have no subsequent concious memory of what you do, because such concious declarative memories depend upon the hippocampus.

Now, you condition them to fear something, by showing it to them whilst stimulating their lateral amygdala. (To be honest, you could just give them a slap in the face and it would probably be just as effective - but that would be a bit unrefined. This is a high-tech evil medical procedure, not a common punch-up.) Maybe you could make them scared of the face of a business rival who you don't want them to cut a deal with. Or you could make a terrorist leader abhor the symbols of his own ideology. The possibilities are endless.

Once you're done, sedate them again and return them to their house. Yeah, you'd have to do this all in the course of one night, but no-one said Inception was going to be easy. With any luck, they'll wake up with no concious recollection of anything, but with the emotional conditioning still intact.

The lack of memory is of course crucial: if they remembered what had happened, they'd realize that the conditioning was an external imposition, and wouldn't be swayed by it. And they'd bust you to the cops, obviously. But without that concious knowledge as to the true source of the feelings, they'd have no alternative interpretation of the fear they now feel - they'd take it as their own, and really start to dislike whatever it was you'd made them afraid of, constructing elaborate rationalizations along the way. The dream is real...

Inception for Dummies

If you haven't watched Inception yet, don't read this post. It's great and I don't want to spoil it for you. So stop. You didn't though, did you, you're still reading this right now. Well, I warned you.

Inception as everyone knows is about people who can hack into other people's dreams to access their subconcious. The plot concerns their attempts to achieve, well, inception - putting an idea into someone's mind, which makes what they usually do, stealing secret ideas, seem easy by comparison.

The problem is that it's easy to plant an idea, but the victim always knows that it's an external imposition - they don't really believe it. Leonardo DiCaprio comes up with the plan of going into the victim's subconcious's subconcious, and planting an emotional idea about his father, in order to lead him to conclude, on his own, that he should break up his father's business empire. I'm not sure what Freud would have thought of this plan.

Could you actually do this? Well. Hacking into people's dreams is high fantasy: we have absolutely no idea how you'd do that, and in the movie the only explanation we get is that it involves fancy machines and unspecified drugs. It's safe to say no-one will be gatecrashing your dream party any time soon.

But here's one way to achieve the same kind of effect, inspired by two recent papers: this one that I wrote about in my last post, finding that electrical stimulation of the hippocampus produces temporary amnesia, and this one covered at Neurophilosophy, finding that stimulating a mouse's lateral amygdala at the same time as playing it a noise makes it fear that noise.

Simple fear conditioning happens in the amygdala, not the hippocampus (although conditioned fear to some partiuclarly complex stimuli, like places, does.) So assuming you were a neurosurgeon with a desire to do some inception and no ethical scruples whatsoever, here's what you might decide to do.

Knock your victim out with a sedative. Keep them unconscious while you implant electrodes in their hippocampus and their amygdala. Wake them up, but make sure that you constantly stimulate their hippocampus to disrupt it, from the moment they awake. This will leave them fully aware, but will mean they'll have no subsequent concious memory of what you do, because such concious declarative memories depend upon the hippocampus.

Now, you condition them to fear something, by showing it to them whilst stimulating their lateral amygdala. (To be honest, you could just give them a slap in the face and it would probably be just as effective - but that would be a bit unrefined. This is a high-tech evil medical procedure, not a common punch-up.) Maybe you could make them scared of the face of a business rival who you don't want them to cut a deal with. Or you could make a terrorist leader abhor the symbols of his own ideology. The possibilities are endless.

Once you're done, sedate them again and return them to their house. Yeah, you'd have to do this all in the course of one night, but no-one said Inception was going to be easy. With any luck, they'll wake up with no concious recollection of anything, but with the emotional conditioning still intact.

The lack of memory is of course crucial: if they remembered what had happened, they'd realize that the conditioning was an external imposition, and wouldn't be swayed by it. And they'd bust you to the cops, obviously. But without that concious knowledge as to the true source of the feelings, they'd have no alternative interpretation of the fear they now feel - they'd take it as their own, and really start to dislike whatever it was you'd made them afraid of, constructing elaborate rationalizations along the way. The dream is real...

What You Really Feel

Arthur Schopenhauer is my favorite 19th century German philosopher. Not that this is enormous praise given my attitude to the others, but anyway, here's one of his pearls of wisdom (source):

If you want to find out your real opinion of anyone, observe the impression made upon you by the first sight of a letter from him.

Does your heart leap, does it sink, do you get butterflies in your stomach, in the moment when you first see a message from that person? That's how you really feel, and if you didn't think you felt that way, you thought wrong.

Schopenhauer's trick relies on the fact that emotion is faster than thought. A letter takes you by surprise: even if you're expecting to hear from someone, you don't know exactly when it will arrive. It arrives: in that first second your emotions have a chance to show through, before your thoughts have got into gear. It works with emails and phone calls as well, of course, but not with any encounter which is planned out in advance.

The point is that you do not enjoy direct and perfect knowledge of your own feelings. You can be wrong about them, just like you could misjudge anyone else's feelings. Maybe you think that you like someone, when you really find them annoying. You believe that you like someone as a friend, but you really feel more than that.

In fact, it's not clear that we have any special insight into our own emotions, beyond that which is available to others. We tend to assume that we do. For one thing, we say they're our emotions: we own them. I'm the one who feels my emotions, and emotions are just feelings, so I must be the expert on them, right?

Yes, but feeling an emotion and understanding it are entirely separate. As I wrote previously, we all interpret our feelings in various ways, and like any act of interpretation, we can be either right or wrong. Suppose I love you and I think "I love you". In that case I'm right. But I could love you and think I don't (maybe I think it's just lust), or then again I could not love you (it is just lust) but think that I do. Any combination of feelings and thoughts is possible.

The notion that our mind is a single monolithic thing, and that we know everything that's in our own mind, is a stubborn one, but quite misleading. In fact we know very little about what goes on in our own heads; 100 billion cells are firing all the time, and we're not aware of any of them. Sometimes we can achieve self-knowledge, but it is never guaranteed.

What You Really Feel

Arthur Schopenhauer is my favorite 19th century German philosopher. Not that this is enormous praise given my attitude to the others, but anyway, here's one of his pearls of wisdom (source):

If you want to find out your real opinion of anyone, observe the impression made upon you by the first sight of a letter from him.

Does your heart leap, does it sink, do you get butterflies in your stomach, in the moment when you first see a message from that person? That's how you really feel, and if you didn't think you felt that way, you thought wrong.

Schopenhauer's trick relies on the fact that emotion is faster than thought. A letter takes you by surprise: even if you're expecting to hear from someone, you don't know exactly when it will arrive. It arrives: in that first second your emotions have a chance to show through, before your thoughts have got into gear. It works with emails and phone calls as well, of course, but not with any encounter which is planned out in advance.

The point is that you do not enjoy direct and perfect knowledge of your own feelings. You can be wrong about them, just like you could misjudge anyone else's feelings. Maybe you think that you like someone, when you really find them annoying. You believe that you like someone as a friend, but you really feel more than that.

In fact, it's not clear that we have any special insight into our own emotions, beyond that which is available to others. We tend to assume that we do. For one thing, we say they're our emotions: we own them. I'm the one who feels my emotions, and emotions are just feelings, so I must be the expert on them, right?

Yes, but feeling an emotion and understanding it are entirely separate. As I wrote previously, we all interpret our feelings in various ways, and like any act of interpretation, we can be either right or wrong. Suppose I love you and I think "I love you". In that case I'm right. But I could love you and think I don't (maybe I think it's just lust), or then again I could not love you (it is just lust) but think that I do. Any combination of feelings and thoughts is possible.

The notion that our mind is a single monolithic thing, and that we know everything that's in our own mind, is a stubborn one, but quite misleading. In fact we know very little about what goes on in our own heads; 100 billion cells are firing all the time, and we're not aware of any of them. Sometimes we can achieve self-knowledge, but it is never guaranteed.

I Feel X, Therefore Y

I'm reading Le Rouge et le Noir ("The Red and the Black"), an 1830 French novel by Stendhal...

One passage in particular struck me. Stendhal is describing two characters who are falling in love (mostly); both are young, have lived all their lives in a backwater provincial town, and neither has been well educated.

In Paris, the nature of [her] attitude towards [him] would have very quickly become plain - but in Paris, love is an offspring of the novels. In three or four such novels, or even in a couplet or two of the kind of song they sing at the Gymnase, the young tutor and his shy mistress would have found a clear explanation of their relations with each other. Novels would have traced out a part for them to play, given them a model to imitate.

The idea that reading novels could change the way people fall in love might strange today, but remember that in 1830 the novel as we know it was still a fairly new invention, and was seen in conservative quarters as potentially dangerous. Stendhal was of course pro-novels (he was a novelist), but he accepts that they have a profound effect on the minds of readers.

Notice that his claim is not that novels create entirely new emotions. The two characters had feelings for each other despite never having read any. Novels suggest roles to play and models to follow: in other words, they provide interpretations as to what emotions mean and expectations as to what behaviours they lead to. You feel that, therefore you'll do this.

This bears on many things that I've written about recently. Take the active placebo phenomenon. This refers to cases in which a drug creates certain feelings, and the user interprets these feelings as meaning that "the drug is working", so they expect to improve, which leads them to feel better and behave as if they are getting better.

As I said at the time, active placebos are most often discussed in terms of drug side effects creating the expectation of improvement, but the same thing also happens with real drug effects. Valium (diazepam) produces a sensation of relaxation and reduces anxiety as a direct pharmacological effect but if someone takes it expecting to feel better, this will also drive improvement via expectation: the Valium is working, I can cope with this.

The same process can be harmful, though, and this may be even more common. The cognitive-behavioural theory of recurrent panic attacks is that they're caused by vicious cycles of feelings and expectations. Suppose someone feels a bit anxious, or notices their heart is racing a little. They could interpret that in various ways. They might write it off and ignore it, but they might conclude that they're about to have a panic attack.

If so, that's understandably going to make them more anxious, because panic is horrible. Anxiety causes adrenaline released, the heart beats ever faster etc., and this causes yet more anxiety until a full-blown panic attack occurs. The more often this happens, the more they come to fear even minor symptoms of physical arousal because they expect to suffer panic. Cognitive behavioural therapy for panic generally consists of breaking the cycle by changing interpretations, and by gradual exposure to physical symptoms and "panic-inducing" situations until they no longer cause the expectation of panic.

This also harks back to Ethan Watters' book Crazy Like Us which I praised a few months back. Watters argued that much mental illness is shaped by culture in the following way: culture tells us what to expect and how people behave when they feel distressed in certain ways, and thus channels distress into recognizable "syndromes" - a part to play, a model to imitate, though probably quite unconsciously. The most common syndromes in Western culture can be found in the DSM-IV, but this doesn't mean that they exist in the rest of the world.

Like Stendhal's, this theory does not attempt to explain everything - it assumes that there are fundamental feelings of distress - and I do not think that it explains the core symptoms of severe mental illness such as bipolar disorder and schizophrenia. But people with bipolar and schizophrenia have interpretations and expectations just like everyone else, and these may be very important in determining long-term prognosis. If you expect to be ill forever and never have a normal life, you probably won't.

I Feel X, Therefore Y

I'm reading Le Rouge et le Noir ("The Red and the Black"), an 1830 French novel by Stendhal...

One passage in particular struck me. Stendhal is describing two characters who are falling in love (mostly); both are young, have lived all their lives in a backwater provincial town, and neither has been well educated.

In Paris, the nature of [her] attitude towards [him] would have very quickly become plain - but in Paris, love is an offspring of the novels. In three or four such novels, or even in a couplet or two of the kind of song they sing at the Gymnase, the young tutor and his shy mistress would have found a clear explanation of their relations with each other. Novels would have traced out a part for them to play, given them a model to imitate.

The idea that reading novels could change the way people fall in love might strange today, but remember that in 1830 the novel as we know it was still a fairly new invention, and was seen in conservative quarters as potentially dangerous. Stendhal was of course pro-novels (he was a novelist), but he accepts that they have a profound effect on the minds of readers.

Notice that his claim is not that novels create entirely new emotions. The two characters had feelings for each other despite never having read any. Novels suggest roles to play and models to follow: in other words, they provide interpretations as to what emotions mean and expectations as to what behaviours they lead to. You feel that, therefore you'll do this.

This bears on many things that I've written about recently. Take the active placebo phenomenon. This refers to cases in which a drug creates certain feelings, and the user interprets these feelings as meaning that "the drug is working", so they expect to improve, which leads them to feel better and behave as if they are getting better.

As I said at the time, active placebos are most often discussed in terms of drug side effects creating the expectation of improvement, but the same thing also happens with real drug effects. Valium (diazepam) produces a sensation of relaxation and reduces anxiety as a direct pharmacological effect but if someone takes it expecting to feel better, this will also drive improvement via expectation: the Valium is working, I can cope with this.

The same process can be harmful, though, and this may be even more common. The cognitive-behavioural theory of recurrent panic attacks is that they're caused by vicious cycles of feelings and expectations. Suppose someone feels a bit anxious, or notices their heart is racing a little. They could interpret that in various ways. They might write it off and ignore it, but they might conclude that they're about to have a panic attack.

If so, that's understandably going to make them more anxious, because panic is horrible. Anxiety causes adrenaline released, the heart beats ever faster etc., and this causes yet more anxiety until a full-blown panic attack occurs. The more often this happens, the more they come to fear even minor symptoms of physical arousal because they expect to suffer panic. Cognitive behavioural therapy for panic generally consists of breaking the cycle by changing interpretations, and by gradual exposure to physical symptoms and "panic-inducing" situations until they no longer cause the expectation of panic.

This also harks back to Ethan Watters' book Crazy Like Us which I praised a few months back. Watters argued that much mental illness is shaped by culture in the following way: culture tells us what to expect and how people behave when they feel distressed in certain ways, and thus channels distress into recognizable "syndromes" - a part to play, a model to imitate, though probably quite unconsciously. The most common syndromes in Western culture can be found in the DSM-IV, but this doesn't mean that they exist in the rest of the world.

Like Stendhal's, this theory does not attempt to explain everything - it assumes that there are fundamental feelings of distress - and I do not think that it explains the core symptoms of severe mental illness such as bipolar disorder and schizophrenia. But people with bipolar and schizophrenia have interpretations and expectations just like everyone else, and these may be very important in determining long-term prognosis. If you expect to be ill forever and never have a normal life, you probably won't.

The World Turned Upside Down

This map is not “upside down”. It looks that way to us; the sense that north is up is a deeply ingrained one. It's grim up north, Dixie is away down south. Yet this is pure convention. The earth is a sphere in space. It has a north and a south, but no up and down.

There’s a famous experiment involving four guys and a door. An unsuspecting test subject is lured into a conversation with a stranger, actually a psychologist. After a few moments, two people appear carrying a large door, and they walk right between the subject and the experimenter.

Behind the door, the experimenter swaps places with one of the door carriers, who may be quite different in voice and appearance. Most subjects don't notice the swap. Perception is lazy: whenever it can get away with it, it merely tells us that things are as we expect, rather than actually showing us stuff. We often do not really perceive things at all. Did the subject really see the first guy? The second? Either?

The inverted map makes us actually see the Earth's geography, rather than just showing us the expected "countries" and "continents". I was struck by how parochial Europe is – the whole place is little more than a frayed end of the vast Eurasian landmass, no more impressive than the one at the other end, Russia's Chukotski. Africa dominates the scene: it can no longer be written off as that poor place at the bottom.

One of the most common observations in psychotherapy of people with depression or anxiety is that they hold themselves to impossibly high standards, although they have a perfectly sensible evaluation of everyone else. Their own failures are catastrophic; other people's are minor setbacks. Other people's successes are well-deserved triumphs; their own are never good enough, flukes, they don't count.

The first step in challenging these unhelpful patterns of thought is to simply point out the double-standard: why are you such a perfectionist about yourself, when you're not when it comes to other people? The idea being to help people to think about themselves in more like healthy way they already think about others. Turn the map of yourself upside down - what do you actually see?

The World Turned Upside Down

This map is not “upside down”. It looks that way to us; the sense that north is up is a deeply ingrained one. It's grim up north, Dixie is away down south. Yet this is pure convention. The earth is a sphere in space. It has a north and a south, but no up and down.

There’s a famous experiment involving four guys and a door. An unsuspecting test subject is lured into a conversation with a stranger, actually a psychologist. After a few moments, two people appear carrying a large door, and they walk right between the subject and the experimenter.

Behind the door, the experimenter swaps places with one of the door carriers, who may be quite different in voice and appearance. Most subjects don't notice the swap. Perception is lazy: whenever it can get away with it, it merely tells us that things are as we expect, rather than actually showing us stuff. We often do not really perceive things at all. Did the subject really see the first guy? The second? Either?

The inverted map makes us actually see the Earth's geography, rather than just showing us the expected "countries" and "continents". I was struck by how parochial Europe is – the whole place is little more than a frayed end of the vast Eurasian landmass, no more impressive than the one at the other end, Russia's Chukotski. Africa dominates the scene: it can no longer be written off as that poor place at the bottom.

One of the most common observations in psychotherapy of people with depression or anxiety is that they hold themselves to impossibly high standards, although they have a perfectly sensible evaluation of everyone else. Their own failures are catastrophic; other people's are minor setbacks. Other people's successes are well-deserved triumphs; their own are never good enough, flukes, they don't count.

The first step in challenging these unhelpful patterns of thought is to simply point out the double-standard: why are you such a perfectionist about yourself, when you're not when it comes to other people? The idea being to help people to think about themselves in more like healthy way they already think about others. Turn the map of yourself upside down - what do you actually see?

Fingers

How many fingers do you have?

10, obviously, unless you've been the victim of an accident or a birth defect. Everyone knows that. You count up to ten on your fingers, for one thing.

But look at your left hand - how many fingers are on it? Little finger, ring finger, middle finger, first finger... thumb. So that's 4. But then we'd only have 8 fingers, and we all know we have 10. Unless the thumb is a finger, but is it?

Hmm. Hard to say. Wikipedia has some interesting facts about this question, and on Google if you start to type in "is the thumb", the top suggested search terms are all about this issue. It's a tricky one. People don't seem to know for sure.

But does that mean there's any real mystery about the thumb? No - we understand it as well as any other part of the body. We know all about the bones and muscles and joints and nerves of the thumb, we know how it works, what it does, even its evolutionary history (see The Panda's Thumb by Steven J Gould, still one of the greatest popular science books ever.) Science has got thumbs covered.

The mystery is in the English language, which isn't quite clear on whether the word "finger" encompasses the human thumb; for some purposes it does, i.e. we have 10 fingers, but for other purposes it probably doesn't, although even English speakers seem to be in two minds about the details (see Google, above).

Notice that although the messiness seems to focus on the thumb, the word "thumb" is perfectly clear. The ambiguity is rather in the word "finger", which can mean either any of the digits of the hand, or, the digits of the hand with three joints. Take a look at your hand again and you'll notice that your thumb lacks a joint compared to the fingers; something I must admit I'd forgotten until Wikipedia reminded me.

Yet it would be very easy to blame the thumb for the confusion. After all, the other 4 fingers are definitely fingers. The fingers are playing by the rules. Only the thumb is a troublemaker. So it comes as somewhat of a surprise to realize that it's the fingers, not the thumb, that are the problem.

*

So words or phrases can be ambiguous, and when they are, they can lead to confusion, but not always in the places you'd expect. Specifically, the confusion seems to occur at the borderlines, the edge cases, of the ambiguous terminology, but the ambiguity is really in the terminology itself, not the edge cases. To resolve the confusion you need to clarify the terminology, and not get bogged down in wondering whether this or that thing is or isn't covered by the term.

It's important to bear in this in mind when thinking about psychiatry, because psychiatry has an awful lot of confusion, and a lot of it can be traced back to ambiguous terms. Take, for example, the question of whether X "is a mental illness". Is addiction a mental illness, or a choice? Is mild depression a mental illness, or a normal part of life? Is PTSD a mental illness, or a normal reaction to extreme events? Is... I could go on all day.

The point is that you will never be able to answer these questions until you stop focussing on the particular case and first ask, what do I mean by mental illness? If you can come up with a single, satisfactory definition of mental illness, all the edge cases will become obvious. But at present, I don't think anyone really knows what they mean by this term. I know I don't, which is why I try to avoid using it, but often I do still use it because it seems to be the most fitting phrase.

It might seem paradoxical to use a word without really knowing what it means, but it isn't, because being able to use a word is procedural knowledge, like riding a bike. The problem is that many of our words have confusion built-in, because they're ambiguous. We can all use them, but that means we're all risking confusing each other, and ourselves. When this gets serious enough the only solution is to stop using the offending word and create new, unambiguous ones. With "finger", it's hardly a matter of life or death. With "mental illness", however, it is.

Fingers

How many fingers do you have?

10, obviously, unless you've been the victim of an accident or a birth defect. Everyone knows that. You count up to ten on your fingers, for one thing.

But look at your left hand - how many fingers are on it? Little finger, ring finger, middle finger, first finger... thumb. So that's 4. But then we'd only have 8 fingers, and we all know we have 10. Unless the thumb is a finger, but is it?

Hmm. Hard to say. Wikipedia has some interesting facts about this question, and on Google if you start to type in "is the thumb", the top suggested search terms are all about this issue. It's a tricky one. People don't seem to know for sure.

But does that mean there's any real mystery about the thumb? No - we understand it as well as any other part of the body. We know all about the bones and muscles and joints and nerves of the thumb, we know how it works, what it does, even its evolutionary history (see The Panda's Thumb by Steven J Gould, still one of the greatest popular science books ever.) Science has got thumbs covered.

The mystery is in the English language, which isn't quite clear on whether the word "finger" encompasses the human thumb; for some purposes it does, i.e. we have 10 fingers, but for other purposes it probably doesn't, although even English speakers seem to be in two minds about the details (see Google, above).

Notice that although the messiness seems to focus on the thumb, the word "thumb" is perfectly clear. The ambiguity is rather in the word "finger", which can mean either any of the digits of the hand, or, the digits of the hand with three joints. Take a look at your hand again and you'll notice that your thumb lacks a joint compared to the fingers; something I must admit I'd forgotten until Wikipedia reminded me.

Yet it would be very easy to blame the thumb for the confusion. After all, the other 4 fingers are definitely fingers. The fingers are playing by the rules. Only the thumb is a troublemaker. So it comes as somewhat of a surprise to realize that it's the fingers, not the thumb, that are the problem.

*

So words or phrases can be ambiguous, and when they are, they can lead to confusion, but not always in the places you'd expect. Specifically, the confusion seems to occur at the borderlines, the edge cases, of the ambiguous terminology, but the ambiguity is really in the terminology itself, not the edge cases. To resolve the confusion you need to clarify the terminology, and not get bogged down in wondering whether this or that thing is or isn't covered by the term.

It's important to bear in this in mind when thinking about psychiatry, because psychiatry has an awful lot of confusion, and a lot of it can be traced back to ambiguous terms. Take, for example, the question of whether X "is a mental illness". Is addiction a mental illness, or a choice? Is mild depression a mental illness, or a normal part of life? Is PTSD a mental illness, or a normal reaction to extreme events? Is... I could go on all day.

The point is that you will never be able to answer these questions until you stop focussing on the particular case and first ask, what do I mean by mental illness? If you can come up with a single, satisfactory definition of mental illness, all the edge cases will become obvious. But at present, I don't think anyone really knows what they mean by this term. I know I don't, which is why I try to avoid using it, but often I do still use it because it seems to be the most fitting phrase.

It might seem paradoxical to use a word without really knowing what it means, but it isn't, because being able to use a word is procedural knowledge, like riding a bike. The problem is that many of our words have confusion built-in, because they're ambiguous. We can all use them, but that means we're all risking confusing each other, and ourselves. When this gets serious enough the only solution is to stop using the offending word and create new, unambiguous ones. With "finger", it's hardly a matter of life or death. With "mental illness", however, it is.

Password

A few days ago, a friend of mine had her GMail account compromised, resulting in much stress for all concerned. This prompted me to change my passwords.

That was three days ago. Since then, I've logged into GMail maybe ten or fifteen times, and every single time I've initially typed the old password. Sometimes, I catch myself and change it before hitting "enter", but usually not. Access denied. Oops. It's getting slightly better, but I think it'll be a good few days before I'm entering the new password as automatically as I did the old one.

It's not hard to see why this kind of thing happens: I'd typed in the old password hundreds, probably thousands, of times over the course of at least a year. It had become completely automatic. That kind of habit takes a long time to learn, so it's no surprise that it takes quite a while to unlearn (though hopefully not quite as long).

Psychologists will recognize the distinction between declarative memory, my concious knowledge of what my new password is, and procedural memory, my ability to unconsciously type it. It's also commonly known as "muscle memory": this is misleading because it's stored in the brain, like all knowledge, but it nicely expresses the feeling that it's your body that has the memory, rather than "you".

Damage to the hippocampus can leave people unable to remember what happened ten minutes ago, but perfectly capable of learning new skills: they just don't remember how they learned them. But you don't have to suffer brain damage to experience procedural knowledge in the absence of declarative recall. I've sometimes found myself unable to remember my password and only reminded myself by going to the login page and successfully typing it. I knew it all along - but only procedurally.

The thing about procedural knowledge is that when it works, you don't notice it's there. So we almost certainly underestimate its contribution to our lives. If you asked me what happens when I log in to GMail, I'd probably say "I type in my username and my password". But maybe it would be more accurate to say: "I go to the login screen, and my brain types my username and password."

Can I take the credit, given that sometimes I - my conciousness - don't even know the password until my brain's helpfully typed it for me? And while in this case I do know it some of the time, much of our procedural knowledge has no declarative equivalent. I can ride a bike, but if you asked me to tell you how I do it, to spell out the complex velocity-weight-momentum calculations that lie behind the adjustments that my muscles constantly make to keep me upright, I'd be stumped.

"I just sit down and pedal." But if I literally did that and nothing more, I'd fall flat on my face. There's a lot more to cycling than that, but I have no idea what it is. So can I ride a bike, or do I just happen to inhabit a brain that can? Isn't saying that I can ride a bike like saying that I can drive just because I have a chauffeur?


Take this train of thought far enough and you reach some disturbing conclusions. Maybe it's not so hard to accept that various skills lie outside the reach of our concious self, but surely the decisions to use those skills are ours alone. Sure, my brain types my username and password for me, but I'm the one who decided to login to GMail - I could have decided to turn the computer off and go for a walk instead. I have Free Will! Like George W. Bush, I'm the Decider. My brain just handles the boring details.

But isn't deciding a skill too? And willing, remembering, thinking, judging, feeling, concluding - I can do all those things, but if I knew how I do them, I'd win the the Nobel Prize in Physiology or Medicine because I'd just have solved the hardest questions of neuroscience. So can I take credit for doing them, or is it my brain?

Ultimately, every concious act must be constructed from unconscious processes; otherwise there would be an infinite regress of conciousness. If the world rested on the back of a giant turtle, what would the turtle stand on? Turtles all the way down?

Link: The Concept of Mind (1949) is a book by the British philosopher Gilbert Ryle, from which I "borrowed" the ideas in this post, and which was probably the one book that most inspired me to study neuroscience.

Password

A few days ago, a friend of mine had her GMail account compromised, resulting in much stress for all concerned. This prompted me to change my passwords.

That was three days ago. Since then, I've logged into GMail maybe ten or fifteen times, and every single time I've initially typed the old password. Sometimes, I catch myself and change it before hitting "enter", but usually not. Access denied. Oops. It's getting slightly better, but I think it'll be a good few days before I'm entering the new password as automatically as I did the old one.

It's not hard to see why this kind of thing happens: I'd typed in the old password hundreds, probably thousands, of times over the course of at least a year. It had become completely automatic. That kind of habit takes a long time to learn, so it's no surprise that it takes quite a while to unlearn (though hopefully not quite as long).

Psychologists will recognize the distinction between declarative memory, my concious knowledge of what my new password is, and procedural memory, my ability to unconsciously type it. It's also commonly known as "muscle memory": this is misleading because it's stored in the brain, like all knowledge, but it nicely expresses the feeling that it's your body that has the memory, rather than "you".

Damage to the hippocampus can leave people unable to remember what happened ten minutes ago, but perfectly capable of learning new skills: they just don't remember how they learned them. But you don't have to suffer brain damage to experience procedural knowledge in the absence of declarative recall. I've sometimes found myself unable to remember my password and only reminded myself by going to the login page and successfully typing it. I knew it all along - but only procedurally.

The thing about procedural knowledge is that when it works, you don't notice it's there. So we almost certainly underestimate its contribution to our lives. If you asked me what happens when I log in to GMail, I'd probably say "I type in my username and my password". But maybe it would be more accurate to say: "I go to the login screen, and my brain types my username and password."

Can I take the credit, given that sometimes I - my conciousness - don't even know the password until my brain's helpfully typed it for me? And while in this case I do know it some of the time, much of our procedural knowledge has no declarative equivalent. I can ride a bike, but if you asked me to tell you how I do it, to spell out the complex velocity-weight-momentum calculations that lie behind the adjustments that my muscles constantly make to keep me upright, I'd be stumped.

"I just sit down and pedal." But if I literally did that and nothing more, I'd fall flat on my face. There's a lot more to cycling than that, but I have no idea what it is. So can I ride a bike, or do I just happen to inhabit a brain that can? Isn't saying that I can ride a bike like saying that I can drive just because I have a chauffeur?


Take this train of thought far enough and you reach some disturbing conclusions. Maybe it's not so hard to accept that various skills lie outside the reach of our concious self, but surely the decisions to use those skills are ours alone. Sure, my brain types my username and password for me, but I'm the one who decided to login to GMail - I could have decided to turn the computer off and go for a walk instead. I have Free Will! Like George W. Bush, I'm the Decider. My brain just handles the boring details.

But isn't deciding a skill too? And willing, remembering, thinking, judging, feeling, concluding - I can do all those things, but if I knew how I do them, I'd win the the Nobel Prize in Physiology or Medicine because I'd just have solved the hardest questions of neuroscience. So can I take credit for doing them, or is it my brain?

Ultimately, every concious act must be constructed from unconscious processes; otherwise there would be an infinite regress of conciousness. If the world rested on the back of a giant turtle, what would the turtle stand on? Turtles all the way down?

Link: The Concept of Mind (1949) is a book by the British philosopher Gilbert Ryle, from which I "borrowed" the ideas in this post, and which was probably the one book that most inspired me to study neuroscience.

Yes We Kant

How does the brain learn about space? Two papers in Science show that neural representations of place and direction appear in baby rats astonishingly early - within just a couple of days of beginning to explore outside the nest.

Two teams of researchers, Langston et al, and Wills et al, found that at just 16 days after birth, rats possess adult-like direction cells and place cells in the hippocampus and entorhinal cortex, areas known to be critical for spatial cognition. A couple of days later, grid cells appear.

Bear in mind that rats are born much earlier in their development than people are. Human babies are born with fully-functioning senses and are able to see. The eyes of baby rats however are sealed shut until about day 14. So this is very convincing evidence that the hippocampal system is "hard-wired" to store representations of space in the way that it does. Sensory input provides the actual data about particular places, but the hard work of designing a way of coding space has already been done by evolution.

That's great news for baby rats, because otherwise they would have to learn not just about their environment, but about the very concept of space. That would be asking a lot because baby rats are not the smartest of creatures. It seems very likely that the same is true of humans. It's tricky to stick electrodes into the brains of babies (the parents tend to object), but we know that in adults, damage to the hippocampus and related areas causes spatial processing and memory deficits just like those seen in rats. It's probably not just space, either - Noam Chomsky has built his career on the theory that we also possess a specialized language-learning mechanism.

These data would have come as no surprise to Kant, whose philosophy was based on the notion that our knowledge of the world is dependent upon the existence of innate mental "categories", such as space and time, which we do not learn by experience, but which rather allow us to make sense of experience. Incidentally, Kant looked a bit like a rat.

Yet a mystery remains, and it has nothing to do with the brain. What's the story behind this pair of all-but-identical articles? They're literally the two most similar scientific papers I have ever read - they found the same results, using the same methods, with only a few minor technical differences.

The fact that two independent groups have shown the same thing is great evidence for the reliability of these findings, but it's very rare for journals to publish simultaneously in this way, although arguably it should happen more often. So what's the story? Did these two groups not know they were working on the same thing, or was there a "Space Race" to publish first? Are they friendly collaborators or bitter rivals? We can only imagine...

Langston, R., Ainge, J., Couey, J., Canto, C., Bjerknes, T., Witter, M., Moser, E., & Moser, M. (2010). Development of the Spatial Representation System in the Rat Science, 328 (5985), 1576-1580 DOI: 10.1126/science.1188210

Wills, T., Cacucci, F., Burgess, N., & O'Keefe, J. (2010). Development of the Hippocampal Cognitive Map in Preweanling Rats Science, 328 (5985), 1573-1576 DOI: 10.1126/science.1188224

Yes We Kant

How does the brain learn about space? Two papers in Science show that neural representations of place and direction appear in baby rats astonishingly early - within just a couple of days of beginning to explore outside the nest.

Two teams of researchers, Langston et al, and Wills et al, found that at just 16 days after birth, rats possess adult-like direction cells and place cells in the hippocampus and entorhinal cortex, areas known to be critical for spatial cognition. A couple of days later, grid cells appear.

Bear in mind that rats are born much earlier in their development than people are. Human babies are born with fully-functioning senses and are able to see. The eyes of baby rats however are sealed shut until about day 14. So this is very convincing evidence that the hippocampal system is "hard-wired" to store representations of space in the way that it does. Sensory input provides the actual data about particular places, but the hard work of designing a way of coding space has already been done by evolution.

That's great news for baby rats, because otherwise they would have to learn not just about their environment, but about the very concept of space. That would be asking a lot because baby rats are not the smartest of creatures. It seems very likely that the same is true of humans. It's tricky to stick electrodes into the brains of babies (the parents tend to object), but we know that in adults, damage to the hippocampus and related areas causes spatial processing and memory deficits just like those seen in rats. It's probably not just space, either - Noam Chomsky has built his career on the theory that we also possess a specialized language-learning mechanism.

These data would have come as no surprise to Kant, whose philosophy was based on the notion that our knowledge of the world is dependent upon the existence of innate mental "categories", such as space and time, which we do not learn by experience, but which rather allow us to make sense of experience. Incidentally, Kant looked a bit like a rat.

Yet a mystery remains, and it has nothing to do with the brain. What's the story behind this pair of all-but-identical articles? They're literally the two most similar scientific papers I have ever read - they found the same results, using the same methods, with only a few minor technical differences.

The fact that two independent groups have shown the same thing is great evidence for the reliability of these findings, but it's very rare for journals to publish simultaneously in this way, although arguably it should happen more often. So what's the story? Did these two groups not know they were working on the same thing, or was there a "Space Race" to publish first? Are they friendly collaborators or bitter rivals? We can only imagine...

Langston, R., Ainge, J., Couey, J., Canto, C., Bjerknes, T., Witter, M., Moser, E., & Moser, M. (2010). Development of the Spatial Representation System in the Rat Science, 328 (5985), 1576-1580 DOI: 10.1126/science.1188210

Wills, T., Cacucci, F., Burgess, N., & O'Keefe, J. (2010). Development of the Hippocampal Cognitive Map in Preweanling Rats Science, 328 (5985), 1573-1576 DOI: 10.1126/science.1188224

Meowvolutionary Psychology

You know that thing cats do when they rub up against your legs? Did they evolve to do that?

The most sensible answer is probably "who cares, it's cute", but bear with me; a closer examination of this adorable behaviour sheds light on some more serious questions.

On one level, they obviously didn't. Cats have only been domesticated since maybe 8,000 BC. For millions of years prior, they evolved to live and hunt on their own, never interacting with humans. Domestication has led to some changes in the cat's behaviour - compared to wildcats they are generally tamer around humans, unsurprisingly - but no-one bred cats to rub up against our legs.

But on another level, evolution must be responsible. Cats all around the world do it, and we don't teach them to do it, they just decide to spontaneously. Maybe we sometimes teach them that it works for getting food, thus making them do it more often, but we don't give them the idea originally. It's an "innate" behaviour.

As I see it, leg-rubbing is based on the cat's instinct for scent-marking objects by rubbing the side of their heads against them (they have glands there although we humans can't smell them). My cats love doing this to chairs, table legs, etc. This behaviour evolved as a way for wildcats to mark out territories etc. They also like to rub up against other friendly cats as a social behaviour, probably as a way of making the whole "herd" smell the same. They do it to your legs, because in their minds you're a member of their herd... or maybe just because your legs are a bit like a chair.

Either way, leg-rubbing is an evolved behaviour, but cats didn't evolve to do it; they do it because of the interaction between their natural instincts and their artificial environment. This goes for a lot of other things too. Cats didn't evolve to drink cow's milk from bowls, they evolved to drink water from puddles, but they drink milk from bowls because evolution decided to make them like (cat's) milk (much like cow's milk), and to drink from wherever they need to. They didn't evolve to play with string, they evolved to catch mice, but... and so on.

How about us? I think the same, broadly speaking, applies. Of course we are unique amongst the animals in having human intelligence, language, conceptual thinking, etc. We are not just domesticated chimps, right? But this doesn't mean we're entirely unique. We have the same drives and emotions as other animals (maybe more, but surely not less), and the same brain mechanisms underly them. This is why if you give a mouse anti-obesity drugs they lose weight, and if you give them Valium they chill out.

One way of thinking about the human situation is that we are indeed just domesticated chimps, but with the catch that in the process of "domestication" we found ourselves transported into an entirely new environment: a more complex world. That's what having a more intelligent brain does for you, really - it expands your world. Compared to a chimp, still less a cat, we inhabit another planet entirely. But the old drives are still operating: we just have new ways of trying to satisfy them.

Here's an example. Few things are more uniquely human than modern surgery - animals can't do it (although my cat is quite good at cutting things open, his patients rarely survive), and it requires a huge amount of forward planning and accumulated knowledge. Of course we didn't evolve to perform operations.

But when a surgeon does cosmetic surgery, they're nevertheless obeying evolution. We find certain patterns of facial shape more attractive than others, e.g. we generally like symmetry, youthfulness, sexual dimorphism, and these preferences are largely innate. Presumably, these preferences evolved to make us want to have babies with people carrying "good genes" of the correct reproductive age. We didn't evolve to modify faces surgically, but cats didn't evolve to rub our legs. The same preferences that have guided the eye of eager singles for millennia now guide the surgeon's hand.

Does the whole of human culture consists of us trying to satisfy our primitive desires with our newly intelligent brains? I don't know. It certainly seems a big stretch to say that all art, politics and music are based on "primitive" preferences. But maybe it'll always take a big stretch to explain all that.

Meowvolutionary Psychology

You know that thing cats do when they rub up against your legs? Did they evolve to do that?

The most sensible answer is probably "who cares, it's cute", but bear with me; a closer examination of this adorable behaviour sheds light on some more serious questions.

On one level, they obviously didn't. Cats have only been domesticated since maybe 8,000 BC. For millions of years prior, they evolved to live and hunt on their own, never interacting with humans. Domestication has led to some changes in the cat's behaviour - compared to wildcats they are generally tamer around humans, unsurprisingly - but no-one bred cats to rub up against our legs.

But on another level, evolution must be responsible. Cats all around the world do it, and we don't teach them to do it, they just decide to spontaneously. Maybe we sometimes teach them that it works for getting food, thus making them do it more often, but we don't give them the idea originally. It's an "innate" behaviour.

As I see it, leg-rubbing is based on the cat's instinct for scent-marking objects by rubbing the side of their heads against them (they have glands there although we humans can't smell them). My cats love doing this to chairs, table legs, etc. This behaviour evolved as a way for wildcats to mark out territories etc. They also like to rub up against other friendly cats as a social behaviour, probably as a way of making the whole "herd" smell the same. They do it to your legs, because in their minds you're a member of their herd... or maybe just because your legs are a bit like a chair.

Either way, leg-rubbing is an evolved behaviour, but cats didn't evolve to do it; they do it because of the interaction between their natural instincts and their artificial environment. This goes for a lot of other things too. Cats didn't evolve to drink cow's milk from bowls, they evolved to drink water from puddles, but they drink milk from bowls because evolution decided to make them like (cat's) milk (much like cow's milk), and to drink from wherever they need to. They didn't evolve to play with string, they evolved to catch mice, but... and so on.

How about us? I think the same, broadly speaking, applies. Of course we are unique amongst the animals in having human intelligence, language, conceptual thinking, etc. We are not just domesticated chimps, right? But this doesn't mean we're entirely unique. We have the same drives and emotions as other animals (maybe more, but surely not less), and the same brain mechanisms underly them. This is why if you give a mouse anti-obesity drugs they lose weight, and if you give them Valium they chill out.

One way of thinking about the human situation is that we are indeed just domesticated chimps, but with the catch that in the process of "domestication" we found ourselves transported into an entirely new environment: a more complex world. That's what having a more intelligent brain does for you, really - it expands your world. Compared to a chimp, still less a cat, we inhabit another planet entirely. But the old drives are still operating: we just have new ways of trying to satisfy them.

Here's an example. Few things are more uniquely human than modern surgery - animals can't do it (although my cat is quite good at cutting things open, his patients rarely survive), and it requires a huge amount of forward planning and accumulated knowledge. Of course we didn't evolve to perform operations.

But when a surgeon does cosmetic surgery, they're nevertheless obeying evolution. We find certain patterns of facial shape more attractive than others, e.g. we generally like symmetry, youthfulness, sexual dimorphism, and these preferences are largely innate. Presumably, these preferences evolved to make us want to have babies with people carrying "good genes" of the correct reproductive age. We didn't evolve to modify faces surgically, but cats didn't evolve to rub our legs. The same preferences that have guided the eye of eager singles for millennia now guide the surgeon's hand.

Does the whole of human culture consists of us trying to satisfy our primitive desires with our newly intelligent brains? I don't know. It certainly seems a big stretch to say that all art, politics and music are based on "primitive" preferences. But maybe it'll always take a big stretch to explain all that.

Serial Killers

Much of Britain is currently following the trial of Steven Griffiths, or as he'd like you to refer to him, the Crossbow Cannibal.

Serial killers are always newsworthy, and Griffiths has killed at least three women in cold blood. (He did use a crossbow, but I think the newspapers made up the cannibalism.) But it's Griffiths's interests that have really got people's attention.

It turns out that before he became a serial killer, he was a man obsessed with... serial killers. His Amazon wish list was full of books about murder. He has a degree in psychology, and he was working on his PhD, in Criminology. Guess what his research was about.

Griffiths is therefore a kind of real life Hannibal Lecter or Dexter, an expert in murderers who is himself one. He's also a good example of the fact that, unlike on TV, real life serial killers are never cool and sophisticated, nor even charmingly eccentric, just weird and pathetic. Not to mention lazy, given that he was still working on his PhD after 6 years...

Yet there is an interesting question: was Griffiths a good criminologist? Does he have a unique insight into serial killers? We'll probably never know, at least not until (or if) the police release some of his writings. But it seems to me that he might have done.

When the average person hears about the crimes of someone like Griffiths, we are not just shocked but confused - it seems incomprehensible. I can understand why someone would want to rob me for my wallet, because I like money too. I can understand how one guy might kill another in a drunken fight, because I've been drunk too. Of course this doesn't mean I condone either crime, but they don't leave me scratching my head; I can see how it happens.

I cannot begin to understand why Griffiths did what he did. My understanding of humanity doesn't cover him. But he is human, so all that really means is that my understanding is limited. Someone understands people like Griffiths, it can't be impossible; but it may be that the only way to understand a serial killer is to be one.

The same may be true of less dramatic mental disorders. Karl Jaspers believed that the hallmark of severe mental illness is symptoms that are impossible to understand: they just exist. I've experienced depression; I've also read an awful lot about it and published academic papers on it. My own illness taught me much more about depression than my reading. Maybe I've been reading the wrong things. I don't think so.

Serial Killers

Much of Britain is currently following the trial of Steven Griffiths, or as he'd like you to refer to him, the Crossbow Cannibal.

Serial killers are always newsworthy, and Griffiths has killed at least three women in cold blood. (He did use a crossbow, but I think the newspapers made up the cannibalism.) But it's Griffiths's interests that have really got people's attention.

It turns out that before he became a serial killer, he was a man obsessed with... serial killers. His Amazon wish list was full of books about murder. He has a degree in psychology, and he was working on his PhD, in Criminology. Guess what his research was about.

Griffiths is therefore a kind of real life Hannibal Lecter or Dexter, an expert in murderers who is himself one. He's also a good example of the fact that, unlike on TV, real life serial killers are never cool and sophisticated, nor even charmingly eccentric, just weird and pathetic. Not to mention lazy, given that he was still working on his PhD after 6 years...

Yet there is an interesting question: was Griffiths a good criminologist? Does he have a unique insight into serial killers? We'll probably never know, at least not until (or if) the police release some of his writings. But it seems to me that he might have done.

When the average person hears about the crimes of someone like Griffiths, we are not just shocked but confused - it seems incomprehensible. I can understand why someone would want to rob me for my wallet, because I like money too. I can understand how one guy might kill another in a drunken fight, because I've been drunk too. Of course this doesn't mean I condone either crime, but they don't leave me scratching my head; I can see how it happens.

I cannot begin to understand why Griffiths did what he did. My understanding of humanity doesn't cover him. But he is human, so all that really means is that my understanding is limited. Someone understands people like Griffiths, it can't be impossible; but it may be that the only way to understand a serial killer is to be one.

The same may be true of less dramatic mental disorders. Karl Jaspers believed that the hallmark of severe mental illness is symptoms that are impossible to understand: they just exist. I've experienced depression; I've also read an awful lot about it and published academic papers on it. My own illness taught me much more about depression than my reading. Maybe I've been reading the wrong things. I don't think so.

Do Cats Hallucinate?

I have two cats. One is about four, and he is a psychopath. The other is sixteen - elderly, in cat terms - and I've recently noticed some changes in her behaviour.

For one, she's become a lot more affectionate, and she demands constant attention - she meows at people on sight, follows you around, and almost always comes and sits on top of you, or on top of whatever you're doing/reading/typing.

But on top of that, she's started pausing in the middle of whatever she's doing and staring at empty corners, or walls. All cats sit down and gaze into space a lot of the time, but this is different - it happens in the middle of normal actions, like eating or walking around. What does this mean?

Could she be hallucinating? Hallucinations are unfortunately not uncommon in elderly people. Seeing and hearing things that aren't there is a major symptom of Alzheimer's, and other forms of dementia. Do cats get Alzheimer's? The internet says: yes. In terms of scientific research there doesn't seem to have been much, but a few studies have found Alzheimer's-like changes (amyloid-beta protein accumulation) in the brains of old cats. Whether these cause the same symptoms as they do in people is unclear, but, why not?

How would you know if an animal was hallucinating? They can't talk about it, and unlike say hunger or pain, they don't have specific ways of communicating it through body language or cries. A hallucinating animal would, presumably, react fairly normally to whatever it thought it saw or heard: so hallucinations would manifest as normal behaviours, but in inappropriate situations. Whether this is what's happening to my cat, I'm not sure, but again, it's possible.

A more philosophical issue is whether we can conclude that this kind of out-of-context behaviour means the animal is experiencing a hallucination. But this is really just the age old question of whether animals have conciousness at all. If they do, then they can presumably hallucinate: if you can be concious of sensations, you can be concious of false sensations.

For what its worth, my view is that animals, at any rate for mammals, are concious. Humans are (although technically we only know for sure that we personally are, and have to assume the same is true of others.) Mammalian brains are structured in a similar way to our own; they're made of the same cells; they use the same neurotransmitters and the same drugs interfere with them in the same ways; pretty much all of the brain regions are there, although the sizes differ.

There's of course a big difference between us and other mammals: we have language, and conceptual thinking, and so forth. But does conciousness depend on that? It seems unlikely, just because most of what we're concious of at any one time isn't anything to do with those specifically human things.

Right now, I'm concious of what I can see, what I can hear, what I can feel with my fingertips, and the thoughts I'm writing down. Only 1/4 of that (to put it crudely) is unique to humans. And I'm not always aware of thoughts or words; there are plenty of times when I'm only aware of sensations and perceptions.

Probably the closest we get to animal conciousness is in strong, primitive experiences like pain, panic and anger, in which we "take leave of our senses" - not meaning that we become unconscious, but that we temporarily stop being able to "think straight" i.e. like a human. That doesn't mean that animals spend all their time in some extreme emotional state, but it's harder for us to know what it's like to be a relaxed cat because generally when we're relaxed, we're thinking (or daydreaming, etc. Although who's to say cats don't? They dream, after all...)

Do Cats Hallucinate?

I have two cats. One is about four, and he is a psychopath. The other is sixteen - elderly, in cat terms - and I've recently noticed some changes in her behaviour.

For one, she's become a lot more affectionate, and she demands constant attention - she meows at people on sight, follows you around, and almost always comes and sits on top of you, or on top of whatever you're doing/reading/typing.

But on top of that, she's started pausing in the middle of whatever she's doing and staring at empty corners, or walls. All cats sit down and gaze into space a lot of the time, but this is different - it happens in the middle of normal actions, like eating or walking around. What does this mean?

Could she be hallucinating? Hallucinations are unfortunately not uncommon in elderly people. Seeing and hearing things that aren't there is a major symptom of Alzheimer's, and other forms of dementia. Do cats get Alzheimer's? The internet says: yes. In terms of scientific research there doesn't seem to have been much, but a few studies have found Alzheimer's-like changes (amyloid-beta protein accumulation) in the brains of old cats. Whether these cause the same symptoms as they do in people is unclear, but, why not?

How would you know if an animal was hallucinating? They can't talk about it, and unlike say hunger or pain, they don't have specific ways of communicating it through body language or cries. A hallucinating animal would, presumably, react fairly normally to whatever it thought it saw or heard: so hallucinations would manifest as normal behaviours, but in inappropriate situations. Whether this is what's happening to my cat, I'm not sure, but again, it's possible.

A more philosophical issue is whether we can conclude that this kind of out-of-context behaviour means the animal is experiencing a hallucination. But this is really just the age old question of whether animals have conciousness at all. If they do, then they can presumably hallucinate: if you can be concious of sensations, you can be concious of false sensations.

For what its worth, my view is that animals, at any rate for mammals, are concious. Humans are (although technically we only know for sure that we personally are, and have to assume the same is true of others.) Mammalian brains are structured in a similar way to our own; they're made of the same cells; they use the same neurotransmitters and the same drugs interfere with them in the same ways; pretty much all of the brain regions are there, although the sizes differ.

There's of course a big difference between us and other mammals: we have language, and conceptual thinking, and so forth. But does conciousness depend on that? It seems unlikely, just because most of what we're concious of at any one time isn't anything to do with those specifically human things.

Right now, I'm concious of what I can see, what I can hear, what I can feel with my fingertips, and the thoughts I'm writing down. Only 1/4 of that (to put it crudely) is unique to humans. And I'm not always aware of thoughts or words; there are plenty of times when I'm only aware of sensations and perceptions.

Probably the closest we get to animal conciousness is in strong, primitive experiences like pain, panic and anger, in which we "take leave of our senses" - not meaning that we become unconscious, but that we temporarily stop being able to "think straight" i.e. like a human. That doesn't mean that animals spend all their time in some extreme emotional state, but it's harder for us to know what it's like to be a relaxed cat because generally when we're relaxed, we're thinking (or daydreaming, etc. Although who's to say cats don't? They dream, after all...)