Ramachandran on Capgras Syndrome, Phantom Limbs & Synaesthesia
Neuroscientist V. S. Ramachandran provides an introduction to how we study the brain's deficits using three cool examples:
- Capgras syndrome: where a man looks at his mother and says: "It looks like my mother but she's an imposter." How can a person recognise his mother's face yet feel it's not her?
- Phantom limbs: why would an amputated limb still hurt? Can this pain be relieved?
- Synaesthesia: Numbers are colours. Notes are colours. Cross-talk between the senses has a higher incidence in creative people: why?
Labels: Neuroscience
Will Solving The 'Hard Problem' of Consciousness Unweave the Rainbow?
[Inkbrushes by Adam Chamness: 1,2]
Some say in fifty years or so we'll have enough neuro-scientific evidence to completely describe the functioning of the brain. The question is, will this mountain of evidence be enough to explain the emergence of human consciousness? Consciousness. This familiar yet indescribable experience we all have, an awareness, something we can't physically point to nor experience from another's viewpoint.Being a hypothetical question about some future state of our knowledge, it has mainly been of academic interest to philosophers. But I actually think it's relevant to all of us because it accesses two fundamental questions about what it means to be human. First, on a practical level, is consciousness amenable to explanation? Second, on a mystical level, if consciousness can be explained, will its essence be lost?
Consciousness: 'easy' and 'hard' problems
An influential approach to consciousness splits the question into the 'easy problems of consciousness' and the 'hard problems of consciousness' (Chalmers, 1995). The so-called 'easy problems' are things like finding out how memory or attention actually work, the nuts and bolts of these functions. And even though these are the easy problems, scientists are still having considerable difficulty with them.
But, argue people like Chalmers, once we've described all these functions, we still won't fully understand consciousness. This is because we won't have addressed the so-called 'hard problem'. This is the feeling of what it is actually like to be you. That ineffable you-ness that no one else can share. Your experience.
Chalmers doesn't represent the most extreme example of this position, there are those who argue we can never truly understand consciousness. At least Chalmers acknowledges there are possibilities, although new conceptual techniques need developing.
There is no 'hard problem'
On the other side of the fence are those who argue the distinction between the 'hard problem' and the 'easy problem' is at best ill-advised and, at worst, plain dangerous. Just because we can't conceive of how consciousness can emerge from the description of the easy problems like attention and memory etc., doesn't mean it never will (Churchland, 1996). Just because we can set up complex philosophical arguments about what might be true in a thought experiment, doesn't mean it explains what is true here and now.
Philosophers of mind like Dennett argue that consciousness emerges from the physical processes of the brain (Dennett, 1996). Effectively he is saying there is no 'hard problem' to explain, some even argue he is saying there is no such thing as consciousness, rather he is redefining consciousness as 'reportability' (Chalmers, 1997).
Unweaving the rainbow
So there's a glance at two views on the so-called 'hard problem' of consciousness. But being a student of psychology, in addition to the actual arguments themselves, I'm naturally drawn to the motivations people might have for which they choose.
While there's a lot of complex discussion in this area, I think it partly comes down to whether you're relaxed about the idea that science might one day be able to explain the essence of human experience. For many people, I think this is an extremely uncomfortable thought. What Keats, talking of Newton's findings, refers to as a fear of 'unweaving the rainbow' - the fear that explaining something might somehow reduce the magic of it - is very real.
What's your view?
You can vote below on whether you think current scientific methods will ever be able to explain consciousness. Of course, it would be great to know your views, so go ahead and post a comment. I'd love to know what you think.
Subscribe to PsyBlog (RSS)
References - Click here to toggle visibilityLabels: Consciousness, Neuroscience
Encephalon #18 Now Online at Pharyngula
Encephalon, the neuroscience blog carnival, is now online at Pharyngula. Encephalon has some of the best posts from around the blogosphere on neuroscience related subjects. The latest issue is devoted to four themes: understanding brains, fixing brains, improving brains and evolving brains. I'd recommend you take a look to discover new ideas, new voices and new blogs.
Encephalon #18
Encephalon #18Labels: Neuroscience
Can Cognitive Neuroscience Tell Us Anything About the Mind?
Cognitive neuroscience - essentially brain scanning - has become all the rage in psychology and related fields. Given the headlong rush by, well, practically everyone, into cognitive neuroscience I still entertain a quaintly unfashionable stance: I'm sceptical. My scepticism is not total though, many cognitive neuroscientists claim that there are many exciting findings to come. They're probably right, but while neuroimaging can certainly tell us much about the brain, there's reason to believe it hasn't told us much about the mind. To understand what I mean by this we need to go back to basics by asking what research is for.
"Does cognitive neuroscience really have the power to distinguish between psychological theories?"Like all scientists, psychologists are continually knocking out new theories to explain the way we think and behave. One of the most important functions of research is its ability to differentiate between two theories. If research doesn't at least provide a clue one way or the other then theoretically, and so practically, it's a waste of time. Does cognitive neuroscience really have the power to distinguish between psychological theories? Is it any use to a cognitive psychologist?
A critic's view
Max Coltheart is Professor of Psychology at Macquarie University in Australia and in a recent journal article he wonders whether cognitive neuroscience has really told us anything useful about the mind so far (Coltheart, 2006). It's important to realise that his emphasis is on the mind, as in cognitive processes, as distinct from the brain, as in physiological processes.
"Neuroscience's strength is in physiological processes..."There's no doubt the mind's cognitive processes are a function of the brain's physiological activity but these two things are nevertheless (currently) separate questions. Cognitive neuroscience's strength is in physiological processes, and as imaging technology improves, so will the importance of its findings in this area. But, again, why should a psychologist care that much which part of the brain lights up in a scanner, if the mind's functioning is still so far removed from our understanding of its physiology?
An example
All this can be difficult to grasp in abstract. Take one of Coltheart's examples. Suppose you're a psychologist interested in how people work out what other people are going to do. Their intentions. Suppose there are only two competing theories that you've got to choose between:
- 'Simulation theory': I literally run a crude simulation of your mental state in my own mind. From this I try and work out what you're going to do next.
- 'Theory theory': I create a theory about you, then try to work out what you're going to do from that.
"...evidence from cognitive neuroscience fails to distinguish between theories."This is just two theories and one study - not exactly a scathing criticism of the whole of cognitive neuroscience. But Coltheart does run through four other examples where evidence from cognitive neuroscience fails to distinguish between theories. Again, remember that we're talking about relatively high level psychological theories here, not low-level physiological processes.
Coltheart goes on to pull quotes from a range of people who argue that, in principle, neuroimaging is useless for psychological theory and understanding of the mind. Here's a good computing metaphor:
"No amount of knowledge about the hardware of a computer will tell you anything serious about the nature of the software that the computer runs. In the same way, no facts about the activity of the brain could be used to confirm or refute some information-processing model of cognition." (Coltheart, 2004, p.22)I personally don't know enough about cognitive neuroscience to argue whether or not this statement is true, but it certainly has intuitive appeal. Considering the enormous quantity of money going into cognitive neuroscience right now, it seems unlikely this would be a majority view amongst psychologists. Not that scientist are slaves to money, of course...Ahem...
What's your view?
There's precious little discussion of Coltheart's criticisms in the blogosphere and there's plenty of good neuroscience blogs around. Let me know what you think, leave a comment below.
Subscribe to PsyBlog (RSS)
ReferencesColtheart, M. (2004) Brain imaging, connectionism and cognitive neuropsychology. Cognitive Neuropsychology, 2, 21-25.
Coltheart, M. (2006). What has functional neuroimaging told us about the mind (so far)? Cortex, 42(3), 323-31.
Ramnani, N., & Miall, R. C. (2004). A circuit in the human brain for predicting the actions of others. Nature Neuroscience, 7, 85-90.
Labels: Neuroscience
Emotion Processing in Autism Spectrum Disorders
Like alexithymia, those with autism spectrum disorders (ASDs) are also known to have problems processing emotional information. This may at least partially account for some core features of autistic behaviour: especially problems in social interactions. After all, ordinary social interactions contain considerable emotional components. This post looks at studies which have examined how those with ASDs may have deficits in the automatic processing of emotions.
Hill and Frith (2003) describe three main cognitive theories of autism. Of these the one that has the clearest parallels with emotional processing theories is Baron-Cohen's 'mindblindness' hypothesis. In this theory, those with ASDs are thought to have problems intuitively understanding the minds of others. But, this does not mean that individuals with autism cannot understand the mental states of others - it's just that they have to explicitly work it out rather than the knowledge being processed implicitly.
Hill, Berthoz and Frith (2004) found problems in the cognitive processing of emotions in individuals with ASDs. They were also seen to have higher levels of depression than both a control group and a group of relations of the individuals with ASDs.
So this give us some general evidence of emotion processing problems in ASDs, but what about the dual process model of appraisal? Some exciting new evidence comes from McIntosh, Reichmann-Decker, Winkielman and Wilbargeret (2006) who examined the way adults and adolescents with ASDs mimic facial expressions.
Copying facial expressions
The mimicking of other people's facial expression is something that we all do naturally. It oils the wheels of social interaction. We perceive the facial expression of others, then quickly and effortlessly flex corresponding muscles in our own faces to reflect the feeling back. McIntosh et al. (2006) contrast this type of automatic mimicry with the slow effortful mimicry we carry out when consciously trying to copy another's expression.
McIntosh et al. (2006) compared the automatic responses of a control group with individuals with ASDs by using facial EMG to measure movement of the major cheek and brow muscles. There were two phases to the experiment, in the first participants simply watched a screen on which were displayed different pictures of happy and sad faces. In the second, participants were asked to copy the expression they saw in the picture.
The results showed that individuals with ASDs did not automatically mimic facial expressions they saw in the pictures, as did the control group. On the other hand, they had no problem imitating facial expression explicitly, indeed they were better at imitation than the control group. McIntosh et al. (2006) argue that this fact rules out alternative explanations of their results which include the individuals with ASDs having problems in perceiving the faces, praxis, or understanding the task they were carrying out.
Mimicry in the brain scanner
From a study carried out by Dapretto, Davies, Pfeifer, et al. (2006) we even have information about the neurological basis for these behavioural findings. In this study participants carried out a task similar to that used by McIntosh et al. (2006) but this time inside an fMRI scanner.
The major difference found in brain activation between the groups was that the individuals with ASDs showed no activation in the so-called 'mirror neuron system'. The mirror neuron system is hypothesised to be involved in understanding the thoughts and actions of others, along with many other functions! If you're new to mirror neurons then start with Mixing Memory's posts here, and here.
Again, individuals with ASDs showed no difference to the control group in imitating faces, and no differences were seen by eye tracking equipment. In other words, both groups were looking at the photos in a similar way. Those with ASDs did, however, show differences in brain activation when they attempted to imitate the face in the photo.
Dapretto et al. (2006) speculate that those with ASDs have deficits in automatic processing through the mirror neuron system, for which other parts of their brains compensate when imitating facial expressions.
ASDs and alexithymia
Both of these imitation studies provide some evidence that individuals with ASDs suffer deficits in their automatic processing of emotions, but are quite capable of imitating emotions consciously. This provides a clear parallel with the studies carried out on people with alexithymia, who also have problems with the automatic unconscious processing of emotions but can clearly describe emotions that are in focal awareness.
ReferencesDapretto, M., Davies, M., Pfeifer, J., et al. (2006). Understanding emotions in others: mirror neuron dysfunction in children with autism spectrum disorders. Nature Neuroscience, 9(1), 28-30.
Gillberg, C., & Rastam, M. (1992). Do some cases of anorexia nervosa reflect underlying autistic conditions? Behavioural Neurology, 5, 27-32.
Hill, E., Berthoz, S., & Frith, U. (2004). Brief Report: Cognitive Processing of Own Emotions in Individuals with Autistic Spectrum Disorder and in Their Relatives. Journal of Autism and Developmental Disorders, 34(2), 229-235.
Hill, E., & Frith, U. (2003). Understanding autism: insights from mind and brain. Philosophical Transactions: Biological Sciences, 358(1430), 281-289.
McIntosh, D., Reichmann-Decker, A., Winkielman, P., Wilbargeret, J. L. (2006). When the social mirror breaks: deficits in automatic, but not voluntary, mimicry of emotional facial expressions in autism. Developmental Science, 9(3), 295-302.
Labels: Autism, Emotion, Neuroscience
What is empathy?
Some of the most striking discoveries in psychology have come from patients with deficits of various kinds. Phineas Gage, one of the most famous patients in psychology, was thought to have suffered emotional blunting - along with personality changes - after a tamping rod was propelled through his frontal lobes. Less dramatically, but no less vitally, it seems highly probable that common psychological disorders have, at their heart, a problem processing emotions. Two examples are alexithymia and autism spectrum disorders, both of which seem to involve problems with empathising. But what is empathy?Like many terms in psychology, it can seem intuitively obvious what 'empathy' means, but on closer inspection the definition is not so clear. de Vignemont and Singer (2006) identify two strands in the literature; the first of which provides a broad definition of empathy as occurring when an affective response is more appropriate to another person. The second, which de Vignemont and Singer (2006) prefer, is much narrower and requires that:
- you feel a particular affective state
- this state feels similar to you and the 'target' of your empathy, but has different causes,
- it stems from you watching or imagining the target's affective state,
- you realise your affective state is a result of empathy.
Automatic empathising?
These definitions of empathy beg the question of how much control we have over our empathising. Individual differences aside for a moment, generally do we automatically empathise with those around us, or is there some extra effort involved? The process model of appraisal, discussed previously on PsyBlog, certainly suggests there is some level of automatism to our emotional processing. In this theory, perceptual components can lead directly, and unconsciously, into appraisal processes and from there to an emotional response.
Neuroscience work reported by de Vignemont and Singer (2006) supports this hypothesis. Studies have found that when people see complete strangers enduring pain, their brain activation responds in a typically empathetic fashion (Morrison, Lloyd, di Pellegrino & Roberts, 2004).
Contextual empathising
But as de Vignemont and Singer (2006) point out, this indiscriminate empathising must be modulated by situational factors otherwise our emotional lives would be a constant riot of confusion. Similarly, the process model of appraisal does not exclusively rely on perception as the sole input for emotional responses, it also takes into account 'associatively activated representations' and 'the contents of focal awareness'. Secondly, and importantly for the process model of appraisal, de Vignemont and Singer (2006) argue that empathy can be 'fast and implicit'.
de Vignemont and Singer (2006) also suggest a number of categories which may help to explain why some of us empathise with others in some contexts but not in others:
- Intrinsic emotional factors - e.g. some emotions may be intrinsically easier to empathise with.
- Relational factors - like appraisal theory de Vignemont and Singer (2006) point out that the relationship between empathiser and target will have an important effect.
- Individual differences
- Situational factors
Early or late appraisal?
The process model of appraisal suggests an early model of appraisal. This means that both the emotional cue and the context are evaluated by appraisal processes before an emotional response is created. The alternative is a late model model which includes a direct link from an emotional cue to an emotional reponse, thereby bypassing appraisal processes. de Vignemont and Singer (2006) point out that there is little current evidence to distinguish between these two paths.
Whatever the process by which empathy operates, it is clearly a vital part of effective social functioning. Just how vital is the subject of constant debate. Many have suggested that empathy increases prosocial behaviour, de Vignemont and Singer (2006) argue that empathy increases social coherence and social communication. Conversely, a lack of empathy is associated with antisocial and aggressive behaviour.
In the next post, I'll move on to look at the research into those disorders which seem to incur an empathy deficit, e.g. alexithymia and autism spectrum disorders.
de Vignemont, F., & Singer, T. (2006). The empathic brain: how, when and why? Trends in Cognitive Sciences, 10(10), 435-41.Morrison, I., Lloyd, D., di Pellegrino, G., & Roberts, N. (2004). Vicarious responses to pain in anterior cingulate cortex: is empathy a multisensory issue. Cogn Affect Behav Neurosci, 4(2), 270-8.Labels: Autism, Emotion, Neuroscience
Blurred Definitions of Affect and Emotion
[Photo by Hugo]
Blurry and confusing definitions are the stock-in-trade of psychologists, just as they are of many other scientists. Perhaps you have noticed that I have been guilty of using the words 'affect' and 'emotion' rather loosely. I'm not the only one. Similar to many other areas of psychology, emotion researchers are far from decided and united on where to draw the lines, and, indeed, if lines can or should be drawn at all.Panksepp (2000) offers the following delineation:
- Emotion is the umbrella term for all of the behavioural, expressive, cognitive and physiological changes that occur.
- Affect is the conscious experience of an emotion.
- Emotional affect is the unconscious component of emotion.
- Non-emotional affect is rather a vague term that just includes everything that isn't an emotional affect, e.g. nausea and pain. [I don't agree with Panksepp here, how can pain be considered non 'action-promoting'?]
The well-known neurologist and emotion researcher Antonio Damasio has suggested the following taxonomy:
- A state of emotion can be started and executed unconsciously.
- A state of feeling is unconscious.
- A state of feeling made conscious which is the emotion and feeling made conscious (I think!)
- Affect, then, is the conscious experience of emotion.
To take a third example, perhaps more typical, Davidson (2003) appears to use the words 'affect' and 'emotion' interchangeably.
"Sin 2: Affect is subcortical. There is a tendency among some investigators to regard emotions as largely subcortical and to sometimes also assume that cognitions are cortical." (Davidson, 2003:129, emphasis added)Incidentally I'll be returning to this article to talk about the seven deadly sins of emotion researchers.
Given the state of confusion over meaning, I'm forced to reserve judgement over the 'correct' definition of affect and emotion. I'd like to go along with the dictionary definition of 'affect' as a "Feeling or emotion, especially as manifested by facial expression or body language" (Dicitonary.com) but, clearly for psychologists and those in related fields, the word's technical usage has yet to settle down.
Damasio, A. (1999). The Feeling of What Happens: Body Emotion and the Making of Consciousness. London: Vintage.Davidson, R. (2003). Seven sins in the study of emotion: Correctives from affective neuroscience. Brain and Cognition, 52(1), 129-132.Panksepp, J. (2000). Affective consciousness and the instinctual motor system: The neural sources of sadness and joy. The Caldron of Consciousness: Motivation, Affect and Self-organization, Advances in Consciousness Research. Amsterdam: John Benjamins Pub. Co.Labels: Emotion, Neuroscience
Separating Emotion From Cognition
[Photo by mhuang]
One of the main points I took away from the discussion on unity is that psychology needs to integrate results from different methodologies in order to better understand psychological phenomena. The emotions are a prime example of where this is happening, perhaps because the late blooming of emotion research has coincided with the explosion of brain imaging paradigms. And so the term 'affective neuroscience' has come into it's own. This post asks whether there's any justification for separating affective neuroscience from cognitive neuroscience.The term 'affective neuroscience' was coined by Jaak Panksepp in the early 1990s to distinguish it from cognitive neuroscience. Panksepp explains his view that affect or feelings are:
"...distinct neurobiological processes in terms of anatomical, neurochemical, and various functional criteria, including peripheral bodily interactions. Emotional and motivational feelings are unique experientially valenced 'state spaces' that help organisms make cognitive choices - e.g., to find food when hungry, water when thirsty, warmth when cold, and companionship when lonely or lusty." (Panksepp, 2003:6)Panksepp departs from LeDoux who, you'll recall (if not go here), thinks conscious emotions are too bound up in the problem of consciousness to be currently amenable to sensible investigations. Panksepp, meanwhile, argues that 'affect', by definition consciously experienced emotion, is important in the study of emotions.
That aside, one of the most important points that Panksepp (2003) addresses is the question of whether affects and cognitions can be separated in any meaningful way. He argues that while it may not be possible untangle cognitions from affect, there is considerable utility in examining the way in which it is 'embodied'. And here lies an important role for the neuroimaging of humans and animal brain research.
So what evidence is there, for Panksepp (2003), that emotions and cognitions can be separated?
- From a considerable amount of research, there seem to be emotional processes that are completely separate, or independent of, pure cognitions.
- Removing the higher parts of animal's brains (decortication) still leaves them with affective responses. Put crudely: without their cortexes, animals can still feel, but can't think anymore.
- Young children appear to display greater emotionality than adults. This might suggest that higher processes, developed later in life, serve to 'dampen' evolutionarily programmed emotional processes.
- Cognition is digital and emotion is analogue.
- Emotions are broadly similar cross-culturally, cognitions are not.
- The right hemisphere of the brain seems more emotionally-skilled whereas the left is more cognitively-skilled.
In the reality of everyday research, Panksepp (2003) argues, it is useful to emphasise the distinction between affects and cognitions if only to encourage a greater focus on emotion.
Panksepp, J. (2003). At the interface of the affective, behavioral, and cognitive neurosciences: Decoding the emotional feelings of the brain. Brain and Cognition, 52(1), 4-14. (Abstract | PDF)Labels: Emotion, Neuroscience