In Sync?

The title of this study (see citation below), Emotions promote social interaction by synchronizing brain activity across individuals, might be misleading to some. It is not about telepathy! It is not about some sort of rhythms or physical vibes! It is about people reacting in similar ways to the same emotional signal – not a surprise, emotional signs are, after all, an important part of communication between people.

 

But the paper is also about what areas of the brain are active in various emotional and arousing situations. It has an informative contrast between of valence and arousal.

Our results thus demonstrate that valence and arousal have distinct roles in synchronizing brain activity—and possibly also behavior—across individuals. These opposite effects on ISC (intersubject correlation) fit with the proposed distinction between valence and arousal representations in the brain and they also highlight the neurobehavioral functions that emotional arousal and valence may have in human social interaction. The key mechanisms that may support similar emotional processing across individuals are automatic and spatially similar focusing of attention toward emotion-laden stimuli and the subsequent mapping of others’ emotional states in the body and brain. Our data suggest that the attention-related mechanism is arousal-contingent, whereas the mapping mechanism is valence-contingent. … Our data show that the restricted processing brought about by negative emotions is reflected in the intersubject similarity in time courses of brain activity: The more negative emotions individuals feel, the more similar is their brain activation in the emotion circuit as well as in the default-mode network, whereas when the subjects experience positive emotions promoting free exploration, their brains process the sensory input more individually, resulting in lower ISC (intersubject correlation).

 

My problem is that the word ‘synchronization’ is somewhat misleading in this paper. I understand synchronization to be the phase locking of two oscillations or the instantaneous matching of two events. I could accept that there is synchrony between two brains but this paper did not measure it. There was no precise timing of events found here. They show subjects are reacting in similar ways but not in synchrony – the precision of timing is just not there; the study protocol cannot show synchrony.

 

The subjects viewed film clips with the dialog removed while undergoing a fRMI scan. They viewed the clips a second time and produced a record of their emotional responses and the intensity of those responses. These were not simple amateur film clips; they were from When Harry Met Sally and The Godfather. In a previous posting in this blog (here) I commented in the power of well-made professional movies to control brain activity.

 

Here are their conclusions (just ignore the synchronization word):

Sharing other individuals’ emotional states enables predictions of their behavior, and shared affective, sensory, and attentional representations may provide the key to understanding other minds. We argue that emotions enhance intersubject synchronization of brain activity and thus tune-in specific brain networks across individuals to support similar perception, experiencing, and prediction of the world. Our findings suggest that such synchronization of emotions across individuals provides an attentional and affective framework for interpreting others’ actions. This hypothesis accords with the proposals that perceived emotional states in others are constantly mapped into corresponding somatic and sensory representations in the observers’ brain. Through this kind of mind-simulation, we may estimate others’ goals and needs more accurately and tune our own behavior accordingly, thus supporting social interaction and coherence. We propose that high arousal serves to direct individuals’ attention similarly to features of the environment, whereas negative valence synchronizes brain circuitries, supporting emotional sensations across individuals. Through these mechanisms emotions could promote social interaction by enhancing the synchrony between brain activity and behavior across different individuals.

 

 

ResearchBlogging.org

Nummenmaa, L., Glerean, E., Viinikainen, M., Jaaskelainen, I., Hari, R., & Sams, M. (2012). Emotions promote social interaction by synchronizing brain activity across individuals Proceedings of the National Academy of Sciences DOI: 10.1073/pnas.1206095109

Clever Hans

Some types of experiments can be prone to a type of error than is often called the Clever Hans phenomenon, where involuntary clues are given by the person conducting the experiment without being aware of these cues prompting the behaviour of the subject.

This problem has been raised as a reason to distrust unconscious priming experiments. Bruce Bower has an excellent blog posting on this subject and I recommend reading it. (here) I have written about experiments that may have been faulty in this way in the past. I have no way of knowing the small details of how experiments were done and therefore no way of knowing whether to be suspicious of any.

So to repeat what I have said in this blog may times – the important evidence is not individual experiments, but consistent results over many labs and many methods. It is not a thread we are after, but a fabric.

I assume that there are well known papers that suffer from some Clever Hans unintentional flaws. I assume that are also flaws in many statistical analyses. I assume that there is a problem with the publication of replicating (or more importantly, unreplicating) papers. Scientist should clean up their act somewhat by, for instance, using the PsychFileDrawer.org blog to post unpublished replication attempts of psychological studies. But I am trying not to throw out the baby with the bath water and still feel that there is a lot of evidence in favour of embodied cognition.

Here is a sentence from Bruce Bower’s blog. Cesario, who studies how responses to the same prime vary in different physical settings, says that priming critics are threatened by evidence that complex thinking doesn’t require conscious thought. It is probably true that they are motivated critics, and it is a good thing that there are motivated critics. People who find it nearly impossible to believe something have the motivation to find any and all flaws they can in experimental evidence.

Those of us sitting on the outside, with perhaps a more open mind, will just have a wait patiently for the fog to clear. I have not been completely convinced either way but if I had to bet money, my money would be on embodied cognition.

Suspicion

That fringe feeling we get that we should be wary, suspicion, rises into consciousness from time to time – but where does it come from?

A recent item in ScienceDaily (here) reports on a paper by Bhatt, Lohrenz, Camerer and Montague, Distinct contributions of the amygdala and parahippocampal gyrus to suspicion in a repeated bargaining game. They separate two types of suspicion.

“We found a strong correlation between the amygdala and a baseline level of distrust, which may be based on a person’s beliefs about the trustworthiness of other people in general, his or her emotional state, and the situation at hand. What surprised us, though, is that when other people’s behavior aroused suspicion, the parahippocampal gyrus lit up, acting like an inborn lie detector.”

One way to think of this is that there is a default level of wariness set by the amygdala. It is on a spectrum from being trusting as a default to being suspicious as a default for each individual and would also change with the danger of the situation and the day to day level of confidence of the individual. The parahippocampal gyrus on the other hand reacts to the probability that a particular person is untrustworthy.

So, the fringe feeling of wariness comes from the amygdala but the attribute of untrustworthiness associated with a specific individual comes from the parahippocampal gyrus.

Perceiving the whole individual person

A method called fMRI-adaptation has been used to show a neural population that is activated by whole individuals rather than just faces or bodies. The fMRI-A effect depends on the adaptation or attenuation of the BOLD signal because of the repetition of a specific stimulus in a neural population that is sensitive to that particular stimulus.

So far fMRI-A has been used to characterize the representations underlying neural responses to a number of visual stimulus classes including faces, headless bodies, objects, scenes, as well as more generally to the binding of objects and background scenes and to the coding of objects presented in peripersonal space.

 

Schmalzl, Zopf, and Williams have recently published a paper (see citation below) in which they use fMRI-A to investigate the neural populations that show selective adaptation to the visual presentation of whole individuals, as opposed to just isolated faces or bodies.

In the fusiform gyrus and extrastriate regions, they found areas of specific adaptation effects for same faces, same bodies, either same faces or same bodies, same whole individuals, whole individuals whether same or different (individual category classification).

While the existence of voxels that show significant adaptation only when both the same face and the same body are presented points into the direction of response selectivity for whole individuals, it cannot be taken as evidence for it. The adaptation effect for whole individuals could be merely additive, namely a sum of face and body specific responses. That is, it could simply reflect the fact that some voxels contain a mixture of face and body selective neurons whose individual category specific response is not strong enough to yield significant adaptation, but whose combined response is. We therefore took our analysis one step further and defined a superadditive contrast for the SFSB (same face same body) condition. Specifically, we defined a new independent contrast that allowed us to investigate whether for some voxels showing significant SFSB adaptation, this adaptation was actually larger than the sum of the adaptation shown for all other conditions.

 

Here is their abstract:

Our ability to recognize other people’s faces and bodies is crucial for our social interactions. Previous neuroimaging studies have repeatedly demonstrated the existence of brain areas that selectively respond to visually presented faces and bodies. In daily life, however, we see “whole” people and not just isolated faces and bodies, and the question remains of how information from these two categories of stimuli is integrated at a neural level. Are faces and bodies merely processed independently, or are there neural populations that actually code for whole individuals? In the current study we addressed this question using a functional magnetic resonance imaging adaptation paradigm involving the sequential presentation of visual stimuli depicting whole individuals. It is known that adaptation effects for a component of a stimulus only occur in neural populations that are sensitive to that particular component. The design of our experiment allowed us to measure adaptation effects occurring when either just the face, just the body, or both the face and the body of an individual were repeated. Crucially, we found novel evidence for the existence of neural populations in fusiform as well as extrastriate regions that showed selective adaptation for whole individuals, which could not be merely explained by the sum of adaptation for face and body respectively. The functional specificity of these neural populations is likely to support fast and accurate recognition and integration of information conveyed by both faces and bodies. Hence, they can be assumed to play an important role for identity as well as emotion recognition in everyday life.

 

 

ResearchBlogging.org

Schmalzl, L., Zopf, R., & Williams, M. (2012). From Head to Toe: Evidence for Selective Brain Activation Reflecting Visual Perception of Whole Individuals Frontiers in Human Neuroscience, 6 DOI: 10.3389/fnhum.2012.00108

Mind-pops

Mind-pops are those little thoughts, words, images or tunes that suddenly pop into your mind at unexpected times and are totally unrelated to your current activity. A recent paper showed that mind-pops were more common in schizophrenics than others. (here) That is not what I want to talk about, it just started me thinking about mind-pops – those I or my friends have. What can prompt mind-pops normally?

 

 

I view them as part of a normal effect. I’m talking to someone and I suddenly cannot remember the name of the actor in the program I am describing. I consciously ask to myself what that name is and a few minutes later, after the conversation has gone on to something else, the actor’s name pops into my head. I have no doubt about why it ‘popped’ – a process was started to find the name, it took some time, but now it is returning the result. If it ‘popped’ two days later, I might or might not make the connection. If it ‘popped’ two weeks later, I might be puzzled by why that name suddenly appeared in my consciousness.

 

 

For many years, I have assumed that there was always a reason, a mind-pop was an answer to a problem of some sort that has been solved unconsciously. It need not be a memory recall problem but often is. We do not know consciously all of the problems that we are currently tackling unconsciously. Many may never have been registered consciously.

 

 

Schizophrenics have difficulties with many aspects of thought so it is not surprising that they may have more or even different sorts of mind-pops. This does not mean they are unnatural for the rest of us, or worrisome. They may just be the answer to a problem that we have just, finally, solved.

A beta version of the brain

New products have teething problems, development bugs; they need beta development, shaking down before they are reliable. We can presume that this may also be true of the evolution of new species. The great innovations come with side-effects. I have encountered people who said this about our chronic back pains being a side-effect of upright walking. It is a great thing but may have a couple of weak spots. We would actually be surprised if evolution didn’t take some time in a shake down of a new species.

 

A recent paper in Cell by 20 authors (this was really a big international effort) has tackled the question of whether autism is the unfortunate result of the malfunctioning of a relatively new aspect of the human brain. The essence of the paper is given in a press release from Yale:

(the team) identified the evolutionary changes that led the NOS1 gene to become active specifically in the parts of the developing human brain that form the adult centers for speech and language and decision-making. This pattern of NOS1 activity is controlled by a protein called FMRP and is missing in Fragile X syndrome, a disorder caused by a genetic defect on the X chromosome that disrupts FMRP production. Fragile X syndrome, the leading inherited form of intellectual disability, is also the most common single-gene cause of autism. The loss of NOS1 activity may contribute to some of the many cognitive deficits suffered by those with Fragile X syndrome, such as lower IQ, attention deficits, and speech and language delays … it is a more recent evolutionary adaptation possibly involved in the wiring of neural circuits important for higher cognitive abilities. The findings of the Cell paper support this hypothesis. The study also provides insights into how genetic deficits in early development, a time when brain circuits are formed, can lead to disorders such as autism, in which symptoms appear after birth.

 

There are a couple of aspects that should be brought up in context of this research. First, this is unlikely to be the only cause of autism. Autism is defined as a set of symptoms (and a not too clearly specified set with arbitrary measures – not a yes/no blood test or the like). A number of causes could end up with similar symptoms. Even a number of genetic causes could end up with the same end result.

 

Second, when the NOS1 activity is disrupted, the brain will not simply step back to a previous version of the homo brain. We should not make the mistake of assuming that our ancestors resembled people with autism. It may be that the functions that were replaced by the products of NOS1 are no longer available.

 

Unconscious cognition and control

There has recently been a review of the relationship between conscious and unconscious processing by van Gaal and others. (Citation below) They looked at an area of common misunderstanding and attempted to clarify it. Here are the highlights of their summarizing discussion:

… we have reviewed recent studies that have focused on the complexity and strength of unconscious information processing in relation to cognitive control (e.g., response inhibition, conflict resolution, and task-switching), the life-time of information maintenance (e.g., working memory, recognition memory) and the possibility to integrate multiple pieces of information across space and time. Unconscious information has been shown to affect various perceptual and high-level cognitive functions and the associated brain areas, including prefrontal cortex. In some cases, unconscious information has been observed to affect behavior and brain activity for relatively long periods of time. Overall, these recent results highlight the power of unconscious information processing, going beyond specific expectations formulated in traditional theoretical models of consciousness and the cognitive functions thought to require consciousness. … one can conclude that the potential function of consciousness might not be related to the initiation of cognitive control functions by specific stimuli that signal the need for increased control (e.g., stop-signals, task-switching cues). These cognitive control operations are probably triggered by a fast feedforward, and unconscious, early sweep of information processing that reaches even regions in the prefrontal cortex. This unconscious fast feedforward sweep can directly affect (the speed of) ongoing cognitive processes. … Although recent evidence has clearly pushed the boundaries regarding the duration of unconscious effects, the general observation is that unconscious events are much less able to elicit (long-term) future behavioral adaptations than conscious events (e.g., post-error slowing, conflict adaptation). Why might this be the case? Theoretical models of consciousness suggest that conscious awareness is related to long-lasting recurrent interactions between (distant) brain regions. This might enable the exchange of information between several spatially separated cognitive modules, which seems to break the automaticity of information processing. Awareness might be beneficial for enabling flexible and durable information processing strategies that are not directly triggered by a specific stimulus, for example when information has to be integrated across longer periods of time to bias information acquisition or signal the need for performance adjustments . Recently, Kunde et al. suggested that awareness might be dispensable when cognitive control is signaled explicitly (by specific control-eliciting stimuli) but not when it has to be inferred implicitly (by the context, or history of events).

 

 

ResearchBlogging.org

van Gaal, S., de Lange, F., & Cohen, M. (2012). The role of consciousness in cognitive control and decision making Frontiers in Human Neuroscience, 6 DOI: 10.3389/fnhum.2012.00121

Seeing auras

For the majority of us, the characteristics of things stay within their sensory categories. We do not see numbers with colours; we do not feel sounds; we do not taste shapes. People who have these strange mixing of the senses, synesthetes, are not that rare. For a long time, the idea of synesthesia was not accepted. Now, it has been shown over and over to be a real way of perceiving, individual to the person but stable and automatic.

Recently a few people have been found that see colour in response to various emotions. Ramachandran studied a man with this type of synesthesia. He saw a blue aura around a person which changes shade when particular emotions were sensed. The researchers placed a target person against a white background and drew a black line on the background around the person. The subject saw the blue aura in the space between the person and the black line. Blue or orange letters were projected onto the background and the subjects was timed in his identification of the letters. Blue letters inside the black line were identified slower than orange letters or blue letters outside the line. Blue letters against blue aura were more difficult to see. The researchers will be looking for cross-activation of V4 colour perception area and other areas (they hypothesis insular cortex, activated during subjective experience of emotion).

A Spanish group under Milan studied healers. One healer in particular, with a very good reputation, was clearly a face-colour synesthete seeing the aura of people, a touch-mirror synesthete who experience touch and pain when seeing it happen to someone else, and also a schizotypy personality tending towards slight paranoia and delusions. The researchers believed that the synesthesia encouraged the healers to believe in their own ability to heal other people, and their confidence caused a significant placebo effect in the healed people. However they believe that synesthesia is not an extrasensory power but a subjective and adorned perception of reality.

Oh well, educated people used to believe that meteorites and ball lightening were silly tales of the ignorant and superstitious. Now we are finding that near death experiences, ghosts and auras may have reasonable explanations and are not faked but simply not understood.

Power of self-directed speech

If we look at how communication works we find that words and phrases have a great influence on attention. They bring into the consciousness of the listener the concepts that are uttered. This is what meaning is – the concepts that a word or phrase can steer attention towards. This is what communication is – the sharing of attention by two (or more) brains on a sequence of concepts.

 

So it is not surprising that it is useful to talk to oneself. What we are doing when we self-talk is to steer our consciousness. In recent paper (see citation below), Lupyan and Swingley look at how self-directed speech affects searching. Here is part of their conclusions:

In this work, we examined effects of self-directed speech on performance on a simple visual task. Speaking the name of the object for which one was searching affected performance on the visual search task relative to intermixed trials on which participants read the word but did not actually speak it before or during search. The effect of speaking depended strongly on the characteristics of the target item. Search was improved for the most familiar and prototypical items – those for which speaking the name is hypothesized to evoke the visual representation that best matches the visual characteristics of the target item. Search was unaffected or impaired as the discrepancy between the name and target – measured by measures of familiarity and imagery concordance – was increased.

 

Facilitation due to speaking also became larger with repeated exposures to the target items. Arguably this occurred because multiple exposures strengthened the associations between the label (e.g., “elephant”) and the visual exemplar (a given picture of an elephant). The idea that saying a category name activates a more prototypical representation of the category is also supported by the finding that speaking the name actually hurts performance for items with low within-category similarity. One implication is that repeating the word “knife” may, for example, help an airport baggage screener spot typical knives, but actually make it more difficult to find less prototypical knives.

 

On our view, the reason speaking the target name affects visual search performance is that speaking its name helps to activate and/or keep active visual (as well as nonvisual) features that are diagnostic of the object’s category, facilitating the processing of objects with representations overlapping those activated by the label. This activation of visual features occurs during silent reading as well. Indeed, it is what allows fore-knowledge of the target to guide search. Self-directed speech, as implemented in the present studies, is hypothesized to further enhance this process.

 

This idea of controlling attention is also shown when people try to keep some piece of information in working memory by repeating it, when they encourage themselves to do something difficult or scaring, when they are learning (or planning) a complex sequence of actions. Searching is not the only activity that benefits from a little talking to yourself.

 

ResearchBlogging.org

Lupyan, G., & Swingley, D. (2011). Self-directed speech affects visual search performance The Quarterly Journal of Experimental Psychology, 1-18 DOI: 10.1080/17470218.2011.647039

The buena vista theory of consciousness

Malcolm MacIver has a posting in the Discovery Blog, Science not Fiction. (here) He connects consciousness with the evolution from marine animals to land animals. His argument goes: (1) marine animals cannot see far compared to their speed (2) therefore marine animals can only react quickly to what they sense (3) moving to land increased their ‘perceptual horizon’ 10,000 fold (4) therefore land animals had time to plan their actions rather than simply react (5) planning needs consciousness.

This puts the first such members of the “buena vista sensing club” into a very interesting position, from an evolutionary perspective. Think of the first animal that gains whatever mutation it might take to disconnect sensory input from motor output (before this point, their rapid linkage was necessary because of the need for reactivity to avoid becoming lunch). At this point, they can potentially survey multiple possible futures and pick the one most likely to lead to success. For example, rather than go straight for the gazelle and risk disclosing your position too soon, you may choose to stalk slowly along a line of bushes (wary that your future dinner is also seeing 10,000 times better than its watery ancestors) until you are much closer.

I am not sure I buy this picture, although it could be behind a big step up in consciousness. One problem is that the theory depends heavily on vision being the main sense. Cetacea (dophins, whales) were land animals that returned to the sea. They did not lose their consciousness but used their hearing as their main sense rather than sight. Their perceptual horizons may be as long or longer than ours. Marine animals use tactile sensing of water movements and electrical sensing as well. One would have to look at the perceptual horizon available from all senses to make a tight argument for the buena vista theory.

There is also the Cephalopods (octopus, squid, cuttlefish) which have never been on land but appear to have no problem with planning and the like. They would not have a same sort of consciousness as vertebrates but it is not a given that they lack a very similar function.

On the other hand, consciousness is costly and slower than reflex so it is not likely to be elaborated in environments where it does not give a yield greater than its cost. Read the post for some interesting crystal ball looks as well as the fuller explanation of the theory.