Friday, July 29, 2011

MindBlog retrospective: A new description of our inner lives.

This is another of my old posts that emerged from the retrospective scan of this blog that I did recently, another interesting perspective I don't want to loose touch with. It drew a number of comments, and a second post several months later discussed them. Here is a repeat of the original post:

I rarely mention my internal experience and sensations on this blog - first, because I have viewed readers as "wanting the beef," objective stuff on how minds work. Second and more important, because my experience of noting the flow of my brain products as emotion laced chunks of sensing/cognition/action - knowing the names of the neurotransmitters and hormones acting during desire, arousal, calming, or affiliation - strikes me as a process which would feel quite alien to most people. Still, if we are materialists who believe that someday we will understand how the brain-body generates our consciousness and sense of a self, we will be able to think in terms like the following (a quote taken from Larissa MacFarquhar's profile of Paul and Patricia Churchland in the Feb. 12 New Yorker Magazine):

"...he and Pat like to speculate about a day when whole chunks of English, especially the bits that consitute folk psychology, are replaced by scientific words that call a thing by its proper name rather than some outworn metaphor... as people learn to speak differently they will learn to experience differently, and sooner or later even their most private introspections will be affected. Already Paul feels pain differently than he used to: when he cut himself shaving now he fells not "pain" but something more complicated - first the sharp, superficial A-delta-fibre pain, and then a couple of seconds later, the sickening, deeper feeling of C-fibre pain that lingers. The new words, far from being reductive or dry, have enhanced his sensations, he feels, as an oenophile's complex vocabulary enhances the taste of wine."

"Paul and Pat, realizing that the revolutionary neuroscience they dream of is still in its infancy, are nonetheless already preparing themselve for this future, making the appropriate adjustments in their everyday conversation. One afternoon recently, Paul says, he was home making dinner when Pat burst in the door, having come straight from a frustrating faculty meeting. "She said, 'Paul, don't speak to me, my serotonin levels have hit bottom, my brain is awash in glucocortocoids, my blood vessels are full of adrenaline, and if it weren't for my endogenous opiates I'd have driven the car into a tree on the way home. My dopamine levels need lifting. Pour me a Chardonnay, and I'll be down in a minute.' " Paul and Pat have noticed that it is not just they who talk this way - their students now talk of psychopharmacology as comfortably as of food."

Thursday, July 28, 2011

The utility of being vague.

I'm just getting to glance at the last few issue of Psychological Science, and find this gem, "In Praise of Vagueness" by Mishra et al., which they introduce as follows:

People are increasingly surrounded by devices that provide highly precise information. For instance, technologically advanced bathroom scales can now give measurements of weight, body fat, and hydration levels within two and even three decimal places. People can find out exactly how many calories they are eating, how much weight they can lift, and how many steps they walk in a typical day. The overarching belief exemplified by the use of such technologies could be summed up by the phrase, “If I can measure it, I can manage it.” In other words, people seem to believe that precise information increases their likelihood of performing better and meeting personal goals (e.g., improving physical strength or losing weight). People generally prefer precise information over vague information because precise information gives them a greater sense of security and confidence in their ability to predict unknown outcomes in their environment. Despite this preference, we have found that vague information sometimes serves people better than precise information does.

Why might individuals perform better when they receive vague information than when they receive precise information? We posit that vague information allows individuals leeway in interpretation so that they form expectancies in accordance with the outcomes that they desire. Further, we posit that these positive expectancies can give rise to favorable performance-related outcomes.
Their experiments examined the progress of people towards goals when they were given precise versus vague (error range given) feedback on that progress. Perhaps the most striking example was provided in the weight loss experiment whose participants gained, on average, one pound over the course of the experiment after being given precise feedback, those given vague feedback lost nearly four pounds. Here is their abstract:
Is the eternal quest for precise information always worthwhile? Our research suggests that, at times, vagueness has its merits. Previous research has demonstrated that people prefer precise information over vague information because it gives them a sense of security and makes their environments more predictable. However, we show that the fuzzy boundaries afforded by vague information can actually help individuals perform better than can precise information. We document these findings across two laboratory studies and one quasi–field study that involved different performance-related contexts (mental acuity, physical strength, and weight loss). We argue that the malleability of vague information allows people to interpret it in the manner they desire, so that they can generate positive response expectancies and, thereby, perform better. The rigidity of precise information discourages desirable interpretations. Hence, on certain occasions, precise information is not as helpful as vague information in boosting performance.

Wednesday, July 27, 2011

Inappropriate cravings? Hold a magnet by your head!

Here's an idea for a BioTech startup!...(I'm not serious)...suggested by an article from McClemon et al. titled "Repetitive Transcranial Magnetic Stimulation of the Superior Frontal Gyrus Modulates Craving for Cigarettes."

BACKGROUND:

Previous functional magnetic resonance imaging studies have shown strong correlations between cue-elicited craving for cigarettes and activation of the superior frontal gyrus (SFG). Repetitive transcranial magnetic stimulation (rTMS) offers a noninvasive means to reversibly affect brain cortical activity, which can be applied to testing hypotheses about the causal role of SFG in modulating craving.

METHODS:

Fifteen volunteer smokers were recruited to investigate the effects of rTMS on subjective responses to smoking versus neutral cues and to controlled presentations of cigarette smoke. On different days, participants were exposed to three conditions: 1) high-frequency (10 Hz) rTMS directed at the SFG; 2) low-frequency (1 Hz) rTMS directed at the SFG; and 3) low-frequency (1 Hz) rTMS directed at the motor cortex (control condition).

RESULTS:

Craving ratings in response to smoking versus neutral cues were differentially affected by the 10-Hz versus 1-Hz SFG condition. Craving after smoking cue presentations was elevated in the 10-Hz SFG condition, whereas craving after neutral cue presentations was reduced. Upon smoking in the 10-Hz SFG condition, ratings of immediate craving reduction as well as the intensity of interoceptive airway sensations were also attenuated.

CONCLUSIONS:

These results support the view that the SFG plays a role in modulating craving reactivity; moreover, the results suggest that the SFG plays a role in both excitatory and inhibitory influences on craving, consistent with prior research demonstrating the role of the prefrontal cortex in the elicitation as well as inhibition of drug-seeking behaviors.
By the way, from Wikipedia via google images, here is the superior frontal gyrus:

Tuesday, July 26, 2011

Watching Humor in the Brain

Bekinschtein et al. look at what may be the brain correlates of "humor as a cognitive cleanup mechanism" mentioned in my June 17 post, at least in the case of jokes that depend on semantic ambiguity resolution:

What makes us laugh? One crucial component of many jokes is the disambiguation of words with multiple meanings. In this functional MRI study of normal participants, the neural mechanisms that underlie our experience of getting a joke that depends on the resolution of semantically ambiguous words were explored. Jokes that contained ambiguous words were compared with sentences that contained ambiguous words but were not funny, as well as to matched verbal jokes that did not depend on semantic ambiguity. The results confirm that both the left inferior temporal gyrus and left inferior frontal gyrus are involved in processing the semantic aspects of language comprehension, while a more widespread network that includes both of these regions and the temporoparietal junction bilaterally is involved in processing humorous verbal jokes when compared with matched nonhumorous material. In addition, hearing jokes was associated with increased activity in a network of subcortical regions, including the amygdala, the ventral striatum, and the midbrain, that have been implicated in experiencing positive reward. Moreover, activity in these regions correlated with the subjective ratings of funniness of the presented material. These results allow a more precise account of how the neural and cognitive processes that are involved in ambiguity resolu
tion contribute to the appreciation of jokes that depend on semantic ambiguity.

Monday, July 25, 2011

Confabulation

Here is an entry from Fiery Cushman on the Edge.org question "What scientific concept would improve everybody's cognitive toolkit?," on how we frequently rationalize our behavior, unaware of unconscious factors that actually guided it. Here are some clips:

We are shockingly ignorant of the causes of our own behavior. The explanations that we provide are sometimes wholly fabricated, and certainly never complete. Yet, that is not how it feels. Instead it feels like we know exactly what we're doing and why. This is confabulation: Guessing at plausible explanations for our behavior, and then regarding those guesses as introspective certainties…The problem is that we get all of our explanations partly right, correctly identifying the conscious and deliberate causes of our behavior. Unfortunately, we mistake "party right" for "completely right", and thereby fail to recognize the equal influence of the unconscious, or to guard against it.

People make harsher moral judgments in foul-smelling rooms, reflecting the role of disgust as a moral emotion. Women are less likely to call their fathers (but equally likely to call their mothers) during the fertile phase of their menstrual cycle, reflecting a means of incest avoidance. Students indicate greater political conservatism when polled near a hand-sanitizing station during a flu epidemic, reflecting the influence of a threatening environment on ideology. They also indicate a closer bond to their mother when holding hot coffee versus iced coffee, reflecting the metaphor of a "warm" relationship.

Automatic behaviors can be remarkably organized, and even goal-driven. For example, research shows that people tend to cheat just as much as they can without realizing that they are cheating. This is a remarkable phenomenon: Part of you is deciding how much to cheat, calibrated at just the level that keeps another part of you from realizing it.

One of the ways that people pull off this trick is with innocent confabulations: When self-grading an exam, students think, "Oh, I was going to circle e, I really knew that answer!" This isn't a lie, any more than it's a lie to say you have always loved your mother (latte in hand), but don't have time to call your dad during this busy time of the month. These are just incomplete explanations, confabulations that reflect our conscious thoughts while ignoring the unconscious ones.

Perhaps you have noticed that people have an easier time sniffing out unseemly motivations for other's behavior than recognizing the same motivations for their own behavior…we jump to the conclusion that others' behaviors reflect their bad motives and poor judgment, attributing conscious choice to behaviors that may have been influenced unconsciously… we assume that our own choices were guided solely by the conscious explanations that we conjure, and reject or ignore the possibility of our own unconscious biases...By understanding confabulation we can begin to remedy both faults.

Friday, July 22, 2011

The importance of our brains’ resting state activity.

Pizoli et al find, in an open access article describing the clinical case of a young boy with epileptic encephalopathy who underwent successful corpus callosotomy surgery for treatment of drop seizures (i.e., separation of connections between the two hemispheres), that resting state brain activity (temporal synchrony across distributed brain regions termed resting-state networks that persists during waking, sleep, and anesthesia) is required for normal brain development and maintenance:

One of the most intriguing recent discoveries concerning brain function is that intrinsic neuronal activity manifests as spontaneous fluctuations of the blood oxygen level–dependent (BOLD) functional MRI signal. These BOLD fluctuations exhibit temporal synchrony within widely distributed brain regions known as resting-state networks. Resting-state networks are present in the waking state, during sleep, and under general anesthesia, suggesting that spontaneous neuronal activity plays a fundamental role in brain function. Despite its ubiquitous presence, the physiological role of correlated, spontaneous neuronal activity remains poorly understood. One hypothesis is that this activity is critical for the development of synaptic connections and maintenance of synaptic homeostasis. We had a unique opportunity to test this hypothesis in a 5-y-old boy with severe epileptic encephalopathy. The child developed marked neurologic dysfunction in association with a seizure disorder, resulting in a 1-y period of behavioral regression and progressive loss of developmental milestones. His EEG showed a markedly abnormal pattern of high-amplitude, disorganized slow activity with frequent generalized and multifocal epileptiform discharges. Resting-state functional connectivity MRI showed reduced BOLD fluctuations and a pervasive lack of normal connectivity. The child underwent successful corpus callosotomy surgery for treatment of drop seizures. Postoperatively, the patient's behavior returned to baseline, and he resumed development of new skills. The waking EEG revealed a normal background, and functional connectivity MRI demonstrated restoration of functional connectivity architecture. These results provide evidence that intrinsic, coherent neuronal signaling may be essential to the development and maintenance of the brain's functional organization.

Thursday, July 21, 2011

Pressure to conform - survey of tight and loose cultures.

Gelfand et al. have constructed a metric they term "tightness-looseness" - the extent to which societies impose social norms, and have collected data across 33 large-scale cultures from ~7,000 individuals. Their questionnaire asked people to rate the appropriateness of 12 behaviors (such as eating or crying) in 15 situations (such as being in a bank or at a party). Then, they compared the responses to an array of ecological and historical factors. From Norenzayan's summary:

...Overall, they found that societies exposed to contemporary or historical threats, such as territorial conflict, resource scarcity, or exposure to high levels of pathogens, more strictly regulate social behavior and punish deviance. These societies are also more likely to have evolved institutions that strictly regulate social norms. At the psychological level, individuals in tightly regulated societies report higher levels of self-monitoring, more intolerant attitudes toward outsiders, and paying stricter attention to time. In this multilevel analysis, ecological, historical, institutional, and psychological variables comprise a loosely integrated system that defines a culture.

These findings complement a growing literature that reveals the power of the comparative approach in explaining critically important features of human behavior. For example, research suggests that the substantial variation in religious involvement among nations can be explained, in large part, by perceived levels of security. Religion thrives when existential threats to human security, such as war or natural disaster, are rampant, and declines considerably in societies with high levels of economic development, low income inequality and infant mortality, and greater access to social safety nets.

Wednesday, July 20, 2011

The Forbidden Fruit Intuition - our inability to cope with what we know about our minds.

I've recently done a scan of old MindBlog posts, and a number of them stand out so strongly for me, that I want to have their ideas repeated, hoping repetition will aid intellectual assimilation. Here then, a post from April 2006 on Thomas Metzinger's brief essay titled "The Forbidden Fruit Intuition", in the initial post I didn't point to his first paragraph,

We all would like to believe that, ultimately, intellectual honesty is not only an expression of, but also good for your mental health. My dangerous question is if one can be intellectually honest about the issue of free will and preserve one's mental health at the same time. Behind this question lies what I call the "Forbidden Fruit Intuition": Is there a set of questions which are dangerous not on grounds of ideology or political correctness, but because the most obvious answers to them could ultimately make our conscious self-models disintegrate? Can one really believe in determinism without going insane?
Here is the original post:

I get frustrated when I try to reconcile what I know from empirical data to be true about my self (see the "I-Illusion" essay on this website) with the common sense feeling of agency and responsibility that we are share.

Our commonsense conceptions of ourselves have co-evolved over hundreds of thousands of years, along with their physiological, homeostatic, neuroendocrine, and limbic emotional correlates. This whole complex (us, that is) can be upset by facing what it can come to know to be true about the impersonal physical processes that actually run our show, finding it impossible to integrate its 'illusory' self image.

Here is a clip, and then its more extended context from the piece by Metzinger on edge.org..his response to the question "What is your dangerous idea." He frames it much better than I can. First the clip:

"I think that the irritation and deep sense of resentment surrounding public debates on the freedom of the will actually has nothing much to do with the actual options on the table. It has to do with the perfectly sensible intuition that our presently obvious answer will not only be emotionally disturbing, but ultimately impossible to integrate into our conscious self-models."

Then the more extended quotation:

"For middle-sized objects at 37° like the human brain and the human body, determinism is obviously true. The next state of the physical universe is always determined by the previous state. And given a certain brain-state plus an environment you could never have acted otherwise. A surprisingly large majority of experts in the free-will debate today accept this obvious fact...."

"Yes, you are a physically determined system. But this is not a big problem, because, under certain conditions, we may still continue to say that you are "free": all that matters is that your actions are caused by the right kinds of brain processes and that they originate in you. A physically determined system can well be sensitive to reasons and to rational arguments, to moral considerations, to questions of value and ethics, as long as all of this is appropriately wired into its brain. You can be rational, and you can be moral, as long as your brain is physically determined in the right way. You like this basic idea: physical determinism is compatible with being a free agent. You endorse a materialist philosophy of freedom as well. An intellectually honest person open to empirical data, you simply believe that something along these lines must be true.

Now you try to feel that it is true. You try to consciously experience the fact that at any given moment of your life, you could not have acted otherwise. You try to experience the fact that even your thoughts, however rational and moral, are predetermined — by something unconscious, by something you can not see. And in doing so, you start fooling around with the conscious self-model Mother Nature evolved for you with so much care and precision over millions of years: You are scratching at the user-surface of your own brain, tweaking the mouse-pointer, introspectively trying to penetrate into the operating system, attempting to make the invisible visible. You are challenging the integrity of your phenomenal self by trying to integrate your new beliefs, the neuroscientific image of man, with your most intimate, inner way of experiencing yourself. How does it feel?

I think that the irritation and deep sense of resentment surrounding public debates on the freedom of the will actually has nothing much to do with the actual options on the table. It has to do with the perfectly sensible intuition that our presently obvious answer will not only be emotionally disturbing, but ultimately impossible to integrate into our conscious self-models.

Or our societies: The robust conscious experience of free will also is a social institution, because the attribution of accountability, responsibility, etc. are the decisive building blocks for modern, open societies. And the currently obvious answer might be interpreted by many as having clearly anti-democratic implications: Making a complex society work implies controlling the behavior of millions of people; if individual human beings can control their own behavior to a much lesser degree than we have thought in the past, if bottom-up doesn't work, then it becomes tempting to control it top-down, by the state. And this is the second way in which enlightenment could devour its own children. Yes, free will truly is a dangerous question, but for different reasons than most people think. "

Tuesday, July 19, 2011

Clips: Animal Joys - Diet and Weight

There's a fun article in today's NYTimes Science section ("The Joy of a Sun Bath, a Snuggle, a Bite of Pâté") reviewing a new book by animal behaviorist Jonathan Balcombe on "hedonic ethology" titled “The Exultant Ark.”


Also, one of the best articles on diet and weight loss, by Jean Brodie, that I've recently seen.

Our Umwelt

I found the following bit to be an engaging and refreshing reminder, from David Eagleman:

In 1909, the biologist Jakob von Uexküll introduced the concept of the umwelt. He wanted a word to express a simple (but often overlooked) observation: different animals in the same ecosystem pick up on different environmental signals. In the blind and deaf world of the tick, the important signals are temperature and the odor of butyric acid. For the black ghost knifefish, it's electrical fields. For the echolocating bat, it's air-compression waves. The small subset of the world that an animal is able to detect is its umwelt. The bigger reality, whatever that might mean, is called the umgebung.

The interesting part is that each organism presumably assumes its umwelt to be the entire objective reality "out there." Why would any of us stop to think that there is more beyond what we can sense?…it rarely strikes us that things could be different. Similarly, until a child learns in school that honeybees enjoy ultraviolet signals and rattlesnakes employ infrared, it does not strike her that plenty of information is riding on channels to which we have no natural access. From my informal surveys, it is very uncommon knowledge that the part of the electromagnetic spectrum that is visible to us is less than a ten-trillionth of it.

Our brains are tuned to detect a shockingly small fraction of the surrounding reality. Our sensorium is enough to get by in our ecosystem, but is does not approximate the larger picture...I think it would be useful if the concept of the umwelt were embedded in the public lexicon. It neatly captures the idea of limited knowledge, of unobtainable information, and of unimagined possibilities. Consider the criticisms of policy, the assertions of dogma, the declarations of fact that you hear every day — and just imagine if all of these could be infused with the proper intellectual humility that comes from appreciating the amount unseen.

Monday, July 18, 2011

Peer pressure influences our memories

Fascinating observations from Edelson et al., who examine how our accurate initial memories of an event can be be changed by hearing different accounts from others. They find that activity in the hippocampus and amygdala brain regions involved in memory can vary, depending on how our memory has been shaped by interacting with others. Here is their abstract:

Human memory is strikingly susceptible to social influences, yet we know little about the underlying mechanisms. We examined how socially induced memory errors are generated in the brain by studying the memory of individuals exposed to recollections of others. Participants exhibited a strong tendency to conform to erroneous recollections of the group, producing both long-lasting and temporary errors, even when their initial memory was strong and accurate. Functional brain imaging revealed that social influence modified the neuronal representation of memory. Specifically, a particular brain signature of enhanced amygdala activity and enhanced amygdala-hippocampus connectivity predicted long-lasting but not temporary memory alterations. Our findings reveal how social manipulation can alter memory and extend the known functions of the amygdala to encompass socially mediated memory distortions.

Friday, July 15, 2011

Stress and the City

The number of the world's people living in cities has increased from 30% to 50% since 1950, and by 2050 is projected to be ~70%. Many experiments, done on insects, rodents, primates, and humans, have shown that extremes of either social isolation or crowding can have harmful effects. Lederbogen et al. have now used functional magnetic resonance imaging to examine specific human brain structures that are affected by urban living, comparing people living in rural areas, towns with more than 10,000 residents, and cities with more than 100,000 residents. They replicated their findings in several separate samples, used two different stress-inducing tasks, and demonstrated that there were no effects of urbanicity on brain activation when participants performed a non-stressful cognitive task. Stress increased participants' heart rate, blood pressure, saliva cortisol, and activity in the amygdala, with city dwellers showing the largest increases. They found that participants' age, education, income, marital and family status, as well as aspects of their health, mood, personality and the amount of social support they had did not significantly influence the effects of urbanicity. Thus they suggest that living in a city environment changes brain response during a social stressor by a distinct, but mysterious, mechanism. Here is the abstract:

More than half of the world’s population now lives in cities, making the creation of a healthy urban environment a major policy priority. Cities have both health risks and benefits1, but mental health is negatively affected: mood and anxiety disorders are more prevalent in city dwellers and the incidence of schizophrenia is strongly increased in people born and raised in cities. Although these findings have been widely attributed to the urban social environment, the neural processes that could mediate such associations are unknown. Here we show, using functional magnetic resonance imaging in three independent experiments, that urban upbringing and city living have dissociable impacts on social evaluative stress processing in humans. Current city living was associated with increased amygdala activity, whereas urban upbringing affected the perigenual anterior cingulate cortex, a key region for regulation of amygdala activity, negative affect and stress. These findings were regionally and behaviourally specific, as no other brain structures were affected and no urbanicity effect was seen during control experiments invoking cognitive processing without stress. Our results identify distinct neural mechanisms for an established environmental risk factor, link the urban environment for the first time to social stress processing, suggest that brain regions differ in vulnerability to this risk factor across the lifespan, and indicate that experimental interrogation of epidemiological associations is a promising strategy in social neuroscience.






http://www.nature.com/nature/journal/v474/n7352/full/474452a.html

http://www.nature.com/nature/journal/v474/n7352/full/nature10190.html

Thursday, July 14, 2011

Effects of blue light on our memory, cognition, and circadian thythm

I ran a vision research laboratory for 30 years,  and in the early 1970s found that installing natural spectrum florescent lights (with more blue wavelengths) in my research laboratory enhanced my relaxation and alertness. My graduate students and post-docs reported the same effect.  Following this subject I've done posts on work documenting this effect, and then subsequently finding that blue light is the best stimulus for a visual pathway that lies outside of the classical (red/green/blue) rod and cone photoreceptor cells of our retinas, driven by a the blue sensitive visual pigment melanopsin in some inner (ganglion) cells of the retina. The amygdala, at the core of our emotional brain, receives direct projections from these light sensitive retinal ganglion cells. Activation of this system also causes changes in brain areas related to working memory. An article by Beil now points to recent work noting consequences of the fact that that blue light is especially effective in suppressing the sleep promoting hormone melatonin that regulates our diurnal sleep-wake cycle. To examine the effects of energy-efficient light bulbs and electronic gadgets with LED screens that have greatly increased levels of blue light wavelengths, some researchers at the University of Basel:

...asked 13 men to sit before a computer each evening for two weeks before going to bed. During one week, for five hours every night, the volunteers sat before an old-style fluorescent monitor emitting light composed of several colors from the visible spectrum, though very little blue. Another week, the men sat at screens backlighted by light-emitting diodes, or LEDs. This screen was twice as blue...Melatonin levels in volunteers watching the LED screens took longer to rise at night, compared with when the participants were watching the fluorescent screens, and the deficit persisted throughout the evening...The subjects also scored higher on tests of memory and cognition after exposure to blue light...The finding adds to a series of others suggesting... that exposure to blue light may keep us more awake and alert, partly by suppressing production of melatonin. An LED screen bright enough and big enough could be giving an alert stimulus at a time that will frustrate the body’s ability to go to sleep later.

Wednesday, July 13, 2011

Watching contextual memories

Our memories from a particular time and place are linked together (recall Proust's Madeleine cookie) and referred to as contextual memory. Benedict Carey points to an elegant study by Manning et al. that has studied 69 neurosurgical patients who were implanted with subdural electrode arrays and depth electrodes during treatment for drug-resistant epilepsy. As electrocorticographic (ECoG) signals were recorded, the patients volunteered to participate in a free recall memory experiment, in which they studied lists of common nouns and then attempted to recall them verbally in any order following a brief delay. Their results suggest that memory is like a streaming video that is bookmarked, both consciously and subconsciously. New memories of even abstract facts are encoded in brain-cell firing sequences that also contains information about what else was happening during and just before the memory was formed. Here is their abstract, followed by a striking figure from the paper:

Psychological theories of memory posit that when people recall a past event, they not only recover the features of the event itself, but also recover information associated with other events that occurred nearby in time. The events surrounding a target event, and the thoughts they evoke, may be considered to represent a context for the target event, helping to distinguish that event from similar events experienced at different times. The ability to reinstate this contextual information during memory search has been considered a hallmark of episodic, or event-based, memory. We sought to determine whether context reinstatement may be observed in electrical signals recorded from the human brain during episodic recall. Analyzing electrocorticographic recordings taken as 69 neurosurgical patients studied and recalled lists of words, we uncovered a neural signature of context reinstatement. Upon recalling a studied item, we found that the recorded patterns of brain activity were not only similar to the patterns observed when the item was studied, but were also similar to the patterns observed during study of neighboring list items, with similarity decreasing reliably with positional distance. The degree to which individual patients displayed this neural signature of context reinstatement was correlated with their tendency to recall neighboring list items successively. These effects were particularly strong in temporal lobe recordings. Our findings show that recalling a past event evokes a neural signature of the temporal context in which the event occurred, thus pointing to a neural basis for episodic memory.


Evidence for context reinstatement in the temporal lobe. (A) Each dot marks the location of a single electrode from our dataset in Montreal Neurological Institute space. We divided our dataset into four regions of interest: temporal lobe (blue, 1,815 electrodes), frontal lobe (red, 1,737 electrodes), parietal lobe (yellow, 512 electrodes), and occipital lobe (green, 138 electrodes).

Tuesday, July 12, 2011

Dopamine, reward, and beliefs

I want to point to comments made by Charles (The Dopamine Project) on the How we form beliefs post below. The Sapolsky video is quite entertaining.

Varies of reward in the brain.

Smith et al. do some interesting tracking of the different circuits that are active in different kinds of reward in the brain. Here is their summary (which is a bit less technical than the abstract pointed to by the link):

Reward can be separated into several components, which include sensory pleasure (liking), incentive motivation triggered by related cues (wanting), and predictive associations that allow cues to raise expectations of the pleasure to come (learning). Attraction to food in the refrigerator when hungry, for example, involves learned predictions of tasty treats, motivation to eat, and finally, pleasure enjoyed on eating. In the brain, signals for each of these components are funneled together through looping pathways connecting the nucleus accumbens with the ventral pallidum (VP), which form a circuit mediating motivation, behavior, and emotions. This circuit is crucial for healthy reward processing, and its dysfunction plays a special role in pathological drug addiction, eating disorders, and emotional disorders. However, it is not known how the different reward components are kept separate within this circuit. If they are funneled together, how are they independently encoded as distinct signals? Here, we report that distinct signatures of neuronal firing in the VP track each reward component. We also report that selective enhancements of liking vs. wanting brought about by specific neurochemical activations in nucleus accumbens can be tracked independently from one another in downstream firing of VP neurons, all without distorting signals related to prediction of reward.


Monday, July 11, 2011

Our brains are hard-wired to make poor choices about harm prevention.

Daniel Gilbert, always an engaging writer, has done a nice piece in Nature "Buried by bad decisions" and I pass on a few clips here:

…should we do everything in our power to stop global warming? To make sure terrorists don't board aeroplanes? To keep Escherichia coli out of the food supply? These seem like simple questions with easy answers only because they describe what we will do without also describing what we won't. When both are made explicit — should we keep hamburgers safe or aeroplanes safe? — these simple questions become vexing. Harm prevention often seems like a moral imperative, but because every yes entails a no, it is actually a practical choice. ..research shows that when human beings make decisions, they tend to focus on what they are getting and forget about what we are forgoing. For example, people are more likely to buy an item when they are asked to choose between buying and not buying it than when they are asked to choose between buying the item and keeping their money “for other purchases”. Although “not buying” and “keeping one's money” are the same thing, the latter phrase reminds people of something they know but typically fail to consider: buying one thing means not buying another.

In the seventeenth century, Blaise Pascal and Pierre de Fermat derived the optimal strategy for betting on games of chance, and in the process demonstrated that wise choices about harm prevention are always the product of two estimates: an estimate of odds (how likely is the harmful event?) and an estimate of consequences (how much harm will it cause?). If we know which harm is most likely and which harm is most severe, then we know which harm to prevent. We should spend less to prevent a natural disaster that will probably leave 3,000 people homeless than a communicable disease that will certainly leave 3 million people dead, and this is perfectly obvious to everyone….Except when it isn't.

Our brains were optimized for finding food and mates on the African savannah and not for estimating the likelihood of a core breach or the impact of overfishing. Nature has installed in each of us a threat-detection system that is exquisitely sensitive to the kinds of threats our ancestors faced — a slithering snake, a romantic rival, a band of men waving sticks — but that is remarkably insensitive to the odds and consequences of the threats we face today…Because we specialize in understanding other minds, we are hypersensitive to the harms those minds produce..we worry more about shoe-bombers than influenza, despite the fact that one kills roughly 400,000 people per year and the other kills roughly none. We worry more about our children being kidnapped by strangers than about becoming obese, despite the fact that abduction is rare and diabetes is not.

We are especially concerned when threats human agents produce are to our dignity, values and honor…Our obsession with morality can also discourage us from embracing practical solutions to pressing problems. The taboo against selling our bodies means that people who have money and need a kidney must die so that people who need money and have a spare kidney can starve. Economic models suggest that drug abuse would decline if drugs were taxed rather than banned7, but many people have zero tolerance for policies that permit immoral behaviour even if they drastically reduce its frequency.

Our species' sociality has always been its greatest advantage, but it may also be its undoing. Because we see the world through a lens of friends and enemies, heroes and villains, alliances and betrayals, virtue and vice, credit and blame, we are riveted by the dramas that matter least and apathetic to the dangers that matter most. We will change our lives to save a child but not our light bulbs to save them all.

What are we to do about the mismatch between the way we think and the problems we should be thinking about? One solution is to frame problems in ways that appeal to our nature. For example, when threats are described as moral violations, apathy often turns to action. Texas highways were awash in litter until 1986, when the state adopted a slogan — 'Don't mess with Texas' — that made littering an insult to the honour of every proud Texan, at which point littering decreased by 72%.

The other way to deal with the mismatch between the threats we face and the way we think is to change the way we think. People are capable of thinking rationally about odds and consequences, and it isn't hard to teach them. Research shows that a simple five-minute lesson dramatically improves people's decision-making in new domains a month later10, and yet that is five minutes more than most people ever get. We teach high-school students how to read Chaucer and do trigonometry, but not how to think rationally about the problems that could extinguish their species.

Friday, July 08, 2011

How we form beliefs

A.C. Grayling offers a review of Michael Shermer's latest book "The Believing Brain: From Ghosts and Gods to Politics and Conspiracies — How We Construct Beliefs and Reinforce Them as Truths," which looks like a fascinating read. Shermer is a psychology professor, the founder of Skeptic magazine and resident sceptical columnist for Scientific American (I've done MindBlog posts on several of these columns). Grayling does such a concise job of summing up Shermer's main points that I pass on chunks of the review here (Sigh...like many of you, I suspect, I read many more reviews of books than actual books.)

Two long-standing observations about human cognitive behaviour provide Michael Shermer with the fundamentals of his account of how people form beliefs. One is the brain's readiness to perceive patterns even in random phenomena. The other is its readiness to nominate agency — intentional action — as the cause of natural events.

Both explain belief-formation in general, not just religious or supernaturalistic belief. Shermer, however, has a particular interest in the latter, and much of his absorbing and comprehensive book addresses the widespread human inclination to believe in gods, ghosts, aliens, conspiracies and the importance of coincidences.

The important point, Shermer says, is that we form our beliefs first and then look for evidence in support of them afterwards. He gives the names 'patternicity' and 'agenticity' to the brain's pattern-seeking and agency-attributing propensities, respectively. These underlie the diverse reasons why we form particular beliefs from subjective, personal and emotional promptings, in social and historical environments that influence their content.

As a 'belief engine', the brain is always seeking to find meaning in the information that pours into it. Once it has constructed a belief, it rationalizes it with explanations, almost always after the event. The brain thus becomes invested in the beliefs, and reinforces them by looking for supporting evidence while blinding itself to anything contrary. Shermer describes this process as “belief-dependent realism” — what we believe determines our reality, not the other way around.

He offers an evolution-based analysis of why people are prone to forming supernatural beliefs based on patternicity and agenticity. Our ancestors did well to wonder whether rustling in the grass indicated a predator, even if it was just the breeze. Spotting a significant pattern in the data may have meant an intentional agent was about to pounce.

Problems arise when thinking like this is unconstrained, he says. Passionate investment in beliefs can lead to intolerance and conflict, as history tragically attests. Shermer gives chilling examples of how dangerous belief can be when it is maintained against all evidence; this is especially true in pseudo-science, exemplified by the death of a ten-year-old girl who suffocated during the cruel 'attachment therapy' once briefly popular in the United States in the late 1990s.

Shermer's account implies that we are far from being rational and deliberative thinkers, as the Enlightenment painted us. Patternicity leads us to see significance in mere 'noise' as well as in meaningful data; agenticity makes us ascribe purpose to the source of those meanings. How did we ever arrive at more objective and organized knowledge of the world? How do we tell the difference between noise and data?

His answer is science. “Despite the subjectivity of our psychologies, relatively objective knowledge is available,” Shermer writes. This is right, although common sense and experience surely did much to make our ancestors conform to the objective facts long before experimental science came into being; they would not have survived otherwise.

Powerful support for Shermer's analysis emerges from accounts he gives of highly respected scientists who hold religious beliefs, such as US geneticist Francis Collins. Although religious scientists are few, they are an interesting phenomenon, exhibiting the impermeability of the internal barrier that allows simultaneous commitments to science and faith. This remark will be regarded as outrageous by believing scientists, who think that they are as rational in their temples as in their laboratories, but scarcely any of them would accept the challenge to mount a controlled experiment to test the major claims of their faith, such as asking the deity to regrow a severed limb for an accident victim.

Shermer deals with the idea that theistic belief is an evolved, hard-wired phenomenon, an idea that is fashionable at present. The existence of atheists is partial evidence against it. More so is that the god-believing religions are very young in historical terms; they seem to have developed after and perhaps because of agriculture and associated settled urban life, and are therefore less than 10,000 years old.

The animism that preceded these religions, and which survives today in some traditional societies such as those of New Guinea and the Kalahari Desert, is fully explained by Shermer's agenticity concept. It is not religion but proto-science — an attempt to explain natural phenomena by analogy with the one causative power our ancestors knew well: their own agency. Instead of developing into science, this doubtless degenerated into superstition in the hands of emerging priestly castes or for other reasons, but it does not suggest a 'god gene' of the kind supposed for history's young religions with their monarchical deities.

This stimulating book summarizes what is likely to prove the right view of how our brains secrete religious and superstitious belief. Knowledge is power: the corrective of the scientific method, one hopes, can rescue us from ourselves in this respect.

Married, with Infidelities

I thoroughly enjoyed reading this article by Mark Oppenheimer in the Sunday NYTimes Magazine. It focuses on the ideas of Dan Savage, who is gay,a devoted husband, proud father, and sex columnist (I am a devoted reader of his weekly column in The Onion). Savage argues that marriage should be about stability, not monogamy.

Thursday, July 07, 2011

Emotion hot spots in our brain - modern phrenology

I am guilty, as well as much of the modern press, of using the discredited shortcut of associating specific emotions with specific brain areas (amygdala = fear; insula = revulsion; anterior cingulate = subjective pain; etc.) rather than noting that none of these emotions can exist in the absence of an extensive network of interacting brain areas. This is the modern equivalent of the 19th century phrenologists who judged character traits by bumps on the skull. I want to pass on the abstract of a meta-analytic review of the brain basis of emotion by Lindquist et al. currently under review by BBS, which rather nails this point. (Email me if you are interested in a copy.) The article has some nice graphics of brain regions they associate with two major approaches: "the locationist approach (i.e., the hypothesis that discrete emotion categories consistently and specifically correspond to distinct brain regions) with the psychological constructionist approach (i.e., the hypothesis that discrete emotion categories are constructed of more general brain networks not specific to those categories). Here is their abstract:

Researchers have wondered how the brain creates emotions since the early days of psychological science. With a surge of studies in affective neuroscience in recent decades, scientists are poised to answer this question. In this paper, we present a meta-analytic summary of the human neuroimaging literature on emotion. We compare the locationist approach (i.e., the hypothesis that discrete emotion categories consistently and specifically correspond to distinct brain regions) with the psychological constructionist approach (i.e., the hypothesis that discrete emotion categories are constructed of more general brain networks not specific to those categories) to better understand the brain basis of emotion. We review both locationist and psychological constructionist hypotheses of brain-emotion correspondence and report metaanalytic findings bearing on these hypotheses. Overall, we found little evidence that discrete emotion categories can be consistently and specifically localized to distinct brain regions. Instead, we found evidence that is consistent with a psychological constructionist approach to the mind: a set of interacting brain regions commonly involved in basic psychological operations of both an emotional and non-emotional nature are active during emotion experience and perception across a range of discrete emotion categories.

Wednesday, July 06, 2011

We are lost in thought.

Some clips from Sam Harris' contribution to this year's Edge Question "What scientific concept would improve everybody's cognitive toolkit?"

While most of us go through life feeling that we are the thinker of our thoughts and the experiencer of our experience, from the perspective of science we know that this is a distorted view. There is no discrete self or ego lurking like a minotaur in the labyrinth of the brain. There is no region of cortex or pathway of neural processing that occupies a privileged position with respect to our personhood. There is no unchanging "center of narrative gravity" (to use Daniel Dennett's phrase). In subjective terms, however, there seems to be one — to most of us, most of the time.

Our contemplative traditions (Hindu, Buddhist, Christian, Muslim, Jewish, etc.) also suggest, to varying degrees and with greater or lesser precision, that we live in the grip of a cognitive illusion. But the alternative to our captivity is almost always viewed through the lens of religious dogma. A Christian will recite the Lord's Prayer continuously over a weekend, experience a profound sense of clarity and peace, and judge this mental state to be fully corroborative of the doctrine of Christianity; A Hindu will spend an evening singing devotional songs to Krishna, feel suddenly free of his conventional sense of self, and conclude that his chosen deity has showered him with grace; a Sufi will spend hours whirling in circles, pierce the veil of thought for a time, and believe that he has established a direct connection to Allah.

The universality of these phenomena refutes the sectarian claims of any one religion. And, given that contemplatives generally present their experiences of self-transcendence as inseparable from their associated theology, mythology, and metaphysics, it is no surprise that scientists and nonbelievers tend to view their reports as the product of disordered minds, or as exaggerated accounts of far more common mental states — like scientific awe, aesthetic enjoyment, artistic inspiration, etc.

Our religions are clearly false, even if certain classically religious experiences are worth having. If we want to actually understand the mind, and overcome some of the most dangerous and enduring sources of conflict in our world, we must begin thinking about the full spectrum of human experience in the context of science.

But we must first realize that we are lost in thought.

Tuesday, July 05, 2011

Introspection and shyness - evolutionary tactic?

I have previously pointed to the work of Jerome Kagan at Harvard; who, along with others, has shown that some of us are born with a predisposition to be timid and more anxious. The temperament we display in early childhood (introvesion versus extroversion, high versus low reactivity, anxiety in unfamiliar versus familiar situations, etc) is largely genetically determined and persists through life. In this vein Susan Cain has recently offered an interesting article on shyness. She first notes the re-framing of shyness into "Social Anxiety Disorder" by drug company TV adds seeking to sell serotonin reuptake inhibitors (S.S.R.I.), cited Zoloft advertisements:

...the ad’s insinuation aside, it’s also possible the young woman is “just shy,” or introverted — traits our society disfavors. One way we manifest this bias is by encouraging perfectly healthy shy people to see themselves as ill...Social anxiety disorder did not officially exist until it appeared the 1980 Diagnostic and Statistical Manual, the DSM-III, the psychiatrist’s bible of mental disorders, under the name “social phobia.” It was not widely known until the 1990s, when pharmaceutical companies received F.D.A. approval to treat social anxiety with S.S.R.I.’s and poured tens of millions of dollars into advertising its existence...Though the DSM did not set out to pathologize shyness, it risks doing so, and has twice come close to identifying introversion as a disorder, too. (Shyness and introversion are not the same thing. Shy people fear negative judgment; introverts simply prefer quiet, minimally stimulating environments.)

...shy and introverted people have been part of our species for a very long time, often in leadership positions...We find them in recent history, in figures like Charles Darwin, Marcel Proust and Albert Einstein, and, in contemporary times: think of Google’s Larry Page, or Harry Potter’s creator, J. K. Rowling.

...We even find “introverts” in the animal kingdom, where 15 percent to 20 percent of many species are watchful, slow-to-warm-up types who stick to the sidelines (sometimes called “sitters”) while the other 80 percent are “rovers” who sally forth without paying much attention to their surroundings. Sitters and rovers favor different survival strategies, which could be summed up as the sitter’s “Look before you leap” versus the rover’s inclination to “Just do it!” Each strategy reaps different rewards.

IN an illustrative experiment, David Sloan Wilson, a Binghamton evolutionary biologist, dropped metal traps into a pond of pumpkinseed sunfish. The “rover” fish couldn’t help but investigate — and were immediately caught. But the “sitter” fish stayed back, making it impossible for Professor Wilson to capture them. Had Professor Wilson’s traps posed a real threat, only the sitters would have survived. But had the sitters taken Zoloft and become more like bold rovers, the entire family of pumpkinseed sunfish would have been wiped out. “Anxiety” about the trap saved the fishes’ lives.

Next, Professor Wilson used fishing nets to catch both types of fish; when he carried them back to his lab, he noted that the rovers quickly acclimated to their new environment and started eating a full five days earlier than their sitter brethren. In this situation, the rovers were the likely survivors. “There is no single best ... [animal] personality,” Professor Wilson concludes in his book, “Evolution for Everyone,” “but rather a diversity of personalities maintained by natural selection.”

The same might be said of humans, 15 percent to 20 percent of whom are also born with sitter-like temperaments that predispose them to shyness and introversion. (The overall incidence of shyness and introversion is higher — 40 percent of the population for shyness, according to the psychology professor Jonathan Cheek, and 50 percent for introversion. Conversely, some born sitters never become shy or introverted at all.)
Cain's article continues with an interesting discussion of the respective advantages and disadvantages of being a sitter or a rover.

Monday, July 04, 2011

MindBlog retrospective - 3rd and 1st person narrative in personality change

Over the past few weeks, I've been scanning the titles of old MindBlog posts (all 2,588 of them, taken 300 at a time because fatigue sets in very quickly in such an activity), glancing through the contents of the ones I recall as being most interesting to me, and assembling a list of ~80 reflecting some major themes. I am struck by the number of REALLY INTERESTING items that I had COMPLETELY forgotten about. (An illustration is the paragraph starting below with the graphic which is a repeat of a post from May 30, 2007.) It frustrates me that I have lost from recall so much good material. And, of course, it is also frustrating that the insight we do mange to retain will not necessarily change us (the subject of this March 23, 2006 post.)


Benedict Carey writes a piece in the Tuesday NY Times science section (PDF here) reviewing work done by a number of researchers on on how the stories people tell themselves (and others) about themselves do or don't help with making adaptive behavior changes. Third person narratives, in which subjects view themselves from a distance - as actors in their own narrative play - correlate with a higher sense of personal power and ability to make personality changes. First person narratives - in which the subject describes the experience of being immersed in their personal plays - are more likely than third person narratives to correlate with passivity and feeling powerless to effect change. This reminds me of Marc Hauser's distinction of being a moral agent or a moral patient. The third person can be a more metacognitive stance, thinking about oneself in a narrative script while the first person can be a less reflective acting out of the script.

In the light of evolution - Cooperation and conflict

The Proceeding of the National Academy has just published the fifth in a series of Colloquia under the general title “In the Light of Evolution.”   The contents of the 17 papers presented are free online, and I thought I would pass on the abstracts of two broad review articles on human evolution:
From Silk and House, "Evolutionary foundations of human prosocial sentiments":

A growing body of evidence shows that humans are remarkably altruistic primates. Food sharing and division of labor play an important role in all human societies, and cooperation extends beyond the bounds of close kinship and networks of reciprocating partners. In humans, altruism is motivated at least in part by empathy and concern for the welfare of others. Although altruistic behavior is well-documented in other primates, the range of altruistic behaviors in other primate species, including the great apes, is much more limited than it is in humans. Moreover, when altruism does occur among other primates, it is typically limited to familiar group members—close kin, mates, and reciprocating partners. This suggests that there may be fundamental differences in the social preferences that motivate altruism across the primate order, and there is currently considerable interest in how we came to be such unusual apes. A body of experimental studies designed to examine the phylogenetic range of prosocial sentiments and behavior is beginning to shed some light on this issue. In experimental settings, chimpanzees and tamarins do not consistently take advantage of opportunities to deliver food rewards to others, although capuchins and marmosets do deliver food rewards to others in similar kinds of tasks. Although chimpanzees do not satisfy experimental criteria for prosociality in food delivery tasks, they help others complete tasks to obtain a goal. Differences in performance across species and differences in performance across tasks are not yet fully understood and raise new questions for further study.
And, from Boyd et al., "The cultural niche: Why social learning is essential for human adaptation."
In the last 60,000 y humans have expanded across the globe and now occupy a wider range than any other terrestrial species. Our ability to successfully adapt to such a diverse range of habitats is often explained in terms of our cognitive ability. Humans have relatively bigger brains and more computing power than other animals, and this allows us to figure out how to live in a wide range of environments. Here we argue that humans may be smarter than other creatures, but none of us is nearly smart enough to acquire all of the information necessary to survive in any single habitat. In even the simplest foraging societies, people depend on a vast array of tools, detailed bodies of local knowledge, and complex social arrangements and often do not understand why these tools, beliefs, and behaviors are adaptive. We owe our success to our uniquely developed ability to learn from others. This capacity enables humans to gradually accumulate information across generations and develop well-adapted tools, beliefs, and practices that are too complex for any single individual to invent during their lifetime.

Friday, July 01, 2011

MindBlog's most popular posts

I've been cruising my blog posting since MindBlog's beginning in Feb. of 2006, cherry picking the posts I think most interesting, to see if any integrative themes or bottom lines magically rise from plethora of topics that have been covered. It is slow going, I'm only up to Dec. of 2007 so far. But, I noted back then that I was occasionally posting Google Feedburner's data on "aggregate item use," i.e., the most read items. So, I just looked that up again, and here it is:

On the art of puttering...

Here is an engaging editorial from the NYTimes I've been meaning to pass on. It's sentiments strike very close to my own experience.

We are a driven people, New Yorkers. Too much to do, not enough time. We keep lists; we crowd our schedules; we look for more efficient ways to organize ourselves — we get things done when we’re not too busy planning to get things done. Even our leisure time is focused, and there is something proactive about our procrastination. We don’t merely put things off. We put things off by piling other things on top of them. As Robert Benchley once noted, “anyone can do any amount of work, provided it isn’t the work he is supposed to be doing at that moment.”

But every now and then there comes a day for puttering. You can’t put it in your book ahead of time because who knows when it will come? No one intends to putter. You simply discover, in a brief moment of self-awareness, that you have been puttering, or, as the English would say, pottering. It often begins with a lost object. Not the infuriating kind that causes you to turn the house upside down while looking at your watch, but the speculative kind. “I wonder where that is,” you think.

You begin to look. Your attention is diverted almost immediately and then diverted again. You move through the morning with a calm, oblivious focus, taking on tasks — incidental ones — in the order they present themselves, which is to say no order at all. Puttering is small-scale, stream-of-consciousness problem-solving. It is setting sail on a sea of random course changes. The day passes, and you have long since forgotten what you were looking for — or that you were looking for anything at all. You feel as though you’ve accomplished a lot, though you have no idea what. It has been a holiday from purpose.