Goal pursuit outside our conscious awareness

Custer and Aarts expand on a favorite topic of mine (see the "I-Illusion" podcast in the left column): how our sense of authorship and agency is an illusion. They review research demonstrating that goals and the motivation to pursue them can arise unconsciously, and propose a mechanism for how this may happen. Here is a mix of their abstract, text clips, and a proposed mechanism:

People often act in order to realize desired outcomes, or goals. Although behavioral science recognizes that people can skillfully pursue goals without consciously attending to their behavior once these goals are set, conscious will is considered to be the starting point of goal pursuit. Indeed, when we decide to work hard on a task, it feels as if that conscious decision is the first and foremost cause of our behavior. That is, we are likely to say, if asked, that the decision to act produced the actions themselves. Recent discoveries, however, challenge this causal status of conscious will. They demonstrate that goals themselves can arise and operate unconsciously - actions are initiated even though we are unconscious of the goals to be attained or their motivating effect on our behavior. Social situations and stimuli in the surroundings activate or prime goals in our minds outside of our awareness, thereby motivating and guiding us.

Figure - The proposed mechanism for unconscious goal pursuit.

Experiments compatible with this model:

Neuroimaging research has discovered that reward cues are processed by limbic structures such as the nucleus accumbens and the ventral striatum. These subcortical areas play a central role in determining the rewarding value of outcomes and are connected to frontal areas in the cortex that facilitate goal pursuit. These reward centers in the brain respond to evolutionarily relevant rewards such as food and sexual stimuli, but also to learned rewards (such as money or status), or words (such as good or nice) that are associated with praise or rewards. This demonstrates that regardless of their shape or form, such positive stimuli induce a reward signal that is readily picked up by the brain.

Other recent research has demonstrated that subliminal primes that are specifically related to rewards can motivate people to increase the effort they invest in behaviors. In one study, participants could earn money by squeezing a handgrip. Before each squeeze, the money that could be earned was indicated by a 1-pound or 1-penny coin on the screen. Whereas on some trials the coin was clearly visible, on others it was presented subliminally. Thus, effects of conscious and unconscious reward cues could be compared within one experiment. It was found that people squeezed harder on high than on low reward trials, regardless of whether the reward was consciously visible or not. Moreover, this effect was accompanied by activation in the brain areas that play a role in reward processing and the recruitment of effort for action…These findings indicate that conscious and unconscious reward cues have similar effects on effort and flexible cognitive processing, which suggests that conscious awareness of rewards is not needed for goal pursuit to occur.

A smooth botox face inhibits emotion processing

Richie Davidson and collaborators at Wisconsin come up with this interesting gem, on the consequences of a face made more smooth and beautiful by Botulinum toxin injections:

How does language reliably evoke emotion, as it does when people read a favorite novel or listen to a skilled orator? Recent evidence suggests that comprehension involves a mental simulation of sentence content that calls on the same neural systems used in literal action, perception, and emotion. In this study, we demonstrated that involuntary facial expression plays a causal role in the processing of emotional language. Subcutaneous injections of botulinum toxin-A (BTX) were used to temporarily paralyze the facial muscle used in frowning. We found that BTX selectively slowed the reading of sentences that described situations that normally require the paralyzed muscle for expressing the emotions evoked by the sentences. This finding demonstrates that peripheral feedback plays a role in language processing, supports facial-feedback theories of emotional cognition, and raises questions about the effects of BTX on cognition and emotional reactivity. We account for the role of facial feedback in language processing by considering neurophysiological mechanisms and reinforcement-learning theory.

The reading module of our brains.

I’ve been meaning to mention an excellent article by Oliver Sachs in the June 28 issue of The New Yorker “A man of letters”. It describes a class of stroke patients who selectively loose the ability to read letters, frequently seeing them as some kind of foreign gibberish, yet can still write (“alexia sine agraphia”). In this article, unlike some of his others which have frustrated me by not getting down to the brain basics, he give an excellent summary of how it is that our brains come to have a specialized module for a skilled activity that was invented only ~5,000 years ago, less than an eye blink in evolutionary time. Here is my editing of chunks that give the bottom line:

There may be objects that are recognized at birth, such as faces, but beyond this the world of objects must be learned through experience and activity: looking, touching, handling, correlating the feel of objects with their appearance...Visual object recognition depends on the inferotemporal cortex..where neuronal function is very plastic...Mark Changizi and colleagues at Caltech, from examining more than a hundred ancient and modern writing systems, have shown that all of them, while geometrically very different, share certain basic topological similarities...which resemble topological invariants in a range of natural settings, leading them to hypothesize that the shapes of letters "have been selected to resemble the conglomeration of contours found in natural scenes, thereby tapping into our already-existing object recognition mechanisms."

The origin of writing and reading cannot be understood as a direct evolutionary adaptation. It is dependent on the plasticity of the brain, and on the fact that, even within the small span of a human lifetime, experience - experiential selection - is as powerful an agent of change as natural selection... We are literate not by virtue of a divine intervention (which Alfred Russel Wallace proposed, contra Darwin) but through a cultural invention and a cultural selection that make a brilliant and creative new use of a preexisting neural proclivity.

Physical contact and financial risk taking

Interesting observations from Levav and Argo:

We show that minimal physical contact can increase people’s sense of security and consequently lead them to increased risk-taking behavior. In three experiments, with both hypothetical and real payoffs, a female experimenter’s light, comforting pat on the shoulder led participants to greater financial risk taking. Further, this effect was both mediated and moderated by feelings of security in both male and female participants. Finally, we established the boundary conditions for the impact of physical contact on risk-taking behaviors by demonstrating that the effect does not occur when the touching is performed by a male and is attenuated when the touch consists of a handshake. The results suggest that subtle physical contact can be strongly influential in decision making and the willingness to accept risk.

Mind reading - How to seem telepathic

Here I attempt to summarize  an article by Eyai and Epley (on enabling mind reading by matching construal levels) by patching together bits of abstract and body text.  The results make the point that accurately reading other minds to know how one is evaluated by others—or how others evaluate themselves—requires focusing one’s evaluative lens at the right level of detail:

People can have difficulty intuiting what others think about them at least partly because people evaluate themselves in more fine-grained detail than observers do. This mismatch in the level of detail at which people construe themselves versus others diminishes accuracy in social judgment. Being a more accurate mind reader requires thinking of oneself at a higher level of construal that matches the observer’s construal (Experiments 1 and 2)*, and this strategy is shown in a further experiment (experiment 4**) to be more effective in this context than perspective taking (putting oneself in other people's shoes).

*Experiment 1 involved predicting judgements of attractiveness. This experiment found subjects to be more accurate in intuiting how attractive they will be judged (by others viewing a recent photo of themselves) in the distant future than in the near future. Experiment 2 involved predicting overall impression of oneself that observers would gain from listening (in the near versus distant future) to a recording they made on various topics. Again, predictions were more accurate for the imagined distant future. Thus altering construal level (near versus distant future) can increase accuracy in two very common and important instances of mind reading in everyday life—intuiting how attractively one will be evaluated by others and intuiting others’ overall impressions of oneself.

Accurately intuiting how others evaluate themselves requires the opposite strategy—thinking about others in a lower level of construal that matches the way people evaluate themselves. **In Experiment 4, University of Chicago undergraduates (N = 62) participated in a procedure similar to that of Experiment 1, except that targets rated how attractive they found themselves, using a scale ranging from 1 (not at all) to 9 (very), and observers received the construal manipulation. Observers were told that the pictures were taken earlier in the day (near condition) or a few months earlier (distant condition), and rated how attractive they thought the targets found themselves to be, using the same scale. Observers were more accurate in the near than in the distant condition.

How our brains resolve competing social signals

Zaki et al. suggest that that two systems that have been the subject of numerous MindBlog posts — the mirror neuron system (MNS) and mental state attribution system (MSAS)— are specialized for processing nonverbal and contextual social cues, respectively, and support the resolution of incongruent social cues (such as facial expression conflicting with verbal content of a message).

...we predicted that these control systems would help resolve conflict by "biasing" processing toward domain-specific neural systems involved in responding to social cues deemed to be task relevant, as reflected in perceivers' behavioral reliance on a given cue type when rating target affect. On the one hand, to the extent that perceivers behaviorally rely on nonverbal cues, biasing could increase activity in regions responsible for processing such cues, including premotor and parietal regions comprising the putative mirror neuron system (MNS). On the other hand, to the extent that perceivers deem contextual cues more relevant, processing could be biased toward systems implicated in drawing inferences about non-observable mental states such as beliefs, including the medial prefrontal, posterior cingulate, temporopolar, and temporoparietal regions comprising the mental state attribution system (MSAS). Because these systems are functionally dissociable and may in some cases inhibit each other, they are strong candidate targets for the effects of social cognitive conflict resolution.

From their abstract:

Cognitive control mechanisms allow individuals to behave adaptively in the face of complex and sometimes conflicting information. Although the neural bases of these control mechanisms have been examined in many contexts, almost no attention has been paid to their role in resolving conflicts between competing social cues, which is surprising given that cognitive conflicts are part of many social interactions. Evidence about the neural processing of social information suggests that two systems—the mirror neuron system (MNS) and mental state attribution system (MSAS)—are specialized for processing nonverbal and contextual social cues, respectively. This could support a model of social cognitive conflict resolution in which competition between social cues would recruit domain-general cognitive control mechanisms, which in turn would bias processing toward the MNS or MSAS. Such biasing could also alter social behaviors, such as inferences made about the internal states of others. We tested this model by scanning participants using functional magnetic resonance imaging while they drew inferences about the social targets' emotional states based on congruent or incongruent nonverbal and contextual social cues. Conflicts between social cues recruited the anterior cingulate and lateral prefrontal cortex, brain areas associated with domain-general control processes. This activation was accompanied by biasing of neural activity toward areas in the MNS or MSAS, which tracked, respectively, with perceivers' behavioral reliance on nonverbal or contextual cues when drawing inferences about targets' emotions. Together, these data provide evidence about both domain-general and domain-specific mechanisms involved in resolving social cognitive conflicts.

Figure: The presence of social cognitive response conflict (i.e., the comparison of incongruent vs congruent trials) recruited activity in several regions associated with domain-general conflict monitoring and control, including the anterior cingulate cortex, right ventrolateral prefrontal cortex, right middle frontal gyrus, and posterior dorsomedial prefrontal cortex

The virtues of a wandering mind.

John Tierney's article on possible uses of mind wandering is worth reading. During our waking hours our minds seem to wander about 30% of the time.  One suggestion is that:

...There’s an evolutionary advantage to the brain’s system of mind wandering...While a person is occupied with one task, this system keeps the individual’s larger agenda fresher in mind...It thus serves as a kind of reminder mechanism, thereby increasing the likelihood that the other goal pursuits will remain intact and not get lost in the shuffle of pursuing many goals.
...Where exactly does the mind go during those moments? By observing people at rest during brain scans, a “default network” that is active when people’s minds are especially free to wander has been identified. When people do take up a task, the brain’s executive network lights up to issue commands, and the default network is often suppressed....But during some episodes of mind wandering, both networks are firing simultaneously...Why both networks are active is up for debate. One school theorizes that the executive network is working to control the stray thoughts and put the mind back on task...Another school of psychologists..theorizes that both networks are working on agendas beyond the immediate task. That theory could help explain why studies have found that people prone to mind wandering also score higher on tests of creativity.

Smilek et al., by the way, note that mind wandering can be assayed by observing blinking: during an extended period of reading, episodes of mind wandering, compared with on-task periods, contain more eye closures (blinks) and fewer fixations on the text ― even as subjects continue to scan the text.

Brain correlates of behavioral traits

A nice study from DeYoung et al. finds, among other things, that extraverts tend to have a larger-than-average orbitofrontal cortex, the region that sits behind the eyes and is especially active when the brain registers rewards. The 'new theory...'  described in their article is no big deal, it involves some reasonable arguments about what brain regions could reasonably be expected to be associated with fundamental behavioral traits such as extraversion, neuroticism, etc :

We used a new theory of the biological basis of the Big Five personality traits to generate hypotheses about the association of each trait with the volume of different brain regions. Controlling for age, sex, and whole-brain volume, results from structural magnetic resonance imaging of 116 healthy adults supported our hypotheses for four of the five traits: Extraversion, Neuroticism, Agreeableness, and Conscientiousness. Extraversion covaried with volume of medial orbitofrontal cortex, a brain region involved in processing reward information. Neuroticism covaried with volume of brain regions associated with threat, punishment, and negative affect. Agreeableness covaried with volume in regions that process information about the intentions and mental states of other individuals. Conscientiousness covaried with volume in lateral prefrontal cortex, a region involved in planning and the voluntary control of behavior. These findings support our biologically based, explanatory model of the Big Five and demonstrate the potential of personality neuroscience (i.e., the systematic study of individual differences in personality using neuroscience methods) as a discipline.

Being calmed by a machine.

I was initially repelled by the prospect, noted in this article, of a future in which robotic animals are routinely used to sooth disoriented and distressed patients - but then thought “Hey, if there is not another human around to do the job, why object if an machine can provide neotenous (cute baby like) stimuli that dampen amygdala and sympathetic nervous system arousal.

Wealth diminishes our ability to savor the ordinary

Quoidbach et al. test

...what Gilbert has termed the experience-stretching hypothesis, that experiencing the best things in life — such as surfing Oahu’s famous North Shore or dining at Manhattan’s four-star restaurant Daniel — may actually mitigate the delight one experiences in response to the more mundane joys of life, such as sunny days, cold beers, and chocolate bars.

Their abstract:

This study provides the first evidence that money impairs people’s ability to savor everyday positive emotions and experiences. In a sample of working adults, wealthier individuals reported lower savoring ability (the ability to enhance and prolong positive emotional experience). Moreover, the negative impact of wealth on individuals’ ability to savor undermined the positive effects of money on their happiness. We experimentally exposed participants to a reminder of wealth and produced the same deleterious effect on their ability to savor as that produced by actual individual differences in wealth, a result supporting the theory that money has a causal effect on savoring. Moving beyond self-reports, we found that participants exposed to a reminder of wealth spent less time savoring a piece of chocolate and exhibited reduced enjoyment of it compared with participants not exposed to wealth. This article presents evidence supporting the widely held but previously untested belief that having access to the best things in life may actually undercut people’s ability to reap enjoyment from life’s small pleasures.

Brain imaging can predict behavior days in advance.

Falk et al. find a brain region that seems to make a more reliable report of people's intentions than their self-reported attitudes and intentions. (It does seems a bit spooky when a machine reports what we are going to do more accurately than we can.)  The medial prefrontal regions which were predictive of behavior are ones I've mentioned in a previous post that predict spontaneous motor behavior several seconds before reportable motor intentions form.  The authors measured neural activity while people were exposed to persuasive messages regarding the value of regular sunscreen use, and then used those values to predict future behavior change in the same individuals (i.e., increased sunscreen use. Successful persuasion-induced behavior change had been observed in this domain in several previous studies.)  The relevant medial prefrontal regions:

..are reliably coactivated across a host of "self" processes.....[and]  have been previously observed in multiple studies of persuasion and attitude change.. .indicating that these regions may be involved in the formation of behavioral intentions that are not accessible to conscious self-report.

Here is a figure and their abstract:

Regions associated with behavior change in a whole brain analysis. These regions have been observed as predictors of spontaneous motor behavior, before and independent of consciously reportable behavioral intentions.

Although persuasive messages often alter people's self-reported attitudes and intentions to perform behaviors, these self-reports do not necessarily predict behavior change. We demonstrate that neural responses to persuasive messages can predict variability in behavior change in the subsequent week. Specifically...a ..region of interest..in medial prefrontal cortex .. was reliably associated with behavior change...activity in this region predicted an average 23% of the variance in behavior change beyond the variance predicted by self-reported attitudes and intentions. Thus, neural signals can predict behavioral changes that are not predicted from self-reported attitudes and intentions alone. Additionally, this is the first functional magnetic resonance imaging study to demonstrate that a neural signal can predict complex real world behavior days in advance.

What we touch influences social judgements.

Here is another example of "embodied cognition"- how our physical environment can influence our thinking. In a previous post I mentioned studies showing that simply holding a warm cup of coffee prompts us to view others as emotionally warmer. And, in another post, I pointed to a study that found that holding a heavy clipboard makes us perceive social-justice issues as more important. Now Ackerman et al. ..(reviewed in ScienceNow).. expand on these studies to note that simply running your hand over sandpaper may make you view social interactions as more hostile and competitive.

Touch is both the first sense to develop and a critical means of information acquisition and environmental manipulation. Physical touch experiences may create an ontological scaffold for the development of intrapersonal and interpersonal conceptual and metaphorical knowledge, as well as a springboard for the application of this knowledge. In six experiments, holding heavy or light clipboards, solving rough or smooth puzzles, and touching hard or soft objects nonconsciously influenced impressions and decisions formed about unrelated people and situations. Among other effects, heavy objects made job candidates appear more important, rough objects made social interactions appear more difficult, and hard objects increased rigidity in negotiations. Basic tactile sensations are thus shown to influence higher social cognitive processing in dimension-specific and metaphor-specific ways.

More on enhanced brain processes in musicians.

From Pallesen et al.:

Musical competence may confer cognitive advantages that extend beyond processing of familiar musical sounds. Behavioural evidence indicates a general enhancement of both working memory and attention in musicians. It is possible that musicians, due to their training, are better able to maintain focus on task-relevant stimuli, a skill which is crucial to working memory. We measured the blood oxygenation-level dependent (BOLD) activation signal in musicians and non-musicians during working memory of musical sounds to determine the relation among performance, musical competence and generally enhanced cognition. All participants easily distinguished the stimuli. We tested the hypothesis that musicians nonetheless would perform better, and that differential brain activity would mainly be present in cortical areas involved in cognitive control such as the lateral prefrontal cortex. The musicians performed better as reflected in reaction times and error rates. Musicians also had larger BOLD responses than non-musicians in neuronal networks that sustain attention and cognitive control, including regions of the lateral prefrontal cortex, lateral parietal cortex, insula, and putamen in the right hemisphere, and bilaterally in the posterior dorsal prefrontal cortex and anterior cingulate gyrus. The relationship between the task performance and the magnitude of the BOLD response was more positive in musicians than in non-musicians, particularly during the most difficult working memory task. The results confirm previous findings that neural activity increases during enhanced working memory performance. The results also suggest that superior working memory task performance in musicians rely on an enhanced ability to exert sustained cognitive control. This cognitive benefit in musicians may be a consequence of focused musical training.

How we learn skilled motor sequences

Because I am a pianist, I found the following bit from Steele and Penhune to be interesting and relevant. They found that:

Performance was separated into two components: accuracy (the more explicit, rapidly learned, stimulus–response association component) and synchronization (the more procedural, slowly learned component).

Here is their whole abstract:

Our capacity to learn movement sequences is fundamental to our ability to interact with the environment. Although different brain networks have been linked with different stages of learning, there is little evidence for how these networks change across learning. We used functional magnetic resonance imaging to identify the specific contributions of the cerebellum and primary motor cortex (M1) during early learning, consolidation, and retention of a motor sequence task. Performance was separated into two components: accuracy (the more explicit, rapidly learned, stimulus–response association component) and synchronization (the more procedural, slowly learned component). The network of brain regions active during early learning was dominated by the cerebellum, premotor cortex, basal ganglia, presupplementary motor area, and supplementary motor area as predicted by existing models. Across days of learning, as performance improved, global decreases were found in the majority of these regions. Importantly, within the context of these global decreases, we found specific regions of the left M1 and right cerebellar VIIIA/VIIB that were positively correlated with improvements in synchronization performance. Improvements in accuracy were correlated with increases in hippocampus, BA 9/10, and the putamen. Thus, the two behavioral measures, accuracy and synchrony, were found to be related to two different sets of brain regions—suggesting that these networks optimize different components of learning. In addition, M1 activity early on day 1 was shown to be predictive of the degree of consolidation on day 2. Finally, functional connectivity between M1 and cerebellum in late learning points to their interaction as a mechanism underlying the long-term representation and expression of a well learned skill.

More on testosterone and human trust.

Johnson and Breedlove offer a commentary on work by Bos et al. mentioned in my June 11 post. They note that:

Women who were already skeptical in their judgment of trustworthy faces did not change their judgment under the influence of testosterone (T). Rather, it was the 12 women who gave the highest ratings of trust under placebo who became significantly more skeptical after T treatment...Because endogenously produced T levels normally vary across time, these findings ... raise the question of whether fluctuating androgen secretion may normally modulate a person’s judgment of whether to trust people. There are circadian rhythms in T secretion, in both men and women, so is there also a circadian rhythm in how they judge trustworthiness in faces? There is also variation in circulating T in women across the menstrual cycle, with a modest peak in circulating T just a few days before ovulation, the very period during which copulation is most likely to result in pregnancy. What’s more, androgens such as T have been reported to boost women’s libido in several studies, including one study using the same sublingual dose of T, which increased sexual arousal. If androgens normally boost female libido, a peak in T before ovulation makes sense to evolutionary psychologists who might expect women to be most interested in sex when they are most fertile. What the present findings suggest is that women might also reach their peak in skepticism about the trustworthiness of other people, presumably including potential mates, at about this same point in the ovulatory cycle. Heightened skepticism about a potential mate’s trustworthiness also makes evolutionary sense in scenarios where a father’s ongoing support is crucial for survival of the infant.

The review also speculates on where T may be acting in the brain:

...the amygdala has been implicated in many studies of social judgment, including making judgments about other people’s faces, and it is also a hotspot for neurons expressing the androgen receptors that T acts upon to regulate gene expression (14, 15). Thus, it is possible that T may alter social judgments by acting directly on the amygdala, perhaps, the authors suggest, by regulating the strength of signaling between the amygdala and other brain regions implicated in social evaluation, such as the orbitofrontal cortex.

Figure - Potential model for hormonal effects on interpersonal trust. The amygdala (center) is active during fearful responses or detecting threat in faces, and many neurons there possess androgen receptors, enabling them to respond to T. Bos et al. (4) suggest that T may reduce interpersonal trust by acting on vasopressinergic neurons in the amygdala to increase communication to brainstem systems that activate fearful responses, while reducing communication to orbitofrontal cortex. Oxytocin boosts interpersonal trust, perhaps by exerting opposing effects on these same systems.

Prefrontal Reward Prediction Errors in Alcohol Dependence

Park et al. (in a collaboration involving, once again,  Ray Dolan at University College) find abnormal functional connectivity between striatum and dorsolateral prefrontal cortex in alcohol-dependent patients.

Patients suffering from addiction persist in consuming substances of abuse, despite negative consequences or absence of positive consequences. One potential explanation is that these patients are impaired at flexibly adapting their behavior to changes in reward contingencies. A key aspect of adaptive decision-making involves updating the value of behavioral options. This is thought to be mediated via a teaching signal expressed as a reward prediction error (PE) in the striatum. However, to exert control over adaptive behavior, value signals need to be broadcast to higher executive regions, such as prefrontal cortex. Here we used functional MRI and a reinforcement learning task to investigate the neural mechanisms underlying maladaptive behavior in human male alcohol-dependent patients. We show that in alcohol-dependent patients the expression of striatal PEs is intact. However, abnormal functional connectivity between striatum and dorsolateral prefrontal cortex (dlPFC) predicted impairments in learning and the magnitude of alcohol craving. These results are in line with reports of dlPFC structural abnormalities in substance dependence and highlight the importance of frontostriatal connectivity in addiction, and its pivotal role in adaptive updating of action values and behavioral regulation. Furthermore, they extend the scope of neurobiological deficits underlying addiction beyond the focus on the striatum.

Dysregulation Nation

Judith Warner does an nice piece in the NYTimes Magazine, in which she notes that problems of self-regulation — of appetite, emotion, impulse and cupidity — may well be the defining social pathology of our time. The ideas of Peter C. Whybrow at UCLA are referenced:

...Under normal circumstances, the emotional, reward-seeking, selfish, “myopic” part of our brain is checked and balanced in its desirous cravings by our powers of cognition — our awareness of the consequences, say, of eating too much or spending too much. But after decades of never-before-seen levels of affluence and endless messages promoting instant gratification...this self-regulatory system has been knocked out of whack. The “orgy of self-indulgence” that spread in our land of no-money-down mortgages, Whybrow wrote in his 2005 book, “American Mania: When More Is Not Enough, ”has disturbed the “ancient mechanisms that sustain our physical and mental balance.”...If you put a person in an environment that worships wealth and favors conspicuous consumption, add gross income inequalities that breed envy and competition, mix in stagnant wages, a high cost of living and too-easy credit, you get overspending, high personal debt and a “treadmill-like existence,” as Whybrow calls it: compulsive getting and spending.

The “yawning void, an insatiable hunger, an emptiness waiting to be filled,” that Lasch identified as animating the typical narcissist of the 1970s has grown only deeper with the passage of time. The Great Recession was supposed to portend a scaling back, a recalibration of our lifestyle, and usher in a new era of making more of less. But the pressures that drive the dysregulated American haven’t abated any since the fall of 2008. Wall Street is resurgent, and unemployment is still high. For too many people, the cycle of craving and debt that drives our treadmill existence simply can’t be broken.

The classical art of memory

Andrea Becchetti notes a correspondence between modern understanding of memory formation in the hippocampus and techniques in the "Art of Memory" developed by Greek and Roman culture:

Formation and consolidation of declarative memories depend on the physiology of the hippocampal formation. Moreover, this brain structure determines the dynamic representation of the spatial environment, thus also contributing to spatial navigation through specialized cells such as “place” and “grid” cells (1). The most interesting recent results by Jacobs et al. (2) further this research field by showing that the entorhinal cortex contains path cells that represent direction of movement (clockwise or counterclockwise). The authors underscore that neurons in the entorhinal cortex encode multiple features of the environmental and behavioral context that can then be memorized by means of operations carried out by the hippocampus. They conclude by suggesting that a fuller characterization of these neurons’ properties and relation to the hippocampal circuit will be necessary to understand the neural basis of cognition. I fully agree with their conclusion and wish to comment on a further aspect of this complex issue, by considering psychological evidence that traces back to the ancient world and is generally neglected by modern neuroscience.

Greek and Roman culture has handed down to us the so-called “art of memory,” a set of methods aimed at improving one’s memory, described in detail by Cicero, Quintilianus, and others. The history of these concepts and their multifarious cultural meaning was masterfully treated by Rossi (3) and Yates (4). In brief, committing to memory long written pieces, word lists, series of numbers, etc. is greatly facilitated by proceeding as follows. First, one chooses a series of objects or places located in a (preferably familiar) spatial environment, such as the architecture details of a building or the landmarks of a certain route. Subsequently, these objects or places are mentally associated to the items to be remembered. The map of environmental images, which is easy to recall, thus provides a direct hint to the more abstract items. Moreover, proceeding along such a mental path directly provides the proper order of the sequence to be memorized (say a poem or speech). For example, Cicero used to associate the main points of his long speeches to specific buildings or other topographical reference points along the familiar route to the Roman Forum.

This method still constitutes the basis of modern mnemonics, which must be deeply rooted in neurology because it seems to be applied unawares even by mnemonists who have never heard of its existence. A famous example is the one described by Luria (5), who was himself unaware of the art of memory. Such venerable psychological evidence makes the neurophysiological association between orientation in space and declarative memory in the hippocampal formation even more suggestive. It supports the notion that the consolidation of human memory is guided by a partially preconfigured system related to external space representation, which may be the evolutionary basis of memory processing of more abstract entities in complex brains. These considerations may also have heuristic value in suggesting how the enthorinal cortex, the hippocampus, and the neocortex interplay during memory consolidation of complex abstract issues.

1. Moser EI Kropff E, Moser MB
(2008) Place cells, grid cells, and the brain’s spatial representation system. Annu Rev Neurosci 31:69–89.
2. Jacobs J, Kahana MJ, Ekstrom AD, Mollison MV, Fried I (2010) A sense of direction in human entorhinal cortex. Proc Natl Acad Sci USA 107:6487–6492.
3. Rossi P (2006) Logic and the Art of Memory (Continuum International, London).
4. Yates F (1992) The Art of Memory (Pimlico, London).
5. Luria AR (1986) The Mind of a Mnemonist: A Little Book About a Vast Memory (Harvard Univ Press, Cambridge, MA).

Binge drinking and the adolescent brain.

Deficits in hippocampus-associated cognitive tasks are observed in alcoholic humans. Taffe et al. show that binge drinking in adolescent macaque monkeys causes long lasting decreases in hippocampus cell division, turnover, and migration. Their results:

...demonstrate that the hippocampal neurogenic niche during adolescence is highly vulnerable to alcohol and that alcohol decreases neuronal turnover in adolescent nonhuman primate hippocampus by altering the ongoing process of neuronal development. This lasting effect, observed 2 mo after alcohol discontinuation, may underlie the deficits in hippocampus-associated cognitive tasks that are observed in alcoholics.

Being hungry or full influences our risk taking.

Dolan's group does some neat experiments showing that having a full stomach makes us more risk aversive in monetary decisions. We act just like other animals, who often express a preference for risky (more variable) food sources when below a metabolic reference point (hungry), and safe (less variable) food sources when sated. We follow an ecological model of feeding behavior, not the behavior predicted by normative economic theory. Thus hormone levels that reflect our metabolic state (ghrelins signalling acute nutrient intake and leptins providing an assay of energy reserves) can, like oxytocin and testosterone, influence our economic choices.