Positive and negative emotions - valence is not value

Having done several recent posts on positive emotions,  and given the continuing rise of the "Be Happy" industry with its Be Happy Apps, I thought it appropriate to pass on this pithy and appropriate critique by June Gruber, of the idea that happiness is always good, sadness is always bad:

One idea in the study of emotion and its impact on psychological health is overdue for retirement: that negative emotions (like sadness or fear) are inherently bad or maladaptive for our psychological well-being, and positive emotions (like happiness or joy) are inherently good or adaptive. Such value judgments are to be understood, within the framework of affective science, as depending on whether an emotion impedes or fosters a person's ability to pursue goals, attain resources, and function effectively within society. Claims of the sort "sadness is inherently bad" or "happiness is inherently good" must be abandoned in light of burgeoning advances in the scientific study of human emotion.

Let's start with negative emotions. Early hedonic theories defined well-being, in part, as the relative absence of negative emotion. Empirically based treatments like cognitive-behavioral therapy also focus heavily on the reduction of negative feelings and moods as part of enhancing well-being. Yet a strong body of scientific work suggests that negative emotions are essential to our psychological well-being. Here are 3 examples. First, from an evolutionary perspective, negative emotions aid in our survival—they provide important clues to threats or problems that need our attention (such as an unhealthy relationship or dangerous situation). Second, negative emotions help us focus: they facilitate more detailed and analytic thinking, reduce stereotypic thinking, enhance eyewitness memory, and promote persistence on challenging cognitive tasks. Third, attempting to thwart or suppress negative emotions—rather than accept and appreciate them—paradoxically backfires and increases feelings of distress and intensifies clinical symptoms of substance abuse, overeating, and even suicidal ideation. Counter to these hedonic theories of well-being, negative emotions are hence not inherently bad for us. Moreover, the relative absence of them predicts poorer psychological adjustment.

Positive emotions have been conceptualized as pleasant or positively valenced states that motivate us to pursue goal-directed behavior. A longstanding scientific tradition has focused on the benefits of positive emotions, ranging from cognitive benefits such as enhanced creativity, social benefits like fostering relationship satisfaction and prosocial behavior, and physical health benefits such as enhanced cardiovascular health. From this work has emerged the assumption—both implicitly and explicitly—that positive emotional states should always be maximized. This has fueled the birth of entire subdisciplines and garnered momentous popular attention. But there's a mounting body of work against the claim that positive emotions are inherently good. First, positive emotions foster more self-focused behavior, including increased selfishness, greater stereotyping of out-group members, increased cheating and dishonesty, and decreased empathic accuracy in some contexts. Second, positive emotions are associated with greater distractibility and impaired performance on detail-oriented cognitive tasks. Third, because positive emotion may promote decreased inhibition it has been associated with greater risk-taking behaviors and mortality rates. Indeed, the presence of positive emotions is not always adaptive and sometimes can impede our well-being and even survival.

We are left to conclude that valence is not value: we cannot infer value judgments about emotions on the basis of their positive or negative valence. There is no intrinsic goodness or badness of an emotion merely because of its positivity or negativity, respectively. Instead, we must refine specific value-based determinants for an emotion's functionality. Towards this end, emerging research highlights critical variables to focus on. Importantly, the context in which an emotion unfolds can determine whether it helps or hinders an individual's goal, or which types of emotion regulatory strategies (reappraising or distracting) will best match the situation. Related, the degree of psychological flexibility someone possesses—including how quickly one can shift emotions or rebound from a stressful situation—promotes critical clinical health outcomes. Likewise, we find that psychological well-being is not entirely determined by the presence of one type or kind of an emotion but rather an ability to experience a rich diversity of both positive and negative emotions. Whether or not an emotion is "good" or "bad" seems to have surprisingly little to do with the emotion itself, but rather how mindfully we ride the ebbs and tides of our rich emotional life.

Hunger promotes acquisition of nonfood objects

Here is a fascinating nugget of information from Xu et al.:

Hunger motivates people to consume food, for which finding and acquiring food is a prerequisite. We test whether the acquisition component spills over to nonfood objects: Are hungry people more likely to acquire objects that cannot satisfy their hunger? Five laboratory and field studies show that hunger increases the accessibility of acquisition-related concepts and the intention to acquire not only food but also nonfood objects. Moreover, people act on this intention and acquire more nonfood objects (e.g., binder clips) when they are hungry, both when these items are freely available and when they must be paid for. However, hunger does not influence how much they like nonfood objects. We conclude that a basic biologically based motivation can affect substantively unrelated behaviors that cannot satisfy the motivation. This presumably occurs because hunger renders acquisition-related concepts and behaviors more accessible, which influences decisions in situations to which they can be applied.

Emotional foundations of cognitive control.

Cognitive control (self control, self regulation) allows us to restrain from temptations of the present to focus on more long term goals. Emotion is usually cast as its enemy. Inzlicht et al. suggest, however, that cognitive control rises from and is dependent on emotional primitives, in particular the negative affect associated with conflicting stimuli.  Their highlights and abstract:

• Cognitive control can be understood as an emotional process. 

• Negative affect is an integral, instantiating aspect of cognitive control. 

• Cognitive conflict has an emotional cost, evoking a host of emotional primitives. 

• Emotion is not an inert byproduct of conflict, but helps in recruiting control.

Often seen as the paragon of higher cognition, here we suggest that cognitive control is dependent on emotion. Rather than asking whether control is influenced by emotion, we ask whether control itself can be understood as an emotional process. Reviewing converging evidence from cybernetics, animal research, cognitive neuroscience, and social and personality psychology, we suggest that cognitive control is initiated when goal conflicts evoke phasic changes to emotional primitives that both focus attention on the presence of goal conflicts and energize conflict resolution to support goal-directed behavior. Critically, we propose that emotion is not an inert byproduct of conflict but is instrumental in recruiting control. Appreciating the emotional foundations of control leads to testable predictions that can spur future research.

Observing brain correlates of self affirmation and its healthy consequences

From the introduction of Falk et. al. :

...according to the World Health Organization, “60% to 85% of people in the world—from both developed and developing countries—lead sedentary lifestyles”...self-relevant health messages can be perceived to be threatening to self-worth and are often met with resistance...Affirmation of core values (self-affirmation) preceding potentially threatening messages can reduce resistance and increase intervention effectiveness Therefore, one way to increase receptivity to messages discouraging sedentary behavior among sedentary individuals may be to affirm their core values in unrelated domains before exposure to the messages.

We focused on the brain’s ventromedial prefrontal cortex (VMPFC) during exposure to potentially threatening health messages emphasizing the need to be more active and less sedentary in a group of sedentary adults. VMPFC is the most common region implicated in self-related processing and is also a key region, along with the ventral striatum, implicated in positive valuation of stimuli.

Their abstract:

Health communications can be an effective way to increase positive health behaviors and decrease negative health behaviors; however, those at highest risk are often most defensive and least open to such messages. For example, increasing physical activity among sedentary individuals affects a wide range of important mental and physical health outcomes, but has proven a challenging task. Affirming core values (i.e., self-affirmation) before message exposure is a psychological technique that can increase the effectiveness of a wide range of interventions in health and other domains; however, the neural mechanisms of affirmation’s effects have not been studied. We used functional magnetic resonance imaging (fMRI) to examine neural processes associated with affirmation effects during exposure to potentially threatening health messages. We focused on an a priori defined region of interest (ROI) in ventromedial prefrontal cortex (VMPFC), a brain region selected for its association with self-related processing and positive valuation. Consistent with our hypotheses, those in the self-affirmation condition produced more activity in VMPFC during exposure to health messages and went on to increase their objectively measured activity levels more. These findings suggest that affirmation of core values may exert its effects by allowing at-risk individuals to see the self-relevance and value in otherwise-threatening messages.

(A) VMPFC ROI. (B) Participants who showed higher levels of VMPFC activity during exposure to health messages subsequently decreased their sedentary behavior more in the month following the scan, controlling for baseline sedentary behavior and demographics.

The high from nicotine depends on whether you think it is there.

Fascinating observations from Gu et al.:

Significance

Nicotine is the primary addictive substance in tobacco, which stimulates neural pathways mediating reward processing. However, pure biochemical explanations are not sufficient to account for the difficulty in quitting and remaining smoke-free among smokers, and in fact cognitive factors are now considered to contribute critically to addiction. Using model-based functional neuroimaging, we show that smokers’ prior beliefs about nicotine specifically impact learning signals defined by principled computational models of mesolimbic dopamine systems. We further demonstrate that these specific changes in neural signaling are accompanied by measurable changes in smokers’ choice behavior. Our findings suggest that subjective beliefs can override the physical presence of a powerful drug like nicotine by modulating learning signals processed in the brain’s reward system.

Abstract

Little is known about how prior beliefs impact biophysically described processes in the presence of neuroactive drugs, which presents a profound challenge to the understanding of the mechanisms and treatments of addiction. We engineered smokers’ prior beliefs about the presence of nicotine in a cigarette smoked before a functional magnetic resonance imaging session where subjects carried out a sequential choice task. Using a model-based approach, we show that smokers’ beliefs about nicotine specifically modulated learning signals (value and reward prediction error) defined by a computational model of mesolimbic dopamine systems. Belief of “no nicotine in cigarette” (compared with “nicotine in cigarette”) strongly diminished neural responses in the striatum to value and reward prediction errors and reduced the impact of both on smokers’ choices. These effects of belief could not be explained by global changes in visual attention and were specific to value and reward prediction errors. Thus, by modulating the expression of computationally explicit signals important for valuation and choice, beliefs can override the physical presence of a potent neuroactive compound like nicotine. These selective effects of belief demonstrate that belief can modulate model-based parameters important for learning. The implications of these findings may be far ranging because belief-dependent effects on learning signals could impact a host of other behaviors in addiction as well as in other mental health problems.

The neurochemistry of music.

I want to point to an interesting review article by Chanda and Levitin, that summaries studies showing how music engages four of our bodies' fundamental neurochemical systems. I pass on the abstract and the start of the introduction to the article to give you an idea of its scope:

Music is used to regulate mood and arousal in everyday life and to promote physical and psychological health and well-being in clinical settings. However, scientific inquiry into the neurochemical effects of music is still in its infancy. In this review, we evaluate the evidence that music improves health and well-being through the engagement of neurochemical systems for (i) reward, motivation, and pleasure; (ii) stress and arousal; (iii) immunity; and (iv) social affiliation. We discuss the limitations of these studies and outline novel approaches for integration of conceptual and technological advances from the fields of music cognition and social neuroscience into studies of the neurochemistry of music. 

Introduction 

Music is one of a small set of human cultural universals, evoking a wide range of emotions, from exhilaration to relaxation, joy to sadness, fear to comfort, and even combinations of these. Many people use music to regulate mood and arousal, much as they use caffeine or alcohol. Neurosurgeons use it to enhance concentration, armies to coordinate movements and increase cooperation, workers to improve attention and vigilance, and athletes to increase stamina and motivation.

The notion that ‘music is medicine’ has roots that extend deep into human history through healing rituals practiced in pre-industrial, tribal-based societies. In contemporary society, music continues to be used to promote health and well-being in clinical settings, such as for pain management, relaxation, psychotherapy, and personal growth. Although much of this clinical use of music is based on ad hoc or unproven methods, an emerging body of literature addresses evidence-based music interventions through peer-reviewed scientific experiments. In this review, we examine the scientific evidence supporting claims that music influences health through neurochemical changes in the following four domains:

(i) reward, motivation and pleasure 

(ii) stress and arousal 

(iii) immunity 

(iv) social affiliation.

These domains parallel, respectively, the known neurochemical systems of

(i) dopamine and opioids 

(ii) cortisol, corticotrophin-releasing hormone (CRH), adrenocorticotropic hormone (ACTH) 

(iii) serotonin and the peptide derivatives of proopiomelanocortin (POMC), including alpha-melanocyte stimulating hormone and beta-endorphin 

(iv) oxytocin.

Although the evidence is often weak or indirect and all studies suffer from important limitations, the reviewed evidence does provide preliminary support for the claim that neurochemical changes mediate the influence of music on health.

The neuroscience of motivated cognition.

I want to point to this interesting open source article by Hughes and Zaki, who review research from social psychology and cognitive neuroscience that provides insight into the structure of motivated cognition (that can bias or distort reality), suggesting that it pervades information processing and is often effortless. Here are the opening paragraphs:

People often believe that their thinking aims squarely at gaining an accurate impression of reality. Upon closer inspection, this assumption collapses. Instead, like the inhabitants of Garrison Keillor's Lake Woebegon, individuals often see themselves and close others as possessing unrealistically high levels of positive attributes such as likeability, morality, and attractiveness. This bias persists among individuals who should know better: over 90% college professors believe their work is better than that of their peers, CIA analysts overestimate the accuracy of their predictions for future events, and doctors overconfidently estimate their medical knowledge.

These cases exemplify the phenomenon of motivated cognition, by which the goals and needs of individuals steer their thinking towards desired conclusions. A variety of motivations pervasively shapes cognition. For example, people wish to live in a coherent and consistent world. This leads people to recognize patterns where there are none, perceive control over random events, and shift their attitudes to be consistent with their past behaviors. People also need to feel good about themselves and about others with whom they identify. As such, people often self-enhance, evaluating themselves as having more desirable personalities and rosier future prospects than their peers, and taking personal credit for successes, but not failures. People likewise elevate their relationship partners and in-group members (e.g., people who share their political affiliation) in demonstrably unrealistic ways. Motivations can also have the opposite effect, leading people to derogate out-group members, even when the lines that divide ‘us’ from ‘them’ are defined de novo by researchers.

The authors follow this by noting studies demonstrating motivated cognition in perception, attention, decision making, etc.

How musical sound becomes rewarding - predictions and the brain

I would like to point out this review in Trends in Cognitive Sciences. Seeing more than the summary below does require a subscription or other access.

•Dopamine release in mesolimbic reward circuits leads to reinforcement tied to predictions and outcomes. 

•Musical pleasure involves complex interactions between dopamine systems and cortical areas. 

•Individual variability in superior temporal cortex may explain varied musical preferences. 

•Cognitive, auditory, affective, and reward circuits interact to make music pleasurable. 

Music has always played a central role in human culture. The question of how musical sounds can have such profound emotional and rewarding effects has been a topic of interest throughout generations. At a fundamental level, listening to music involves tracking a series of sound events over time. Because humans are experts in pattern recognition, temporal predictions are constantly generated, creating a sense of anticipation. We summarize how complex cognitive abilities and cortical processes integrate with fundamental subcortical reward and motivation systems in the brain to give rise to musical pleasure. This work builds on previous theoretical models that emphasize the role of prediction in music appreciation by integrating these ideas with recent neuroscientific evidence.

I will pass on some clips that summarize brain areas involved in auditory and music perception:

The superior temporal cortex (STC), which houses both primary and secondary auditory areas, is involved in a wide range of auditory processing relevant to music, including processing pitch and extraction of pitch and tonal relationships. It is also thought to store templates of sound events that we have accumulated over the years. Electrical stimulation of the STC elicits musical hallucinations, and increased activity in this region is associated with imagery and familiarity of music, suggesting that it stores previously heard auditory information. Acquired auditory information stored in this region may provide the basis for expectancy generation during music listening.

To appreciate music is to recognize patterns by sequencing structural information, recognizing the underlying structure, and forming predictions. These processes are continuously updated, refined, and revised with incoming information. These operations typically involve the frontal cortices of the brain, particularly the Inferior frontal gyrus (IFG)...The IFG and STG are often co-activated, and may possibly work together to process various aspects of music. Furthermore, there is evidence that white matter connectivity in this pathway is associated with the ability to learn new syntactic structures in the auditory domain. Finally, disruption of STG–IFG pathways has been observed in people with congenital amusia who show music perception deficits.

...dopaminergic coding of cues predicting upcoming rewards, and dopaminergic signaling of positive prediction errors, are essential to the high incentive reward value of musical experience. [One study] combined [¹¹C]-raclopride positron emission tomography and fMRI to show dopamine release in two regions of the striatum (caudate and nucleus accumbens, NAcc) while participants listened to self-selected highly pleasurable music. This study also found differential hemodynamic responses in these regions during anticipation versus experience of peak pleasure moments in the music

Subjective status shapes political preferences.

Brown-Iannuzzi et al. suggest that people's subjective perception of their socioeconomic status (SES) has a large influence on whether they support wealth redistribution as a remedy for increasing economic inequality in America. This is distinct from attitudes based on economic ideologies and economic self-interest. Here is their abstract, followed by their description of their studies:

Economic inequality in America is at historically high levels. Although most Americans indicate that they would prefer greater equality, redistributive policies aimed at reducing inequality are frequently unpopular. Traditional accounts posit that attitudes toward redistribution are driven by economic self-interest or ideological principles. From a social psychological perspective, however, we expected that subjective comparisons with other people may be a more relevant basis for self-interest than is material wealth. We hypothesized that participants would support redistribution more when they felt low than when they felt high in subjective status, even when actual resources and self-interest were held constant. Moreover, we predicted that people would legitimize these shifts in policy attitudes by appealing selectively to ideological principles concerning fairness. In four studies, we found correlational (Study 1) and experimental (Studies 2–4) evidence that subjective status motivates shifts in support for redistributive policies along with the ideological principles that justify them.

In Study 1, we measured subjective and objective SES and predicted that higher subjective SES would be associated with greater opposition to redistributive policies, independently of objective SES. In Study 2, we manipulated subjective SES, hypothesizing that participants induced to feel high status would be less supportive of redistribution and would endorse a more conservative ideology to justify that position than would participants induced to feel low status. In Study 3, we gained greater experimental control by creating an economic game in which players earned money and a portion of the profits of high earners were redistributed to low earners. We manipulated how well participants performed relative to other players, and we predicted that players who performed better would support less redistribution and would justify their preferences on the basis of ideological principles. In Study 4, we sought to replicate this finding and investigated whether the manipulation of subjective status led high-status participants to perceive other participants who disagreed with them as biased by self-interest. Together, these studies investigated whether subjective status may lead to political division.

[The results provide evidence] that perceptions of relative status can cause changes in political preferences. In Study 1, feeling higher in relative status was associated with lower support for redistribution. In Study 2, feeling higher in status caused reduced support for redistribution. In Study 3, we manipulated relative status in the context of an economic game and obtained similar results. Although participants could not profit from their recommendations, they recommended rule changes to reduce redistribution when they believed they had outperformed most other players. These changes were accompanied by shifts in construals of what counts as fair. Study 4 replicated these effects and showed that participants’ status affected their perceptions of bias in another player. High-status participants thought a player who recommended increased redistribution was more biased by self-interest than a player who recommended cutting redistribution. Together, these results suggest that subjective feelings of status can drive opinions toward redistribution, along with ideological views that justify those positions. An implication of the present work is that growing subjective perceptions of class differences may drive increased political polarization.

Perceived control promotes persistence and influences brain response to setbacks

From Bhanji et al:

Highlights

•We report two distinct neural mechanisms for persistence through adversity 

•Perceiving control over setbacks increases persistence 

•Striatum activity relates to persisting after setbacks by correcting mistakes 

•Ventromedial prefrontal activity mediates effects of negative affect on persistence

Summary

How do people cope with setbacks and persist with their goals? We examine how perceiving control over setbacks alters neural processing in ways that increase persistence through adversity. For example, a student might retake a class if initial failure was due to controllable factors (e.g., studying) but give up if failure was uncontrollable (e.g., unfair exam questions). Participants persisted more when they perceived control over setbacks, and when they experienced increased negative affect to setbacks. Consistent with previous observations involving negative outcomes, ventral striatum and ventromedial prefrontal (VMPFC) activity was decreased in response to setbacks. Critically, these structures represented distinct neural mechanisms for persistence through adversity. Ventral striatum signal change to controllable setbacks correlated with greater persistence, whereas VMPFC signal change to uncontrollable setbacks mediated the relationship between increased negative affect and persistence. Taken together, the findings highlight how people process setbacks and adapt their behavior for future goal pursuit.

From Whalen and Kelly's review :

The vmPFC is necessary for regulating our emotional responses...in the present study, the negative affect change is the catalyst that kicks vmPFC into a higher gear and effects adaptive change (i.e., persistence)...when negative affect accompanies uncontrollable setbacks, as is often the case, the vmPFC activity is necessary to adapt to the emotional reaction and, in so doing, preserve persistence.

The ventral striatum on the other hand is important for signaling prediction errors when behavioral outcomes do not match our expectations...when we believe we have control over situations, the ventral striatum can use value signals to motivate future behavior...this striatal effect is problem focused compared to the prefrontal effect that is more emotion focused.

A fetching point about Paul Whalen's and William Kelley's review is that it starts with the example of two professors currently employed at Dartmouth College.

One applied, and he was hired on his very first try (we’ll call him Bill in this example). Imagine that the other; well, he needed more chances before his eventual hire (we’ll call him P.W. to protect his identity). What dictates whether someone will persist when they encounter a setback? Is it the person who remains calm in the moment, not letting this single event rattle her? Or is it the person who reacts strongly to defeat and heavily reinvests in the project, determined to change things the next time? To borrow from Shakespeare, tell us where is persistence bred, or in the heart, or in the head (The Merchant of Venice, 3.2)? ...Bhanji and Delgado (2014) provide clear evidence of the latter.

Guess who Bill and P.W. actually are!

Positive thinking can sabotage desired outcomes.

The point is a simple one - imagining success in attaining a goal can make one strive less diligently towards it. Gabriele Oettingen has summarized her research over the past 15-20 years on how this plays out in different areas of endeavour, in a new book “Rethinking Positive Thinking: Inside the New Science of Motivation.” (I know this because she has done what now seems imperative for for getting one's ideas to briefly rise about the noise level facing readers in the general public: she has done a marketing piece in The New York Times - another example of this is Graziano's piece on his theory of consciousness also in the "Gray Matter" NYTimes series - to which I devoted an extended MindBlog post ).

Oettingen's NYTimes piece gives links to her studies showing that women in a weight reduction program who imaged successful completion of the program lost fewer pounds than those who imagined themselves less positively, and that students instructed to imagine a great week ahead report feeling less energized and accomplish less than students instructed to write down any thoughts about the coming week. She then notes experiments on what she suggests as the most effective strategy, combining positive thinking with realism by mentally contrasting them.

Neuroanatomy predicts individual risk attitudes.

Gilaie-Dotan et al. show that the volume of a region in the right posterior parietal cortex is relatively larger in individuals with higher risk tolerance (i.e. those more likely to choose a risky option). This region had previously been linked to uncertainty of reward, decision making, and the subjective value of uncertain rewards in both monkey and human brains.

Over the course of the last decade a multitude of studies have investigated the relationship between neural activations and individual human decision-making. Here we asked whether the anatomical features of individual human brains could be used to predict the fundamental preferences of human choosers. To that end, we quantified the risk attitudes of human decision-makers using standard economic tools and quantified the gray matter cortical volume in all brain areas using standard neurobiological tools. Our whole-brain analysis revealed that the gray matter volume of a region in the right posterior parietal cortex was significantly predictive of individual risk attitudes. Participants with higher gray matter volume in this region exhibited less risk aversion. To test the robustness of this finding we examined a second group of participants and used econometric tools to test the ex ante hypothesis that gray matter volume in this area predicts individual risk attitudes. Our finding was confirmed in this second group. Our results, while being silent about causal relationships, identify what might be considered the first stable biomarker for financial risk-attitude. If these results, gathered in a population of midlife northeast American adults, hold in the general population, they will provide constraints on the possible neural mechanisms underlying risk attitudes. The results will also provide a simple measurement of risk attitudes that could be easily extracted from abundance of existing medical brain scans, and could potentially provide a characteristic distribution of these attitudes for policy makers.

Does one novelty lead to another?

Barbar Jazney summarizes interesting work by Tria et al.:

Life would be boring if things were always the same. Tria and colleagues explore whether novelties—discoveries of things new to us—are independent of each other or whether one novelty leads to another. They analyzed selected text, online music, Wikipedia, and a social tagging site and measured how the number of different elements grew with time. Although two of the data sets contained innovations (items new to everyone) and two contained novelties (items new to individual users), they all showed the same kinetics and probability distributions. Modeling analyses suggested that novelties are not independent of each other. As the authors state, each novelty “comes with a cloud of other potentially new ideas that are thematically adjacent to it and hence can be triggered by it.”

Here is the Tria et al. article abstract:

Novelties are a familiar part of daily life. They are also fundamental to the evolution of biological systems, human society, and technology. By opening new possibilities, one novelty can pave the way for others in a process that Kauffman has called “expanding the adjacent possible”. The dynamics of correlated novelties, however, have yet to be quantified empirically or modeled mathematically. Here we propose a simple mathematical model that mimics the process of exploring a physical, biological, or conceptual space that enlarges whenever a novelty occurs. The model, a generalization of Polya's urn, predicts statistical laws for the rate at which novelties happen (Heaps' law) and for the probability distribution on the space explored (Zipf's law), as well as signatures of the process by which one novelty sets the stage for another. We test these predictions on four data sets of human activity: the edit events of Wikipedia pages, the emergence of tags in annotation systems, the sequence of words in texts, and listening to new songs in online music catalogues. By quantifying the dynamics of correlated novelties, our results provide a starting point for a deeper understanding of the adjacent possible and its role in biological, cultural, and technological evolution.

Genetic influence on our valuation of free choice

Cockburn et al. find an interesting correlation: A polymorphism in DARPP-32, a gene linked to dopaminergic striatal plasticity and individual differences in reinforcement learning, predicts how strongly people exhibit preference for options they have freely chosen over equally valued options they have not. Here is their abstract, along with a statement of highlights:

 Highlights

Participants exhibit a biased preference for freely chosen rewarding options

DARPP-32 genotype predicts choice bias as a function of expected value

Bias is mirrored by a model that amplifies positive free-choice learning signals

Choice bias is the byproduct of a mechanism that refines learning signal fidelity

Summary

Humans exhibit a preference for options they have freely chosen over equally valued options they have not; however, the neural mechanism that drives this bias and its functional significance have yet to be identified. Here, we propose a model in which choice biases arise due to amplified positive reward prediction errors associated with free choice. Using a novel variant of a probabilistic learning task, we show that choice biases are selective to options that are predominantly associated with positive outcomes. A polymorphism in DARPP-32, a gene linked to dopaminergic striatal plasticity and individual differences in reinforcement learning, was found to predict the effect of choice as a function of value. We propose that these choice biases are the behavioral byproduct of a credit assignment mechanism responsible for ensuring the effective delivery of dopaminergic reinforcement learning signals broadcast to the striatum.

Is our microbiome manipulating us to look out for itself?

Links between our gut and our brain, especially via the vagus nerve, can regulate stress disorders such as depression and anxiety. Growing evidence shows that the microbes in our gut can influence this by releasing various neurotransmitters (like dopamine and serotonin) near the rich bed of nerve endings that surround the gut. A lactobacillus found in Yoghurt can alter the GABA inhibitory neurotransmitter system and reduce stress induced behaviors in mice, an effect that requires the intact vagus nerve. I would suggest you have a look at Zimmer's summary of work suggesting that gut bacteria, in addition to helping to break down our food, fight off infections and nurture our immune system, might be a puppet master altering our food preferences to benefit themselves. In mice, bacteria can alter levels of hormones that govern appetite. Possibly they could influence various food cravings in humans.

How chronic pain saps our motivations and desires - the mechanism.

Fields gives a nice summary of work by Schwartz et al., who find a detailed synaptic mechanism for how chronic pain saps our motivations and desires. I pass on the article's abstract and a summary graphic by Schwartz.

Several symptoms associated with chronic pain, including fatigue and depression, are characterized by reduced motivation to initiate or complete goal-directed tasks. However, it is unknown whether maladaptive modifications in neural circuits that regulate motivation occur during chronic pain. Here, we demonstrate that the decreased motivation elicited in mice by two different models of chronic pain requires a galanin receptor 1–triggered depression of excitatory synaptic transmission in indirect pathway nucleus accumbens medium spiny neurons. These results demonstrate a previously unknown pathological adaption in a key node of motivational neural circuitry that is required for one of the major sequela of chronic pain states and syndromes.

Glutamate inputs excite nucleus accumbens medium spiny neurons. Chronic pain reduces AMPA receptor function in the DADR2-expressing class of these neurons, thereby reducing their activation by glutamate input. This decreases the motivation to work for a food reward.

Motivation not improved by multiple motives.

Wrzesniewski et al. do an interesting study of 11,320 West Point cadets over a period of ten years.

Although people often assume that multiple motives for doing something will be more powerful and effective than a single motive, research suggests that different types of motives for the same action sometimes compete. More specifically, research suggests that instrumental motives, which are extrinsic to the activities at hand, can weaken internal motives, which are intrinsic to the activities at hand. We tested whether holding both instrumental and internal motives yields negative outcomes in a field context in which various motives occur naturally and long-term educational and career outcomes are at stake. We assessed the impact of the motives of over 10,000 West Point cadets over the period of a decade on whether they would become commissioned officers, extend their officer service beyond the minimum required period, and be selected for early career promotions. For each outcome, motivation internal to military service itself predicted positive outcomes; a relationship that was negatively affected when instrumental motives were also in evidence. These results suggest that holding multiple motives damages persistence and performance in educational and occupational contexts over long periods of time.

Here is a bit more detail from the start of the results section:

Across two different survey measures administered by the institution at the start of their first year, cadets indicated how much each of a set of reasons offered represented their reasons for attending West Point, which allowed them to endorse any number of reasons at various levels of strength (response scales for the two measures ranged from very important to not important on a 1–3 Likert-type scale; and very positive to very negative on a 1–5 Likert-type scale). Reasons offered in the survey ranged from the prospect of getting a good job (instrumental), to economic necessity (cadets do not pay tuition), to a desire to be an Army officer (internal). Of the various reasons offered, two types were of key interest: reasons indicating an internal desire to become an Army officer and reasons indicating an instrumental desire to gain eventual outcomes associated with attending West Point. The data are archival; thus, none of the items in the surveys completed by cadets perfectly captured the distinction between “internal” and “instrumental” motives. For example, there were no items intended to capture a “pure” internal motive, defined to mean that the activity of becoming a West Point cadet was a meaningful and valuable end in itself (3). However, this motive is “internal” in the sense that the desire to be an Army officer requires that one do the things that Army officers do. In this way, it is akin to “being a soldier” (internal) rather than “getting a good job” (instrumental)....A total of 31 reasons appeared in the surveys and were subjected to exploratory factor analysis...

Increased self control without increased willpower

Here is a fascinating bit of work from Magen et. al., who show that a simple cognitive reframing of the classic immediate or delayed gratification test makes energy requiring willpower less necessary.

In our paradigm, instead of presenting choices in a traditional hidden-zero format (e.g., “Would you prefer [A] $5 today OR [B] $10 in a month?”), choices are presented in an explicit-zero format, which references the nonreward consequences of each choice (e.g., “Would you prefer [A] $5 today and $0 in a month OR [B] $0 today and $10 in a month?”). Including future outcomes in all choice options has been argued to reduce the attentional bias toward immediate rewards that contributes to impulsive behavior.

Here, then, is their abstract:

People often exert willpower to choose a more valuable delayed reward over a less valuable immediate reward, but using willpower is taxing and frequently fails. In this research, we demonstrate the ability to enhance self-control (i.e., forgoing smaller immediate rewards in favor of larger delayed rewards) without exerting additional willpower. Using behavioral and neuroimaging data, we show that a reframing of rewards (i) reduced the subjective value of smaller immediate rewards relative to larger delayed rewards, (ii) increased the likelihood of choosing the larger delayed rewards when choosing between two real monetary rewards, (iii) reduced the brain reward responses to immediate rewards in the dorsal and ventral striatum, and (iv) reduced brain activity in the dorsolateral prefrontal cortex (a correlate of willpower) when participants chose the same larger later rewards across the two choice frames. We conclude that reframing can promote self-control while avoiding the need for additional willpower expenditure.

Gratitude reduces economic impatience.

Whenever I come across yet another self-help laundry list of useful tricks for feeling better, and try a few, I repeatedly find that briefly following instructions to practice feeling gratitude has a very salutary, calming, effect...taking the edge off any impatience I might be feeling. DeSteno et al. look at this in a more systematic way, distinguishing the effect of gratitude from more positive global emotions of happiness with respect impatience, or short-term gratification. 75 study participants were split in three groups with different emotion-induction conditions: being asked to write brief essays on experiences of feeling grateful, happy, or neutral. They then made choices between receiving smaller cash amounts (ranging from $11 to $80) immediately and larger cash amounts (ranging from $25 to $85) at a point from 1 week to 6 months in the future. Their results clearly revealed that gratitude reduces excessive economic impatience (the temporal discounting of future versus immediate rewards) compared with the neutral and happy conditions, which were about equal. Here is their abstract:

The human mind tends to excessively discount the value of delayed rewards relative to immediate ones, and it is thought that “hot” affective processes drive desires for short-term gratification. Supporting this view, recent findings demonstrate that sadness exacerbates financial impatience even when the sadness is unrelated to the economic decision at hand. Such findings might reinforce the view that emotions must always be suppressed to combat impatience. But if emotions serve adaptive functions, then certain emotions might be capable of reducing excessive impatience for delayed rewards. We found evidence supporting this alternative view. Specifically, we found that (a) the emotion gratitude reduces impatience even when real money is at stake, and (b) the effects of gratitude are differentiable from those of the more general positive state of happiness. These findings challenge the view that individuals must tamp down affective responses through effortful self-regulation to reach more patient and adaptive economic decisions.

We transfer reward in a bottom-up search task to a top-down search task.

Lee and Shomstein make the interesting observation that a reward-based contingency learned in a bottom-up search task can be transferred to a subsequent top-down search task. They define the two kinds of search task in their introduction:

Research has demonstrated that the allocation of attention is controlled by two partially segregated networks of brain areas. The top-down attention system, which recruits parts of the intraparietal and superior frontal cortices, is specialized for selecting stimuli on the basis of cognitive factors, such as current goals and expectations. The bottom-up attention system, by contrast, recruits the temporoparietal and inferior frontal cortices, and is involved in processing stimuli on the basis of stimulus-driven factors, such as physical salience and novelty.

Here is their abstract:

Recent evidence has suggested that reward modulates bottom-up and top-down attentional selection and that this effect persists within the same task even when reward is no longer offered. It remains unclear whether reward effects transfer across tasks, especially those engaging different modes of attention. We directly investigated whether reward-based contingency learned in a bottom-up search task was transferred to a subsequent top-down search task, and probed the nature of the transfer mechanism. Results showed that a reward-related benefit established in a pop-out-search task was transferred to a conjunction-search task, increasing participants’ efficiency at searching for targets previously associated with a higher level of reward. Reward history influenced search efficiency by enhancing both target salience and distractor filtering, depending on whether the target and distractors shared a critical feature. These results provide evidence for reward-based transfer between different modes of attention and strongly suggest that an integrated priority map based on reward information guides both top-down and bottom-up attention.