Financial reward undermines intrinsic incentives.

Kurayama et al. measure brain activity during conditions of apparent intrinsic and extrinsic motivation to show striking evidence for a phenomenon often noted in social psychology — namely, extrinsic incentives (pay) can undermine intrinsic incentives (fun).

Contrary to the widespread belief that people are positively motivated by reward incentives, some studies have shown that performance-based extrinsic reward can actually undermine a person's intrinsic motivation to engage in a task. This “undermining effect” has timely practical implications, given the burgeoning of performance-based incentive systems in contemporary society. It also presents a theoretical challenge for economic and reinforcement learning theories, which tend to assume that monetary incentives monotonically increase motivation. Despite the practical and theoretical importance of this provocative phenomenon, however, little is known about its neural basis. Herein we induced the behavioral undermining effect using a newly developed task, and we tracked its neural correlates using functional MRI. Our results show that performance-based monetary reward indeed undermines intrinsic motivation, as assessed by the number of voluntary engagements in the task. We found that activity in the anterior striatum and the prefrontal areas decreased along with this behavioral undermining effect. These findings suggest that the corticobasal ganglia valuation system underlies the undermining effect through the integration of extrinsic reward value and intrinsic task value.

Living for "The Whoosh"

Scanning my long list of links that haven't quite made it into a MindBlog post, I note this Op-Ed piece by David Brooks from Dec. 31, in which he summarizes the main arguments in a new history of Western Philosophy by Dreyfus and Kelly, "All Things Shining."

Dreyfus and Kelly start with Vico’s old idea that each age has its own lens through which people see the world. In the Middle Ages, for example, “people could not help but experience themselves as determined or created by God.” They assumed that God’s plans encompassed their lives the way we assume the laws of physics do...For the past hundred years or so, we have lived in a secular age...individuals have to find or create their own meaning.

Dreyfus and Kelly...are on to something important when they describe the way — far more than in past ages — sports has risen up to fill a spiritual void...Spiritually unmoored, many people nonetheless experience intense elevation during the magical moments that sport often affords. They call this experience “whooshing up.” We get whooshed up at a sports arena, at a political rally or even at magical moments while woodworking or walking through nature...We should not expect these experiences to cohere into a single “meaning of life.” Transcendent experiences are plural and incompatible...Our most vibrant institutions are collective, not individual or religious. They are there to create that group whoosh: the sports stadium, the concert hall, the political rally, the theater, the museum and the gourmet restaurant. Even church is often more about the ecstatic whoosh than the theology...Real life is more about serial whooshes than coherent meaning. (Though they try, Dreyfus and Kelly don’t give us a satisfying basis upon which to distinguish the whooshing some people felt at civil rights rallies from the whooshing others felt at Nazi rallies.)

Examples of the relativity of our sensing time...

Two recent articles give fascinating glimpses of how plastic our sense of time can be. Jiga-Boy et al. show that our perception of temporal distance to a future event is shaped by the effort we must invest to realize the event. In a series of five experiments they showed:

...that the perception of temporal distance to a future event is shaped by the effort one must invest to realize the event...when actors are faced with realizing an event by a certain deadline, more effortful events are perceived as closer in time, regardless of the objective temporal distance to the deadline. This negative relationship is reversed, however, when deadlines are absent. Finally, priming high effort reduced perceived temporal distance to an event, whereas priming low effort increased perceived temporal distance to the event.

Carrozzo et al. find that animacy speeds up time in the brain:

...observers were asked to intercept a moving target or to discriminate the duration of a stationary flash while viewing different scenes. Time estimates were systematically shorter in the sessions involving human characters moving in the scene than in those involving inanimate moving characters. Remarkably, the animate/inanimate context also affected randomly intermingled trials which always depicted the same still character...The existence of distinct time bases for animate and inanimate events might be related to the partial segregation of the neural networks processing these two categories of objects, and could enhance our ability to predict critically timed actions.

Modeling the World in the Brain

Berkes et al. show that spontaneous activity in the visual brain adapts during development to resemble the activity generated by external natural scenes. Here is background from the Science summary:

There is a wide consensus in neuroscience that the brain uses internal models to interpret external stimuli and to make predictions about future events. Despite this consensus and a rich history of studies providing ample behavioral evidence about optimal internal models in the brain, it has been difficult to identify the neural signatures of these internal models. Using statistical methods to analyze recordings from the visual cortex of ferrets, Berkes et al. found that neuronal firing patterns during spontaneous activity were similar to those during evoked activity. During development, it seems that the internal model in the visual cortex gradually adapts to the properties of natural visual scenes.

And the abstract:

The brain maintains internal models of its environment to interpret sensory inputs and to prepare actions. Although behavioral studies have demonstrated that these internal models are optimally adapted to the statistics of the environment, the neural underpinning of this adaptation is unknown. Using a Bayesian model of sensory cortical processing, we related stimulus-evoked and spontaneous neural activities to inferences and prior expectations in an internal model and predicted that they should match if the model is statistically optimal. To test this prediction, we analyzed visual cortical activity of awake ferrets during development. Similarity between spontaneous and evoked activities increased with age and was specific to responses evoked by natural scenes. This demonstrates the progressive adaptation of internal models to the statistics of natural stimuli at the neural level.

Further debate on anti-aging molecule resveratrol

As a drug trial is stopped, the current and former leaders of the pharmaceutical company Sirtris disagree on whether we should be taking resveratrol, the putative anti-aging compound. My previous post on MindBlog's resveratrol experiment and its side effects drew numerous comments and accounts of personal experiences. (By the way, entering 'resveratrol' in the 'Search MindBlog:' box in the column to your left pulls up 18 MindBlog posts referring to resveratrol.)

The dark side of oxytocin

Nicholas Wade does a further discussion of work I mentioned in my June 22 post on several studies on oxytocin (the 'trust' hormone).

The love and trust it promotes are not toward the world in general, just toward a person’s in-group. Oxytocin turns out to be the hormone of the clan, not of universal brotherhood. Psychologists trying to specify its role have now concluded it is the agent of ethnocentrism.

Difficulty of seeing changes in moving objects.

A nice demonstration by Suchow and Alvarez. Play the movie while looking at the small white speck in the center of the ring. At first, the ring is motionless and it's easy to tell that the dots are changing color. When the ring begins to rotate, the dots suddenly appear to stop changing. But in reality they are changing the entire time. Take a look.

How our brains optimize our rewards

In the absence of other options, we use trial-and-error (reinforcement) learning to discover which of our actions are most likely to yield rewards. We can avoid multiple errors, however, if we receive some instruction on our choice selections. Li et al., (open access) observe the brain areas whose activations correlate with these two approaches by designing an experiment with two sessions using a simple probabilistic reward task. In the “feedback” session, participants’ choices were only based on the win/loss feedback, and in the “instructed” session participants could also incorporate the correct cue-reward probability information provided by experimenter to guide choice behavior (see Figure 1 for experimental design). The bottom line is that we use our dorsolateral prefrontal cortex to dynamically adjust outcome responses in valuation regions depending on the usefulness of action-outcome information. Here is their abstract:

Recent research in neuroeconomics has demonstrated that the reinforcement learning model of reward learning captures the patterns of both behavioral performance and neural responses during a range of economic decision-making tasks. However, this powerful theoretical model has its limits. Trial-and-error is only one of the means by which individuals can learn the value associated with different decision options. Humans have also developed efficient, symbolic means of communication for learning without the necessity for committing multiple errors across trials. In the present study, we observed that instructed knowledge of cue-reward probabilities improves behavioral performance and diminishes reinforcement learning-related blood-oxygen level-dependent (BOLD) responses to feedback in the nucleus accumbens, ventromedial prefrontal cortex, and hippocampal complex. The decrease in BOLD responses in these brain regions to reward-feedback signals was functionally correlated with activation of the dorsolateral prefrontal cortex (DLPFC). These results suggest that when learning action values, participants use the DLPFC to dynamically adjust outcome responses in valuation regions depending on the usefulness of action-outcome information.

Yet another ESP controversy.

Great outrage (described in the NYTimes article by Benedict Carey) is accompanying the forthcoming publication by The Journal of Personality and Social Psychology of a paper (link to PDF of paper is in Carey article) by Daryl J. Bem, who describes experiments over 10 years with ~10,000 students testing their ability to accurately sense random events. The critics maintain that extraordinary claims (conflicting with known science) require extraordinary validation (better than the usual 'less than 1/100 chance of being due to random correlation). Several critiques are being published alongside the Bem article, some presumably taking note  of the issues raised in Jonah Lehrer article that I described in a recent post,"The Truth Wears Off."  The last 50 years has seen multiple instances of seemingly (statistically significant) results on ESP,  drug effects, psychological mechanisms,  disappear over time as the experiments are repeated. (added note: in yesterday's NY Times Carey gives an excellent discussion of the statistics involved, in very simple language.)

Our digital afterlives - Deric's version

The NYTimes Sunday magazine has an interesting article by Rob Walker, raising issues that had been in my penumbra of awareness but that I've now felt forced to address directly. What happens to all the stuff you have put on the internet (photos, blogs, etc.) when you die? You should read the article.

I'll give you my own version of the issues it raises: Like many of us, I entered the web world via an early micro-computer (Apple II in my case, which appeared before the early IBM PC) with a slow phone modem. I got into chat rooms on AOL (using a pseudonym, then used that pseudonym for my first website on geocities.com, which was purchased by Yahoo, and the no-longer-relevant pseudonym was the account name used when I purchased the dericbownds.net domain name that now contain mindblog.dericbownds.net, which is simply a pointer used by google.com (i.e., blogspot.com), which actually hosts MindBlog. The images for the blog are stored, however, not by google, but on my own yahoo-hosted website at dericbownds.net/uploaded_images. Beyond this, I have data on several photo sites, five email addresses, logins and memberships and data on 10-20 social web sites, 61 piano performances on YouTube (with more to come), contact and calendar data on google...... What a mess!

So, what happens when I get run over by a truck tomorrow? I've recently (securely..not by email) passed on to my son and daughter a document titled Hit_By_Bus that hopefully contains enough information for them to sort through this mess and delete most of the material out there (hopefully condensing to a posthumus residue that covers family, university career, dericbownds.net, mindblog, and the piano performances). I don't envy their job, but I'm too lazy to do it myself.

So..what have you done? (Only about a third of Americans even have a will.)

Gay or Straight - same brain regions activated by love partner.

Here is an interesting bit from Semir Zeki, a well know vision scientist who has also studies brain correlates of artistic appreciation and brain systems and networks that are critical for the sentiment of romantic love. The article contains useful references. The abstract:

We pursued our functional magnetic resonance imaging (fMRI) studies of the neural correlates of romantic love in 24 subjects, half of whom were female (6 heterosexual and 6 homosexual) and half male (6 heterosexual and 6 homosexual). We compared the pattern of activity produced in their brains when they viewed the faces of their loved partners with that produced when they viewed the faces of friends of the same sex to whom they were romantically indifferent. The pattern of activation and de-activation was very similar in the brains of males and females, and heterosexuals and homosexuals. We could therefore detect no difference in activation patterns between these groups.

"Not tonight, dear" chemical signal in women's tears.

Anytime I see an article on article on evidence for a new human pheromone (a chemical signal that we secrete and sense - from arm pits, sweat, crotch, whatever) I pass it it on. Below is the abstract from  Gelstein et al, and here is a brief account from the NYTimes.

Emotional tearing is a poorly understood behavior that is considered uniquely human. In mice, tears serve as a chemosignal. We therefore hypothesized that human tears may similarly serve a chemosignaling function. We found that merely sniffing negative-emotion–related odorless tears obtained from women donors, induced reductions in sexual appeal attributed by men to pictures of women’s faces. Moreover, after sniffing such tears, men experienced reduced self-rated sexual arousal, reduced physiological measures of arousal, and reduced levels of testosterone. Finally, functional magnetic resonance imaging revealed that sniffing women's tears selectively reduced activity in brain-substrates of sexual arousal in men.

People believe they have more free will than others

Interesting observations from Pronin and Kuglera:

Four experiments identify a tendency for people to believe that their own lives are more guided by the tenets of free will than are the lives of their peers. These tenets involve the a priori unpredictability of personal action, the presence of multiple possible paths in a person's future, and the causal power of one's personal desires and intentions in guiding one's actions. In experiment 1, participants viewed their own pasts and futures as less predictable a priori than those of their peers. In experiments 2 and 3, participants thought there were more possible paths (whether good or bad) in their own futures than their peers’ futures. In experiment 4, participants viewed their own future behavior, compared with that of their peers, as uniquely driven by intentions and desires (rather than personality, random features of the situation, or history)

...Philosophers have long speculated that the introspective feeling of free will provides the force behind people's belief in it. By placing heavy weight on our own introspections (but not those of others), we may find ourselves uniquely convinced of our own free will. In some ways, this conviction is likely to be liberating—endowing us with a greater feeling of power in our lives.

Is the face alive? - the eyes tell us.

Looser and Wheatley do a nice study, reported in Psychological Science, on how we determine whether a face is dead or alive. A review of the work in Science Now has some nice videos of morphing faces along a gradient of animacy. The authors paired doll faces with a similar-looking human faces and used morphing software to blend the two, ending up with a spectrum of pictures that ranged from fully human to part human-part doll to purely doll. Volunteers consistently looked mainly at the eyes, and selected as the dividing point those faces that were about two-thirds along the continuum, closer to the human end. They also attributed the capability of thought to those faces.

The social sense - Theory of mind in 7-month old human infants.

A core component of our social cognition is the capacity to formulate a representation of what someone else believes to be true, even if that belief is false, and it has generally been accepted that this ability (theory of mind, or ToM) does not appear until children are 3-4 years old. Kovács et al. have found a behavioral paradigm, that when applied to both adults and infants, suggests that they form representations of others' beliefs in the same way. They developed a method for investigating ToM mechanisms that, in contrast to variants of the standard false belief task, is implicit, makes no reference to others’ beliefs, and requires no behavioral predictions of what agents will do on the basis of their beliefs. They used an object detection task to investigate two questions. First, are belief computations automatically triggered by the mere presence of an agent in adults and in infants as young as 7 months, even when the beliefs are entirely irrelevant to the task participants have to perform? Second, are beliefs about others’ beliefs stored in a format sufficiently similar to our own representations about the environment that both types of representations can affect our behavior?

Human social interactions crucially depend on the ability to represent other agents’ beliefs even when these contradict our own beliefs, leading to the potentially complex problem of simultaneously holding two conflicting representations in mind. Here, we show that adults and 7-month-olds automatically encode others’ beliefs, and that, surprisingly, others’ beliefs have similar effects as the participants’ own beliefs. In a visual object detection task, participants’ beliefs and the beliefs of an agent (whose beliefs were irrelevant to performing the task) both modulated adults’ reaction times and infants’ looking times. Moreover, the agent’s beliefs influenced participants’ behavior even after the agent had left the scene, suggesting that participants computed the agent’s beliefs online and sustained them, possibly for future predictions about the agent’s behavior. Hence, the mere presence of an agent automatically triggers powerful processes of belief computation that may be part of a “social sense” crucial to human societies.

Brain correlates of choice-induced preference change.

In an interesting article, Izuma et al. call classical cognitive dissonance theory into question. Their observations suggest that our preference for our choice between two equally desirable items is established by the act of choosing, not by a subsequent reduction of our preference for one of them. In other words, the mere act of rejecting favorite goods actually reduces preferences for them. Their abstract gives a clear summary of their observations:

According to many modern economic theories, actions simply reflect an individual's preferences, whereas a psychological phenomenon called “cognitive dissonance” claims that actions can also create preference. Cognitive dissonance theory states that after making a difficult choice between two equally preferred items, the act of rejecting a favorite item induces an uncomfortable feeling (cognitive dissonance), which in turn motivates individuals to change their preferences to match their prior decision (i.e., reducing preference for rejected items). Recently, however, Chen and Risen [Chen K, Risen J (2010) J Pers Soc Psychol 99:573–594] pointed out a serious methodological problem, which casts a doubt on the very existence of this choice-induced preference change as studied over the past 50 y. Here, using a proper control condition and two measures of preferences (self-report and brain activity), we found that the mere act of making a choice can change self-report preference as well as its neural representation (i.e., striatum activity), thus providing strong evidence for choice-induced preference change. Furthermore, our data indicate that the anterior cingulate cortex and dorsolateral prefrontal cortex tracked the degree of cognitive dissonance on a trial-by-trial basis. Our findings provide important insights into the neural basis of how actions can alter an individual's preferences.

Influence of language on perception

Landau et al. show that hearing recorded sentences describing faces (versus places) enhances a subsequent electrophysiological marker of brain responses to pictures of faces, while seeing pictures of faces diminishes the subsequent responses. This shows that language influences early stages of visual processing.

We examined the effect of linguistic comprehension on early perceptual encoding in a series of electrophysiological and behavioral studies on humans. Using the fact that pictures of faces elicit a robust and reliable evoked response that peaks at ~170 ms after stimulus onset (N170), we measured the N170 to faces that were preceded by primes that referred to either faces or scenes. When the primes were auditory sentences, the magnitude of the N170 was larger when the face stimuli were preceded by sentences describing faces compared to sentences describing scenes. In contrast, when the primes were visual, the N170 was smaller after visual primes of faces compared to visual primes of scenes. Similar opposing effects of linguistic and visual primes were also observed in a reaction time experiment in which participants judged the gender of faces. These results provide novel evidence of the influence of language on early perceptual processes and suggest a surprising mechanistic description of this interaction: linguistic primes produce content-specific interference on subsequent visual processing. This interference may be a consequence of the natural statistics of language and vision given that linguistic content is generally uncorrelated with the contents of perception.

The wolfpack effect.

An interesting piece of work from Gao et al. showing how the perception of animacy influences our interactive behavior.

Imagine a pack of predators stalking their prey. The predators may not always move directly toward their target (e.g., when circling around it), but they may be consistently facing toward it. The human visual system appears to be extremely sensitive to such situations, even in displays involving simple shapes. We demonstrate this by introducing the wolfpack effect, which is found when several randomly moving, oriented shapes (darts, or discs with “eyes”) consistently point toward a moving disc. Despite the randomness of the shapes’ movement, they seem to interact with the disc—as if they are collectively pursuing it. This impairs performance in interactive tasks (including detection of actual pursuit), and observers selectively avoid such shapes when moving a disc through the display themselves. These and other results reveal that the wolfpack effect is a novel “social” cue to perceived animacy. And, whereas previous work has focused on the causes of perceived animacy, these results demonstrate its effects, showing how it irresistibly and implicitly shapes visual performance and interactive behavior.

Sample display (a) and manipulations (b–e) from the first experiment. The task was to detect whether one shape (the wolf) was chasing another (the sheep). Arrows indicate motion and were not present in the displays. In the wolfpack condition (a, b), all darts stayed oriented toward the task-irrelevant green square, regardless of their motion directions. This condition generated the wolfpack effect. In the perpendicular condition (c), each dart was always oriented orthogonally to the square. In the match condition (d), each dart was always oriented in the direction in which it was moving at that moment. And in the disc condition (e), the objects had no visible orientation.

A contrarian view of energy prospects.

John Tierney describes a wager he made in 2005 with Matthew Simmons, who bet $5,000 that the price of oil, then about $65 a barrel, would more than triple in the next five years, so that the average price of oil over the course of 2010 would be at least $200 a barrel in 2005 dollars....The average for 2010 has been just under $80, which is the equivalent of about $71 in 2005 dollars — a little higher than the $65 at the time of the bet, but far below the $200 threshold set by Mr. Simmons. (Tierney's mentor was the economist Julian L. Simon, a leader of the Cornucopians, optimists who believed there would always be abundant supplies of energy and other resources. Simon won a bet in the 1980s with Paul Ehrlich and two natural resources experts over the prices of five metals.) What happened to the grim predictions of declining oil reserves and rising prices? Perhaps there has been a temporary respite (which unfortunately will not help alternative energy efforts):

Giant new oil fields have been discovered off the coasts of Africa and Brazil. The new oil sands projects in Canada now supply more oil to the United States than Saudi Arabia does. Oil production in the United States increased last year, and the Department of Energy projects further increases over the next two decades...The really good news is the discovery of vast quantities of natural gas. It’s now selling for less than half of what it was five years ago. There’s so much available that the Energy Department is predicting low prices for gas and electricity for the next quarter-century. Lobbyists for wind farms, once again, have been telling Washington that the “sustainable energy” industry can’t sustain itself without further subsidies...As gas replaces dirtier fossil fuels, the rise in greenhouse gas emissions will be tempered, according to the Department of Energy. It projects that no new coal power plants will be built, and that the level of carbon dioxide emissions in the United States will remain below the rate of 2005 for the next 15 years even if no new restrictions are imposed.

Maybe something unexpected will change these happy trends, but for now I’d say that Julian Simon’s advice remains as good as ever. You can always make news with doomsday predictions, but you can usually make money betting against them.

New brain circuits form online during rapid learning

Shtyrov et. al. show that after just 14 minutes of learning exposure to a new word, presentations of this word cause increased responses in the language cortex, reflecting rapid mapping of new word forms onto neural representations.

Humans are unique in developing large lexicons as their communication tool. To achieve this, they are able to learn new words rapidly. However, neural bases of this rapid learning, which may be an expression of a more general cognitive mechanism, are not yet understood. To address this, we exposed our subjects to familiar words and novel spoken stimuli in a short passive perceptual learning session and compared automatic brain responses to these items throughout the learning exposure. Initially, we found enhanced activity for known words, indexing the ignition of their underlying memory traces. However, just after 14 min of learning exposure, the novel items exhibited a significant increase in response magnitude matching in size with that to real words. This activation increase, as we would like to propose, reflects rapid mapping of new word forms onto neural representations. Similar to familiar words, the neural activity subserving rapid learning of new word forms was generated in the left-perisylvian language cortex, especially anterior superior-temporal areas. This first report of a neural correlate of rapid learning suggests that our brain may effectively form new neuronal circuits online as it gets exposed to novel patterns in the sensory input. Understanding such fast learning is key to the neurobiological explanation of the human language faculty and learning mechanisms in general.