Language evolved to fit the human brain, rather than the reverse.

I thought this PNAS article from Chater et al. on language evolution was interesting. Here are a few excerpts from their introduction, followed by their abstract (and here is a commentary in a following issue of PNAS):

...the default prediction from a Darwinian perspective on human psychological abilities is the adaptationist view, that genes for language coevolved with human language itself for the purpose of communication...A challenge for the adaptationists is to pinpoint an evolutionary mechanism by which a language module could become genetically encoded. The problem is that many of the linguistic properties purported to be included in the language module are highly abstract and have no obvious functional basis—they cannot be explained in terms of communicative effectiveness or cognitive constraints—and have even been suggested to hinder communication...

A shift from initially learned linguistic conventions to genetically encoded principles necessary to evolve a language module may appear to require Lamarckian inheritance. The Baldwin effect provides a possible Darwinian solution to this challenge, however. Baldwin proposed that characteristics that are initially learned or developed over the lifespan can become gradually encoded in the genome over many generations, because organisms with a stronger predisposition to acquire a trait have a selective advantage. Over generations, the amount of environmental exposure required to develop the trait decreases, and eventually no environmental exposure may be needed—the trait is genetically encoded.

Chater et al. modeled several different simulations of the circumstances under which a similar evolutionary mechanism could genetically assimilate properties of language in a domain-specific module. Here is their abstract:

Language acquisition and processing are governed by genetic constraints. A crucial unresolved question is how far these genetic constraints have coevolved with language, perhaps resulting in a highly specialized and species-specific language “module,” and how much language acquisition and processing redeploy preexisting cognitive machinery. In the present work, we explored the circumstances under which genes encoding language-specific properties could have coevolved with language itself. We present a theoretical model, implemented in computer simulations, of key aspects of the interaction of genes and language. Our results show that genes for language could have coevolved only with highly stable aspects of the linguistic environment; a rapidly changing linguistic environment does not provide a stable target for natural selection. Thus, a biological endowment could not coevolve with properties of language that began as learned cultural conventions, because cultural conventions change much more rapidly than genes. We argue that this rules out the possibility that arbitrary properties of language, including abstract syntactic principles governing phrase structure, case marking, and agreement, have been built into a “language module” by natural selection. The genetic basis of human language acquisition and processing did not coevolve with language, but primarily predates the emergence of language. As suggested by Darwin, the fit between language and its underlying mechanisms arose because language has evolved to fit the human brain, rather than the reverse.

Happy 200th birthday to Charles Darwin!

MindBlog's third Podcast - Mindstuff: A user's guide

This podcast (here is the mp3, 30 min., 13.8 MB download) builds on the description of the nature and evolutionary history of our "I" that is developed in the first two Podcasts, "The I-Illusion" and "The Beast Within." In this podcast, which I am calling Mindstuff: A user's guide, I address a not-so-hidden agenda for many of us trying to understand our minds and brains: wanting to find insights or tools that bring more ease to the living of our daily lives, tools that might also enhance our effectiveness in tasks we wish to accomplish. I am adding some material to, and abstracting from, writing on my website, dericbownds.net. This is as close as I will get to offering my own version of a self-help manual that is based on our limited knowledge of how our minds actually work.

Worldwide human energy networking

In the last article of the Nature Magazine "Being Human" series, Melanie Moses discusses humanity's greatest challenge: how to reduce the demand for energy in increasingly complex, networked and energy-dependent societies. A few excerpts:

To manage our impact on the environment and understand the ramifications of our actions in an increasingly interconnected world, we need a macroscopic view as well as a detailed understanding of the structure of the networks we have created. The bigger picture is beginning to emerge from theoretical approaches that reveal the structure and dynamics of networks, how networks change as they grow, and how networks constrain individual behaviour.

The Metabolic Theory of Ecology (MTE) offers one way to understand the dynamics of flow through networks. The mathematical foundation of MTE was developed a decade ago by a group of biologists and physicists who wanted to explain why so many characteristics of plants and animals systematically depend on their mass in a very peculiar way. The theory posits that much of the life history of an animal (such as how long it lives, how often it reproduces and how much it eats) is determined by geometric and dynamic properties of the cardiovascular network that controls its metabolism.

According to the theory, the larger the animal, the longer its cardiovascular system (its network of arteries and capillaries) takes to deliver resources to its cells. That delivery time, which in turn dictates the animal's metabolic rate, is proportional to the animal's mass raised to the power of ¼. Thus, because its circulatory system works less efficiently, an elephant grows systematically more slowly than a mouse, with a slower heart rate, a lower reproductive rate and a longer lifespan

... the implications of this basic idea — that networks become predictably less efficient as they grow — are profound. Indeed, MTE offers insights that could revolutionize the way we understand, predict and manage large networked systems. As well as suggesting that larger systems process energy proportionally more slowly than smaller ones, it implies that the rate at which a system processes energy drives much of its broad-scale behaviour, whether that system is an organism, society or technology.

Several crucial messages are emerging from early work on human-engineered networks. Human societies are complex systems that persist by consuming energy, but energy consumption cannot be lessened simply by reducing individual demand. Any one person's consumption and, possibly, fertility rate, is affected by structures at higher levels. Relating the behaviour of individuals to global-scale problems will require understanding those individuals as nodes in a network, in which the behaviour of one affects the whole society and where the collective behaviour of the society constrains the behaviour of individuals.

...potentially more efficient ways to design infrastructure are emerging. My colleagues and I recently showed that some at least partially decentralized networks, such as computer networks and urban roads in cities (where half the world's population now resides), can increase in size more efficiently than purely centralized ones. For example, our models show that traffic, and so oil consumption, can be proportionally reduced as cities expand, as long as multiple recreational and commercial centres are placed near residential areas. Moreover, Luís Bettencourt and his colleagues recently showed that certain factors, such as innovation and wealth creation, increase super-linearly with city population. In this instance, the more people in a city, the more each person benefits from the collective ability to interact.

...we need to understand how social and infrastructure networks constrain individual behaviour, and structure cities and societies in ways that increase innovation-inducing interactions but reduce transport and travel distances. By doing so, we'll stand a better chance of meeting the needs of a large, voracious and growing human population without decimating the resources available to future generations.

Fingerprints enhance the sense of touch.

Here is a curious factoid, or near factoid. From Miller's review of Scheibert et al.:

After a series of experiments with a sensor designed to mimic a small patch of skin on a human fingertip, Alexis Prevost, Georges Debrégeas, and their colleagues at the École Normale Supérieure in Paris conclude that fingerprints likely enhance the perception of texture by increasing vibrations in the skin as fingers rub across a textured surface. In particular, fingerprints amplify vibrations in the frequency range that best stimulates Pacinian corpuscles, mechanoreceptors in the skin important for texture perception...The ridges made the vibrations picked up by the underlying sensor up to 100 times stronger...The new results leave open why human fingerprints are arranged in elliptical swirls....the amplification effect was strongest when the textured glass slid perpendicular to the ridges, so it's possible that the loops ensure that no matter how the fingers move, some ridges are always optimally oriented.

God needn't actually exist to have evolved

Here are some clips from a brief essay by Jesse Bering, who is director of The Institute of Cognition and Culture, Queens University, Belfast.

What if I were to tell you that God were all in your mind? That God, like a tiny spec floating at the edge of your cornea producing the image of a hazy, out-of-reach orb accompanying your every turn, were in fact an illusion, a psychological blemish etched onto the core cognitive substrate of your brain?...Consider, briefly, the implications of seeing God this way, as a sort of scratch on our psychological lenses rather than the enigmatic figure out there in the heavenly world most people believe him to be. Subjectively, God would still be present in our lives. In fact rather annoyingly so. As a way of perceiving, he would continue to suffuse our experiences with an elusive meaning and give the sense that the universe is communicating with us in various ways.

...in the natural sciences, the concept of God as a causal force tends to be an unpalatable lump of gristle. Although treating God as an illusion may not be entirely philosophically warranted, therefore, it is in fact a scientifically valid treatment. Because the human brain, like any physical organ, is a product of evolution, and since natural selection works without recourse to intelligent forethought, this mental apparatus of ours evolved to think about God quite without need of the latter's consultation, let alone his being real.

...the human brain has many such odd quips that systematically alter, obscure, or misrepresent entirely the world outside our heads. That's not a bad thing necessarily; nor does it imply poor adaptive design. You have undoubtedly seen your share of optical illusions before, such as the famous Müller-Lyer image where a set of arrows of equal length with their tails in opposite directions creates the subjective impression that one line is actually longer than the other. You know, factually, the lines are of equal length, yet despite this knowledge your mind does not allow you to perceive the image this way. There are also well-documented social cognitive illusions that you may not be so familiar with. For example, David Bjorklund, a developmental psychologist, reasons that young children's overconfidence in their own abilities keeps them engaging in challenging tasks rather than simply giving up when they fail. Ultimately, with practice and over time, children's actual skills can ironically begin to more closely approximate these earlier, favorably warped self-judgments. Similarly, evolutionary psychologists David Buss and Martie Haselton argue that men's tendency to over-interpret women's smiles as sexual overtures prompts them to pursue courtship tactics more often, sometimes leading to real reproductive opportunities with friendly women.

...from both a well-being and a biological perspective, whether our beliefs about the world 'out there' are true and accurate matters little. Rather, psychologically speaking, it's whether they work for us—or for our genes—that counts. As you read this, cognitive scientists are inching their way towards a more complete understanding of the human mind as a reality-bending prism. What will change everything? The looming consensus among those who take Occam's Razor seriously that the existence of God is a question for psychologists and not physicists.

For memory enhancement, the kind of sleep you get is important

Van Der Werf et al. have recorded electroencephalograms from people as they slept, setting off a beeping sound when the electroencephalograms were consistent with slow-wave (deeper) sleep, thus causing subjects to move into a shallower sleep stage without awakening. Although the total amount of sleep that subjects got was unchanged, these people did worse on a later test of scene recall than subjects who had slept normally. When the subjects were later scanned in a functional magnetic resonance imaging scanner, they also showed reduced hippocampal activation while they were encoding the to-be-remembered scenes. Thus the hippocampus appears to be particularly sensitive to shallow, but intact, sleep.

The unconscious psychology of color.

When I first started the vision research laboratory I ran for 30 years at the University of Wisconsin, I experimented with the color spectrum of the fluorescent lights used over the laboratory benches. Those that had more blue and green, more like natural sunlight, clearly made my students feel more relaxed and creative. This was consonant with psychological studies that had shown reds to have more arousing and blue more calming effects humans as well as other animals. Mehta and Zhu have made some fascinating further observations reported in Science and noted in a NY Times article by Belluck which gives examples of similar studies. Work done against the background color red is relatively more accurate, while with blue it is more creative. Here is a clip from the Mehta and Zhu abstract, followed by a graphic from the NY Times article.

We demonstrate that red (versus blue) color induces primarily an avoidance (versus approach) motivation and that red enhances performance on a detail-oriented task, whereas blue enhances performance on a creative task. Further, we replicate these results in domains of product design and persuasive message evaluation, and illustrate that these effects occur outside of individuals’ consciousness . We also provide process evidence suggesting that the activation of alternative motivations mediates the effect of color on cognitive task performances.

Supersizing the Mind

Supersizing the Mind: Embodiment, Action, and Cognitive Extension, a recent book by philosopher Andy Clark is reviewed by Melvyn Goodale in Nature, and I pass on some clips from his review, because Clark's views exactly mirror the sentiments expressed in my Biology of Mind Book:

In Supersizing the Mind, philosopher Andy Clark makes the compelling argument that the mind extends beyond the body to include the tools, symbols and other artefacts we deploy to engage the world. According to Clark and other proponents of the 'extended mind' hypothesis, the laptop on which I am writing this review is coupled to my brain and has become part of my mind. Manipulating sentences on the screen can prompt new insights and new ways of conveying ideas, a reiterative cognitive process that would be difficult to achieve without such a tool. The same argument applies to my BlackBerry, to the white board in my office, and even to the conversations I might have with my colleagues. Cognition, Clark argues, is not 'brain-bound' but a dynamic interaction between the neural circuits inside our skulls, our bodies and the objects and events in the outside world.

Clark explores in detail the consequences of embodied and extended cognition for our conscious perception of the world. He acknowledges that the "intimacy of brain, body, world, and action" must have implications for our perceptual experience, but ultimately rejects the idea of enactive perception championed by philosopher Alva Noë, in which our experience is seen as nothing more than the sensorimotor routines that we use to interact with the world. For Clark, perception is shaped by the way in which we explore this world. But at the same time, he argues, our conscious experience of objects and events is not bound to the details of the sensorimotor routines that mediate that exploration. These routines, he suggests, are controlled by encapsulated systems with operating characteristics that are not privy to conscious, or even unconscious, scrutiny and whose activity is removed from the information they convey. In rejecting Noë's sensorimotor model, Clark argues that conscious perception does not depend on a "common sensorimotor currency" but arises from a subtle interplay between brain, body and environment, "replete with special-purpose streaming and with multiple, quasi-independent forms of internal, and external, representation and processing".

If Clark is right, and I think he is, then simply studying what goes on in the brain will tell us only part of what happens as cognitive activity unfolds. To capture the richness of thought, we have to step outside the box and embrace the world beyond the skull.

MindBlog's third birthday.

This Sunday will be Mindblog's 3rd birthday, the first posting was on Feb. 8, 2006. I started it after reading an article on blogging in the New York Times, and decided that I might as well pass on some of the reading and thinking that I was doing anyway. I had no idea that by now (~1,450 posts later) it would be reaching ~10,000 people a month, of which half are in the United States. I want to thank readers who have commented on the posts or sent sent me emails with further ideas.

Apply mild electric current to your head, improve your motor skills

Balakar describes experiments of Reis et al. , who

...trained two groups of 12 volunteers each to use a joystick to move a cursor as quickly and accurately as possible through an obstacle course on a computer screen. The task was difficult enough to ensure that performance would improve over five days of practice.

During the practice sessions, all participants had electrodes connected over the primary motor cortex, the part of the brain that plans and executes movements. One group was stimulated with a mild current through the connection and the other was not. After five days of practice, the group that received the current was significantly better at the task, both in speed and accuracy.

Never ending childhood...

Alison Gopnik suggests that our new scientific understanding of neural plasticity and gene regulation, along with the global spread of schooling, will let us remain children forever — or at least for much longer.

Across species, a long childhood is correlated with an evolutionary strategy that depends on flexibility, intelligence and learning. There is a developmental division of labor. Children get to learn freely about their particular environment without worrying about their own survival — caregivers look after that...We grown-ups are production and marketing. We start out as brilliantly flexible but helpless and dependent babies, great at learning everything but terrible at doing just about anything. We end up as much less flexible but much more efficient and effective adults, not so good at learning but terrific at planning and acting.

For most of human history babies and toddlers used their spectacular, freewheeling, unconstrained learning abilities to understand fundamental facts about the objects, people and language around them — the human core curriculum. At about 6 children also began to be apprentices. Through a gradual process of imitation, guidance and practice they began to master the particular adult skills of their particular culture...School, a very recent human invention, completely alters this program. Schooling replaces apprenticeship. School lets us all continue to be brilliant but helpless babies...school is also an extension of the period of infant dependence — since we don't actually do anything useful in school, other people need to take care of us — all the way up to a Ph.D. School doesn't include the gradual control and mastery of specific adult skills that we once experienced in apprenticeship. Universal and extended schooling means that the period of flexible learning and dependence can continue until we are in our thirties, while independent active mastery is increasingly delayed.

...there may be an intrinsic trade-off between flexibility and effectiveness, between the openness that we require for learning and the focus that we need to act. Child-like brains are great for learning, but not so good for effective decision-making or productive action. There is some evidence that adolescents even now have increasing difficulty making decisions and acting independently, and pathologies of adolescent action like impulsivity and anxiety are at all-time historical highs. Fundamental grown-up human skills we once mastered through apprenticeship, like cooking and caregiving itself, just can't be acquired through schooling. (Think of all those neurotic new parents who have never taken care of a child and try to make up for it with parenting books). When we are all babies for ever, who will be the parents? When we're all children who will be the grown-ups?

Psychosocial stress inhibits prefrontal function

Wow, this piece of work is both sobering and optimistic. These imaging studies by Liston, McEwen, and Casey (full access article) show that diminished performance in an attention shifting task induced by stress correlates with reduction of functional connectivity within a frontoparietal network. These changes, however, are reversed if stress is removed. Here is their abstract:

Relatively little is known about the long-term neurobiological sequelae of chronic stress, which predisposes susceptible patients to neuropsychiatric conditions affecting the prefrontal cortex (PFC). Animal models and human neuroimaging experiments provide complementary insights, yet efforts to integrate the two are often complicated by limitations inherent in drawing comparisons between unrelated studies with disparate designs. Translating from a rodent model of chronic stress where we have shown reversible disruption of PFC function, we show that psychosocial stress induces long-lasting but reversible impairments in behavioral and functional magnetic resonance imaging (fMRI) measures of PFC function in humans. Twenty healthy adults, exposed to 1 month of psychosocial stress, confirmed by a validated rating scale, were scanned while performing a PFC-dependent attention-shifting task. One month later, they returned for a second scanning session after a period of reduced stress, and their performance was compared with a twice-scanned, matched group of low-stress controls. Psychosocial stress selectively impaired attentional control and disrupted functional connectivity within a frontoparietal network that mediates attention shifts. These effects were reversible: after one month of reduced stress, the same subjects showed no significant differences from controls. These results highlight the plasticity of PFC networks in healthy human subjects and suggest one mechanism by which disrupted plasticity may contribute to cognitive impairments characteristic of stress-related neuropsychiatric conditions in susceptible individuals.

Drinking coffee lowers dementia

A reassuring note for those of us who are coffee drinkers.

Synchrony and Cooperation

From Wiltermuth and Heath, slightly edited:

The decline of the bayonet and the advent of the machine gun have made marching in step a terrible, if not suicidal, combat tactic; yet armies still train by marching in step. Similarly, religions around the world incorporate synchronous singing and chanting into their rituals. Why? We suggest that acting in synchrony with others can foster cooperation within groups by strengthening group cohesion. The widespread presence of cultural rituals involving synchrony may have evolved as partial solutions to the free-rider problem, the tendency for some individuals to shoulder less than their share of the burden of producing public goods and participating in collective action.

Their abstract:

Armies, churches, organizations, and communities often engage in activities—for example, marching, singing, and dancing—that lead group members to act in synchrony with each other. Anthropologists and sociologists have speculated that rituals involving synchronous activity may produce positive emotions that weaken the psychological boundaries between the self and the group. This article explores whether synchronous activity may serve as a partial solution to the free-rider problem facing groups that need to motivate their members to contribute toward the collective good. Across three experiments, people acting in synchrony with others cooperated more in subsequent group economic exercises, even in situations requiring personal sacrifice. Our results also showed that positive emotions need not be generated for synchrony to foster cooperation. In total, the results suggest that acting in synchrony with others can increase cooperation by strengthening social attachment among group members.

Some description of the experiments:

In the first experiment an experimenter led 30 participants (60% female; mean age = 20, SD= 2.0) in groups of 3 on walks around campus. In the synchronous condition, participants walked in step. In the control condition, they walked normally. After their walk, participants completed a questionnaire designed to convince participants that they had finished the experiment....In an ostensibly separate experiment, a second experimenter conducted the Weak Link Coordination Exercise, which models situations in which group productivity is a function of the lowest level of input...the game measures expectations of cooperation.

In a second experiment groups were randomly assigned to one of four conditions: In the control condition (i.e., the no-singing, no-moving condition), participants (American students) listened to "O Canada," held a plastic cup above the table, and silently read the lyrics to the anthem. In the synchronous-singing condition, participants listened to the anthem, held the cup, and sang the words "O Canada" at the appropriate times. In the synchronous-singing-and-moving condition, participants listened to the anthem, sang the words "O Canada," and moved cups from side to side in time with the music. In the asynchronous condition, participants sang and moved cups, but participants each listened to the anthem at a different tempo, causing them to move their cups at different rates and sing "O Canada" at different times. Participants in all conditions were told that they might hear the same or different versions of "O Canada," but only participants in the asynchronous condition actually heard different versions. Participants in the two synchrony conditions cooperated more in the subsequent Weak Link Coordination Exercise described in Study 1 than did participants in the control or asynchronous conditions.

The third experiment used the same synchrony, asynchrony, and control groups as the second to show that after behaving in synchrony with others, people contribued more to a public account in a commons dilemma known as a public-goods game. Moving in synchrony boosted cooperation even when behaving cooperatively conflicted with personal self-interest.

Conceptual similarity of biological and cultural development

I found this brief essay by Brian Goodwin fascinating. I tried to reduce it to a few excerpts, but end up wanting to pass on the entire piece:

I anticipate that biology will go through a transforming revelation/revolution that is like the revolution that happened in physics with the development of quantum mechanics nearly 100 years ago. In biology this will involve the realisation that to make sense of the complexity of gene activity in development, the prevailing model of local mechanical causality will have to be abandoned. In its place we will have a model of interactive relationships within gene transcription networks that is like the pattern of interactions between words in a language, where ambiguity is essential to the creation of emergent meaning that is sensitive to cultural history and to context. The organism itself is the emergent meaning of the developmental process as embodied form, sensitive to both historical constraint within the genome and to environmental context, as we see in the adaptive creativity of evolution. What contemporary studies have revealed is that genes are not independent units of information that can be transferred between organisms to alter phenotypes, but elements of complex networks that act together in a morphogenetic process that produces coherent form and function as embodied meaning.

A major consequence that I see of this revelation in biology is the realisation that the separation we have made between human creativity as expressed in culture, and natural creativity as expressed in evolution, is mistaken. The two are much more deeply related than we have previously recognised. That humans are embedded in and dependent on nature is something that no-one can deny. This has become dramatically evident recently as our economic system has collapsed, along with the collapse of many crucial ecosystems, due to our failure to integrate human economic activity as a sustainable part of Gaian regulatory networks. We now face dramatic changes in the climate that require equally dramatic changes in our technologies connected with energy generation, farming, travel, and human life-style in general.

On the other hand, the recognition that culture is embedded in nature is not so evident but will, I believe, emerge as part of the biological revelation/revolution. Biologists will realise that all life, from bacteria to humans, involves a creative process that is grounded in natural languages as the foundation of their capacity for self-generation and continuous adaptive transformation. The complexity of the molecular networks regulating gene activity in organisms reveals a structure and a dynamic that has the self-similar characteristics and long-range order of languages. The coherent form of an organism emerges during its development as the embodied meaning of the historical genetic text, created through the process of resolving ambiguity and multiple possibilities of form into appropriate functional order that reflects sensitivity to context. Such use of language in all its manifestations in the arts and the sciences is the essence of cultural creativity.

In conclusion, I see the deep conceptual changes that are currently happening in biology as a prelude and accompaniment to the cultural changes that are occurring in culture, facilitating these and ushering in a new age of sustainable living on the planet.

MindBlog's second PodCast - "The Beast Within"

This second podcast (39 minutes, 17.9 MB, .mp3 format), like the first, is a reduced form of an essay on my website. It talks about those components of our human actions, feelings, and mental lives that are more similar to those of other animals than most of us realize, and notes the introspective access we have to these more simple levels of our mind. I am going to attempt to keep future podcasts in the 10-30 minute length range.

Note: I am very grateful for the feedback on my first podcast attempt last Wednesday ("The I-Illusion"). I am generating these in the .mp3 audio format using the Apple Garage Band Program. I don't want to get too immersed in the techie side of this, but would ask if any of you have a problem with this presentation, or would like to suggest a different presentation. I think I may have managed to make the podcasts available on iTunes via the Feedburner service.

I don't believe in atheists

The title of this post is the title of a new book by Chris Hedges. A reader pointed out this interesting interview with Hedges at Salon.com. He takes on "The New Atheists," who he accuses of preaching a fundamentalism as dangerous as the religious fundamentalist belief systems they attack, nudging the secular left to embrace the same kind of bigotry and chauvinism and intolerance that marks the radical Christian right. Both divide the world into "us" and "them" and fail to have empathy. One Hedges comment from the interview:

I write in the book that not believing in God is not dangerous. Not believing in sin is very dangerous. I think both the Christian right and the New Atheists in essence don't believe in their own sin, because they externalize evil. Evil is always something out there that can be eradicated. For the New Atheists, it's the irrational religious hordes. I mean, Sam Harris, at the end of his first book, asks us to consider a nuclear first strike on the Arab world. Both Hitchens and Harris defend the use of torture. Of course, they're great supporters of preemptive war, and I don't think this is accidental that their political agendas coalesce completely with the Christian right.

Incorporation of misinformation during memory reconsolidation

Chan et al. report a counter-intuitive finding. You would think that because memory retrieval is a powerful memory enhancer, recalling a witnessed event prior to receiving misinformation about it should reduce eyewitness suggestibility. They report just the opposite:

People's later memory of an event can be altered by exposure to misinformation about that event. The typical misinformation paradigm, however, does not include a recall test prior to the introduction of misinformation, contrary to what real-life eyewitnesses encounter when they report to a 911 operator or crime-scene officer. Because retrieval is a powerful memory enhancer (the testing effect), recalling a witnessed event prior to receiving misinformation about it should reduce eyewitness suggestibility. We show, however, that immediate cued recall actually exacerbates the later misinformation effect for both younger and older adults. The reversed testing effect we observed was based on two mechanisms: First, immediate cued recall enhanced learning of the misinformation; second, the initially recalled details became particularly susceptible to interference from later misinformation, a finding suggesting that even human episodic memory may undergo a reconsolidation process. These results show that real-life eyewitness memory may be even more susceptible to misinformation than is currently envisioned.

It's hard to be dignified when your name is....

The figure is from Sarah Lyall's New York Times article.