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.

Some monday morning music

A comment on the mindblog podcast I posted last week reminded me that I haven't been posted much of my music lately. I did pass on one recording made on the Steinway upright in my snowbird condo here in Fort Lauderdale last January, but this year I've decided to wait for more recordings until I get back to Madison and my Steinway B, which has a gorgeous sound. Here is a Debussy's first Arabesque done on that instrument.

The epistemology of everything

I thought this essay was so striking that I want to pass it on in its entirety (I started to excerpt chunks, but found every sentence worthwhile, and so stopped). It is completely consonant with the ideas in my "I-Illusion" lecture and podcast.

Understanding that the outside world is really inside us and the inside world is really outside us will change everything. Both inside and outside. Why?.."There is no out there out there", physicist John Wheeler said in his attempt to explain quantum physics. All we know is how we correlate with the world. We do not really know what the world is really like, uncorrelated with us. When we seem to experience an external world that is out there, independent of us, it is something we dream up...Modern neurobiology has reached the exact same conclusion. The visual world, what we see, is an illusion, but then a very sophisticated one. There are no colours, no tones, no constancy in the "real" world, it is all something we make up. We do so for good reasons and with great survival value. Because colors, tones and constancy are expressions of how we correlate with the world...The merging of the epistemological lesson from quantum mechanics with the epistemological lesson from neurobiology attest to a very simple fact: What we percieve as being outside of us is indeed a fancy and elegant projection of what we have inside. We do make this projection as as result of interacting with something not inside, but everything we experience is inside...Is it not real? It embodies a correlation that is very real. As physicist N. David Mermin has argued, we do have correlations, but we do not know what it is that correlates, or if any correlata exists at all. It is a modern formulation of quantum pioneer Niels Bohr's view: "Physics is not about nature, it is about what we can say about nature."

So what is real, then? Inside us humans a lot of relational emotions exists. We feel affection, awe, warmth, glow, mania, belonging and refusal towards other humans and to the world as a whole. We relate and it provokes deep inner emotional states. These are real and true, inside our bodies and percieved not as "real states" of the outside world, but more like a kind of weather phenomena inside us...That raises the simple question: Where do these internal states come from? Are they an effect of us? Did we make them or did they make us? Love exists before us (most of us were conceived in an act of love). Friendship, family bonds, hate, anger, trust, distrust, all of these entities exist before the individual. They are primary. The illusion of the ego denies the fact that they are there before the ego consciously decided to love or hate or care or not. But the inner states predate the conscious ego. And they predate the bodily individual...The emotional states inside us are very, very real and the product of biological evolution. They are helpful to us in our attempt to survive. Experimental economics and behavioral sciences have recently shown us how important they are to us as social creatures: To cooperate you have to trust the other party, even though a rational analysis will tell you that both the likelihood and the cost of being cheated is very high. When you trust, you experience a physiologically detectable inner glow of pleasure. So the inner emotional state says yes. However, if you rationally consider the objects in the outside world, the other parties, and consider their trade-offs and motives, you ought to choose not to cooperate. Analyzing the outside world makes you say no. Human cooperation is dependent on our giving weight to what we experience as the inner world compared to what we experience as the outer world.

Traditionally, the culture of science has denied the relevance of the inner states. Now, they become increasingly important to understanding humans. And highly relevant when we want to build artefacts that mimic us...Soon we will be building not only Artificial Intelligence. We will be building Artificial Will. Systems with an ability to convert internal decisions and values into external change. They will be able to decide that they want to change the world. A plan inside becomes an action on the outside. So they will have to know what is inside and outside...In building these machines we ourselves will learn something that will change everything: The trick of perception is the trick of mistaking an inner world for the outside world. The emotions inside are the evolutionary reality. The things we see and hear outside are just elegant ways of imagining correlata that can explain our emotions, our correlations. We don't hear the croak, we hear the frog.

When we understand that the inner emotional states are more real than what we experience as the outside world, cooperation becomes easier. The epoch of insane mania for rational control will be over...What really changes is they way we see things, the way we experience everything. For anything to change out there you have to change everything in here. That is the epistemological situation. All spiritual traditions have been talking about it. But now it grows from the epistemology of quantum physics, neurobiology and the building of robots...We will be sitting there, building those Artificial Will-robots. Suddenly we will start laughing. There is no out there out there. It is in here. There is no in here in here. It is out there. The outside is in here. Who is there?

That laughter will change everything.

Estrogen receptors in the male medial amygdala disrupt social behavior.

A series of classic studies have shown that in Prairie Voles two neuropeptides, oxytocin and vasopressin, are primary modulators of pair-bond formation and parental behaviors. Genetic manipulations have been able to switch male behaviors between pair-bonding and promiscuous, and correlations between similar behaviors in human males and their genetic variations have been found. Recently Cushing et al. have made another observation on male voles which one expects will also be carried over to human males: Prosocial behavior correlates with a low density of estrogen receptors in the lateral amygdala, and genetic manipulations which increase the number of these receptors decrease pair-bonding and prosocial behaviors. It will be interesting to follow efforts to translate these findings to human social bonding, especially in relation to neuropsychiatric disorders characterized by an inability to form normal social bonds, such as autism. Here is their abstract:

Studies using estrogen receptor (ER) knock-out mice indicate that ER masculinizes male behavior. Recent studies of ER and male prosocial behavior have shown an inverse relationship between ER expression in regions of the brain that regulate social behavior, including the medial amygdala (MeA), and the expression of male prosocial behavior. These studies have lead to the hypothesis that low levels of ER are necessary to "permit" the expression of high levels of male prosocial behavior. To test this, viral vectors were used to enhance ER in male prairie voles (Microtus ochrogaster), which display high levels of prosocial behavior and low levels of MeA ER. Adult male prairie voles were transfected with ER in the MeA (MeA-ER) or the caudate–putamen (ER control) or luciferase (MeA-site-specific control), and 3 weeks later tested for spontaneous alloparental behavior and partner preference. Enhancing ER in the MeA altered/reduced male prosocial behavior. Only one-third of MeA-ER males, compared with all control males, were alloparental. MeA-ER males also displayed a significant preference for a novel female. This is a critical finding because the manipulations of neuropeptides, oxytocin and vasopressin, can inhibit the formation of a partner preference, but do not lead to the formation of a preference for a novel female. The results support the hypothesis that low levels of ER are necessary for high levels of male prosocial behavior, and provide the first direct evidence that site-specific ER expression plays a critical role in the expression of male prosocial behavior.

The dolphin as gourmet chef: how to prepare cuttlefish

From the abstract of Finn et al. :

...a wild female Indo-Pacific bottlenose dolphin (Tursiops aduncus) was observed and recorded repeatedly catching, killing and preparing cuttlefish for consumption using a specific and ordered sequence of behaviours. Cuttlefish were herded to a sand substrate, pinned to the seafloor, killed by downward thrust, raised mid-water and beaten by the dolphin with its snout until the ink was released and drained. The deceased cuttlefish was then returned to the seafloor, inverted and forced along the sand substrate in order to strip the thin dorsal layer of skin off the mantle, thus releasing the buoyant calcareous cuttlebone. This stepped behavioural sequence significantly improves prey quality through 1) removal of the ink (with constituent melanin and tyrosine), and 2) the calcareous cuttlebone.

Soul-travel for selfless beings

Thomas Metzinger, one of my favorite philosophers, offers this piece on this years Edge.org question "What will change everything."

John Brockman points out that new technology leads not only to new ways of perceiving ourselves, but also to a process he calls "recreating ourselves." Could this become true in an even deeper and more radical way than through gene-technology? The answer is yes.

It is entirely plausible that we may one day directly control virtual models of our own bodies directly with our brain. In 2007, I first experienced taking control of a computer-generated whole-body model myself. It took place in a virtual reality lab where my own physical motions were filmed by 18 cameras picking up signals from sensors attached to my body. Over the past two years, different research groups in Switzerland, England, Germany and Sweden have demonstrated how, in a passive condition, subjects can consciously identify with the content of a computer-generated virtual body representation, fully re-locating the phenomenal sense of self into an artificial, visual model of their body.

In 2008, in another experiment, we saw that a monkey on a treadmill could control the real-time walking patterns a humanoid robot via a brain-machine interface directly implanted into its brain. The synchronized robot was in Japan, while the poor monkey was located thousands of miles away, in the US. Even after it stopped walking, the monkey was able to sustain locomotion of the synchronized robot for a few minutes—just by using the visual feedback transmitted from Japan plus his own "thoughts" (whatever that may turn out to be).

Now imagine two further steps.

First, we manage to selectively block the high-bandwidth "interoceptive" input into the human self-model—all the gut feelings and the incessant flow of inner body perceptions that anchor the conscious self in the physical body. After all, we already have selective motor control for an artificial body-model and robust phenomenal self-identification via touch and sight. By blocking the internal self-perception of the body, we could be able to suspend the persistent causal link to the physical body.

Second, we develop richer and more complex avatars, virtual agents emulating not only the proprioceptive feedback generated by situated movement, but also certain abstract aspects of ongoing global control itself—new tools, as Brockman would call them. Then suddenly it happens that the functional core process initiating the complex control loop connecting physical and virtual body jumps from the biological brain into the avatar.

I don't believe this will happen tomorrow. I also don't believe that it would change everything. But it would change a lot.

Neural correlates of third party punishment.

Legal decision making involves assessing the defendant's responsibility for the crime and choosing an appropriate punishment. To determine the neural correlates of these processes, Buckholtz et al. have used functional MRI to scan volunteers who made legal decisions based on written scenarios. The level of activity in the right dorsolateral prefrontal cortex correlated with the level of responsibility that the volunteers assigned to the defendant, whereas activity in the amygdala, the medial prefrontal cortex and the posterior cingulate cortex predicted punishment magnitude, indicating that distinct neural systems underlie the two processes in legal decision making. Here is their abstract:

Legal decision-making in criminal contexts includes two essential functions performed by impartial “third parties:” assessing responsibility and determining an appropriate punishment. To explore the neural underpinnings of these processes, we scanned subjects with fMRI while they determined the appropriate punishment for crimes that varied in perpetrator responsibility and crime severity. Activity within regions linked to affective processing (amygdala, medial prefrontal and posterior cingulate cortex) predicted punishment magnitude for a range of criminal scenarios. By contrast, activity in right dorsolateral prefrontal cortex distinguished between scenarios on the basis of criminal responsibility, suggesting that it plays a key role in third-party punishment. The same prefrontal region has previously been shown to be involved in punishing unfair economic behavior in two-party interactions, raising the possibility that the cognitive processes supporting third-party legal decision-making and second-party economic norm enforcement may be supported by a common neural mechanism in human prefrontal cortex.

MindBlog's first PodCast: "The I-Illusion"

Posting the podcast of the web radio show this past Monday motivated me to follow through on composing a few of my own podcasts for MindBlog. When I asked for opinions on this possibility last Oct. 31, most respondents indicated a preference for 5-30 min chunks of material. I decided to warm up by translating a lecture I have given, "The I-Illusion," into podcast form. (Here is the mp3 (10 Mb) download.) You can find the web version here. The podcast version is a condensed form of the web lecture (It is 45 min instead of 1 hr), but it has more recent material not included in the web lecture.

Seeing who we hear and hearing who we see

In an article with the title of this post Seyfarth and Cheney make the following comments on work by Proops et al.

Imagine that you're working in your office and you hear two voices outside in the hallway. Both are familiar. You immediately picture the individuals involved. You walk out to join them and there they are, looking exactly as you'd imagined. Effortlessly and unconsciously you have just performed two actions of great interest to cognitive scientists: cross-modal perception (in this case, by using auditory information to create a visual image) and individual recognition (the identification of a specific person according to a rich, multimodal, and individually distinct set of cues, and the placement of that individual in a society of many others). Proops, McComb, and Reby show that horses do it, too, and just as routinely, without any special training. The result, although not surprising, is nonetheless the first clear demonstration that a non-human animal recognizes members of its own species across sensory modalities. It raises intriguing questions about the origins of conceptual knowledge and the extent to which brain mechanisms in many species—birds, mammals, as well as humans—are essentially multisensory.

According to a traditional view, multisensory integration takes place only after extensive unisensory processing has occurred. Multimodal (or amodal) integration is a higher-order process that occurs in different areas from unimodal sensory processing, and different species may or may not be capable of multisensory integration...An alternative view argues that, although different sensory systems can operate on their own, sensory integration is rapid, pervasive, and widely distributed across species. The result is a distributed circuit of modality-specific subsystems, linked together to form a multimodal percept...A third view argues that many neurons are multisensory, able to respond to stimuli in either the visual or the auditory domain (for example), and capable of integrating sensory information at the level of a single neuron as long as the two sorts of information are congruent. As a result, “much, if not all, of neocortex is multisensory”. By this account, perceptual development does not occur in one sensory modality at a time but is integrated from the start.

Here is the experiment as described in the Proops et al. abstract:

...we use a cross-modal expectancy violation paradigm to provide a clear and systematic demonstration of cross-modal individual recognition in a nonhuman animal: the domestic horse. Subjects watched a herd member being led past them before the individual went of view, and a call from that or a different associate was played from a loudspeaker positioned close to the point of disappearance. When horses were shown one associate and then the call of a different associate was played, they responded more quickly and looked significantly longer in the direction of the call than when the call matched the herd member just seen, an indication that the incongruent combination violated their expectations. Thus, horses appear to possess a cross-modal representation of known individuals containing unique auditory and visual/olfactory information. Our paradigm could provide a powerful way to study individual recognition across a wide range of species.

Eating dirt is good for you.

I have always attributed my robust immune system (I don't get colds) to the fact that when I was 1-5 years old I was crawling or running around barefoot in the hot Texas summer, eating dirt, pill bugs, and dog shit. Brody does a nice summary of what is now the accepted view: that exposure while young to a diverse array of bacteria, viruses, and worms trains the immune system in what is and is not important, essentially programs it for later adult life. Children raised in super hygiene environments are more likely to develop allergies, asthma, and autoimmune disorders.