Monthly Archives: January 2015

More about neurons

I want to make a point here that we know less about the brain than is generally acknowledged. Our picture of the functioning of a neuron is taken as more or less settled knowledge; only small refinements are likely. But the refinements that are regularly published are not small. Now we have a paper (citation below) that is extraordinary.

Bywalez and others have shown that the little spines on the dendrite trees of neurons can themselves act as miniature neurons accomplishing computations similar to a full neuron (at least in the olfactory bulb part of the brain and probably other parts too) and that some synapses can be two sided, transmitting signals in both directions. This allows dendrite to dendrite communication. In effect the neck of the spine can isolate the spine from the rest of the neuron, allowing it to reach an action potential level of voltage in its area without interference from the rest of the dendrite tree, and so it is able to send a signal backwards out of the spine.

classic neuron

We are used to thinking of neurons as, in effect, huge add-gates that take a multitude of synapses giving inputs of various strengths and those inputs are combined in the dendrites into a voltage level in the main cell body. If that voltage is above a threshold, an action potential voltage, a signal, is propagated down the neuron’s axon to the dendrites other, usually distant, neurons. There it influences how those other neurons act by contributing a positive or negative voltage to the receiving dendrites’ totals. It is fairly easy to imagine how this works and to mimic it with electronic circuits.

But neuroscience keeps finding exceptions to this theory. There are glial cells assisting and interfering with the process and they can communicate with each other by a different mechanism. There are signals that bypass the whole dendrite calculation and input their signal at the cell body root of the axon, thereby over-riding other inputs. There are axon to axon synapses. Neurons can multitask by calculating and then sending two separate message codes to two separate groups of receiving neurons. Signals can go backwards up the axon. Some neurons can learn timing delays in their signaling. And now this: action potentials can be generated in the little spines of the dendrites and some synapses are not one way transmitters with pre and post halves, but can work both ways. The standard model is getting tattered with exceptions. No doubt there are many more exceptions to come. I venture that we are nowhere near understanding neurons and neuron network behavior.

Bywalez, W., Patirniche, D., Rupprecht, V., Stemmler, M., Herz, A., Pálfi, D., Rózsa, B., & Egger, V. (2015). Local Postsynaptic Voltage-Gated Sodium Channel Activation in Dendritic Spines of Olfactory Bulb Granule Cells Neuron DOI: 10.1016/j.neuron.2014.12.051

Some visual-form areas are really task areas

There are two paths for visual information, one to the motor areas (dorsal ‘where’ stream) and one to the areas concerned with consciousness, memory and cognition (ventral ‘what’ stream). The visual ventral stream has areas for the recognition of various categories of object: faces, body parts, letters for example. But are these areas really ‘visual’ areas or can they deal with input from other senses? There is recent research into an area concerned with numerals. (see citation below) There are some reasons to doubt a ‘vision only’ processing in these areas. “…cortical preference in the ‘visual’ cortex might not be exclusively visual and in fact might develop independently of visual experience. Specifically, An area showing preference for reading, at the precise location of the VWFA (visual word-form area), was shown to be active in congenitally blind subjects during Braille reading large-scale segregation of the ventral stream into animate and inanimate semantic categories have also been shown to be independent of visual experience. More generally, an overlap in the neural correlates of equivalent tasks has been repeatedly shown between the blind and sighted using different sensory modalities.” Is an area specialized in one domain because of cultural learning through visual experience or is the specialization the result of the specific connectivity of an area?

Abboud and others used congenitally blind subjects to see if the numeral area could process numerals arriving from auditory signals. Congenitally blind subjects cannot have categorical area that are based on visual learning. The letter area and numeral area are separate even though the letter symbols and numeral symbols are very similar – in fact can be identical. The researchers predicted that the word area had connections to language areas and the numeral area connected to quantitative areas.

eye-music application

The subjects were trained in eye-music, a sight substitute based on time, pitch, timbre and volume. While being scanned, the subjects heard the same musical description of an object and were asked to identify the object as part of a word, part of a number, or a colour. Roman numerals were used to give a large number of identical musical descriptions of numbers and letters. What they found was that the numeric task gave activation in the same area as it does in a sighted person and that blind and sighted subjects had the same connections, word area to language network and numeral area to quantity network. It is the connectivity patterns, independent of visual experience, that create the visual numeral-form area. “…neither the sensory-input modality and visual experience, nor the physical sensory stimulation itself, play a critical role in the specialization observed in this area. ” It is which network is active (language or quantity) that is critical.

…these results are in agreement with the theory of cultural recycling, which suggests that the acquisition of novel cultural inventions is only feasible inasmuch as it capitalizes on prior anatomical and connectional constraints and invades pre- existing brain networks capable of performing a function sufficiently similar to what is needed by the novel invention. In addition, other factors such as the specifics of how literacy and numeracy are learned, as well as the distinctive functions of numerals and letters in our education and culture, could also account for the segregation of their preferences.

Here is the abstract: “Distinct preference for visual number symbols was recently discovered in the human right inferior temporal gyrus (rITG). It remains unclear how this preference emerges, what is the contribution of shape biases to its formation and whether visual processing underlies it. Here we use congenital blindness as a model for brain development without visual experience. During fMRI, we present blind subjects with shapes encoded using a novel visual-to-music sensory-substitution device (The EyeMusic). Greater activation is observed in the rITG when subjects process symbols as numbers compared with control tasks on the same symbols. Using resting-state fMRI in the blind and sighted, we further show that the areas with preference for numerals and letters exhibit distinct patterns of functional connectivity with quantity and language-processing areas, respectively. Our findings suggest that specificity in the ventral ‘visual’ stream can emerge independently of sensory modality and visual experience, under the influence of distinct connectivity patterns. ”

Abboud, S., Maidenbaum, S., Dehaene, S., & Amedi, A. (2015). A number-form area in the blind Nature Communications, 6 DOI: 10.1038/ncomms7026

Which consciousness are we talking about?

Oliver Burkeman wrote an article for the Guardian on consciousness research and philosophical thinking. I was pleasantly surprised with the historical discussion of the consciousness ideas and with (what seemed to me) a fairly balanced discussion. The new Stoppard play “The Hard Question”, may have prompted him to write the article and may account for the large number of readers. Here is a link.

Despite my liking the piece there were some places that stopped me cold.

Right at the start there is a paragraph that sums up many of the problems I had with the article. “Two decades later, we know an astonishing amount about the brain … But like an obnoxious relative who invites himself to stay for a week and then won’t leave, the Hard Problem remains.” I keep encountering this idea – that we know how the brain works. What I see is the iceberg picture. We may or may not have 10% of an understanding of the brain (less I think). Our ignorance is enormous, so not understanding this or that problem should not be surprising and should not imply the it is insoluble or even particularly stubborn, as brain problems go.

After explaining Chalmer’s philosphical zombie idea (ie people who have no conscious experience but act exactly as normal people) we have Chalmer’s justification for using the idea of zombies. “If you were approached by me and my doppelgänger, not knowing which was which, not even the most powerful brain scanner in existence could tell us apart. And the fact that one can even imagine this scenario is sufficient to show that consciousness can’t just be made of ordinary physical atoms. So consciousness must, somehow, be something extra – an additional ingredient in nature.” What bearing does being able to imagine a thing have to do with its possibility, let alone its existence? That Chalmer can imagine zombies does not mean they are possible. If it is true, as I believe it is, that consciousness is required for many processes in the brain, then a zombie is impossible, even if Chalmer can imagine one. That this may sound like a logical deduction depends on ignorance of what consciousness does and how it does it. If consciousness is a physical process and if it is required for normal thought and action then a zombie is impossible. The zombie idea simply begs the question.

Consciousness, according to Dennett’s theory, is like a conjuring trick: the normal functioning of the brain just makes it look as if there is something non-physical going on. To look for a real, substantive thing called consciousness, Dennett argues, is as silly as insisting that characters in novels, such as Sherlock Holmes or Harry Potter, must be made up of a peculiar substance named “fictoplasm”; the idea is absurd and unnecessary, since the characters do not exist to begin with. … However hard it feels to accept, we should concede that consciousness is just the physical brain, doing what brains do. ” I think it is fair to say that Dennett does not think that the physical mechanisms that are associated with consciousness are an illusion but only that the idea that consciousness is something separate from the functioning of the physical brain is an illusion. It really depends what you are calling consciousness - how it is defined. Burkeman seems to me to not make this problem, of defining consciousness, clear.

Burkeman’s closing picture of the important thinkers from both sides of this disagreement, discussing the question on an arctic trip and ending the experience without having convinced one another to change their views, is a good illustration. They are trying to explain different things that go by the same name. Their notions appear to the other side to be somewhat ridiculous and missing the point. The other side can talk but just do not address their sort of consciousness.

I am sure that Crick was right in his belief that if the neural correlates of consciousness are all found and connected that consciousness will cease to be a puzzle but will be seen as a physical process of the brain. It was this belief that prompted him to spend his later years documenting some of those correlates.

Wolf to dog

Why were dogs domesticated so early? How was it done? A recent paper (citation below) looks at how much of dog behaviour might have been already in the wolf with no effort needed to produce it in the dog. All that may have been needed was to have the wolf lose its fear of man and accept man as a partner.

The researchers, Range and Viranyi, looked at the levels of tolerance and attentiveness in wolves and dogs that were living in the same sort of group and enclosure with the same interaction with humans during their whole lives. In other words they compared like with like rather than pets with wild animals. They were looking at cooperation which has its foundation in two traits. Social tolerance, the ease with which animals live and ‘work’ together, is “usually measured in the context of feeding, which is not accompanied with aggression or, if aggression occurs, it is bidirectional and ritualized.” Tolerance points to particular social emotions and communication. Social attentiveness, the amount of monitoring of companions, is important in cooperation, to know a partner’s behavior and intentions by close observation. Following another’s gaze is an indication of attentiveness. They put forward a hypothesis: “Based on findings that in intraspecific contexts wolves are at least as socially attentive and tolerant as dogs, the Canine Cooperation Hypothesis postulates that dog-human cooperation evolved on the basis of wolf-wolf cooperation. In contrast to many domestication hypotheses, it suggests that dogs did not need to be selected for a general increase in their social attentiveness and tolerance. ”

There was one experiment in particular that I found very interesting. “… we investigated gaze following into distant space and around barriers in wolves. This ability to coordinate with others’ head orientation to look in the same direction is considered a key step toward an understanding of others mental states like attention and intention and thus, is potentially also very important for being able to successfully cooperate. However, while gaze following into distant space could be simply a socially facilitated orientation response (i.e., a predisposition to look where others are looking) , gaze following around barriers, where individuals need to reposition themselves to look behind the obstacle and assess the visual persepctive of the cue-giver different from their own, has been suggested to require a mental representation of the looker’s visual perspective or learning how visual barriers impair perceptions. Accordingly, this latter ability to track another’s gaze around obstacles seems to be cognitively more advanced, and has been suggested to occur especially in species with high levels of cooperative and competitive interactions. Our results showed that wolves followed human gaze as readily as conspecific gaze implying their high social attention and their readiness to accept humans as social partners who might provide important information. ” I have thought that some dogs such as seeing-eye dogs had the ability to envisage the size, shape and mobility of their charges as if they could imagine ‘walking in their shoes”. This sort of ‘dog owners’ belief has been criticized heavily but has not changed the opinion of many owners. It is nice to see some experimental evidence of that type of ability in canines.

Here is the abstract : “At present, beyond the fact that dogs can be easier socialized with humans than wolves, we know little about the motivational and cognitive effects of domestication. Despite this, it has been suggested that during domestication dogs have become socially more tolerant and attentive than wolves. These two characteristics are crucial for cooperation, and it has been argued that these changes allowed dogs to successfully live and work with humans. However, these domestication hypotheses have been put forward mainly based on dog-wolf differences reported in regard to their interactions with humans. Thus, it is possible that these differences reflect only an improved capability of dogs to accept humans as social partners instead of an increase of their general tolerance, attentiveness and cooperativeness. At the Wolf Science Center, in order to detangle these two explanations, we raise and keep dogs and wolves similarly socializing them with conspecifics and humans and then test them in interactions not just with humans but also conspecifics. When investigating attentiveness toward human and conspecific partners using different paradigms, we found that the wolves were at least as attentive as the dogs to their social partners and their actions. Based on these findings and the social ecology of wolves, we propose the Canine Cooperation Hypothesis suggesting that wolves are characterized with high social attentiveness and tolerance and are highly cooperative. This is in contrast with the implications of most domestication hypotheses about wolves. We argue, however, that these characteristics of wolves likely provided a good basis for the evolution of dog-human cooperation.

Range, F., & Virányi, Z. (2015). Tracking the evolutionary origins of dog-human cooperation: the “Canine Cooperation Hypothesis” Frontiers in Psychology, 5 DOI: 10.3389/fpsyg.2014.01582

Another sensory channel

There is another recent discovery to highlight how little we know about our nervous system. Theories are accepted because we believe we have a handle on the anatomy, physiology, biochemistry and biophysics of the nervous systems. But the ‘facts’ change regularly. This time it is connections between the gut and the brain – a direct sensory path and a door through which viruses can pass from gut to brain.

The paper (see citation below) deals with a type of cell in the gut lining that has been thought to communicate with the brain via hormone secretion. The researchers have shown that the cells are in physical contact with neurons and communicate directly. Further, they show that viruses can pass through that physical contact and enter a neuron. This research adds another layer of communication between gut and brain.

The cells, called enteroendocrine cells, are sensory cells reacting to chemicals in the gut. It was thought that the cells produced hormones that traveled through the bloodstream to sensory neurons. This may still be true but it is now known that the enteroendocrine cells grow long processes, neuropods, that reach nerves and form synaptic-like contact with the nerves. They are accompanied by enteric glia cells and respond to neurotrophins.

This communication is important. “Satiety, food preference, and even mood behaviors are a few of the functions modulated by gut chemosensation. Ingested nutrients and bacterial by-products contacting the gut epithelium stimulate enteroendocrine cells.

Here is the abstract: “Satiety and other core physiological functions are modulated by sensory signals arising from the surface of the gut. Luminal nutrients and bacteria stimulate epithelial biosensors called enteroendocrine cells. Despite being electrically excitable, enteroendocrine cells are generally thought to communicate indirectly with nerves through hormone secretion and not through direct cell-nerve contact. However, we recently uncovered in intestinal enteroendocrine cells a cytoplasmic process that we named neuropod. Here, we determined that neuropods provide a direct connection between enteroendocrine cells and neurons innervating the small intestine and colon. Using cell-specific transgenic mice to study neural circuits, we found that enteroendocrine cells have the necessary elements for neurotransmission, including expression of genes that encode pre-, post-, and transsynaptic proteins. This neuroepithelial circuit was reconstituted in vitro by coculturing single enteroendocrine cells with sensory neurons. We used a monosynaptic rabies virus to define the circuit’s functional connectivity in vivo and determined that delivery of this neurotropic virus into the colon lumen resulted in the infection of mucosal nerves through enteroendocrine cells. This neuroepithelial circuit can serve as both a sensory conduit for food and gut microbes to interact with the nervous system and a portal for viruses to enter the enteric and central nervous systems.

Bohórquez, D., Shahid, R., Erdmann, A., Kreger, A., Wang, Y., Calakos, N., Wang, F., & Liddle, R. (2015). Neuroepithelial circuit formed by innervation of sensory enteroendocrine cells Journal of Clinical Investigation DOI: 10.1172/JCI78361

Co-evolution of language and tool-making

It has been more or less accepted that genetic evolution can affect culture and that cultural evolution can affect genetics. But many favour one direction over the other. A recent paper looks at a long sustained period of genetic/cultural co-evolution. (Morgan, Uomini, Rendell, Chouinard-Thuly, Street, et al.; Experimental evidence for the co-evolution of hominin tool-making teaching and language. Nature Communications 6, 2015). The paper is a ScienceDaily item (here ).

Early homo species, our ancestors Homo habilis and Australopithecus garhi, used stone tools for two and a half million years. Through the first 700,000 years the tools, called Oldowan, remained unchanged. The researches show that stone-knapping is not easy to learn. The lack of any improvements to the Oldowan tools probably was because language would have been required to teach more sophisticated techniques. After this long period, about 1.8 million years ago, a new set of stone tools appeared, called the Acheulean, that were more technologically challenging. The researchers show that this knapping skill would have needed language to learn from a master.

The researchers set up learning chains where one person was shown and taught a particular knappng skill. That person then taught another and the skill was passed down a chain of learners. Various teaching techniques were used in the chains. It was found that language was needed to learn some skills successfully. Thus they suggest that the Acheulean improvements to tools were due to the start of proto-languages and that knapping and language evolved together. The driving evolutionary pressure was the advantage of better tools.

This picture is very different from the ‘history of language’ put forward by Chomsky. First because the process is seen as long and gradual. Second because it is basically developed as a teaching aid, a form of communication. “Our findings suggest that stone tools weren’t just a product of human evolution, but actually drove it as well, creating the evolutionary advantage necessary for the development of modern human communication and teaching. Our data show this process was ongoing two and a half million years ago, which allows us to consider a very drawn-out and gradual evolution of the modern human capacity for language and suggests simple ‘proto-languages’ might be older than we previously thought.

Here is the abstract: “Hominin reliance on Oldowan stone tools—which appear from 2.5 mya and are believed to have been socially transmitted—has been hypothesized to have led to the evolution of teaching and language. Here we present an experiment investigating the efficacy of transmission of Oldowan tool-making skills along chains of adult human participants (N=184) using five different transmission mechanisms. Across six measures, transmission improves with teaching, and particularly with language, but not with imitation or emulation. Our results support the hypothesis that hominin reliance on stone tool-making generated selection for teaching and language, and imply that (i) low-fidelity social transmission, such as imitation/emulation, may have contributed to the ~700,000 year stasis of the Oldowan technocomplex, and (ii) teaching or proto-language may have been pre-requisites for the appearance of Acheulean technology. This work supports a gradual evolution of language, with simple symbolic communication preceding behavioural modernity by hundreds of thousands of years.


Questioning oxytocin research

You may have heard of oxytocin as the “moral molecule” or the “hug hormone” or the “cuddle chemical”. Unleashed by hugs, available in a handy nasal spray, and possessed with the ability to boost trust, empathy and a laundry list of virtues, it is apparently the cure to all the world’s social ills. Except it’s not.” That was written by Ed Yong in July 2012. He was not the first of the last to question the hype.

And yet 6 months later we have io9 website with the headline, “10 Reasons Why Oxytocin Is The Most Amazing Molecule In The World”. And they are: it’s easy to get, a love potion that’s built right in, it helps Mom to be Mom, reduces social fears, healing and pain relief, a diet aid, an anti-depressant, stress relief, increases generosity, it’s what makes us human. It even helps autism! But “oxytocin increases in-group trust, it produces the opposite feeling for those in the out-group — so it’s not the “perfect drug” some might proclaim it to be.

But like right brained/left brained people it is a myth that just will not go away. The hype just continued with a number of clinics and authors making lots of money from it.

There is no doubt that oxytocin is a powerful hormone and does have some of these effects. But probably not all. Now it turns out that some, perhaps much, of the research is flawed. A new paper (citation below) looks at the tests used to measure oxytocin. They found much of the testing unreliable because of how samples were prepared. Christensen and others, looked at previously published results and found much variation in typical concentrations of oxytocin in human plasma including baseline levels.

There is considerable disagreement regarding typical levels for oxytocin. “we identified 47 publications … to demonstrate high variability in ‘‘normal’’ and expected oxytocin concentrations. Average concentrations within each publication ranged from 0.5 pg/mL to 3.6 ng/mL, with a mean of 169 pg/mL across all 47 studies. (note the big difference in units picagrams to nanograms) In analyzing the methods used in these publications, the largest apparent contributor to this variability, by far, was the use of pre-assay sample extraction. (to avoid components in the serum interfering in the test) Without any sort of extraction, 23 publications produced a mean concentration of 360.9 pg/mL (SD: 731.6), while extracted samples produced a mean of 10.4 pg/ mL (SD: 20.4) in the remaining 24 publications.” They also cautioned against using rodent data on behaviour in a human context, as rodent levels of oxytocin can be 2000 times those in humans – so there must be some differences in its physiology. They also question how much is known about the relationship between blood oxytocin and the amount in various regions of the brain.

In their first experiment they used the two popular kits for measuring oxytocin on samples with and without extraction and with and without 10pg/ml of added oxytocin (to measure the percentage recovery in the test). The ELISA test had unacceptable variation without extraction and the RIA test could not recover the added oxytocin without extraction. They used the RIA test with extraction in the second experiment which was to test the effect of oxytocin on trust in the Prisoner’s Dilemma setting, with known partners and with strangers. Using these improved methods, they could not replicate the published effects.

This clearly demands re-investigations of the various effects attributed to oxytocin.

Here is the abstract: “Expanding interest in oxytocin, particularly the role of endogenous oxytocin in human social behavior, has created a pressing need for replication of results and verification of assay methods. In this study, we sought to replicate and extend previous results correlating plasma oxytocin with trust and trustworthy behavior. As a necessary first step, the two most commonly used commercial assays were compared in human plasma via the addition of a known quantity of exogenous oxytocin, with and without sample extraction. Plasma sample extraction was found to be critical in obtaining repeatable concentrations of oxytocin. In the subsequent trust experiment, twelve samples in duplicate, from each of 82 participants, were collected over approximately six hours during the performance of a Prisoner’s Dilemma task paradigm that stressed human interpersonal trust. We found no significant relationship between plasma oxytocin concentrations and trusting or trustworthy behavior. In light of these findings, previous published work that used oxytocin immunoassays without sample extraction should be reexamined and future research exploring links between endogenous human oxytocin and trust or social behavior should proceed with careful consideration of methods and appropriate biofluids for analysis.

Christensen, J., Shiyanov, P., Estepp, J., & Schlager, J. (2014). Lack of Association between Human Plasma Oxytocin and Interpersonal Trust in a Prisoner’s Dilemma Paradigm PLoS ONE, 9 (12) DOI: 10.1371/journal.pone.0116172


Stone faced

The extent to which emotions are shown and felt in the body as well as in consciousness is being uncovered. Facial expressions are an example but also posture and bodily feelings. A recent paper looks at the effect of an immobilized face on remembering and recalling emotional words. This adds to previous experiments on the initial recognition of emotional words. This face-emotion tie is a case of embodiment. By and large we automatically show our emotions on our faces and we read others’ emotions from their faces. Further if we force our face into the expression of a particular emotion, we feel that emotion. It is a two-way street as far as communicating and displaying emotion. What about processing emotion? Can the response to emotional words be affected by the face? Yes.

Here is the abstract for the paper (Baumeister, Rumiati, Foroni; When the mask falls: The role of facial motor resonance in memory for emotional language; Acta Psychologica Vol 155, Feb 2015; doi:10.1016/j.actpsy.2014.11.012): “The recognition and interpretation of emotional information (e.g., about happiness) has been shown to elicit, amongst other bodily reactions, spontaneous facial expressions occurring in accordance to the relevant emotion (e.g. a smile). Theories of embodied cognition act on the assumption that such embodied simulations are not only an accessorial, but a crucial factor in the processing of emotional information. While several studies have confirmed the importance of facial motor resonance during the initial recognition of emotional information, its role at later stages of processing, such as during memory for emotional content, remains unexplored. The present study bridges this gap by exploring the impact of facial motor resonance on the retrieval of emotional stimuli. In a novel approach, the specific effects of embodied simulations were investigated at different stages of emotional memory processing (during encoding and/or retrieval). Eighty participants underwent a memory task involving emotional and neutral words consisting of an encoding and retrieval phase. Depending on the experimental condition, facial muscles were blocked by a hardening facial mask either during encoding, during retrieval, during both encoding and retrieval, or were left free to resonate (control). The results demonstrate that not only initial recognition but also memory of emotional items benefits from embodied simulations occurring during their encoding and retrieval.

Processing into memory and retrieval from memory was inhibited for emotional words but not for neutral words when movement of facial muscles was blocked. “Benefits from embodied simulations” is one way to look at it. But it implies that emotion is not an activity of the whole body but of just the brain with the body doing some assistance (although I suspect the authors feel the assistance is very important). Over the spectrum of emotions we have the involvement to varying degrees of the bodies muscles including gut feelings, heart rate, breathing rate, flushing/blushing, goose bumps, skin temperature, hair movements, pupil size as well as skeletal muscles. This is not a little simulation add-on. We often feel the fright a fraction sooner than we recognize the danger. It sometimes takes a long time to figure out what exactly made us feel angry. And in a social animal the communication of emotion is important to peace and cooperation. We communicate automatically with face, voice, posture, and actions. It takes great skill and concentration to hide “tells”.

I think we should view emotions as integrated reactions of our whole body (the whole nervous system, not just our brain/mind) to our environment.


Talking to babies

When babies learn language, they learn more than language. According to a recent paper they also learn cognition. This news reminded me of something I had read months ago and I went back and found it. Here is the abstract of the paper, followed by the story illustrating the absence of good language learning.

Abstract of paper (Vouloumanos, Waxman; Listen up! Speech is for thinking during infancy; Trends in Cognitive Sciences Vol 18, issue 12 Dec 2020): “Infants’ exposure to human speech within the first year promotes more than speech processing and language acquisition: new developmental evidence suggests that listening to speech shapes infants’ fundamental cognitive and social capacities. Speech streamlines infants’ learning, promotes the formation of object categories, signals communicative partners, highlights information in social interactions, and offers insight into the minds of others. These results, which challenge the claim that for infants, speech offers no special cognitive advantages, suggest a new synthesis. Far earlier than researchers had imagined, an intimate and powerful connection between human speech and cognition guides infant development, advancing infants’ acquisition of fundamental psychological processes.

From Catherine Porter’s Column Aug 2014, Why Senegalese women have been afraid to talk to their babies - Fears of evil spirits have kept parents from talking to their babies, but that is changing thanks to a program that teaches about brain development. (here) : “10-year-old children in Senegal, deemed incomprehensibly dull by an international early literacy test six years ago. … The results were a blow to the Senegalese government, which pours a quarter of its national budget into education. … Tostan, a well-known non-governmental organization in Senegal, began asking the same questions. Staff members launched focus groups, to research local ideas about schools and child development. After four months, they concluded the root of the problem stretched beyond schools into village homes. Parents, although loving, were not speaking directly to their babies. Many avoided looking deeply into their babies’ eyes. … a baby in rural Senegal would hear about 200 words an hour, Tostan founder and chief executive officer Molly Melching says. Most of those were orders. No wonder they weren’t learning how to read, Melching posited. The language part of their brains was vastly underdeveloped. … The concept of djinns comes from both ancient African religions and the Koran. They are spirits, which can be helpful or hurtful. The hurtful ones, locals believe, can possess them. … Djinns are attracted to babies by jealousy, many locals believe. So, looking a baby in the eye is taboo, as is speaking directly to her. … “In our culture, if you talk with your child, you risk losing him,” says Tostan’s Penda Mbaye. She recalls how she was talking to her first baby when her grandmother warned her about djinns. “After that, I didn’t dare to do it.” … It is one thing to change the national course curriculum, or teacher training, or even severe malnutrition that stunts children’s brains. It’s another to change people’s cultural beliefs and corresponding behaviour. … Tostan facilitators developed a year-long class curriculum for parents. It includes lessons on everything from infant nutrition and children’s rights to sleep schedules and baby massage. The most important part though, is the new understanding of children’s growing brains. “We delve into brain development in a non-judgmental way,” Melching says.

This program seems to be working and mothers are enthusiastic, enjoying being able to interact with and talk to their babies. In a few years the data will be in and it will be seen what difference communication with babies brings. It is expected to not just improve language skills but IQ and general cognition.

Why introspection doesn’t work

What do we have when we introspect? – we have consciousness of a memory of a short part of the recent stream of consciousness. We are not looking directly at an instant of consciousness. We are looking at recently past consciousness and we are not looking at an instant but at whatever is grouped in one unit of memory. The consciousness that we experience is not permanent – it was gone almost immediately leaving only a little memory. As soon as we try to examine its details, we are looking at a memory. Unless we have a photographic memory, a lot of detail is lost in forming a memory and there is a ‘smudging’ of the experience over a somewhat longer period of time in the memory process. There is no reason to believe that a recalled memory is identical to the original conscious experience. We experience consciousness but we cannot actually examine it directly, only the memory of it.

Well, the memory of recent conscious experience might by useful. Suppose it is very close to the conscious experience – what does that give us? Conscious experience is not what it seems. It seems like consciousness is looking directly at the input of sensory information. But this is not so. Its formation is entirely opaque; we cannot experience the making of conscious experience. The creation of consciousness is a purely unconscious process and it is complex. The conscious experience is constructed from the sensory input and the prediction of what the sensory input was assumed to be, and our knowledge of the world. It is many layers of processing from the raw sensory input. Our consciousness of movement is the movement we planned and not necessarily the resulting movement. Everything is constructed including the ‘self’ that experiences the conscious stream. Our conscious models of thoughts, decisions, values, and emotions are constructed with even less contact with the real operations of the brain than sensory/motor information. Examining this stream of consciousness with a conscious examination of it is playing in a hall of mirrors.

Consciousness does not exist to allow us to understand our brain. Why should it? Why would there be any evolutionary pressure for our brains to understand our brains? What the brain constructs is experiences and it does it in a way that makes them a useful memory library we can use and learn from. If we want to learn about our own brains there is a problem with the usefulness of introspection. It can only answer some ‘what’ questions of limited value. To understand how the brain works we really want the ‘how’ and ‘why’ questions addressed and they are precisely what memory of consciousness or even consciousness experience itself cannot give us.

We must forget about studying our brains from subjective, inside observation. We must treat our brains objectively to gain understanding of how they work. There are many people who do not accept this and insist that we can study the mind in a subjective way. Indeed, to some people the subjective mind is the only interesting part of thought or brain which is worth studying. This subjective approach seems to me to be a waste of time and effort. It is rather boring (scientifically) at best and misleading at worst. All that this studying would give us is what we already have. It will give us a subjective experience of a copy of a subjective experience. It will not give us what consciousness physically is or how or why it is as it is.