Original article: Czupryn, A. et al., Science 334, 1133 (2011).

Neurons are a highly specialized group of cells that transmit electrical stimuli to elicit responses in the body. This high specialization comes with a price: with few exceptions, neurons cannot divide to replace nonfunctional ones. Over the past decade, cell therapy, that is treatment of a disease by introducing new cells, has emerged as a new hope for neurological disorders such as spinal cord injury, Alzheimer’s disease, and Parkinson’s disease, albeit with numerous challenges. One of the major problems in the field is to make the newly-introduced cells integrate into the neural circuitry of the host organism. This proof-of-concept study showed that it is possible for transplanted neurons to functionally integrate into the host brain and cure obesity in a specific genetic mouse model. This genetic mouse model lacks the ability to sense leptin, a hormone that regulates body weight and metabolism. Thus, these mice are prone to obesity and diabetes. The authors transplanted progenitor neurons isolated from the hypothalamus-a part of the brain that regulates numerous functions including metabolism, hunger and body temperature-of normal embryonic mice to the hypothalami of newborn diseased mice. Twenty weeks after the transplantation, cells were shown to be functionally integrated into the native circuitry. Integrated neurons were able to create electrical stimuli, transmit signals and, unlike the native neurons, respond to the hormone, leptin. Amazingly, transplanted mice were 30% lower in body weight and diabetes-free compared to the obese non-transplanted counterparts. The results were dramatic, despite the fact that only a few of the transplanted neurons were actually converted to the neurons that play a role in energy metabolism and leptin response. The authors explain this phenomenon by stating that the transplanted neurons may work as “antennas” to sense leptin and regulate other neurons in the native circuitry. Although current research is far from human application, it is still an important step towards treatment of detrimental neurological diseases.

2- A new record in solar cell efficiency

Original Article: Yella, A. et al., Science 334, 629 (2011).

Since their discovery in 1991, dye-sensitized solar cells (also known as Grätzel cells) have offered great potential despite their low efficiency values. They consist of dye-soaked titania nanoparticles coupled to an iodide-based electrolyte that allows for absorption of light and its conversion to electricity through the fast transport of electrons. According to a report in Science, researchers from ecole Polytechnique Federale de Lausanne (EPFL) have substantially improved the efficiency values over 12%, making this type of solar cells a feasible contender to the incumbent silicon solar cells. To store the most sunlight, these cells absorb the colors of the light spectrum with the highest energies and reject the rest such as the green light. In addition to the increase in cell efficiency, Grätzel and coworkers have also reduced their cost by replacing expensive ruthenium dyes with a zinc-based dye. Finally, they have improved the voltage output by using a cobalt electrolyte, a redox system that is more compatible than the previous iodide systems. This new system with improved components has also increased the theoretical maximum efficiency to 30%, which will require further optimization in device design and engineering to achieve. The only major drawback is the use of organic solvents potentially limiting the efforts for large-scale fabrication.

3- IQ can still change in teenage years

Original Article: Ramsden S. et al., Nature 479, 113 (2011).

Intelligence quotient (IQ) is a standardized measure of human intellectual capacity that takes into account a wide range of cognitive skills. IQ is generally considered to be stable across the lifespan, with scores at one time point being used to predict educational achievement and employment prospects in later years. However Prof. Cathy Price and colleagues have found that verbal and non-verbal IQ can rise or fall in the teenage years. They tested 33 teenagers-19 boys and 14 girls-in 2004, when they were 12 to 16 years old, and again in 2008, when they were 16 to 20 years old. Each time, the teens took IQ tests that measured their verbal and nonverbal abilities. Then, using magnetic resonance imaging, the researchers scanned the teenagers’ brains while they performed verbal tasks, such as reading or naming objects, and nonverbal tasks, such as solving visual puzzles with their hands. The idea was to match their test scores with a picture of their brain structure and activity at each time. The test results revealed dramatic changes between their first testing and their second: verbal and nonverbal IQ scores of participants rose or fell by as many as 20 points (on a scale with an average score of 100). Some teens improved or declined in either their verbal or nonverbal skills, while others improved in one area and declined in the other. The brain scans mirrored the score differences. For example, in teens whose verbal IQ scores had increased, the scans showed increased gray matter density in a region of the brain activated by speech. Teens whose nonverbal skills had improved showed changes in a brain region associated with motor movements of the hand. The authors note that these were the largest changes observed, and that there might be many more that were not noticed.

4- A coordination path from an infant’s heart to the mother’s heart

Original Article: Feldman, R. et al., Infant Behavior and Development 34, 569 (2011).

A group of researchers sat 40 pairs of mothers and 3-month-old infants face-to-face, equipped with sticky skin electrodes on either side of their hearts. Beat for beat, mother and child’s hearts thumped together almost instantly as they shared loving looks or contented coos. This cardiac coupling worked only for moms with their own babies, and only when the duos synchronized smiles and other cheerful social behaviors. The researchers suspect that when humans mirror each other’s facial expressions, they may switch on specific areas in the brain that tell the heart when to thump. Melding with mom lasts longer than just a few beats, however. Babies who don’t tune in with their mothers are less empathetic as teenagers, according to previous work from the same group. Premature infants or those whose mothers have postpartum depression may be most at risk for losing this social skill because they miss out on early opportunities to interact with their mothers. The authors state that future research is required to examine the impact of interaction synchrony on other physiological processes, such as hormonal release or brain activation.

A more systematic approach to language and cognition began in the 1920s. During the 20s and 30s Edward Sapir and Benjamin Lee Whorf separately claimed that language is the main factor in the constructive process, that, in effect, language determines thought. Whorf claimed in his Collected Papers on Metalinguitics that language is the prime factor in objectification of reality. Language determines thought and certain aspects of it restrict our view of the world. A weaker form of the ‘language hypothesis’ does not insist that language determines thought, but that language predisposes the way people think.

During the 50s, when behaviourism was the intellectual fashion, there were not many studies on language and cognition. The stimulus-response-reinforcement model favoured by the behaviourists was applied to language acquisition by Skinner in his book Verbal Behaviour. According to Skinner, verbal behaviour can be acquired if the set of appropriate responses is frequently followed by reinforcement. Reinforcement, he claimed, is equally important after language has been acquired. The purpose and function of reinforcement is to maintain the strength of the response. Language acquisition and verbal behaviour are regarded as mechanical processes. Verbal behaviour can only develop in a social context, with the participation of another person or audience. The speaker learns to speak eventually only in the presence of a listener; the reinforcement that a speaker needs is absent or present when a listener is absent or present. This view treats language as a learning behaviour that can be changed or manipulated with the help of reinforcement, or deprivation, in other words ‘a specific controlling condition … control of verbal stimuli.’

Skinner presents three different types of behaviour which control the verbal stimuli: the echoic, the textual and the intraverbal. ‘Echoic’ behaviour is when the response consists of a sound pattern reproducing something very similar to the stimulus. It is established in the child through the special reinforcement that Skinner calls ‘educational’. Educational reinforcement is provided by institutions whose behaviour is influenced by economic reinforcement: for example, when a teacher gets some financial (or other) rewards for teaching the child how to acquire language effectively. ‘Textual’ behaviour relates to learning how to read. It too is established through educational reinforcement. The stimulus in this case is a text which may be in the form of pictures, formalised pictographs, characters or (more commonly) letters or symbols of an alphabet. ‘Textual’ behaviour describes the way people acquire the skill of writing. Writing behaviour has all the characteristics of ‘echoic’ behaviour, but expressed in visual rather than auditory terms. Three stages are distinguished: the stage of producing the necessary materials, the stage of making differentiated marks, and the stage of transmitting these marks to the reader.

In the case of intraverbal behaviour there is no correspondence between stimulus and response-produced, as in echoic behaviour or as in the correspondence between different dimensional systems as in the textual behaviour. This allows the consideration of all types of vocal and textual stimuli and responses in all combinations at the same time. Interestingly, Skinner regards translation as a ‘special case of intraverbal behaviour’.

Skinner’s approach to thought was abstract, not empirically based. His view was that the results of human thought can be most unpredictable and are therefore severely difficult to explain. So, the simplest and most satisfactory way of explaining thought is to consider it as a behaviour. Thought is not a secretive way of influencing the behaviour, but it is behaviour itself, the ‘sum total’ of the responses to the world and the environment the behaviour ‘lives’ in. He concludes: ‘When we study human thought we study behaviour.’

In the 60s the debate about language was between two conflicting positions. The behaviourist accounts of language and language-acquisition in terms of association, and the approach of Chomsky and his colleagues who presented a linguistic analysis strongly linked with psychology. Their basic argument was that the stimuli-response theory was highly irrelevant with respect to language acquisition. Being mainly interested in the syntactic forms of language they believed that the deep structures of sentences are abstract and inexplicable by the simplistic arguments put forward by the behaviourists. Their debate with the behaviourists, and the theoretical papers in which they criticized and cast doubt on their views, did not leave much room for attention to childhood development and how the processes of that development affect their language acquisition.

Piaget, although not a psychologist by profession (he started out as a biologist), showed a great interest in the way children think. He believed, in contradistinction to Sapir-Whorf, that thought determines language, a position since known as the ‘cognition hypothesis’. The basic difference between language studies in the 60s and Piaget’s approach was that Piaget’s interest was in children aged six and above, and investigated the first structured language during and shortly after the stage of two-word utterance. He discussed language and the thinking of the child, the language function, the questions that children put, and understanding between children.

Piaget and Chomsky came to be the most recognised and respected representatives of the cognitive movement; their work has inspired and influenced so many and to such an extent, that one can rightly speak of a school of thought within the field of cognitive studies. Chomsky had revolutionary and controversial views about language and thought sharply contrasted with anything that had come before. He claimed that every child has an innate knowledge system that contains abstract linguistic structures that are not taught rather, they are already part of the child’s system from birth. He hypothesized that under those circumstances, there must exist a set of grammatical rules that would produce syntactic descriptions for any sentence in any given language. Piaget on the other hand believed that a child must go through several stages to acquire an adult level of logical thought. The effect of the environment on a child’s thought and language is, for Piaget, crucial. Language is an extremely broad set of human capacities. Identical mental operations underlie one’s encounters with a wide range of materials and topics such as space, time, casualty and morality. So the later forms of thought can be located in earlier forms. Piaget examined the child and his mind as an active and constructive agent, that slowly gains knowledge and logic through developing cognitive processes. Chomsky’s view was different; he saw the mind as a set of pre-programmed units fully equipped, that need only a modest trigger from the environment to function. In other words Piaget considered human linguistic capacities as a product of a general ‘constructed’ intellectual development, whereas Chomsky insisted that they are a highly specialised part of the human genetic inheritance, largely separate from any other human faculty. They are, Chomsky said, a kind of an innate knowledge that has only to unfold. The Piagetian cognitive hypothesis claims that language derives from thought. Chomsky takes a radically different view, arguing that language is divorced from thinking. He claims that each human intellectual faculty is located in different areas of the brain, maturing at its own rate and through distinct processes. To make this statement more comprehensible, Chomsky used the analogy of bodily organs: he regarded the mind as a set of organs, like the liver or the lungs or the heart. A heart is not taught to beat, but matures according to its own genetic timetable. The same is true of ‘language’ as well as to other ‘organs of the mind’, that are programmed to function over time according to a genetic timetable.

Although both used and developed models provided by biology and logic, they showed interest in very different kinds of examples and explanations. Piaget tried to give a rich description of the stages that children pass through to achieve a higher level of knowledge. So he developed an elaborate technical vocabulary, rooted in biology, and he based his conclusions upon errors that children made when he gave them his famous challenging puzzles to solve. His ability to give convincing answers to the problems of the development of knowledge, and his hard work in collecting and synthesizing an enormous amount of data, are his big contribution to this field.

Chomsky’s contribution is no less important. His difference from Piaget is that he was not concerned to describe behavioural phenomena; his concern was the development of linguistic science and how its approach and methods could carry into the social sciences. His views of language as a part of an innate and universal system of knowledge and language are the same, had huge influence, although it is an hypothesis impossible to prove.

In October 1975, Jean Piaget and Noam Chomsky were invited to express their ideas and present their theories in a meeting which took place at the Abbaye de Royaumont in France. The historical importance of this ‘rendezvous’ was noted by the psychology and linguistic community all over the world and even scientists from behavioural and empirical areas attended the occasion. Piaget and Chomsky exchanged views about language and cognition, but, as people who attended the Royaumont meeting commented, there was no agreed conclusion, only exploration of issues.

It is hardly surprising that no firm conclusions were reached at that meeting. The study of cognition is not an empirical study of given data or facts susceptible to quantitative measurement or experimentation. The subject-matter has to do with human psychology, where different views, theories, methods and experiments are used, different schools are created and several disciplines such as anthology, biology, philosophy etc. are involved together. Without ignoring the important contribution of schools such as behaviourism, psychoanalysis etc., only the further development of the cognitive movement appears likely to give satisfactory answers to issues that arise everyday about language and thought. The charm of uncertainty will draw the passion for further research that will lead from mere confusion to a new theory, a new argument for appraisal or debate.

Useful reading 

• Appel, M,H. (1977) Topics in Cognitive Development.
• Drorni, E. (1993) Language and Cognition: A Developmental Perspective.
• Massimo, P. (1979) Language and Learning.
• Skinner, B. (1957) Verbal Behaviour.
• Vasniadou, S. (1993) Language and Thought.
• Vhorf B.L. (1952) Collected Papers on Metalinguitics.