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Flexibly controlling behavior to achieve a desired goal depends on the ability to monitor one’s own performance. A key open question is how performance monitoring can be both flexible to support multiple tasks and specialized to support specific tasks. We characterized performance monitoring representations by recording single neurons in the human medial frontal cortex (MFC). Subjects performed two tasks that involve three types of cognitive conflict. Neurons encoding error, conflict and predicted control demand in one or both tasks coexisted in the same population. Collectively, they gave rise to a representational geometry that simultaneously allowed task specialization and generalization. Representations of conflicts were compositional. Neurons encoding conflict retrospectively served to update estimates of control demand as predicted by a Bayesian model. These findings reveal how the MFC representation of evaluative signals are both abstract and specific, suggesting a mechanism for computing and maintaining control demand estimates across trials and tasks.

A plant-herbivore information “arms race” The consumption of plants by herbivores has driven the evolution of many diverse plant defense chemicals to which herbivores have constantly adapted. The transmission of chemical information at the community level is less known but important given the plethora of plant and herbivore species, especially in tropical communities. Zu et al. propose an information “arms race” approach to explain plant-herbivore chemical communication at the community level (see the Perspective by Solé). To test their conceptual framework, they used field data of herbivore-plant interactions and plant–volatile organic compound associations in a tropical dry forest. Their approach provides an understanding of the functioning and persistence of systems where individuals send and receive information in the form of signals to which other individuals react and, in turn, affect the behavior of other participants in these systems. Science , this issue p. 1377 ; see also p. 1315

A Varied Bouquet Pollinators display innate attractions to odor, but can also learn to associate odor with a nectar reward. Riffell et al. (p. 200 , published online 6 December; see the Perspective by Knaden and Hansson ) characterized the odor profile for flowers to which hawkmoths are innately attracted and found that the majority contain a distinct chemical profile, which is uniquely represented on their olfactory lobe. The moths could also be trained to associate nonattractive odors with a reward and thus learn novel odor attractions. Though learning altered neurons within the antennal lobe, the innate preferences were not changed.

The majority of pathogens, including many of medical and veterinary importance, can infect more than one species of host. Population biology has yet to explain why perceived evolutionary advantages of pathogen specialization are, in practice, outweighed by those of generalization. Factors that predispose pathogens to generalism include high levels of genetic diversity and abundant opportunities for cross-species transmission, and the taxonomic distributions of generalists and specialists appear to reflect these factors. Generalism also has consequences for the evolution of virulence and for pathogen epidemiology, making both much less predictable. The evolutionary advantages and disadvantages of generalism are so finely balanced that even closely related pathogens can have very different host range sizes.

The growing number of complete microbial genome sequences provides a powerful tool for studying the biology of microorganisms. In combination with assays for function, genomic-based approaches can facilitate efficient and directed research strategies to elucidate mechanisms of bacterial pathogenicity. As genomic information accrues, the challenge remains to construct a picture of the biology that accurately reflects how individual genes collaborate to create the complex world of microbial specialization.

New experimental strategies reveal spatial and temporal features of protein synthesis and degradation in cells [Also see Research Article by Jan et al. and Reports by Williams et al. and Foresti et al. ]

The takeover wave of the 1980s moved large enterprises toward specialization and away from the diversification of the 1960s. The easy availability of funds made acquisitions affordable, while the hands-off antitrust policy allowed mergers between two firms in the same industry. Hostile takeovers and leveraged buyouts fostered the break up of conglomerates and the sell-off of divisions to buyers in the same industry; they helped speed the economy-wide move toward specialization. The poor performance of conglomerates indicates that this trend toward specialization is likely to make U.S. industry more competitive. Current state antitakeover laws are probably the result of intense lobbying by managers trying to entrench themselves; these laws do not promote competitiveness of U.S. industry. In contrast, the current accommodating federal antitrust stance encourages specialization.

Before he became America's first de facto science adviser and before he helped lay the foundation for the National Science Foundation, Vannevar Bush was a professor of Electrical Engineering and, eventually, dean of Engineering and vice president at the Massachusetts Institute of Technology (MIT). In those capacities, he came in contact with some of the nation's best and brightest minds in their formative years. But after two decades in such a rarified academic environment, Bush had become disenchanted by the increasing specialization of undergraduate curricula in science and engineering in America ( 1 ). He felt that education in these fields placed too much emphasis on information transferral from teacher to student and too little on deep understanding and intellectual synthesis by the student. Bush was among the first to anticipate that massive amounts of information would someday be universally and readily available to all, such that our ability to communicate knowledge through classes would become far less important than our ability to inspire students to do something creative, and valuable, with it.

The human brain is exceedingly complex and studying it encompasses gathering information across a range of levels, from molecular processes to behavior. The sheer breadth of this undertaking has perhaps led to an increased specialization of brain research and a concomitant fragmentation of our knowledge. A potential solution is to integrate all of this knowledge into a coherent simulation of the brain ( 1 ). However, simply “building” a brain from the bottom up by replicating its parts, connections, and organization fails to capture its essential function—complex behavior ( 2 ). Instead, just as engineers can only construct cars and computers because they know how they work, we will only be able to construct a brain if we know how it works—that is, if we understand the computations that are carried out in individual brain areas, and how these computations are implemented on the level of neural networks. On page 1202 of this issue, Eliasmith et al. ( 3 ) make headway toward this benchmark by presenting just such a large-scale computational model of the human brain that can simulate a variety of complex behaviors.

In multicellular organisms, cells carry out a diverse array of complex, specialized functions. This specialization occurs mostly through the expression of cell type—specific genes and proteins that generate the appropriate structures and molecular networks. A central challenge in the biomedical sciences, however, has been to identify the distinct lineages and phenotypes of the specialized cells in organ systems, and track their molecular evolution during differentiation. On page 687 of this issue, Bendall et al. ( 1 ) offer a brilliant proof of principle for a novel technology—mass cytometry—and provide a uniquely detailed view of cell differentiation in the human hematopoietic system. They used this technology to simultaneously examine 34 attributes of human bone marrow cells and then create a superimposed map showing the complex interactions of cell signaling molecules, all at an unprecedented level of resolution. This opens a new chapter in single-cell biology.

Given the pace at which the scientific landscape changes, even practicing scientists can find it difficult to keep up with advances outside their fields of specialization. Imagine the daily challenge faced by classroom science teachers, who are trying to remain current with a broad range of scientific content and to incorporate the new information into existing curricula. This integration requires a depth and breadth of science knowledge not provided by the professional development available to most elementary, and even some secondary, school teachers.

In humans the two cerebral hemispheres of the brain are functionally specialized with the left hemisphere predominantly mediating language skills. The basis of this lateralization has been proposed to be differential localization of the linguistic, the motoric, or the symbolic properties of language. To distinguish among these possibilities, lateralization of spoken language, signed language, and nonlinguistic gesture have been compared in deaf and hearing individuals. This analysis, plus additional clinical findings, support a linguistic basis of left hemisphere specialization.

The data deluge is already here (special section on Dealing with Data, 11 February, p. [692][1]). As a community, we should encourage young scientists to prepare for careers, such as bioinformatics, that will help address data issues. We should also find ways to move beyond specialization in one field and teach interdisciplinary flexibility. Scientists are needed who can communicate with the molecular biologists, pathologists, and geneticists as well as the bio informaticians, programmers, and IT specialists. Unfortunately, the best way to train this next generation of scientists is unclear. Current interdisciplinary PhD programs do not ensure that coursework is balanced across disciplines. One alternative would be to encourage wet-lab trained PhD students to apply for post-doc positions in bioinformatics. This would provide the foundation to understand and communicate with both the bench scientist and bioinformatician, but it also requires that we as a community be willing to take a chance and hire bench-trained PhDs with some bioinformatics affinity over the bioinformatics-only trained PhDs who are currently in short supply. [1]: /lookup/doi/10.1126/science.331.6018.692

[Figure][1] CREDIT: WIKIMEDIA COMMONS During the past 10 years, we have had our first glimpse of why individuals differ so much from one another. This is not the right place to revisit the nature-nurture wars or to reflect on the extent to which our impression of high phenotypic variability in humans is a narcissistic illusion. For the moment, let us just acknowledge the obvious: In any small group of people, we see a lot of variation in traits we care about—and not just those that affect health. Geneticists shy away from studying these traits—and for good reason. They prefer not to revisit a subject whose premature investigation accounted for the worst moments of their young science. Nonetheless, questions about the genetic basis of variability among generally healthy humans will not go away. Public fascination alone will keep it alive, as will the realization that genetics is unlikely to revolutionize medicine until we develop a better understanding of normal phenotypic variation. So, what have our first glimpses of variation in the genomes of generally healthy people taught us? First, balancing selection, the evolutionary process that favors genetic diversification rather than the fixation of a single “best” variant, appears to play a minor role outside the immune system. Local adaptation, which accounts for variation in traits such as pigmentation, dietary specialization, and susceptibility to particular pathogens is also a second-tier player. What is on the top tier? Increasingly, the answer appears to be mutations that are “deleterious” by biochemical or standard evolutionary criteria. These mutations, as has long been appreciated, overwhelmingly make up the most abundant form of nonneutral variation in all genomes. A model for human genetic individuality is emerging in which there actually is a “wild-type” human genome—one in which most genes exist in an evolutionarily optimized form. There just are no “wild-type” humans: We each fall short of this Platonic ideal in our own distinctive ways. [1]: pending:yes

BEIJING-- China9s prestigious Beijing University will launch a pilot class next month to test the idea that a liberal arts education is more beneficial to students than a narrowly focused course of study. The radical approach runs counter to a half-century of specialization in Chinese higher education. If successful, it will be extended to all students--a giant step beyond concurrent reforms at some of the country9s leading universities that focus only on the cream of the crop (see sidebar).

It is well established that abilities such as language are mediated by specific brain regions in adulthood, but it is still a matter of debate whether such specialization is present from birth or whether it emerges during the course of early childhood development. In an elegant Perspective, Dorothy Bishop discusses whether new findings in infants with Williams syndrome (WS)--a disorder in which it has been claimed that language abilities are largely retained even though other cognitive impairments abound--may help to resolve this debate ( Paterson et al.).

SCIENTIFIC PUBLICATIONSUse of the expression "new paradigm" in the scientific literature has been growing steadily throughout the 1990s; last year alone, 124 papers in leading journals invoked the term in their titles or abstracts. Yet according to an analysis by the Institute for Scientific Information, most of these papers seem to have little impact: Those using the term were cited less often, on average, than those that avoided it. Some say that the rise of new paradigms is linked to the increasing specialization of science; others say the term is used to attract attention and funding.

Toyoko Akiyama fosters a movement to counter specialization by giving all students a real taste of her biology lab.

The ability of parent cells to send progeny on a new and different course underlies all complex life, and researchers are beginning to learn how this happens from yeast. Mother yeast cells are sexually ambidextrous, able to switch between two mating types. But their daughters lack this switching ability. The reason, according to recent research, may lie in a cellular railway running between mother and daughter. Moving along cytoskeletal “railway tracks,” motor proteins shuttle in an unknown regulatory factor that, working through a newly discovered protein called Ash1p, prevents mating-type switching. This pathway is now one of the most carefully mapped journeys toward cell specialization known.

Developmental BiologyBoston, Massachusetts—In this issue of Science ( [p. 637][1] and [p. 641][2]), a team of researchers in Paris and Cambridge, Massachusetts, has provided a clue to a central mystery in developmental biology: How do two cells with identical sets of genes develop along different paths? In one species of bacteria, a protein called SpoIIE initiates a cascade of biochemical changes on only one side of a burgeoning cell membrane, causing one of the new cells to become a specialized bacterial spore. This asymmetrical process may depend on differences in the cell sizes, a phenomenon that also seems to play a role in cell specialization in other species. [1]: /lookup/doi/10.1126/science.270.5236.637 [2]: /lookup/doi/10.1126/science.270.5236.641

Baby babbling is the universal developmental milestone before the onset of language production in humans, yet little is known about whether the neural determinants of this behavior are fundamentally linguistic ([1][1], [2][2]) or reflect only oral-motor developments ([3][3], [4][4]). In adults, the

Cuckoos lay their eggs in the nests of many other bird species, leaving the unwitting hosts to raise their young, but individual females specialize in nests of just one kind of host bird. Such specialization should lead to the formation of new cuckoo species but has mysteriously failed to do so. Now, a study on page 471 shows why: Male cuckoos mate with females that parasitize many different hosts, homogenizing the cuckoo genes and preventing the development of new species.

It has been suggested that the inverted hand position of left-handers during writing indicates the left hemisphere of their brain is linguistically specialized and that the writing of these left-handers may be controlled via ipsilateral pathways. Electroencephalograph alpha asymmetry measures at central and parietal leads, as well as dichotic tests, differentiated right-handers from left-handers, but not inverters from noninverters. Electroencephalograph differences between hand posture groups did appear, but only at occipital leads during reading and writing tasks. Regardless of hand posture or speech lateralization, the right central region of the brain is significantly involved in the control of left-handed writing.

The Council is not engaged in the supranational formulation of policy and planning on scientific research and technology, but has made considerable progress in coordinating research policies and plans on a limited number of scientific and technical problems of priority interest and of common concern to all members. The establishment of national science-planning institutions in CEMA countries and the adoption of a uniform approach to the formulation of national science policies and plans must be considered basic procedures for achieving international coordination of their efforts. The creation of organizational units within CEMA to deal specifically with the coordination of science policies and plans represents a strengthening of the institutional framework that is necessary for coordination of an internationally cooperative effort in research and technology. Moreover, CEMA9s 1-year plan for science and technology has probably been of considerable value as a pilot project for the formulation of the research plan for 1966-70. The delineation of a limited number of important scientific and technical problems of common interest to the members, and the allocation of research projects to a country having the highest capability to conduct them, hold considerable promise for financial savings and for improved utilization of the limited scientific manpower and research facilities of the CEMA countries. While all these measures are significant in CEMA9s attempt to improve coordination of science policy and planning, only time will enable true assessment of their effectiveness. The Council9s scheme for the specialization of labor in research and technology has met and will undoubtedly continue to meet, considerable opposition by various segments of the scientific communities because of deep-rooted and long-standing national prejudices, and reluctance of vested interests to give up research activities in which they are interested and to which their professional futures are tied. Moreover, opposition to CEMA-sponsored programs for specialization in research will continue to stem from the desire of some member countries further to reduce Russian influence in their domestic affairs. While recognizing the financial savings that can accrue to them from division of labor in research within CEMA, the smaller countries cannot be unaware that there is probably a limit to which the Soviet Union, with its vast scientific and technological base, is willing to participate in the division of-labor scheme. As a world power, the Soviet Union can hardly become dependent upon other members of CEMA in any field. Nevertheless, by promoting the coordination of research plans and a division of labor among CEMA members, the Soviet Union stands to gain by having its scientific-research effort augmented in several fields by the efforts of other members.

During natural movements, the motoneurons innervating a single muscle have different patterns of activity that are correlated with differences in synaptic input. The caudal abducens motoneurons fire phasically in synchronous bursts before rapid posterior eye movements; the rostral abducens motoneurons fire only tonically when the eye is fixed or moving slowly. This physiological difference is not related to motoneuron size. In this respect the abducens motoneurons violate the "size principle" that has been advanced for spinal motoneurons. The difference is probably related to the present finding that the caudal but not the rostral cells receive numerous electrical synapses that are known to have a role in synchronizing phasic activity.

Specialization of the right hemisphere for spatial processing was studied in 200 normal boys and girls between 6 and 13 years of age. Boys performed in a manner consistent with right hemisphere specialization as early as the age of 6. Girls showed evidence of bilateral representation until the age of 13. The results suggest a sexual dimorphism in the neural organization underlying cognition during a major period of childhood. The results, which have implications for reading instruction, are discussed in terms of a possible sex difference in neural plasticity during development and the clinical consequences of such a difference.

Believing as I do that geology in the immediate future will have a greater application, that with that application we shall see its expansion, I present the suggestions in this paper. They are based upon careful consideration, analyses, deductions from assembled views and opinions. Specialization will mean more and better geologists but also a greater graduate school population which must be fed from the undergraduate curriculum. There, and there particularly, is the basement complex on which to build. The greatest immediate need in geology is a broad, adequate undergraduate preparation, not so much geology itself, but in a slightly appalling list of collateral "must" subjects. Once this foundation is attained, graduate work in its several fields will care for itself.

Cave-adapted arthropods have evolved in lava tubes in Hawaii. This is the first report of cavernicoles from the Hawaiian islands. The specialization of the cavernicolous insects and the recent origin of the lava tubes suggest that subterranean connections between lava tubes regularly occur and provide dispersal routes. The discovery that lava tubes were colonized by representatives of the adaptively radiating native fauna offers significant potential for evolutionary studies.