Information transmission from tumor cells to non‐tumor cells in the surrounding microenvironment via microvesicles is a more recently studied form of intercellular signaling that can have a marked impact on the tumor microenvironment. Tumor‐derived microvesicles (TMVs) are packed with information including signaling proteins and nucleic acids, and can be taken up by target cells, enabling paracrine signaling. While previous research has focused on how vesicles released from pathologic cells differ from normal cells, the heterogeneity that exists within the TMV (...) population itself is not fully characterized, and only beginning to be appreciated. In this review, we summarize current understanding of the biogenesis and roles of shed TMVs in the tumor microenvironment, and speculate on the consequences for tumor cell signaling in light of the hypothesis that there exists variance within the TMV population. The analysis of differential signaling upon cell‐TMV interactions provides insights into potential mechanisms of intercellular communication. (shrink)

The endoplasmic reticulum (ER) organelle is the key intracellular site of both protein and lipid biosynthesis. ER dysfunction, termed ER stress, can result in protein accretion within the ER and cell death; a pathophysiological process contributing to a range of metabolic diseases and cancers. ER stress leads to the activation of a protective signalling cascade termed the Unfolded Protein Response (UPR). However, chronic UPR activation can ultimately result in cellular apoptosis. Emerging evidence suggests that cells undergoing ER stress and (...) UPR activation can release extracellular signals that can propagate UPR activation to target tissues in a cell non‐autonomous signalling mechanism. Separately, studies have determined that the UPR plays a key regulatory role in the biosynthesis of bioactive signalling lipids including sphingolipids and ceramides. Here we weigh the evidence to combine these concepts and propose that during ER stress, UPR activation drives the biosynthesis of ceramide lipids, which are exported and function as cell non‐autonomous signals to propagate UPR activation in target cells and tissues. (shrink)

During tumor evolution, cancer cells use the tumor‐stroma crosstalk to reorganize the microenvironment for maximum robustness of the tumor. The success of immune checkpoint therapy foretells a new cancer therapy paradigm: an effective cancer treatment should not aim to influence the individual components of super complex intracellular interactomes (molecular targeting), but try to disrupt the intercellular interactions between cancer and stromal cells, thus breaking the tumor as a whole. Arguments are provided in favor of a hypothesis that such interactions include (...) formation of synapse‐like structures (interfaces) where the interacting cells are located at a distance of ∼10–15 nm. Within these interfaces, molecules initiating and strengthening the interaction are organized, and allow optimum cross‐signaling; a very confined intercellular space facilitates the concentration of secreted cytokines, enhancing the paracrine cross‐communication. These features of tumors form a druggable cancer hallmark the tumor‐stroma symbiotic crosstalk—which represents a new target for efficient cancer drug discovery. (shrink)

The neuregulin gene encodes a series of polypeptide growth factors that can influence the growth state of target vertebrate cells in culture. Recently, three studies have explored the in vivo function of the neuregulin signaling system in mice by disrupting the genes encoding the neuregulin ligand(1) and two of its receptors, ErbB2(2) and ErbB4(3). Each of the genes is essential for development, and aberrations in cardiac and neural development are particularly prominent in mutant embryos. The observed defects, together with the (...) localization of expression of the neuregulin signaling components within these tissues, highlight a paracrine mechanism for neuregulin‐mediated intercellular communication. (shrink)

Developmental biology is a theory of interpretation. Developmental signals are interpreted differently depending on the previous history of the responding cell. Thus, there is a context for the reception of a signal. While this conclusion is obvious during metamorphosis, when a single hormone instructs some cells to proliferate, some cells to differentiate, and other cells to die, it is commonplace during normal development. Paracrine factors such as BMP4 can induce apoptosis, proliferation, or differentiation depending upon the history of the (...) responding cells. In addition, organisms have evolved to alter their development in response to differences in temperature, diet, the presence of predators, or the presence of competitors. This allows them to develop the phenotype, within the limits imposed by the genotype, best suited for the immediate habitat of the organism. Most developing organisms have also evolved to expect developmental signals from symbionts, and these organisms develop abnormally if the symbiont signals are not present. Thus Hoffmeyer’s “vertical semiotic system” of genetic communication and “horizontal semiotic system” of ecological communication are integrated during development. (shrink)

Cellular interactions in the mammalian ovarian follicle between its germ‐line and somatic cell components are crucial for its development and function. These interactions are mediated by both membrane gap junctions and paracrine factors. Somatic cell‐to‐oocyte communication is essential for oocyte growth and the regulation of meiotic maturation. In particular, granulosa cells provide nutrients and molecular signals that regulate oocyte development. Oocytes, on the other hand, promote the organization of the follicle, the proliferation of granulosa cells, and the differentiation and (...) function of cumulus cells, a subset of granulosa cells. Determining the nature of the oocyte‐to‐granulosa cell signals remains a key challenge for future work. (shrink)

In this article we discuss the molecular signaling mechanisms that coordinate interactions between Schwann cells and the neurons of the peripheral nervous system. Such interactions take place perpetually during development and in adulthood, and are critical for the homeostasis of the peripheral nervous system (PNS). Neurons provide essential signals to control Schwann cell functions, whereas Schwann cells promote neuronal survival and allow efficient transduction of action potentials. Deregulation of neuron–Schwann cell interactions often results in developmental abnormalities and diseases. Recent investigations (...) have shown that during development, neuronally provided signals, such as Neuregulin, Jagged, and Wnt interact to fine‐tune the Schwann cell lineage progression. In adult, the signal exchange between neurons and Schwann cells ensures proper nerve function and regeneration. Identification of the mechanisms of neuron–Schwann cell interactions is therefore essential for our understanding of the development, function and pathology of the peripheral nervous system as a whole. -/- . (shrink)

Mouse pre‐implantation development appears to be under the control of paracrine and autocrine growth factors. The epithelium of the oviduct and the uterus together, with the population of macrophages and lymphocytes present in the reproductive tract from the onset of pregnancy, are thought to be the major sources of paracrine growth factors targeted to the developing embryos. Some of the growth factors are synthesized by both uterine epithelial cells and activated lympho‐hematopoietic cells, suggesting a partial overlap of the (...) regulatory signals used by the reproductive and lympho‐hematopoietic systems. Such growth factors may be the long sought‐after mediators of the synchrony between the pre‐implantation embryo and the sex‐steroid hormone‐induced changes in the uterus. (shrink)

‘Virtue signaling’ is the practice of using moral talk in order to enhance one’s moral reputation. Many find this kind of behavior irritating. However, some philosophers have gone further, arguing that virtue signaling actively undermines the proper functioning of public moral discourse and impedes moral progress. Against this view, I argue that widespread virtue signaling is not a social ill, and that it can actually serve as an invaluable instrument for moral change, especially in cases where moral argument alone does (...) not suffice. Specifically, virtue signaling can change the broader public’s social expectations, which can in turn motivate the adoption of new, positive social norms. I also argue that the reputation-seeking motives underlying virtue signaling impose important constraints on virtue signalers’ behavior, which serve to keep the worst excesses of virtue signaling in check. (shrink)

Natural languages are compositional in that the meaning of complex expressions depends on those of the parts and how they are put together. Here, I ask the following question: why are languages compositional? I answer this question by extending Lewis–Skyrms signaling games with a rudimentary form of compositional signaling and exploring simple reinforcement learning therein. As it turns out: in complex worlds, having compositional signaling helps simple agents learn to communicate. I am also able to show that learning the meaning (...) of a function word, once meanings of atomic words are known, presents no difficulty. (shrink)

Virtue signaling serves to express moral and ethical values publicly, showcasing commitment to social and sustainable ideals. This research, conducted with non-WEIRD samples to mitigate the prevalent WEIRD bias (i.e., the tendency to solely rely on samples from Western, educated, industrialized, rich, and democratic societies), examines whether the scarcely studied virtue-signaling construct mediates the influence of consumers’ attachment anxiety (vs. avoidance) on their green purchase behavior and prosocial responses. Drawing on attachment theory and the emerging virtue-signaling literature, the current work (...) reports the results from three studies (_N_ total = 898) in which consumers’ attachment patterns were not only measured, as in most prior related research, but also manipulated. Study 1 confirmed the unique ability of measured attachment anxiety, but not attachment avoidance, to predict consumers’ green purchase behavior and prosocial tendencies, with virtue signaling mediating these links. Study 2 manipulated participants’ attachment patterns, finding further support for the mediating role of virtue signaling between attachment anxiety (vs. avoidance) and these dependent variables. Study 3 provided a more nuanced account for our virtue-signaling conceptualization by documenting that self-oriented, but not other-oriented, virtue signaling mediated the link between attachment anxiety and both our key outcomes in public contexts. From a managerial viewpoint, these findings indicate that anxiously attached consumers constitute a potentially lucrative segment for companies seeking to expand their market share of sustainable and ethically produced products. (shrink)

Why do people share or publicly engage with fake stories? Two possible answers come to mind: (a) people are deeply irrational and believe these stories to be true; or (b) they intend to deceive their audience. Both answers presuppose the idea that people put the stories forward as true. But I argue that in some cases, these outlandish (yet also very popular) stories function as signals of one's group membership. This signaling function can make better sense of why, despite their (...) unusual nature or lack of a factual basis, some of these stories are so widespread. (shrink)

Costly signaling theories of religion contend that religious belief and behaviors function as costly signals of cooperative intent. Such signals are evolvable because they allow likely cooperators to find one another, while excluding potential cheats or free riders that would be unwilling to pay the price associated with sending the signal. As a result, under the right conditions, religious costly signaling can emerge as an evolutionary stable strategy. However, reliability certifying costly signaling can evolve and stabilize only when certain necessary (...) conditions are satisfied. In this paper we argue that current versions of the theory do not adequately demonstrate that these conditions are met. (shrink)

Ethological theories usually attribute semantic content to animal signals. To account for this fact, many biologists and philosophers appeal to some version of teleosemantics. However, this picture has recently came under attack: while mainstream teleosemantics assumes that representational systems must cooperate, some biologists and philosophers argue that in certain cases signaling can evolve within systems lacking common interest. In this paper I defend the standard view from this objection.

Tosi and Warmke discuss cases where the speaker intends for the audience to take their expressions as evidence of good moral character. However, another possibility exists that similarly exploits the social communicative architecture. A contribution to public moral discourse may also attempt to strut by demonstrating evidence of bad moral character, by purposely failing to meet the evaluative standards of its audience—or, paradigmatically for my purposes, a particular section of its actual or notional audience. I call this kind of communication (...) vice signaling. On their face, virtue signaling and vice signaling may seem to be opposites, since the labels imply that they are signaling opposite things. But certain cases of vice signaling are in fact also cases of virtue signaling. These are the cases where someone flaunts the standards of an out-group in order to demonstrate solidarity, seriousness, or some other virtue to their in-group. In this paper I attempt to describe these cases and point out the moral risks and opportunities they present. (shrink)

In game-theoretic signaling models, evolution tends to favor perfectly precise signaling systems, but in the natural world communication is almost always imprecise. I argue that standard explanations for this discrepancy are only partially sufficient, and I show that communication is often ambiguous because signal senders take advantage of context sensitivity. As evidence, I make two additions to the signaling model: a cost for more complex signaling strategies and the ability to combine information in signals with independent information. Analysis and simulation (...) of the altered model shows that it leads to the predicted outcome of evolution favoring ambiguous signaling. (shrink)

Virtue signaling—using public moral discourse to enhance one’s moral reputation—is a familiar concept. But, what about profile pictures framed by “Vaccines work!”? Or memes posted to anti-vaccine groups echoing the group’s view that “Only sheep believe Big Pharma!”? These actions don’t express moral views—both claims are empirical (if imprecise). Nevertheless, they serve a similar purpose: to influence the judgments of their audience. But, where rainbow profiles guide their audience to view the agent as morally good, these acts guide their audience (...) to view the agent as epistemically good. They are instances of epistemic virtue signaling. The first goal of this paper is to offer an account of epistemic virtue signaling. I argue that epistemic virtue signaling occurs through both behavioral and propositional signals, and serves purposes similar to those of moral virtue signaling across a wide variety of discourses. The second is to show that there is much work for this concept to do. In particular, this concept illuminates a double bind faced by those who suffer from and seek to overcome testimonial injustice. I close by demonstrating how this double bind arises in the dissolution of medical autonomy, focusing on the care gap faced by pregnant women of color in the United States today, as compared with their white counterparts. (shrink)

The signaling theory of religion has many claimed virtues, but these are not necessarily all realizable at the same time. Modeling choices involve trade-offs, and the available options here have not traditionally been well understood. This paper offers an overview of signaling theory relevant to the signaling theory of religion, arguing for a narrow, “core” reading of it. I outline a broad taxonomy of the choices on offer for signaling models, and examples of how previous and potential approaches to modeling (...) religious signaling meet or fail to meet the initial promise of the theory. A pluralist approach to religious signaling seems possible, but this would require a high level of detail and specificity with respect to both formal models and target systems. (shrink)

It is notable that all of the leading theories of blame have to employ ungainly fixes to deflect one or more apparent counterexamples. What these theories share is a content‐based theory of blame's nature. Such approaches overlook or ignore blame's core unifying feature, namely, its function, which is to signal the blamer's commitment to a set of norms. In this paper, we present the problems with the extant theories and then explain what signaling is, how it functions in blame, why (...) appealing to it resolves the problems in other theories, what the signaling function implies for a wider range of gray‐area cases, and what the larger significance is of blame's core function for interpersonal interactions in a variety of (non‐moral) normative domains. (shrink)

What signals do firms in emerging economies send to stakeholders when they adopt corporate social responsibility practices? We argue that in emerging economies, firms that adopt CSR practices positively signal investors that their firms have superior capabilities for filling institutional voids. From an institution-based view, we hypothesize that the institutional environment moderates the signaling effect of CSR on a firm’s financial performance. Based on a sample of firms from ten Asian emerging economies, we find a positive relationship between CSR practices (...) and financial performance. This positive relationship is stronger in the less developed capital market than in the more developed one. The financial benefits of CSR practices are also more salient in the low information diffusion market than in the high one. We emphasize that signaling theory and the institution-based view can jointly contribute to the CSR literature. (shrink)

We employ the Social Signaling Model and life history of a Western Dani big-man, Tibenuk, to analyze a neglected curiosity in the career of the big-man type. The big-man is renowned as an economic entrepreneur, the master of material displays. In New Guinea, however, big-men had invariably first gained fame and some influence as eminent warriors. The SSM accounts for this two-part career path by proposing that small-scale social organization rests on honest, competitive signaling of individual and collective fighting strength, (...) with leaders being those who excel in these contests. The performances for which big-men are already known, conspicuous ceremonial displays, broadcast this strength indirectly. Explicitly conceptualized as symbolic fighting, they constituted indexical proxies for their sponsors’ individual and collective willingness and ability to fight. Success on the battlefield, though, signaled fighting strength more directly. Men therefore had to demonstrate strength on both the battlefield and the ceremonial ground if they were to become big-men. This was Tibenuk’s achievement. When he was young and at his physical peak, he demonstrated outstanding capability in war. War is a young man’s game, however, and as his physical capacities waned, he shifted to politics, an older man’s game, honing his political talents and developing extensive political networks that allowed him to sponsor massive pig feasts, the principal form of conspicuous ceremonial display. Tibenuk’s career also reveals synergies between warrior and political talents that hitherto have been overlooked in big-man analysis. (shrink)

Special relativity is said to prohibit faster-than-light (superluminal) signaling, yet controversy regularly arises as to whether this or that physical phenomenon violates the prohibition. I argue that the controversy is a result of a lack of clarity as to what it means to ‘signal’, and I propose a criterion. I show that according to this criterion, superluminal signaling is not prohibited by special relativity.

An important finding of the game theoretic research on signaling games is the insight that under many circumstances, a signal obtains credibility by incurring costs to the sender. Therefore it seems questionable whether or not cheap talk—signals that are not payoff relevant—can serve to transmit information among rational agents. This issue is non-trivial in strategic interactions where the preferences of the players are not aligned. Researchers like Crawford & Sobel, Rabin, and Farrell demonstrated, however, that even in the case of (...) partially divergent interests, cheap talk may be informative. They assume that signals have an exogenously given meaning that is common knowledge between the players, and they explore the conditions under which such a signal is credible. This discussion has obvious relevance to the program of Gricean pragmatics in linguistics. According to Grice’s "Cooperative Principle”, this research tradition only considers scenarios where the interests of the players are aligned. Nevertheless, the assumption of differential signaling costs introduces an element of non-aligned interests. The present paper proposes a framework that combines these two research strands. Using an inference protocol of iterated best response, it gives a recipe for how the interlocutors derive rationalizable strategies from exogeneously given "literal” meanings of signals. No special assumptions about the alignment of interests or signaling costs are made. After introducing the formal model, the paper sketches several applications of this model to problems in linguistic pragmatics, like scalar implicatures, the division of pragmatic labor, and the interpretation of measure terms. (shrink)

Between 300,000 and 250,000 years ago early humans in Africa and Eurasia began to use durable material substances and objects as media for signaling. Initially material signals were confined to ochre and other pigments, but over time objects such as beads were also added as technologies for sending messages. Changes in the types of materials used, their durability and costs, and the contexts of their disposal indicate a series of transitions in how early humans employed signaling media. Signaling theory from (...) biology suggests that shifts in technologies over the course of the Pleistocene reflect problems in coordinating action and resolving conflicts within increasingly large and internally differentiated societies. (shrink)

We consider how human subjects establish signaling conventions in the context of Lewis-Skyrms signaling games. These experiments involve games where there are precisely the right number of signal types to represent the states of nature, games where there are more signal types than states, and games where there are fewer signal types than states. The aim is to determine the conditions under which subjects are able to establish signaling conventions in such games and to identify a learning dynamics that approximates (...) how they succeed when they do. Our results suggest that human agents tend to use a win-stay/lose-shift with inertia dynamics to establish conventions in such games. We briefly consider the virtues and vices of this low-rationality dynamics. (shrink)

Mechanical stimulation has a critical role in the development and maintenance of the skeleton. This function requires the perception of extracellular stimuli as well as their conversion into intracellular biochemical responses. This process is called mechanotransduction and is mediated by a plethora of molecular events that regulate bone metabolism. Indeed, mechanoreceptors, such as integrins, G protein‐coupled receptors, receptor protein tyrosine kinases, and stretch‐activated Ca2+ channels, together with their downstream effectors coordinate the transmission of load‐induced signals to the nucleus and the (...) expression of bone‐related genes. During the past decade, scientists have gained increasing insight into the molecular networks implicated in bone mechanotransduction. In the present paper, we consider the major signaling cascades and transcription factors that control bone and cartilage mechanobiology and discuss the influence of the mechanical microenvironment on the determination of skeletal morphology. (shrink)

Starting from logical structures of classical and quantum mechanics we reconstruct the logic of so-called no-signaling theories, where the correlations among subsystems of a composite system are restricted only by a simplest form of causality forbidding an instantaneous communication. Although such theories are, as it seems, irrelevant for the description of physical reality, they are helpful in understanding the relevance of quantum mechanics. The logical structure of each theory has an epistemological flavor, as it is based on analysis of possible (...) results of experiments. In this note we emphasize that not only logical structures of classical, quantum and no-signaling theory may be treated on the same ground but it is also possible to give to all of them a common ontological basis by constructing a “phase space” in all cases. In non-classical cases the phase space is not a set, as in classical theory, but a more general object obtained by means of category theory, but conceptually it plays the same role as the phase space in classical physics. (shrink)

I introduce an extension of the Lewis-Skyrms signaling game, analysed from a dynamical perspective via simple reinforcement learning. In Lewis’ (Convention, Blackwell, Oxford, 1969) conception of a signaling game, salience is offered as an explanation for how individuals may come to agree upon a linguistic convention. Skyrms (Signals: evolution, learning & information, Oxford University Press, Oxford, 2010a) offers a dynamic explanation of how signaling conventions might arise presupposing no salience whatsoever. The extension of the atomic signaling game examined here—which I (...) will refer to as a salience game—introduces a variable parameter into the atomic signaling game which allows for degrees of salience, thus filling in the continuum between Skyrms’ and Lewis’ models. The model does not presuppose any salience at the outset, but illustrates a process by which accidentally evolved salience is amplified, to the benefit of the players. It is shown that increasing degrees of salience allow populations to avoid sub-optimal pooling equilibria and to coordinate upon conventions more quickly. (shrink)

The branch of evolutionary theory known as signaling theory attempts to explain various forms of communication. Social scientists have explained many traditional rituals as forms of communication that promote cooperative social relationships among participants. Both evolutionists and social scientists have realized the importance of trust for the formation and maintenance of cooperative social relationships. These factors have led to attempts to apply signaling theory to traditional cultural rituals in various ways. This paper uses the traditional ritual of mumming in small (...) Newfoundland fishing villages to evaluate alternative hypotheses about the connection between rituals, communication, trust, and cooperation. Mumming is found to be most consistent with the hypothesis that it is a ritual of trust wherein participants take a specific type of risk: the risk of harm at the hands of other participants. Individuals who take this risk actively signal their trust. Conversely, individuals who restrain themselves from inflicting harm on other participants actively signal their trustworthiness. (shrink)

This study examines the practices of Equine Assisted Therapy and Learning in Australia. Among Equine Assisted Therapy and Equine Assisted Learning centers there is a large degree of variation in practice worldwide. The current study outlines a range of practices in two states in Australia whereeatandealhave arisen and evolved from models developed elsewhere. The philosophical foundations, training and certification processes followed along with the types and training of horses involved are compared across facilities. The findings of the study illustrated the (...) large variation ineatandealin current practice in Australia. The results suggested that if the practices ofeatandealare to move out of the “fringe” of mental health and learning professional practice and into the mainstream, their theoretical underpinnings, certification and licensure procedures, and methodology of practice must become more clearly defined. (shrink)

What are the functional units of the brain? If the function of the brain is to process information-carrying signals, then the functional units will be the senders and receivers of those signals. Neurons have been the default candidate, with action potentials as the signals. But there are alternatives: synapses fit the action potential picture more cleanly, and glial activities (e.g., in astrocytes) might also be characterized as signaling. Are synapses or nonneuronal cells better candidates to play the role of functional (...) units? Will informational signaling still be the best model for brain function if we move beyond the neuron doctrine? (shrink)

Although the popularity of Humane Education Programs as a method of teaching compassion and caring for all living beings is increasing, there is a need for rigorous, methodologically sound research evaluating the efficacy of HEP. Recent calls for the inclusion of HEP within broader humanistic, environmental, and social justice frameworks underline the importance of HEP beyond a simple “treatment of animals” model. Lack of methodological rigor in the majority of published HEP studies and dispersal across disparate fields , however, means (...) that there is a potential for the popular use of HEP to outstrip our understanding of the variables that impact efficacy. The current study discusses some of these issues and presents a pilot study of a literature-only HEP intervention. Comparisons with an age-matched control group indicated that the four-week HEP resulted in an increase in measures of empathy and treatment of animals, although only the increase in empathy levels was significant. This paper discusses the implications of the current results and areas in need of future consideration. (shrink)

Signaling of relations is an open question in rhetorical structure theory. Discourse markers are the unmistakable signals of a relation. However, it may be argued that all relations – and not only those involving discourse markers – are signaled in some way. Based on this assumption, this article focuses on two causal relations, ‘Cause’ and ‘Result’, working on an RST double-annotated corpus in Spanish. The main objectives are to identify different signals of Cause and Result relations and to evaluate the (...) ambiguity resulting from those signals. Results demonstrate that a) almost all Cause and Result relations on the corpus are signaled; b) each signal obtains differentiated annotation agreements; and c) patterns of annotation disagreement are grounded in the nature of the signal and not in the relations’ semantic features. (shrink)

Cooption and modularity are informative concepts in evolutionary developmental biology. Genes function within complex networks that act as modules in development. These modules can then be coopted in various functional and evolutionary contexts. Hormonal signaling, the main focus of this review, has a modular character. By regulating the activities of genes, proteins and other cellular molecules, a hormonal signal can have major effects on physiological and ontogenetic processes within and across tissues over a wide spatial and temporal scale. Because of (...) this property, we argue that hormones are frequently involved in the coordination of life history transitions (LHTs) and their evolution (LHE). Finally, we promote the usefulness of a comparative, non-model system approach towards understanding how hormones function and guide development and evolution, highlighting thyroid hormone function in echinoids as an example. BioEssays 27:64–75, 2005. © 2004 Wiley Periodicals, Inc. (shrink)

Voices on the political right have long claimed that the welfare state ought to be kept small, and that charities can take over many of the tasks involved in helping those at the bottom of society. The arguments in favor of this claim are controversial, but even if they are accepted at face value the policy proposal remains problematic. For the proposal presupposes that charities would, in fact, be able to raise enough money to provide adequate help to those in (...) need, and therefore assumes that charities are able to very significantly increase the number and/or size of donations they receive. We argue that there are good reasons for doubting that charities will be able to do this. Our argument turns on the fact that the most powerful strategy for eliciting donations—namely, allowing donors to use their donation to signal their pro-sociality—has an inbuilt upper limit. If too much emphasis is placed on the signaling opportunities donating to charity provides, donating no longer functions as an effective signal and the motivation to donate declines. (shrink)

In signaling games, a sender has private access to a state of affairs and uses a signal to inform a receiver about that state. If no common association of signals and states is initially available, sender and receiver must coordinate to develop one. How do players divide coordination labor? We show experimentally that, if players switch roles at each communication round, coordination labor is shared. However, in games with fixed roles, coordination labor is divided: Receivers adjust their mappings more frequently, (...) whereas senders maintain the initial code, which is transmitted to receivers and becomes the common code. In a series of computer simulations, player and role asymmetry as observed experimentally were accounted for by a model in which the receiver in the first signaling round has a higher chance of adjusting its code than its partner. From this basic division of labor among players, certain properties of role asymmetry, in particular correlations with game complexity, are seen to follow. (shrink)

Evolving signaling systems can be said to induce partitions on the space of world states as they approach equilibrium. Formalizing this claim provides a general framework for understanding what it means for language to “cut nature at its seams”. In order to avoid taking our current best science as providing the adaptive target for all evolving systems, the state space of the world must be characterized exclusively in terms of the coincidence of stimuli and payoffs that drives the evolution of (...) cognitive complexity. Cognition exploits the reliable clustering of events in this space. Using this framework to analyze our ordinary concepts of truth and justification, it appears that while justification can be a simple matter of conforming to historically entrenched strategies, truth cannot be fully specified on the basis of the system’s causal history, but requires a robust clustering in the larger world state space. (shrink)

Steroid hormones are signaling molecules important for normal growth, development and differentiation of multicellular organisms. Brassinosteroids (BRs) are a class of polyhydroxylated steroids that are necessary for plant development. Molecular genetic studies in Arabidopsis thaliana have led to the cloning and characterization of the BR receptor, BRI1, which is a transmembrane receptor serine/threonine kinase. The extracellular domain of BRI1, which is composed mainly of leucine‐rich repeats, can confer BR responsivity to heterologous cells and is required for BR binding. Although downstream (...) components of BR action are mostly unknown, multiple genes whose expression are regulated by BRs have been identified and suggest mechanisms by which BRs affect cell elongation and division. BioEssays 23:1028–1036, 2001. © 2001 John Wiley & Sons, Inc. (shrink)

A novel account of virtue signaling and what makes it bad has recently been offered by Justin Tosi and Brandon Warmke. Despite plausibly vindicating the folk’s conception of virtue signaling as a bad thing, their account has recently been attacked by both Neil Levy and Evan Westra. According to Levy and Westra, virtue signaling actually supports the aims and progress of public moral discourse. In this paper, we rebut these recent defenses of virtue signaling. We suggest that virtue signaling only (...) supports the aims of public moral discourse to the extent it is an instance of a more general phenomenon that we call norm signaling. We then argue that, if anything, virtue signaling will undermine the quality of public moral discourse by undermining the evidence we typically rely on from the testimony and norm signaling of others. Thus, we conclude, not only is virtue signaling not needed, but its epistemological effects warrant its bad reputation. (shrink)

Intercellular signaling plays a major role in the development of vertebrate and invertebrate embryos. In several cases, including the induction of mesoderm and neural ectoderm induction in Xenopus and the induction of the vulva in C. elegans, multiple intercellular signals are utilized. This review examines a number of examples of signaling in development wherein two signals combine to affect the fate of a cell. The examples are placed in distinct categories, based on whether the signals synergize with or antagonize one (...) another, and on the inductive potential of the individual signals. These types of combinatorial signaling events are suggested to be a general feature of embryonic development. (shrink)

An extensive body of research documents that women experience a motherhood penalty at work whereas men experience a fatherhood premium. Yet much of this work presupposes that employers are aware of a worker’s parental status. Given the different consequences that parenthood has on outcomes such as pay and promotions, it is conceivable that men and women may deploy their status as parents differently when interacting with employers. Drawing on in-depth interviews with a racially diverse sample, this article examines how mothers (...) and fathers working in the service sector use their parental status when negotiating work and child care responsibilities. Mothers, particularly black mothers, were less likely to openly discuss their children at work. In some cases, women purposefully concealed from their employers the fact that they were mothers or found other ways of signaling their commitment to their jobs. Fathers, on the other hand, were more likely to discuss their children with their employers and overwhelmingly characterized their managers as understanding of their parenting obligations. Together, these findings help us understand how mothers and fathers navigate the consequences of parenthood in the workplace and add nuance to previous studies of motherhood penalties and fatherhood premiums. (shrink)

Discussions of virtue signaling to date have focused exclusively on the signaling of the moral virtues. This article focuses on intellectual virtue signaling: the status-seeking advertising of supposed intellectual virtues. Intellectual virtue signaling takes distinctive forms. It is also far more likely to be harmful than moral virtue signaling, because it distracts attention from genuine expertise and gives contrarian opinions an undue prominence in public debate. The article provides a heuristic by which to identify possible instances of intellectual virtue signaling. (...) When people with no relevant expertise rapidly move to offer their opinions on a wide range of topics as soon as these topics become fashionable or newsworthy, and especially when these opinions are contrarian, we should suspect them of intellectual virtue signaling. (shrink)

Although the popularity of Humane Education Programs as a method of teaching compassion and caring for all living beings is increasing, there is a need for rigorous, methodologically sound research evaluating the efficacy of HEP. Recent calls for the inclusion of HEP within broader humanistic, environmental, and social justice frameworks underline the importance of HEP beyond a simple “treatment of animals” model. Lack of methodological rigor in the majority of published HEP studies and dispersal across disparate fields , however, means (...) that there is a potential for the popular use of HEP to outstrip our understanding of the variables that impact efficacy. The current study discusses some of these issues and presents a pilot study of a literature-only HEP intervention. Comparisons with an age-matched control group indicated that the four-week HEP resulted in an increase in measures of empathy and treatment of animals, although only the increase in empathy levels was significant. This paper discusses the implications of the current results and areas in need of future consideration. (shrink)

The paper offers a model of Kant's claim that unity of consciousness entails objectivity of experience. This claim has nothing especially to do with thought, language or the categories but is a general truth about arbitrary signaling systems of the sort modeled in the paper. In conclusion I draw some consequences for various forms of idealism.

Ever since it was discovered in hydra, regeneration has remained a stimulating question for developmental biologists. Cellular approaches have revealed that, within the first few hours of apical or basal hydra regeneration, differentiation and determination of nerve cells are the primary cellular events detectable. The head and foot activators (HA, FA), neuropeptides that are released upon injury, are signaling molecules involved in these processes. In conditions where it induces cellular differentiation or determination, HA behaves as an agonist of the cyclic (...) AMP (cAMP) pathway involving the modulation of CREB nuclear transcription factor activity. This cascade would be required for proper regeneration, regardless of whether the polarity involved is apical or basal. Modulations of the protein kinase C pathway, which have been shown to affect apical or basal positional values, might signal to bring about this polarity; however, endogenous ligands responsible for this modulation are as yet unknown. (shrink)

The fate of eukaryotic proteins, from their synthesis to destruction, is supervised by the ubiquitin–proteasome system (UPS). The UPS is the primary pathway responsible for selective proteolysis of intracellular proteins, which is guided by covalent attachment of ubiquitin to target proteins by E1 (activating), E2 (conjugating), and E3 (ligating) enzymes in a process known as ubiquitylation. The UPS can also regulate protein synthesis by influencing multiple steps of RNA (ribonucleic acid) metabolism. Here, recent publications concerning the interplay between the UPS (...) and different types of RNA are reviewed. This interplay mainly involves specific RNA‐binding E3 ligases that link RNA‐dependent processes with protein ubiquitylation. The emerging understanding of their modes of RNA binding, their RNA targets, and their molecular and cellular functions are primarily focused on. It is discussed how the UPS adapted to interact with different types of RNA and how RNA molecules influence the ubiquitin signaling components. (shrink)

Focal adhesion kinase (FAK) is a nonreceptor protein‐tyrosine kinase implicated in controlling cellular responses to the engagement of cell‐surface integrins, including cell spreading and migration, survival and proliferation. Aberrant FAK signaling may contribute to the process of cell transformation by certain oncoproteins, including v‐Src. Progress toward elucidating the events leading to FAK activation following integrin‐mediated cell adhesion, as well as events downstream of FAK, has come through the identification of FAK phosphorylation sites and interacting proteins. A signaling partnership is formed (...) between FAK and Src‐family kinases, leading to tyrosine phosphorylation of FAK and associated ‘docking’ proteins Cas and paxillin. Subsequent recruitment of proteins containing Src homology 2 domains, including Grb2 and c‐Crk, to the complex is likely to trigger adhesion‐induced cellular responses, including changes to the actin cytoskeleton and activation of the Ras‐MAP kinase pathway. (shrink)

The evolutionarily conserved Notch signaling pathway regulates a broad spectrum of cell fate decisions and differentiation processes during fetal and postnatal life. It is involved in embryonic organogenesis as well as in the maintenance of homeostasis of self‐renewing systems. In this article, we review the role of Notch signaling in the hematopoietic system with particular emphasis on lymphocyte development and highlight the similarities in Notch function between Drosophila and mammalian differentiation processes. Recent studies indicating that aberrant NOTCH signaling is frequently (...) linked to the induction of T leukemia in humans will also be discussed. BioEssays 27:1117–1128, 2005. © 2005 Wiley Periodicals, Inc. (shrink)

We propose a signaling pathway in which cell‐extracellular matrix (ECM) adhesion components PINCH‐1 and kindlin‐2 sense mechanical signals from ECM and link them to proline biosynthesis, a vital metabolic pathway for macromolecule synthesis, redox balance, and ECM remodeling. ECM stiffening promotes PINCH‐1 expression via integrin signaling, which suppresses dynamin‐related protein 1 (DRP1) expression and mitochondrial fission, resulting in increased kindlin‐2 translocation into mitochondria and interaction with Δ1‐pyrroline‐5‐carboxylate (P5C) reductase 1 (PYCR1). Kindlin‐2 interaction with PYCR1 protects the latter from proteolytic degradation, (...) leading to elevated PYCR1 level. Additionally, PINCH‐1 promotes P5C synthase (P5CS) expression and P5C synthesis, which, together with increased PYCR1 level, support augmented proline biosynthesis. This signaling pathway is frequently activated in fibrosis and cancer, resulting in increased proline biosynthesis and excessive collagen matrix production, which in turn further promotes ECM stiffening. Targeting this signaling pathway, therefore, may provide an effective strategy for alleviating fibrosis and cancer progression. (shrink)