Culture,biology, and human behavior

Social scientists have not integrated relevant knowledge from the biological sciences into their explanations of human behavior. This failure is due to a longstanding antireductionistic bias against the natural sciences, which follows on a commitment to the view that social facts must be explained by social laws. This belief has led many social scientists into the error of reifying abstract analytical constructs into entities that possess powers of agency. It has also led to a false nature-culture dichotomy that effectively undermines the place of biology in social scientific explanation. Following the principles of methodological individualism, we show how behavioral explanations supported by data and theory from the neurosciences can be used to correct the errors of reificationist thinking in the social sciences. We outline a mechanistic approach to the explanation of human behavior with the hope that the biological sciences will begin to find greater acceptance among social scientists.     

Testosterone,cortisol, and human competition

Testosterone and cortisol figure prominently in the research literature having to do with human competition. In this review, we track the history of this literature, concentrating particularly on major theoretical and empirical contributions, and provide commentary on what we see as important unresolved issues. In men and women, athletic competition is typically associated with an increase in testosterone (T) and cortisol (C). Hormone changes in response to non-athletic competition are less predictable. Person (e.g., power motivation, mood, aggressiveness, social anxiety, sex, and baseline levels of T and C) and context (e.g., whether a competition is won or lost, the closeness of the competition, whether the outcome is perceived as being influenced by ability vs. chance, provocations) factors can influence hormone responses to competition. From early on, studies pointed to a positive relationship between T and dominance motivation/status striving. Recent research, however, suggests that this relationship only holds for individuals with low levels of C – this is the core idea of the dual-hormone hypothesis, and it is certain that the broadest applications of the hypothesis have not yet been realized. Individuals differ with respect to the extent to which they embrace competition, but the hormonal correlates of competitiveness remain largely unexplored. Although rapid increases in both T and C associated with competition are likely adaptive, we still know very little about the psychological benefits of these hormonal changes. Administration studies have and will continue to contribute to this inquiry. We close with a discussion of what, we think, are important methodological and mechanistic issues for future research.     

Microbes, warfare, religion, and human institutions

A significant number of practicing microbiologists are not aware of the historical impact of infectious agents on the development of human institutions. Microbes have played a profound role in warfare, religion, migration of populations, art, and in diplomacy. Boundaries of nations have changed as a result of microbial diseases. Infectious agents have terminated some kingdoms and elevated others. There is a need for microbiologists to have a historical perspective of some of the major ways in which a pathogen may influence civilized populations. Conditions may exist in contemporary society for a repeat of some of the kinds of plagues suffered by previous societies. The purpose of this paper is to review examples of situations where pathogenic microbes have forced societal modifications on centers of human population.     

Responses to human CGRP,ADM, and PAMP in human thymic arteries

Responses to human CGRP, adrenomedullin (ADM), and proadrenomedullin NH2-terminal 20 peptide (PAMP) were studied in small human thymic arteries. CGRP, ADM, and PAMP produced concentration-dependent vasodilator responses in arteries preconstricted with the thromboxane mimic U-46619. Responses to ADM and PAMP were attenuated, whereas responses to CGRP were not altered by endothelial denudation. Inhibitors of nitric oxide synthase and guanylyl cyclase attenuated responses to ADM and PAMP but not to CGRP. The CGRP1 receptor antagonist CGRP(8-37) attenuated responses to CGRP and ADM but not to PAMP. Responses to CGRP were reduced by SQ-22536 and Rp-cAMPS, inhibitors of adenylyl cyclase and PKA. These data suggest that responses to CGRP and ADM are mediated by CGRP(8-37)-sensitive receptors and that the endothelial ADM receptor induces vasodilation by a nitric oxide-guanylyl cyclase mechanism, whereas a smooth muscle CGRP receptor signals by a cAMP-dependent mechanism. A different endothelial receptor recognizes PAMP and signals by a nitric oxide-dependent mechanism.     

On human speech,syntax, and language

The evolution of human speech and syntax, which appear to be the defining characteristics of modern human beings, is discussed. Speech depends on the morphology of the mouth, tongue, and larynx which yield the human «vocal tract», and neural mechanisms that facilitate the perception of speech and make possible the control of the articulatory gestures that underly speech. The neural mechanisms that underly human syntax may have derived by means of the Darwinian process of preadaption from the structures of the brain that first evolved to facilitate speech motor control. Recent data consistent with this theory are presented; deficits in the comprehension of syntax of normal aged people are correlated with a slowdown in speech rate.     

Biofeedback,voluntary control,and human potential

This paper examines some of the philosophical and scientific relationships involving self-control, voluntary control, and psychophysiologic self-regulation. The role of biofeedback in mediating conscious and unconscious processes is explored. Demonstrations of superior voluntary control and its relationship to belief, confidence, and expectation are examined. Biofeedback demonstrates the potential of control to oneself, creating confidence in one's ability to establish enhanced and peak performance in athletics, education, and psychophysiologic therapy. Emphasis is placed on the power of images in all human functioning, and in enhancing human potential.Presidential address presented at the meetings of the Biofeedback Society of America, March 23, 1986, San Francisco.     

Human dignity, bioethics, and human rights

The authors analyse and assess the Universal Draft Declaration on Bioethics and Human Rights published by UNESCO. They argue that the Draft has two main weaknesses. It unnecessarily confines the scope of bioethics to life sciences and their practical applications. And it fails to spell out the intended role of human dignity in international ethical regulation.     

Polycystins, calcium signaling, and human diseases

Autosomal dominant polycystic kidney disease (ADPKD) is a major, inherited nephropathy affecting over 1:1000 of the worldwide population. It is a systemic condition with frequent hepatic and cardiovascular manifestations in addition to the progressive development of fluid-filled cysts from the tubules and collecting ducts of affected kidneys. The pathogenesis of cyst formation is currently thought to involve increased proliferation of epithelial cells, mild dedifferentiation, and fluid accumulation. In the past decade, study of ADPKD led to the discovery of a unique family of highly complex proteins, the polycystins. Loss-of-function mutations in either of two polycystin proteins, polycystin-1 or polycystin-2, give rise to ADPKD. These proteins are thought to function together as part of a multiprotein complex that may initiate Ca2+ signals, directing attention to the regulation of intracellular Ca2+ as a possible misstep that participates in cyst formation. Here we review what is known about the Ca2+ signaling functions of polycystin proteins and focus on findings that have significantly advanced our physiological insight. Special attention is paid to the recently discovered role of these proteins in the mechanotransduction of the renal primary cilium and the model it suggests.     

Peroxisomes, lipid metabolism, and human disease

In the past few years, much has been learned about the metabolic functions of peroxisomes. These studies have shown that peroxisomes play a major role in lipid metabolism, including fatty acid β-oxidation, etherphospholipid biosynthesis, and phytanic acid α-oxidation. This article describes the current state of knowledge concerning the role of peroxisomes in these processes, especially in relation to various peroxisomal disorders in which there is an impairment in peroxisomal lipid metabolism.     

Oxytocin,testosterone, and human social cognition

I describe an integrative social‐evolutionary model for the adaptive significance of the human oxytocinergic system. The model is based on a role for this hormone in the generation and maintenance of social familiarity and affiliation across five homologous, functionally similar, and sequentially co‐opted contexts: mothers with offspring, female and male mates, kin groups, individuals with reciprocity partners, and individuals within cooperating and competing social groups defined by culture. In each situation, oxytocin motivates, mediates and rewards the cognitive and behavioural processes that underlie the formation and dynamics of a more or less stable social group, and promotes a relationship between two or more individuals. Such relationships may be positive (eliciting neurological reward, reducing anxiety and thus indicating fitness‐enhancing effects), or negative (increasing anxiety and distress, and thus motivating attempts to alleviate a problematic, fitness‐reducing social situation). I also present evidence that testosterone exhibits opposite effects from oxytocin on diverse aspects of cognition and behaviour, most generally by favouring self‐oriented, asocial and antisocial behaviours. I apply this model for effects of oxytocin and testosterone to understanding human psychological disorders centrally involving social behaviour. Reduced oxytocin and higher testosterone levels have been associated with under‐developed social cognition, especially in autism. By contrast, some combination of oxytocin increased above normal levels, and lower testosterone, has been reported in a notable number of studies of schizophrenia, bipolar disorder and depression, and, in some cases, higher oxytocin involves maladaptively ‘hyper‐developed’ social cognition in these conditions. This pattern of findings suggests that human social cognition and behaviour are structured, in part, by joint and opposing effects of oxytocin and testosterone, and that extremes of such joint effects partially mediate risks and phenotypes of autism and psychotic‐affective conditions. These considerations have direct implications for the development of therapies for alleviating disorders of social cognition, and for understanding how such disorders are associated with the evolution of human cognitive‐affective architecture.     

Fear, faces, and the human amygdala

The amygdala's historical role in processing stimuli related to threat and fear is being modified to suggest a role that is broader and more abstract. Amygdala lesions impair the ability to seek out and make use of the eye region of faces, resulting in impaired fear perception. Other studies in rats and humans revive earlier proposals that the amygdala is important not only for fear perception as such, but also for detecting saliency and biological relevance. Debates about some features of this processing now suggest that while the amygdala can process fearful facial expressions in the absence of conscious perception, and while there is some degree of preattentive processing, this depends on the context and is not necessarily more rapid than cortical processing routes. A large current research effort extends the amygdala's putative role to a number of psychiatric illnesses.