The study of cellular senescence and proliferative lifespan is becoming increasingly important because of the promises of autologous cell therapy, the need for model systems for tissue disease and the implication of senescent cell phenotypes in organismal disease states such as sarcopenia, diabetes and various cancers, among others. Here, we explain the concepts of proliferative cellular lifespan and cellular senescence, and we present factors that have been shown to mediate cellular lifespan positively or negatively. We review much (...) recent literature and present potential molecular mechanisms by which lifespan mediation occurs, drawing from the fields of telomere biology, metabolism, NAD+ and sirtuin biology, growth factor signaling and oxygen and antioxidants. We conclude that cellular lifespan and senescence are complex concepts that are governed by multiple independent and interdependent pathways, and that greater understanding of these pathways, their interactions and their convergence upon specific cellular phenotypes may lead to viable therapies for tissue regeneration and treatment of age‐related pathologies, which are caused by or exacerbated by senescent cells in vivo. (shrink)

Autobiographical memories of older adults show fewer episodic and more non-episodic elements than those of younger adults. This semantization effect is attributed to a loss of episodic memory ability. However the alternative explanation by an increasing proclivity to search for meaning has not been ruled out to date. To test whether a decrease in episodicity and an increase in meaning-making in autobiographical narratives are related across the lifespan, we used different instructions, one focussing on specific episodes, the other on (...) embedding events in life, in two lifespan samples. A continuous decrease of episodic quality of memory was confirmed. An increase of search for meaning was confirmed only up to middle adulthood. This non-inverse development of episodicity and searching for meaning in older age speaks for an autonomous semantization effect that is not merely due to an increase in interpretative preferences. (shrink)

When it comes to specifying the moral duties we bear towards future generations, most political philosophers position themselves on what could be regarded as a safe ground. A variant of the Lockean proviso is commonplace in the literature on intergenerational justice, taking the form of an obligation to bestow upon future people a minimum of goods necessary for reaching a certain threshold of well-being (Meyer, 2017). Furthermore, even this minimum is often frowned upon, given the non-identity problem and the challenges (...) this presents to the topic of justice between generations. Additional issues are raised at the level of non-ideal theory, the most significant being the problem of non-compliance (Gosseries and Meyer, 2009).In this paper I intend to probe the limits of “practical political possibility” (Rawls 1999), by inquiring whether embracing the sufficiency view (Frankfurt, 1987; Crisp, 2003; Benbaji, 2005) as a distributive pattern and capabilities as a metric can lead to more burdensome obligations for present generations. More specifically, I try to show that we have a duty to invest in research that aims at prolonging the lifespan of humans (the idea can already be found in the sufficientarian literature, for instance in Farrelly, 2007). Moreover, given the Earth’s limited resources, we ought to encourage the terraforming of other planets in order to make them inhabitable for (future) people.I argue that these two seemingly far-fetched projects are in fact worthwhile goals to pursue on the one hand, and moral obligations on the other hand. Nonetheless, they are not the only ones we ought to take on; for instance, we must simultaneously pursue them and try to improve the prospects of those who fall under a sufficiency threshold here and now. That is, specifying these (prima facie) duties towards future generations is connected with stronger obligations towards the current generation.Towards the end of the paper I engage in a discussion regarding the role of the feasibility constraint in a theory of justice, as rationales pertaining to feasibility are perhaps going to be the most recurrent criticisms raised against my proposal. To that end, I defend limitarian policies, which aim at setting an upper limit to how much money individuals are allowed to possess (Robeyns, 2017; Volacu and Dumitru, 2019). (shrink)

Alzheimer's disease is characterized by plaques of amyloid-beta peptide, cleaved from amyloid-beta protein precursor . Our hypothesis is that lifespan profiles of AD-associated mRNA and protein levels in monkeys would differ from mice and that differential lifespan expression profiles would be useful to understand human AD pathogenesis. We compared profiles of AbetaPP mRNA, AbetaPP protein, and Abeta levels in rodents and primates. We also tracked a transcriptional regulator of the AbetaPP gene, specificity protein 1 , and the beta (...) amyloid precursor cleaving enzyme . In mice, AbetaPP and SP1 mRNA and their protein products were elevated late in life; Abeta levels declined in old age. In monkeys, SP1, AbetaPP, and BACE1 mRNA declined in old age, while protein products and Abeta levels rose. Proteolytic processing in both species did not match production of Abeta. In primates, AbetaPP and SP1 mRNA levels coordinate, but an inverse relationship exists with corresponding protein products as well as Abeta levels. Comparison of human DNA and mRNA sequences to monkey and mouse counterparts revealed structural features that may explain differences in transcriptional and translational processing. These findings are important for selecting appropriate models for AD and other age-related diseases. (shrink)

Dietary restriction (DR) is the most consistent environmental manipulation to extend lifespan. Originally thought to be caused by a reduction in caloric intake, recent evidence suggests that macronutrient intake underpins the effect of DR. The prevailing evolutionary explanations for the DR response are conceptualized under the caloric restriction paradigm, necessitating reconsideration of how or whether these evolutionary explanations fit this macronutrient perspective. In the authors’ opinion, none of the current evolutionary explanations of DR adequately explain the intricacies of observed (...) results; instead a context‐dependent combination of these theories is suggested which is likely to reflect reality. In reviewing the field, it is proposed that the ability to track the destination of different macronutrients within the body will be key to establishing the relative roles of the competing theories. Understanding the evolution of the DR response and its ecological relevance is critical to understanding variation in DR responses and their relevance outside laboratory environments. (shrink)

Recent developments in biogerontology—the study of the biology of ageing—suggest that it may eventually be possible to intervene in the human ageing process. This, in turn, offers the prospect of significantly postponing the onset of age-related diseases. The biogerontological project, however, has met with strong resistance, especially by deontologists. They consider the act of intervening in the ageing process impermissible on the grounds that it would (most probably) bring about an extended maximum lifespan—a state of affairs that they deem (...) intrinsically bad. In a bid to convince their deontological opponents of the permissibility of this act, proponents of biogerontology invoke an argument which is grounded in the doctrine of double effect. Surprisingly, their argument, which we refer to as the ‘double effect argument’, has gone unnoticed. This article exposes and critically evaluates this ‘double effect argument’. To this end, we first review a series of excerpts from the ethical debate on biogerontology in order to substantiate the presence of double effect reasoning. Next, we attempt to determine the role that the ‘double effect argument’ is meant to fulfil within this debate. Finally, we assess whether the act of intervening in ageing actually can be justified using double effect reasoning. (shrink)

There is an ongoing debate about the ethics of research on lifespan extension: roughly, using medical technologies to extend biological human lives beyond the current “natural” limit of about 120 years. At the same time, there is an exploding interest in the use of artificial intelligence (AI) to create “digital twins” of persons, for example by fine-tuning large language models on data specific to particular individuals. In this paper, we consider whether digital twins (or digital doppelgängers, as we refer (...) to them) could be a path toward a kind of life extension—or more precisely, a kind of person extension—that does not rely on biological continuity. We discuss relevant accounts of consciousness and personal identity and argue that digital doppelgängers may at least help us achieve some of the aims or ostensible goods of person-span extension, even if they may not count as literal extensions of our personhood on dominant philosophical accounts. We also consider relational accounts of personhood and discuss how digital doppelgängers may be able to extend personhood in a relational sense, or at least secure some of the goods associated with relevant relationships. We conclude by suggesting that a research program to investigate such issues is relevant to ongoing debates about the ethics of extending the human lifespan. (shrink)

This paper explores the added value of studying intra- and inter-speaker variation in grammaticalisation based on idiolect corpora. It analyses the usage patterns of the English let alone construction in a self-compiled William Faulkner corpus against the backdrop of aggregated community data. Vast individual differences (early Faulkner vs. late Faulkner vs. peers) in frequencies of use are observed, and these frequency differences correlate with different degrees of grammaticalisation as measured in terms of host-class and syntactic context expansion. The corpus findings (...) inform general issues in current cognitive-functional research, such as the from-corpus-to-cognition issue and the cause/consequence issue of frequency. They lend support to the usage-based view of grammaticalisation as a lifelong, frequency-sensitive process of cognitive automation. To substantiate this view, this paper proposes a self-feeding cycle of constructional generalisation that is driven by the interplay of frequency, entrenchment, partial sanction and habituation. (shrink)

In the Paraplegia Case, we must choose either to preserve the life of a paraplegic for 10 years or that of someone in full health for the same duration. Non-consequentialists reject a benefit-maximising view, which holds that since the person in full health will have a higher quality of life, we ought to save him straightaway. In the Unequal Lifespan Case, we face a choice between saving one person for 5 years in full health and another for 25 years (...) in full health. Frances Kamm has recently unfurled an Equal Respect Argument in an effort to support the position that while we ought to give each person a 50% chance of being saved in the Paraplegia Case, we are morally permitted to save straightaway the person who would live longer in the Unequal Lifespan case. The article tries to show that a Kant-inspired account of the dignity of persons is far more successful than Kamm's argument in supporting this position. The Kant-inspired account owes this success to its conceiving of respect for persons not primarily as respect for their pursuit of what is of value for them, but rather as respect for the value in them. (shrink)

A critical note on Peter Lamarque and Nigel Walter’s ‘The Application of Narrative to the Conservation of Historic Buildings’.

Problems of distributive justice throughout the lifespan are not new. Yet, the increased aging rate of contemporary societies and an array of new life‐extending technologies (LETs) make these problems more and more urgent and complicated. This chapter analyzes the moral and political impact of the LET. There are three kinds of “intergenerational” justice: justice between non‐coexisting generations, justice between partially co‐existing generations, and justice between coexisting generations. The advantage of considering LETs in the light of justice between age groups (...) is that we can assume a complete‐life view. LETs significantly modify the duration and the features of each stage of life. A consideration of the specific needs and features of each stage of life in a lifespan‐enhanced society is needed to regulate policies and offer fair equality of opportunity to each age group. (shrink)

Natural selection in the laboratory has been used to produce populations of Drosophila with genetically increased lifespan. These populations have been used to determine the physiological basis of postponed ageing and its pleiotropic concomitants. It appears that many loci and a number of physiological alterations are involved in increased lifespan.

There is an ongoing debate about the ethics of research on lifespan extension: roughly, using medical technologies to extend biological human lives beyond the current “natural” limit of about 120 years. At the same time, there is an exploding interest in the use of artificial intelligence (AI) to create “digital twins” of persons, for example by fine-tuning large language models on data specific to particular individuals. In this paper, we consider whether digital twins (or digital doppelgängers, as we refer (...) to them) could be a path toward a kind of life extension—or more precisely, a kind of person extension—that does not rely on biological continuity. We discuss relevant accounts of consciousness and personal identity and argue that digital doppelgängers may at least help us achieve some of the aims or ostensible goods of person-span extension, even if they may not count as literal extensions of our personhood on dominant philosophical accounts. We also consider relational accounts of personhood and discuss how digital doppelgängers may be able to extend personhood in a relational sense, or at least secure some of the goods associated with relevant relationships. We conclude by suggesting that a research program to investigate such issues is relevant to ongoing debates about the ethics of extending the human lifespan. (shrink)

This book is unique in presenting evidence on development across the lifespan across multiple levels of description. The authors use a well-defined disorder - Williams syndrome, to explore the impact of genes, brain development, behaviour, as well as the individual's environment on development.

We report the results of two studies that examine folk metaethical judgments about the objectivity of morality. We found that participants attributed almost as much objectivity to ethical statements as they did to statements of physical fact and significantly more objectivity to ethical statements than to statements about preferences or tastes. In both studies, younger participants attributed less objectivity to ethical statements than older participants. Females were observed to attribute slightly less objectivity to ethical statements than males, and we found (...) important interactions between attributions of objectivity and other factors, such as how strong participants’ moral opinions were and how much disagreement about the issue they perceived to exist within society. We believe our results have significant implications for debates about the nature of folk morality and about the nature of morality in general. (shrink)

ABSTRACTPerception of emotion in the face is a key component of human social cognition and is considered vital for many domains of life; however, little is known about how this ability differs across the lifespan for men and women. We addressed this question with a large community sample of persons ranging from younger than 15 to older than 60 years of age. Participants were viewers of the television show “Tout le Monde Joue”, and the task was presented on television, (...) with participants responding via their mobile devices. Applying latent variable modeling, and establishing measurement invariance between males and females and across age, we found that, for both males and females, emotion perception abilities peak between the ages of 15 and 30, with poorer performance by younger adults and declining performance after the age of 30. In addition, we show a consistent advantage by females across the lifespan, which decreases in magnitude with increasing age. This large scale study with a wide ran... (shrink)

Recent work on a small European cave salamander (Proteus anguinus) has revealed that it has exceptional longevity, yet it appears to have unexceptional defences against oxidative damage. This paper comes at the end of a string of other studies that are calling into question the free‐radical damage theory of ageing. This theory rose to prominence in the 1990s as the dominant theory for why we age and die. Despite substantial correlative evidence to support it, studies in the last five years (...) have raised doubts over its importance. In particular, these include studies of mice with the major antioxidant genes knocked out (both singly and in combination), which show the expected elevation in oxidative damage but no impact on lifespan. Combined, these findings raise fundamental questions over whether the free‐radical damage theory remains useful for understanding the ageing process, and variation in lifespan and life histories.Editor's suggested further reading in BioEssays Blind cave salamanders age very slowly: A new member of Methuselah's Bestiary Abstract. (shrink)

As individuals grow older, they usually require assistance with the daily tasks of self-care. This type of assistance, ancillary care, is essential to maintaining the health of those who need these services. In his prudential lifespan account, Norman Daniels includes access to such services making his account an attractive proposal given the current demographic shift. In this paper, I examine the prudential lifespan account through the lens of old age and I focus on the two concepts on which (...) the lifespan account relies. I show that these two concepts, normal species functioning and opportunity cannot buttress Daniels’s lifespan account; at least it cannot do so for older persons. The tensions that I identify in the prudential lifespan account in relation to aging are instructive for the more recent proposals to include aging in a theory of health and health justice. In addition, my analysis allows me to demonstrate that Daniels’s view of opportunity is irreconcilable to capabilities, the latter being more adaptable to the realities of aging. If capabilities appear more promising, it is nonetheless imperative that the specificities of extended care, such as the need for unpaid caregiving, be taken into consideration. (shrink)

Suls provides a useful review of research interested in the contribution of chronic negative emotions to coronary heart disease. Despite widespread support for a link between negative emotions and the etiology of disease, it is largely unknown if discrete negative emotions, particularly anger, sadness, and anxiety contribute to the development of physical disease in different ways. In this comment, we argue that answering this question will require a more comprehensive analysis of the unique characteristics of discrete emotions as well as (...) conceptually refined assumptions about how discrete emotions develop and change across the adult lifespan. (shrink)

This commentary is a call to action for researchers to create and use genome-wide association studies (GWASs) with previously missed age groups (e.g., infancy, elderly), which will improve our ability to ask important developmental questions using genetic data to trace pathways across the lifespan.

The acquisition of complex motor, cognitive, and social skills, like playing a musical instrument or mastering sports or a language, is generally associated with implicit skill learning . Although it is a general view that SL is most effective in childhood, and such skills are best acquired if learning starts early, this idea has rarely been tested by systematic empirical studies on the developmental pathways of SL from childhood to old age. In this paper, we challenge the view that childhood (...) and early school years are the prime time for skill learning by tracking age-related changes in performance in three different paradigms of SL. We collected data from participants between 7 and 87 years for a Serial Reaction Time Task testing the learning of motor sequences, an Artificial Grammar Learning task testing the extraction of regularities from auditory sequences, and Probabilistic Category Learning in the Weather Prediction task , a non-sequential categorization task. Results on all three tasks show that adolescence and adulthood are the most efficient periods for skill learning, since instead of becoming less and less effective with age, SL improves from childhood into adulthood and then later declines with aging. (shrink)

This paper argues that a precautionary approach to scientific progress of the sort advocated by Walter Glannon with respect to life-extending therapies involves both incoherence and irresolvable paradox. This paper demonstrates the incoherence of the precautionary approach in many circumstances and argues that with respect to life-extending therapies we have at present no persuasive reasons for a moratorium on such research.

The wish to extend the human lifespan has a long tradition in many cultures. Optimistic views of the possibility of achieving this goal through the latest developments in medicine feature increasingly in serious scientific and philosophical discussion. The authors of this paper argue that research with the explicit aim of extending the human lifespan is both undesirable and morally unacceptable. They present three serious objections, relating to justice, the community and the meaning of life.

Meeting everyday challenges and responding in a goal-directed manner requires both the ability to maintain the current task set in face of distractors—stable cognitive control, and the ability to flexibly generate or switch to a new task set when environmental requirements change—flexible cognitive control. While studies show that the development varies across individual component processes supporting cognitive control, little is known about changes in complex stable and flexible cognitive control across the lifespan. In the present study, we used the (...) newly developed Cognitive Control Challenge Task to examine the development of complex stable and flexible cognitive control across the lifespan and to gain insight into their interdependence. A total of 340 participants from two samples participated in the study, in which they were asked to complete the C3T along with a series of standard tests of individual components of cognitive control. The results showed that the development of both stable and flexible complex cognitive control follows the expected inverted U-curve. In contrast, the indeces of task set formation and task set switching cost increase linearly across the lifespan, suggesting that stable and flexible complex cognitive control are subserved by separable cognitive systems with different developmental trajectories. Correlations with standard cognitive tests indicate that complex cognitive control captured by the C3T engages a broad range of cognitive abilities, such as working memory and planning, and reflects global processing speed, jointly suggesting that the C3T is an effective test of complex cognitive control that has both research and diagnostic potential. (shrink)

Could age be a valid criterion for rationing? In Just health, Norman Daniels argues that under certain circumstances age rationing is prudent, and therefore a morally permissible strategy to tackle the problem of resource scarcity. Crucial to his argument is the distinction between two problem-settings of intergenerational equity: equity among age groups and equity among birth cohorts. While fairness between age groups can involve unequal benefit treatment in different life stages, fairness between birth cohorts implies enjoying approximate equality in benefit (...) ratios. Although both questions of fairness are distinct, the resolution of the one depends on resolution of the other. In this paper, I investigate whether Daniels’ account of age rationing could be defended as a fair way of setting limits to healthcare entitlements. I will focus on two main points. First, I will consider whether the age group problem could be resolved without appealing to a conception of the good. Second, I will demonstrate that the connection between the age group problem and the birth cohort problem runs deeper than Daniels initially thought—and that it ultimately suggests a method for prioritisation in problem solving strategies. (shrink)

The ability to resist distracting stimuli whilst voluntarily focusing on a task is fundamental to our everyday cognitive functioning. Here, we investigated how this ability develops, and thereafter declines, across the lifespan using a single task/experiment. Young children (5–7 years), older children (10–11 years), young adults (20–27 years), and older adults (62–86 years) were presented with complex visual scenes. Endogenous (voluntary) attention was engaged by having the participants search for a visual target presented on either the left or right (...) side of the display. The onset of the visual scenes was preceded – at stimulus onset asynchronies (SOAs) of 50, 200, or 500 ms – by a task-irrelevant sound (an exogenous crossmodal spatial distractor) delivered either on the same or opposite side as the visual target, or simultaneously on both sides (cued, uncued, or neutral trials, respectively). Age-related differences were revealed, especially in the extreme age-groups, which showed a greater impact of crossmodal spatial distractors. Young children were highly susceptible to exogenous spatial distraction at the shortest SOA (50 ms), whereas older adults were distracted at all SOAs, showing significant exogenous capture effects during the visual search task. By contrast, older children and young adults' search performance was not significantly affected by crossmodal spatial distraction. Overall, these findings present a detailed picture of the developmental trajectory of endogenous resistance to crossmodal spatial distraction from childhood to old age and demonstrate a different efficiency in coping with distraction across the four age-groups studied. (shrink)

This book presents a coherent framework for the balanced development of emotions and cognition throughout the lifespan. It synthesizes rich sources across psychology and neuroscience to show that the brain is hard-wired for basic emotions as well as reasoning, and that these structures mature as individuals learn social rules in interactions with others and progress through complex relationships. In contrast to traditional views that held emotions and cognition to be opposing domains, the author builds on recent views that emphasize (...) the ideal of a cooperative relationship among the two domains. Central to this construct is the fragile balance of expansion and stability that is crucial to both cognitive and affective development: how it can be nurtured for optimal functioning, and how, in contrast, the absence of such a caring context functions to derail growth and encourage pathology that can be carried into later stages of the lifespan. This groundbreaking volume: Traces historical changes in conceptions of the relation between reason and emotion from ancient philosophy to modern science. Expands on Piaget's theories of alternating phases of equilibrium in cognitive development and details how these contribute toward integrated cognitive-emotional growth. Discusses neurobiological mechanisms contributing to balance between emotional and cognitive development. Presents examples of the integration of cognitive/emotional development from infancy to adulthood. Explores the relationships between affect and cognition in later life. Integrating Emotions and Cognition Throughout the Lifespan is an essential resource for researchers, graduate students, and clinicians in a range of disciplines, including developmental psychology, aging, educational philosophy, biological psychology, and personality/social psychology.. (shrink)

Why do the two sexes have different lifespans and rates of aging? Two hypotheses based on asymmetric inheritance of sex chromosomes (“unguarded X”) or mitochondrial genomes (“mother's curse”) explain sex differences in lifespan as sex‐specific maladaptation leading to increased mortality in the shorter‐lived sex. While asymmetric inheritance hypotheses equate long life with high fitness, considerable empirical evidence suggests that sexes resolve the fundamental tradeoff between reproduction and survival differently resulting in sex‐specific optima for lifespan. However, selection for sex‐specific (...) values in life‐history traits is constrained by intersexual genetic correlations resulting in intra‐locus sexual conflict over optimal lifespan. The available data suggest that the evolution of sexual dimorphism only partially resolves these conflicts. Sexual conflict over optimal trait values, which has been demonstrated in model organisms and in humans, is likely to play a key role in shaping the evolution of lifespan, as well as in maintaining genetic variation for sex‐specific diseases. (shrink)

This article explores the problem of justice between age-groups. Specifically, it presents a challenge to a leading theory in this field, Norman Daniels' Prudential Lifespan Account. The challenge relates to a key assumption that underlies this theory, namely the assumption that all individuals live complete lives of equal length. Having identified the roles that this assumption plays, the article argues that the justifications Daniels offers for it are unsatisfactory and that this threatens the foundation of his position, undermining his (...) claim that ‘the fact that we all age’ makes age a special problem of distributive justice. This shows that the problem of justice between age-groups is not special in the way Daniels proposes; rather it involves the same irreducibly interpersonal distributive decisions as other problems of justice. The consequences of this argument are several-fold. Most importantly, it shows that the Rawlsian account of justice to which Daniels hopes to attach his theory to requires significantly greater benefits to be conferred on those in earlier age-groups relative to those in later age-group, not a distribution similar to simultaneous equality as Daniels proposes. (shrink)

The literature on human enhancement is awash with discussions about whether it really would be desirable to increase our lifespan, cognitive power, physical strength above and beyond that which we currently consider to be healthy or normal. Almost all of these discussions hang on the question of whether it makes sense to draw a morally relevant distinction between those interventions that count as therapies and those that count as enhancements. Roughly, therapies are interventions that aim to restore health or (...) normality to capacities or functions that are diseased or otherwise operating at a sub-normal level; enhancements aim to improve on the healthy or normal level of functioning. Focusing on the case of lifespan enhancement, Andrea Sauchelli considers the desirability of enhancement from a perspective that is independent of the debate about the therapy/enhancement distinction. His starting point is an argument from Walter Glannon, who holds that ‘deep life-extending... (shrink)

Multiple self approaches purport that to have equal concern about all stages of one’s life is not a requirement of rationality. This poses a challenge to the prudential lifespan account which Norman Daniels advocates in Just health: meeting health needs fairly. Daniels has criticised the multiple self approach in earlier works, most extensively in Am I my parents keeper? In Just health, he only takes up the issue except in one footnote, presumably because he is convinced that his preceding (...) discussions settled the matter. This article argues that Daniels underestimates the force of the multiple self objection to prudential lifespan account. (shrink)

Genomic sequencing (GS) is increasingly used in paediatric medicine to aid in screening, research and treatment. Some health systems are trialling GS as a first-line test in newborn screening programmes. Questions about what to do with genomic data after it has been generated are becoming more pertinent. While other research has outlined the ethical reasons for storing deidentified genomic data to be used in research, the ethical case for storing data for future clinical use has not been explicated. In this (...) paper, we examine the ethical case for storing genomic data with the intention of using it as a lifetime health resource. In this model, genomic data would be stored with the intention of reanalysis at certain points through one’s life. We argue this could benefit individuals and create an important public resource. However, several ethical challenges must first be met to achieve these benefits. We explore issues related to privacy, consent, justice and equality. We conclude by arguing that health systems should be moving towards futures that allow for the sequential interrogation of genomic data throughout the lifespan. (shrink)

Life history theory suggests that in risky and uncertain environments the optimal reproductive strategy is to reproduce early in order to maximize the probability of leaving any descendants at all. The fact that early menarche facilitates early reproduction provides an adaptationist rationale for our first two hypotheses: that women who experience more risky and uncertain environments early in life would have (1) earlier menarche and (2) earlier first births than women who experience less stress at an early age. Attachment theory (...) and research provide the rationale for our second two hypotheses: that the subjective early experience of risky and uncertain environments (insecurity) is (3) part of an evolved mechanism for entraining alternative reproductive strategies contingent on environmental risk and uncertainty and (4) reflected in expected lifespan. Evidence from our pilot study of 100 women attending antenatal clinics at a large metropolitan hospital is consistent with all four hypotheses: Women reporting more troubled family relations early in life had earlier menarche, earlier first birth, were more likely to identify with insecure adult attachment styles, and expected shorter lifespans. Multivariate analyses show that early stress directly affected age at menarche and first birth, affected adult attachment in interaction with expected lifespan, but had no effect on expected lifespan, where its original effect was taken over by interactions between age at menarche and adult attachment as well as age at first birth and adult attachment. We discuss our results in terms of the need to combine evolutionary and developmental perspectives and the relation between early stress in general and father absence in particular. (shrink)

Emoji appear to be an important cue to judge whether a statement is sarcastic in computer-mediated communication. In this study, we investigated whether the smiling emoji, an indicator of sarcastic intention in the Chinese culture, exerts an influence on sarcasm interpretation across the lifespan. Statements accompanied with or without a smiling emoji were compared in unambiguous (Experiment 1) and ambiguous (Experiment 2) contexts. The results of Experiment 1 illustrated that for teenagers and the 20-year-olds the smiling emoji enhanced the (...) perceived sarcasm of sarcastic statements significantly. However, there was no difference in interpreting sarcastic statements with or without a smiling emoji in other age groups. Experiment 2 replicated the results of Experiment 1. We found both teenagers and the 20-year-olds were more likely to arrive at a sarcastic interpretation of the ambiguous statement followed by a smiling emoji, which were less frequent in participants aged in their 30s, 40s, 50s and individuals over 60 years old. This might be because people of varying ages differ in decoding the emotions of the emoji. Age-related differences in the use of sarcasm and participants’ experiences with using emoji might be possible factors that were closely related to the interpretation of emoji-based sarcasm. (shrink)

What the causes of aging are and which factors define lifespan are key questions in the understanding of aging. Here, it is argued that cellular life involves (i) inevitable accumulation of damage resulting from imperfectness and heterogeneity of every cellular process, and (ii) dilution of damage when cells divide. While severe damage is cleared by protective systems, milder damage can only be diluted. This is due to the high cost of accuracy, the greater number of damage forms compared to (...) protective systems, and the constraints on cellular life inherited from the prokaryotic world. This strategy also applies to cancer cells, which are particularly dependent on damage dilution. Imposing restriction on cell division necessarily leads to aging. Interventions that extend lifespan act through metabolic reprogramming, thereby changing both damage composition and the rate of damage accumulation. Thus, heterogeneity leading to myriad mild damage forms represents the cause of aging, whereas the processes that affect the damage landscape and damage accumulation are lifespan regulators. (shrink)

Ritual behaviors of some form exist in every society known to anthropologists. Despite this universality, we have little understanding of how ritual behavior varies within populations or across the lifespan, nor the determinants of this variation. Here we test hypotheses derived from life history theory by using behavioral observations and oral interview data concerning participant variation in Fijian kava-drinking ceremonies. We predicted that substantial variation in the frequency and duration of participation would result from (1) trade-offs with reproduction and (...) (2) the intrinsic status differences between ritual participants. We demonstrate that when controlling for household composition, men with young offspring participated less frequently and exhibited greater variance in their time spent at ceremonies than men without young children. However, men with a larger number of total dependents in their household participated more frequently than those with fewer. Moreover, we found that men’s ascribed rank, level of education, and reliance on wage labor all significantly predict their frequency of attendance. We also found that the number of dependents a man has in his household is positively correlated with total food production, and the amount of kava he cultivates. In general, these results suggest that ritual participation is part of an important strategy employed by Fijian men for both achieving status and developing social alliances. Variation in participation in kava ceremonies by Fijian men therefore reflects the constraints of their current life history condition and their inherited rank. (shrink)