Generational differences in societies are characteristics generally attributed to people’s age that constitute a sociocultural phenomenon. Divisions in the generations differ across nations and extend even to civilizations. Perception and recognition of the different characteristics of each generation affect the cooperation between people in social, political, and economic capacities, and subsequently extend to entities in the public, informal, commercial, and nongovernmental sectors. From the perspective of social justice, it is important to draw attention to how workplace management techniques (...) are used to promote equal opportunities among representatives of various generations. (shrink)

The search for meaningful work has been of interest to researchers from a variety of disciplines for decades and seems to have grown even more recently. Much of the literature assumes that employees share a sense of what is meaningful in work and there isn’t much attention given to how and why meanings might differ. Researchers have not only called for more research studying demographic differences in definitions of meaning :77–90, 2014), but also more research utilizing mixed methods to (...) study psychological concepts like meaningful work Handbook of multimethod measurement in psychology, American Psychological Association, Washington, 2006). This study specifically examines differences across generational cohorts on their prioritization of sources of meaningful work through qualitative, in-depth interviews followed by a more generalizable, quantitative survey. Findings from the qualitative study show that generational cohorts define the meaning in their jobs differently, and they hold negative perceptions about the lack of desire for meaning in each of the other cohorts. Study 2 maps generational cohorts on the comprehensive model of meaningful work designed by Lips-Wiersma and Morris :491–511, 2009) to reveal that although there are some differences in prioritization of sources of meaningful work, all generational cohorts share similar desire to “develop and become themselves” when asked about their definitions of meaningful work. Implications and future research are discussed. (shrink)

Can Rawls’s theory provide a framework for assessing obligations to future generations? Extending the veil of ignorance so that participants in the original position do not know to which generation they belong appears to fail in this endeavour. Earlier generations cannot improve their situation by “cooperating” with later generations. Such circumstances, lacking mutuality, leave no room for an agreement or contract. Nevertheless, the original position can be reconstructed so as to model relations of mutuality between generations even if these are (...) absent from the real world. This chapter assesses earlier attempts to do this and provides a rationale for viewing the just savings principle as a clause in the full formulation of the difference principle. (shrink)

We asked whether and how generations vary in their perceptions on moral matters ranging from their justifications of crime and questions concerning bodily autonomy. In our exploratory study using data from the World Values Survey, we found that Generations Y and Z are more likely than their older counterparts to justify crimes, such as cheating on taxes or stealing property, and to favor greater bodily autonomy in issues such as suicide and abortion. They also rank lower the importance of God (...) and national pride. Implications are offered for employers who wish to motivate and incentivize a multi-generational workforce. (shrink)

The COVID-19 pandemic has changed the landscape of working conditions world-wide, fast tracking the reality of the digital-driven workplace. Concepts such as remote working, working-from-home and hybrid working models are now considered as the “new normal.” Employes are expected to advance, flourish and survive in this digitally connected landscape. Different age and generational groups may experience this new organizational landscape differently and may expect different organizational outcomes in exchange for their inputs. Accordingly, the study investigated differences regarding the (...) value-oriented psychological contract expectations of employes from different generational groups. An ANOVA test for significant mean differences and a post hoc test for multiple comparisons were conducted on a sample of employes in the services industry in Southern Africa and other European countries. The observed generational cohort differences regarding value-orientated psychological contract expectations for job characteristics and work-life balance could be utilized to develop interventions and strategies to promote retention of employes in the post-pandemic digital-orientated workplace. (shrink)

This article presents our research into cultural differences in the motivation of Generation Y knowledge workers. The goal of our research was to verify whether the motivation of young knowledge workers (members of Generation Y) could be assessed only in relation to the specifics of their generation, or whether it is necessary to take their national cultural background into account as well. The research carried out among two hundred respondents in four countries has confirmed that it is essential to (...) take into account both generation differences and cultural differences. (shrink)

Although generational differences have been studied in developed countires, not much information is available about generational cohorts and how they differ in terms of work ethics in developing countries. A cross-sectional study was conducted with a sample of 301 respondents from South Africa. Work ethics of three generational cohorts were measured, namely the Baby Boomers, Generation X, and Generation Y. The main finding of this research was that statistically significant differences and similarities were found between (...) the various generational cohorts in terms of work ethics facets. Statistically significant generational differences were indicated for hard work and delay of gratification. (shrink)

Philosophical issues such as free will and the role of consciousness in human action have become a topic of interest to neuroscience. While this contribution is of great value to extend our knowledge on these issues, the lack of clarity about the concepts being investigated may interfere with the interpretation of the relevant results. An interesting experiment (Bode et al., 2011) that investigates whether decisions are generated consciously or unconsciously suggests a conclusion about whether human beings decide freely. These issues (...) are considered relevant philosophical issues, but the experiment lacks conceptual precision, and this weighs on the interpretations of data and results. I argue that further conceptual analysis of decisions shows that the experiment investigates one kind of decision, while it unwarrantedly draws conclusions about human decisions in general. A better understanding of what is considered to be a decision helps clarify to which extent the results show that decisions are generated unconsciously. This shows that conceptual precision is crucial for research on the area as well as methodological rigor. (shrink)

Shared brain regions have been found for processing action and language, including the left inferior frontal gyrus, the premotor cortex, and the inferior parietal lobule. However, in the context of action and language generation that shares the same action semantics, it is unclear whether the activity patterns within the overlapping brain regions would be the same. The changes in effective connectivity affected by these activity patterns are also unclear. In this fMRI study, participants were asked to perform hand action and (...) verb generation tasks toward object pictures. We identified shared and specific brain regions for the two tasks in the left PMC, IFG, and IPL. The mean activation level and multi-voxel pattern analysis revealed that the activity patterns in the shared sub-regions were distinct for the two tasks. The dynamic causal modeling results demonstrated that the information flows for the two tasks were different across the shared sub-regions. These results provided the first neuroimaging evidence that the action and verb generation were task context driven in the shared regions, and the distinct patterns of neural information flow across the PMC-IFG-IPL neural network were affected by the polymodal processing in the shared regions. (shrink)

AbstractOver the past 20 years, there has been considerable expansion, particularly spirituality theory in the workplace. Simultaneously, there has been a growth of research, most especially in practitioner publication into generational differences. The study's context is human resource (HR) policy and procedures in the workplace. Through this prism, generational perspectives and religious theory are compared and scrutinised within the United Kingdom. Two major religious groups (Muslim and Christian) and three-generational categories (Millennials, Generation X, and Baby Boomers) (...) were selected to explore different attitudes, with participants identifying as belonging to religious groups outside of these two major religions, categorised as 'Other.' This study adopts a quantitative approach, with questionnaires gathering employees' perceptions of spirituality policy within their place of work. Although the study found differences in expectations between the religious groups and between the three generations, there is greater homogeneity than a difference in that the results provide limited support for workplace spirituality. Indeed, the study raises more questions than answers. The study uncovered areas ripe for informed debate around personal values, generations, and spirituality in the workplace. This is a relatively new research area, and our findings are in line with others that suggest that employee spiritual well-being is both underresearched and underexplored by organisations. Changing the current intransigence around the place of spirituality is overdue. (shrink)

A weighted total of 630 pupils aged 1440. Among 1440-year-olds, especially females. Among 3015-year-old Glasgow Asians 86% were so born, indicating that they are the children of migrants. Generational differences in these comparisons cannot be due to positive selection of the migrant generation for height, and are attributed to improved environment, including nutrition and public health measures. This suggests the possibility of corresponding improvements in coronary and diabetic risk.

(1991). Different forms of causation in dynamical systems: Determinism, pattern generation, and information. World Futures: Vol. 30, No. 4, pp. 221-237.

This article focuses on the gap and conflicts in Italy between the so-called ‘historical feminists’ of the 1960s and 1970s, and the generation of young women who entered the public and political arena from 1990 onwards. It discusses the absence of a critical and self-critical perspective within the Italian historical feminist tradition, the various political conflicts that emerged before and during the Berlusconi right-wing government at the beginning of 2000 and the absence of an active visible presence of young women (...) in the media and in politics. (shrink)

BackgroundAge related differences were found in prevention behavior, showing that older individuals tend to be the most proactive. The aim of the study was the identification of psychological predictors on COVID-19 prevention behavior in women, across four generations. In addition, the predictive role of the psychological variables was explored through the lens of negative and positive information processing perspective on total and domain-specific COVID-19 prevention behavior.MethodsA cross-sectional research was conducted. The sample included 834 Hungarian speaking women. The assessed variables (...) were: COVID-19 knowledge, risk perception, COVID-19 health anxiety, negative automatic thoughts, psychological flexibility, and four domains of COVID-19 prevention behavior (social distancing, general hygiene, information seeking, health behavior). A three-level hierarchical linear regression analysis was conducted to investigate the predictors of preventive behavior in each generation.ResultsA diversity across generations was found. In case of baby boomer generation, the final model explained 32.4% of the variance for total prevention behavior [F(14,215) = 8.847,p< 0.001], and only perceived risk made a significant contribution. For Gen X the final model accounted for 21.1% of variance of total prevention behavior [F(14,341) = 7.788,p< 0.001], marital status, perceived risk, COVID-19 health anxiety, and negative automatic thoughts made significant contributions. In case of Gen Y the final model accounted for 6.2% of variance on total prevention behavior [F(14,147) = 1.761,p= 0.05], only perceived risk had a contribution to the final model. For Gen Z the final model accounted for 23.4% of variance on total preventive behavior [F(13,71) = 2.979,p= 0.002], and only psychological flexibility made a contribution to the model. The results on the distinct domains of COVID-19 prevention behavior emphasized details in the dissimilarity among generations.ConclusionThe role of generational identity on COVID-19 prevention behavior is relevant. The coexistence of negative and positive information processing may have its beneficial role in certain areas of prevention. (shrink)

For the last thirty years or so, there has been a search underway for a theory that can accommodate our intuitions in regard to moral duties to future generations. The object of this search has proved surprisingly elusive. The classical moral theories in the literature all have perplexing implications in this area. Classical Utilitarianism, for instance, implies that it could be better to expand a population even if everyone in the resulting population would be much worse off than in the (...) original. The main problem has been to find an adequate population theory, that is, a theory about the moral value of states of affairs where the number of people, the quality of their lives, and their identities may vary. Since, arguably, any reasonable moral theory has to take these aspects of possible states of affairs into account when determining the normative status of actions, the study of population theory is of general import for moral theory. A number of theories have been proposed in the literature that purport to avoid counterintuitive implications such as the one mentioned above. The suggestions are diverse: introducing novel ways of aggregating welfare into a measure of value, revising the notion of a life worth living, questioning the way we can compare and measure welfare, counting people’s welfare differently depending on the temporal location or the modal features of their lives, and challenging the logic of axiological and normative concepts. We investigate the concepts and assumptions involved in these theories as well as their implications for population theory. In our discussion, we propose a number of intuitively appealing and logically weak adequacy conditions for an acceptable population theory. Finally, we consider whether it is possible to find a theory that satisfies all of these conditions. We prove that no such theory exists. (shrink)

Neither of the explanations O'Brien & Opie offer to account for “subject unity” succeeds. Subject unity cannot arise from constructed personal narratives, because such narratives presuppose a prior unity of experience. Subject unity also cannot arise from projection of experiences to the same position in space, as reflection on pregnant women and the spatially deluded reveals.

The connection between whole and part is intimate: not only can we share the same space, but I’m incapable of leaving my parts behind; settle the nonmereological facts and you thereby settle what is a part of what; wholes don’t seem to be an additional ontological commitment over their parts. Composition as identity promises to explain this intimacy. But it threatens to make the connection too intimate, for surely the parts could have made a different whole and the whole have (...) had different parts. In this paper I attempt to offer an account of parthood that is intimate enough but not too intimate: the parts generate the whole, but they are not themselves the whole. (shrink)

Many psychological studies have shown that human‐generated sequences are hardly ever random in the strict mathematical sense. However, what remains an open question is the degree to which this (in)ability varies between people and is affected by contextual factors. Herein, we investigated this problem. In two studies, we used a modern, robust measure of randomness based on algorithmic information theory to assess human‐generated series. In Study 1 (), in a factorial design with task description as a between‐subjects variable, we tested (...) the effects of context and mental fatigue on human‐generated randomness. In Study 2 (), in online research, in experimental design, we further investigated the effect of mental fatigue on the randomness of human‐generated series and the relationship between the need for cognition (NFC) and the ability to produce random‐like series. Results of Study 1 show that the activation of the ability to produce random‐like series depends on the relevance of the contextual cues (), whether they activate known representations of a random series generator and consequently help to avoid the production of trivial sequences. Our findings from both studies on the effect of mental fatigue (Study 1 – ; Study 2 – ) and cognitive motivation () demonstrate that regardless of the context or task's novelty people quickly lose interest in the random series generation. Therefore, their performance decreases over time. However, people high in the NFC can maintain the cognitive motivation for a longer period and consequently on average generate more random series. In general, our results suggest that when contextual cues and intrinsic constraints are in optimal interaction people can temporarily escape the structured and trivial patterns and produce more random‐like sequences. (shrink)

The current work represents a piece of research on the family firm of the semasiological, interpretive or culture creation type. In it we carry out a comparative analysis of the organizational culture of this type of firm along with firms not considered to be family firms, using as theoretical framework generally accepted theories in business administration, such as the systems, neoinstitutional, transformational leadership, and social identity theories. Our findings confirm the existence of certain elements of culture, especially values and allow (...) us to propose a value-based model to help family firms to survive through different family generations. (shrink)

Should we remain neutral between our interests and those of future generations? Or are we ethically permitted or even required to depart from neutrality and engage in some measure of intergenerational discounting? This Article addresses the problem of intergenerational discounting by drawing on two different intellectual traditions: the social welfare function (“SWF”) tradition in welfare economics, and scholarship on “prioritarianism” in moral philosophy. Unlike utilitarians, prioritarians are sensitive to the distribution of well-being. They give greater weight to well-being changes affecting (...) worse-off individuals. Prioritarianism can be captured, formally, through an SWF which sums a concave transformation of individual utility, rather than simply summing unweighted utilities in utilitarian fashion. The Article considers the appropriate structure of a prioritarian SWF in intergenerational cases. The simplest case involves a fixed and finite intertemporal population. In that case, I argue, policymakers can and should maintain full neutrality between present and future generations. No discount factor should be attached to the utility of future individuals. Neutrality becomes trickier when we depart from this simple case, meaning: (1) “non-identity” problems, where current choices change the identity of future individuals; (2) population-size variation, where current choices affect not merely the identity of future individuals, but the size of the world’s future population (this case raises the specter of what Derek Parfit terms “the repugnant conclusion,” i.e., that dramatic reductions in the average level of individual well-being might be compensated for by increases in population size); or (3) an infinite population. The Article grapples with the difficult question of outfitting a prioritarian SWF to handle non-identity problems, population-size variation, and infinite populations. It tentatively suggests that a measure of neutrality can be maintained even in these cases. (shrink)

Many psychometricians and behavioral geneticists believe that high heritability of IQ test scores within racial groups coupled with environmental hypotheses failing to account for the differences between the mean scores for groups lends plausibility to explanations of mean differences in terms of genetic factors. This two-component argument cannot be sustained when viewed in the light of the conceptual and methodological themes introduced in Taylor . These themes concern the difficulties of moving from the statistical analysis of variance of (...) observed traits to investigation of measurable genetic factors and measurable environmental factors. One such theme is that quantities estimated by an AOV of observed traits cannot be equated with measurable genetic or environmental factors involved in the development of those traits. Once this distinction is clear, the argument that environmental factors have failed to explain the differences lacks weight because it does not consider whether genetic factors have been more successful. This article exposes additional flaws in the lines of thinking associated with the two-component argument, with the distinction between passive, reactive, and active associations between genetic and environmental factors, and with the reciprocal causation models Dickens and Flynn propose in order to reconcile high estimates of heritability and large IQ test score gains between generations. Human heritability estimates are irrelevant in developing explanations of differences across groups or across generations. My critique is directed at opening up more conceptual space for deriving empirically validated models of developmental pathways whose components are heterogeneous and differ among individuals at any one time and over generations. (shrink)

Departing from the debate about the importance of gender ideology in the integration of Muslim minorities in Western Europe, this article studies the association between Islamic religiosity and gender ideology among second-generation Turkish and Moroccan men and women in Belgium. Islamic religiosity is conceptualized as consisting of religious identification, religious practices, and belief orthodoxy. The comparability of this model across genders and national origin groups is tested with recently collected survey data. The association between Islamic religiosity and gender ideology is (...) analyzed with regard to gender and ethnic differences. Taking a number of control variables into account, the analysis reveals no significant differences between national origin groups. More importantly, Islamic religiosity is found to be only weakly negatively associated with gender egalitarianism; this association is somewhat stronger for men than for women. These results challenge the alleged strong connection between Islamic religiosity and traditional gender ideology and highlight the importance of taking gender differences into account when studying religiosity among Muslim minorities in Europe. (shrink)

The main objective of this collection of papers is to explore ideas of generation and transformation in the context of postdependency discourse as it may be traced in women’s writing published in Bengali, Polish, Czech, Russian and English. As we believe, literature does not have merely a descriptive function or a purely visionary quality but serves also as a discursive medium, which is rhetorically sophisticated, imaginatively influential and stimulates cultural dynamics. It is an essential carrier of collective memory and a (...) significant indicator of group identity. Along with philosophy, literature explores the intellectual and emotional, aesthetic and ethical components of our lives, and, while focusing on a single feeling or unique event or phenomenon, aspires to capture the universal attributes of human experience. Hence, we intend to juxtapose interpretations of literature originating in very different cultural milieus, such as the Central East European and South Asian,with the literary treatment of the philosophical dilemmas that challenge authors of various nationalities in times of great political, economic and social upheaval and transformation following long periods of dependency and suppression, caused either by colonial and imperialist domination or by communist ideology. (shrink)

The contemporary use of the term ‘complexity’ frequently indicates that it is considered a unified concept. This may lead to a neglect of the range of different theories that deal with the implications related to the notion of complexity. This paper, integrating both the English and the Latin traditions of research associated with this notion, suggests a more nuanced use of the term, thereby avoiding simplification of the concept to some of its dominant expressions only. The paper further explores the (...) etymology of ‘complexity’ and offers a chronological presentation of three generations of theories that have shaped its uses; the epistemic and socio‐cultural roots of these theories are also introduced. From an epistemological point of view, this reflection sheds light on the competing interpretations underlying the definition of what is considered as complex. Also, from an anthropological perspective it considers both the emancipatory as well as the alienating dimensions of complexity. Based on the highlighted ambiguities, the paper suggests in conclusion that contributions grounded in contemporary theories related to complexity, as well as critical appraisals of their epistemological and ethical legitimacy, need to follow the recursive feedback loops and dynamics that they constitute. In doing so, researchers and practitioners in education should consider their own practice as a learning process that does not require the reduction of the antagonisms and the complementarities that shape its own complexity. (shrink)

In recent public administration literature, much attention is paid to changes in public service values, including ethical values, that guide public service. This paper reports on the results of an empirical survey conducted among a group of Turkish governors and district governors (including those in service and retired) who are from different generations. By focusing on the transformation of value preferences of Turkish governors and district governors, this study tries to identify variations in values, particularly about public service ethics, in (...) accordance with the age and the length of tenure in public service. The findings of the research show a traditional and more or less consistent value pattern for Turkish governors and district governors. The most important public service values expressed by the respondents are consistent with often-mentioned crucial public service values in the literature. New or emerging values have not been present enough among the most important public service values. In brief, the results do not lend support to the often-assumed hypothesis that traditional public service values are devaluated or degraded by the emergence of businesslike values. In other words, new emerging values could not sneak into the public service culture in any convincing manner in spite of many years of NPM rhetoric and recipes. (shrink)

This study examines the feature of reasoning talk used by 37 Chinese families at the dinner table across three generations with the background of co-parenting and in consideration of different communicative contexts. Drawing upon Hasan’s semantic framework, reasons were mainly coded as logical or social types. We categorize the communicative context of reasoning talk into contextualized and decontextualized topics. When the proportion of social reasoning was found slightly higher than that of logical reasoning, the families’ reasoning talk account for only (...) 3.85% of the total language. Specifically, the count of mothers’ total reasoning talk was significantly above other family members, while there were no significant differences among the other participants. The effect of the communicative contexts on family members’ social reasoning was found. The reasoning talk grounded on local rules and coercive power occurred significantly more frequently in contextualized than decontextualized context. A higher rate of local-rule grounded reasoning talk of all family members appeared in contextualized than decontextualized context, and this gap was particularly obvious among mothers. These findings reveal the significant role of mothers in family communications and confirm the pedagogical values of decontextualized communicative context for promoting children’s learning opportunities at the dinner table. (shrink)

Emotion regulation has the odd distinction of being a wildly popular construct whose scientific existence is in considerable doubt. In this article, we discuss the confusion about whether emotion generation and emotion regulation can and should be distinguished from one another. We describe a continuum of perspectives on emotion, and highlight how different (often mutually incompatible) perspectives on emotion lead to different views about whether emotion generation and emotion regulation can be usefully distinguished. We argue that making differences in (...) perspective explicit serves the function of allowing researchers with different theoretical commitments to collaborate productively despite seemingly insurmountable differences in terminology and methods. (shrink)

Significant transformations in postmodern society determine the need to form a space of digital communications and the involvement of information and communication technologies. Such trends make significant demands on various categories of professionals, including managers in the field of tourism. The aim of this research is to study the psychological peculiarities of morality in the representatives of digital Generations Y and Z in the field of tourism. In accordance with the aim, we paid attention to the study of such components (...) of moral regulation as ethics attitude, moral foundations, justice sensitivity and moral disengagement. The research involved 200 participants being represented by volunteers from five regions of Ukraine, including 100 respondents in the age of 25-30 who formed part of the Generation Y group; the other 100 participants in the age of 18-23 formed the Generation Z group. The results show that millennials are more idealistic. The intercrossing of the factors of idealism and relativism allows us to characterize millennials as situationalists, and centennials as subjectivists. It is ascertained that millennials are characterised by such important moral foundations for judgments as “Faithfulness”, “Purity”, which is reflected in the greater importance of “Ethics of community”. At the same time, it was found that centennials place more emphasis on the moral foundations of care and justice, and as a result, they are more committed to the “Ethics of autonomy” and “Progressivism”. The research confirmed the uniqueness and specificity of the moral regulation of different digital generations of representatives of the tourism industry. (shrink)

Generations and Geographies brings together a collection of artists, critics and researchers to consider the question of sexual difference and its significance in the production and reception of visual representation by women artists.

Self-generation of knowledge can activate deeper cognitive processing and improve long-term retention compared to the passive reception of information. It plays a distinctive role within the concept of inquiry-based learning, which is an activity-oriented, student-centered collaborative learning approach in which students become actively involved in knowledge construction. This approach allows students to not only acquire content knowledge, but also an understanding of investigative procedures/inquiry skills – in particular the control-of-variables strategy (CVS). From the perspective of cognitive load theory, generating answers (...) and solutions during inquiry-based learning is inefficient as it imposes an intrinsic and extraneous load on learners. Previous research on self-generation of content knowledge in inquiry-based learning has demonstrated that (1) a high cognitive load impairs retention of the generated information, (2) feedback is a fundamental requirement for self-generation of complex content knowledge, (3) self-generation success is key to long-term retention and (4) generating and rereading place different demands on learners. However, there is still no research on the self-generation of scientific reasoning skills and the interaction between the retention of these skills with prior knowledge, feedback and self-generation success. That is why this experiment was conducted. The focus of this research is to analyze the distinctive role of self-generation of scientific reasoning skills within the concept of inquiry-based learning and to identify the influence of prior knowledge and self-generation success on short-term and long-term retention. For this purpose, an experiment involving 133 6th and 7th graders was conducted. An inquiry activity that included the self-generation of scientific reasoning skills was compared to an inquiry task that had students simply read information about the experimental design. We used both an immediate and a delayed test to examine which treatment better developed a deeper understanding of CVS and an ability to apply this knowledge to novel problems (transfer). Direct instruction was clearly superior to self-generation in facilitating students’ acquisition of CVS immediately after the inquiry task. However, after a period of one week had elapsed, both treatment conditions turned out to be equally effective. A generation effect was only found among students with high self-generation success after a 1-week delay. (shrink)

In this article, we explore the implications of a Rawlsian theory for intergenerational issues. First, we confront Rawls's way of locating his `just savings' principle in his Theory of Justice with an alternative way of doing so. We argue that both sides of his intergenerational principle, as they apply to the accumulation phase and the steady-state stage, can be dealt with on the bases, respectively, of the principle of equal liberty and of the difference principle. We then proceed by focusing (...) on the implications of applying maximin to his steady-state stage. One central claim is that, in principle, Rawlsians should consider not only generational dissavings, but also generational savings, as unfair. This principle suffers a series of exceptions on which we focus in the fourth section of the article. In some cases, growth can be maximin compatible. (shrink)

While many different mechanisms contribute to the generation of spatial order in biological development, the formation of morphogenetic fields which in turn direct cell responses giving rise to pattern and form are of major importance and essential for embryogenesis and regeneration. Most likely the fields represent concentration patterns of substances produced by molecular kinetics. Short range autocatalytic activation in conjunction with longer range “lateral” inhibition or depletion effects is capable of generating such patterns (Gierer and Meinhardt, 1972). Non-linear reactions are (...) required, and mathematical criteria were derived to design molecular models capable of pattern generation. The classical embryological feature of proportion regulation can be incorporated into the models. The conditions are mathematically necessary for the simplest two-factor case, and are likely to be a fair approximation in multi-component systems in which activation and inhibition are systems parameters subsuming the action of several agents. Gradients, symmetric and periodic patterns, in one or two dimensions, stable or pulsing in time, can be generated on this basis. Our basic concept of autocatalysis in conjunction with lateral inhibition accounts for self-regulatory biological features, including the reproducible formation of structures from near-uniform initial conditions as required by the logic of the generation cycle. Real tissue form, for instance that of budding Hydra, may often be traced back to local curvature arising within an initially relatively flat cell sheet, the position of evagination being determined by morphogenetic fields. Shell theory developed for architecture may also be applied to such biological processes. (shrink)