Selection Theory Research Articles

Beyond chronological age: exploring how different future time perspective influences the health tourism intention

BackgroundThe burgeoning field of health tourism has garnered significant attention due to its integration of health and leisure, reflecting a growing consumer demand for wellness-oriented travel experiences. Based on the socioemotional selectivity theory, this study examines the relationship between future time perspective, health awareness, involvement, and health tourism intention. It aims to understand how different dimensions of future time perspective influence the intention to engage in health tourism, beyond the traditional chronological age.MethodsA cross-sectional survey was conducted among individuals aged 16 years and above with normal cognitive function. Data was collected through online questionnaires distributed on popular Chinese social media platforms, WeChat and QQ. A total of 536 valid questionnaires were returned, with a validity rate of 91.47%. The study employed the structural equation modeling (SEM) to test the proposed hypotheses.ResultsThe effect of different dimensions of future time perspective on health tourism intention differed. Limited future time perspective (LFTP) positively influenced health tourism intention, while open-ended future time perspective (OFTP) did not have a significant effect on health tourism intention. Involvement and health awareness not only directly influence health tourism intention, but also mediate the relationship between future time perspective (OFTP and LFTP) and health tourism intention respectively. Moreover, there is a significant difference in the effect of LFTP on healthy tourism intention between different age groups.ConclusionsThe findings highlight the importance of considering subjective time perspectives in understanding health tourism intention. Health tourism companies should focus on strategies that enhance health awareness and consumer involvement to capitalize on the positive effects of health tourism intention. Additionally, the study suggests that marketing efforts should be tailored to address the specific needs and goals of individuals with different future time perspectives, thereby optimizing the appeal of health tourism products. Future research should explore these relationships across diverse populations and contexts to further refine the understanding of health tourism decision-making.

Multi-Borrowing Practices and Loan Repayment of Micro and Small Enterprises in Trade Sector in Meru County, Kenya

In Kenya, the increase in multi-borrowing and its effects on loan repayment is a growing concern for microfinance institutions. The general purpose of this research was to establish the effect of multi-borrowing on loan repayment among MSEs in Meru County. Specifically, the study aimed to determine how the number of loans borrowed, interest payable, and the financial literacy of borrowers influenced loan repayment within Meru County Microfinance. The research was anchored on information asymmetry, prospect theory, moral hazard, and adverse selection theories. The study targeted 6,000 MSE owners who were members of Meru County Microfinance, from which a sample of 200 borrowers was selected. A descriptive research design was employed to assess how multiple borrowings affected loan repayment. Cluster and random sampling methods were used to identify respondents across the seven branches of Meru County Microfinance. Primary data was collected using questionnaires, and analyzed by use of descriptive, correlational, and regression analysis techniques. Inferential analysis was conducted at a 0.05 significance threshold, utilizing the Statistical Package for Social Sciences (SPSS) version 28 for data analysis. Ethical standards were strictly observed throughout the study. The study revealed that the number of loans borrowed had a significant impact on loan repayment among MSEs in Meru County. Effective management of borrowing was crucial for better repayment outcomes. Interest payable was identified as a critical factor affecting loan repayment; enterprises with well-managed credit risk practices, including the adjustment of interest rates and repayment schedules, exhibited better repayment performance. Furthermore, the level of financial literacy positively influenced loan repayment, with higher financial literacy levels leading to improved loan management and repayment behaviors. The study concluded that the number of loans borrowed significantly affected loan repayment, although its impact was less direct compared to other factors. Interest payable had the most substantial effect on loan repayment, with effective credit risk management correlating strongly with better repayment outcomes. Additionally, a higher level of financial literacy was found to significantly enhance loan repayment. Based on the findings, it is recommended that micro and small enterprises regularly review and manage their borrowing policies to improve loan repayment. Financial institutions should implement clear policies on irrecoverable loan provisions and adopt robust credit management practices to ensure better loan repayment. Moreover, enhancing financial literacy among borrowers is crucial for improving loan repayment, and thus, targeted financial education programs should be developed. Policymakers should also evaluate and update regulatory frameworks to support effective loan management and repayment practices within microfinance institutions.

Bayesian Selection of Relaxed-clock Models: Distinguishing Between Independent and Autocorrelated Rates.

In Bayesian molecular-clock dating of species divergences, rate models are used to construct the prior on the molecular evolutionary rates for branches in the phylogeny, with independent and autocorrelated rate models being commonly used. The two classes of models, however, can result in markedly different divergence time estimates for the same dataset, and thus selecting the best rate model appears important for obtaining reliable in- ferences of divergence times. However, the properties of Bayesian rate model selection are not well understood, in particular when the number of sequence partitions analysed increases and when age calibrations (such as fossil calibrations) are misspecified. Further- more, Bayesian rate model selection is computationally expensive as it requires calculation of marginal likelihoods by MCMC sampling, and therefore methods that can speed up the model selection procedure without compromising its accuracy are desirable. In this study, we use a combination of computer simulations and real data analysis to investigate the sta- tistical behaviour of Bayesian rate model selection and we also explore approximations of the likelihood to improve computational efficiency in large phylogenomic datasets. Our simulations demonstrate that the posterior probability for the correct rate model converges to one as more molecular sequence partitions are analysed and when no calibrations are used, as expected due to asymptotic Bayesian model selection theory. Furthermore, we also show the model selection procedure is robust to slight misspecification of calibrations, and reliable inference of the correct rate model is possible in this case. However, we show that when calibrations are seriously misspecified, calculated model probabilities are com- pletely wrong and may converge to one for the wrong rate model. Finally, we demonstrate that approximating the phylogenetic likelihood under an arcsine branch-length transform can dramatically reduce the computational cost of rate model selection without compro- mising accuracy. We test the approximate procedure on two large phylogenies of primates (372 species) and flowering plants (644 species), replicating results obtained on smaller datasets using exact likelihood. Our findings and methodology can assist users in selecting the optimal rate model for estimating times and rates along the Tree of Life.

Parasitic Approach to the Development of Modern Cosmetic Industry

Abstract: This is a literature review study focused on the connection between parasite stress and the development of the modern beauty industry. It is hypothesized that parasite stress may consequently result in contributing to females consumption of cosmetic products and plastic surgeries. The research begins with how natural selection theory, sexual selection theory, and parasite stress theory are contributing to the shaping of human mate preferences. Two types of consequences of parasitic infections are introduced: facial-benefitting and facial-disrupting. These two types of impact on female faces all result in increasing and reinforcing social comparison among females. The social comparison evolved throughout time contributing to mate selection and modern times manifestations in the cosmetic industry. It is suggested that future research in this field can explore the connection between parasite stress and differences in self-esteem between males and females.

Modal volatility function

We in this article propose a novel non‐parametric estimator for the volatility function within a broad context that encompasses nonlinear time series models as a special case. The new estimator, built on the mode value, is designed to complement existing mean volatility measures to reveal distinct data features. We demonstrate that the suggested modal volatility estimator can be obtained asymptotically as well as if the conditional mean regression function were known, assuming observations are from a strictly stationary and absolutely regular process. Under mild regularity conditions, we establish that the asymptotic distributions of the resulting estimator align with those derived from independent observations, albeit with a slower convergence rate compared to non‐parametric mean regression. The theory and practice of bandwidth selection are discussed. Moreover, we put forward a variance reduction technique for the modal volatility estimator to attain asymptotic relative efficiency while maintaining the asymptotic bias unchanged. We numerically solve the modal regression model with the use of a modified modal‐expectation‐maximization algorithm. Monte Carlo simulations are conducted to assess the finite sample performance of the developed estimation procedure. Two real data analyses are presented to further illustrate the newly proposed model in practical applications. To potentially enhance the accuracy of the bias term, we in the end discuss the extension of the method to local exponential modal estimation. We showcase that the suggested exponential modal volatility estimator shares the same asymptotic variance as the non‐parametric modal volatility estimator but may exhibit a smaller bias.

The aging of emotional words processing in implicit and explicit emotion task: an ERP study.

This study examined how cognitive aging affects emotional word processing using event-related potential technique. Young and older adults completed both implicit lexical decision and explicit emotion categorization tasks involving positive, negative, and neutral words. Behaviorally, older adults displayed a negative emotion effect in the implicit task, which was absent in young adults. While both age groups exhibited both positive and negative emotion effects in the explicit task, older adults demonstrated a greater positivity bias compared to young adults. Event-related potential technique data revealed that young adults exhibited an early negative emotion effect on the P2 and a late emotion effect on the late positivity potentials in the implicit task. In contrast, older adults exhibited an early negativity bias effect on the P2, as well as both negative and positive emotion effects on the N400, and positive emotion effects on the late positivity potentials. In the explicit task, young adults showed both early and late negative emotion effects on the P2 and late positivity potentials, while older adults showed both negative and positive emotion effects on the late positivity potentials. The results suggest distinct processing mechanisms for emotion words in young and older adults, involving both bottom-up and top-down mechanisms, which support the socioemotional selectivity theory.

Anthropocentrism and Inheritance in Our Mutual Friend: Return, Recognition, Reanimation

Abstract In decentering “Man,” a category long rhetorically constructed as the privileged species of a divine creator, Charles Darwin’s theory of natural selection necessitated a reexamination of how human subjectivity should be represented in fiction. This article uses the example of Charles Dickens’s Our Mutual Friend (1864) to track and scientifically contextualize how anthropocentrism is constructed and interrogated in fiction after publication of On the Origin of Species (1859). Competing nineteenth-century theories of species transmutation recognized physiological fluidity and variation within species and type, yet unlike Darwin, they sought to define uniquely human qualities of mind. Literary narratives, such as Dickens’s final completed novel, engaged this intellectual project—attempting to stabilize a dominant form of human subjectivity while recognizing shifting varieties of being. Protagonist John Harmon is oddly vacant as an imagined human consciousness; his actions create or resolve conflict within the story, but he fails to demonstrate any stable motivation. Depicting the initial misrecognition, and eventual recognition, of an English heir newly returned from abroad, Our Mutual Friend articulates cultural anxieties about the potential mutability of identity and type and the origins and durability of English dominance. Its post-Darwinian model of consciousness challenges traditional realist valorization of the individualistic, agential subject.

Female ornamentation in European serins is related to age but not to male mate choice and social competition

Sexual selection theory has provided explanation for the evolution and function of elaborate male traits, yet less effective in explaining female trait expression. Consequently, there remains a significant gap in our understanding of how female ornamentation is maintained and what factors drive its evolution. The European serin (Serinus serinus) displays a dichromatic carotenoid-based plumage, with a yellow patch on the breast in both males and females, although with females displaying less conspicuous colouration. While yellow colouration in male serins serves a dual function in social contexts, both sexual and nonsexual, the potential signal role of this colouration in females remains unknown. This study investigates the relationship between female traits, measures of fitness and the potential sexual and social function of female plumage colouration. To achieve this, we conducted a male mate choice experiment and a social competition experiment for access to limited food, similar to those previously employed with male serins. We found a relation between yellow plumage colouration and age classes, with older females displaying more colourful plumage. The mate choice experiment did not reveal a male sexual preference based on carotenoid-based plumage colouration in females. Furthermore, while females established steep hierarchies within groups, dominance over food was not associated with plumage colour. These findings suggest that in the European serin, female plumage may be subject to direct natural selection for less conspicuous colours or may result from genetic correlation of a male-selected trait.

The logic of conventional and reversed Bateman gradients.

The Bateman gradient is a central concept in sexual selection theory that relates reproductive success to mate number, with important consequences for sex-specific selection. The conventional expectation is that Bateman gradients are steeper in males than females, implying that males benefit more from multiple mating than females do. This claim is supported by much empirical evidence as well as mathematical modelling. However, under some reproductive systems, reversed Bateman gradients are observed, perhaps most notably in syngnathid fishes with male pregnancy. Unlike conventional Bateman gradients, the causal basis of such reversed Bateman gradients has never been modelled mathematically. Here, we present a sex-neutral mathematical model demonstrating how restrictions in capacity for carrying or incubating gametes and embryos (brooding) interact with anisogamy, generating both conventional and reversed Bateman gradients from a single mathematical model. The results clearly demonstrate how anisogamy tends to cause conventional Bateman gradients, but diminishing male brooding capacity under male pregnancy or nesting causes a gradual reversal from conventional to fully 'reversed' Bateman gradients.

10 Years of Communication & Sport: A Review of Theory, Method, and Authorship

Inspired by the regular reflections and suggestions for the future that regularly appear within Communication & Sport, this paper reports the result of a systematic review of a sample of articles from the first 10 vol of the journal to document the most common methods, forms of data employed, theoretical frameworks (and how they are applied), and nationality of author affiliation. Results reflect that the analysis of media texts, either qualitative or quantitative in nature, is the most common methodological approach. Moreover, qualitative approaches dominate the journal. With respect to theories or organizing frameworks, a select few theories appear most frequently, and frameworks related to gender are most common (i.e., hegemonic masculinity, heteronormativity, etc.). Furthermore, most references to theories or framework are just that—mere references. Only a minority of references offered theories as the guiding framework for the articles in which they appeared. To further advance legitimacy of the field, we offer suggestions for expanding the methodological approaches employed within the field, as well as suggestions for the explicit treatment of theory.

Men and women transitioning to singlehood in young adulthood and midlife.

Research has long shown that men suffer more from romantic breakups than women. We predicted that men would on average be less inclined to initiate separation, decline with the separation more in well-being and increase more in loneliness, are less satisfied with singlehood, and desire a new partner more than women. We theorized that these gender differences in separation adaptation could be linked to men's higher reliance on their partners for emotional support. Because socioemotional selectivity theory suggests that with age people shift toward more fulfilling social connections, we also expected men's dependency on their partners for emotional support to be smaller in midlife than in young adulthood. To examine our hypotheses, we analyzed multiyear within-person longitudinal change data from 1,530 mostly unmarried participants from the annual German pairfam study who had experienced a relationship dissolution. We applied propensity score matching to compare separation-related changes in well-being and loneliness to case-matched controls who remained in a romantic relationship. Results showed that men relative to women were less likely to initiate separation, less satisfied with singlehood, and wished for a partner more. In contrast to our expectations, the gender differences observed did not differ by age, and no gender differences were found in separation-related changes in well-being and loneliness. Dissolution-related effects on well-being were only evident for marital relationships, while dissolution-related effects on loneliness were equally strong for marital and nonmarital dissolutions. Our study suggests that previous findings on gender-specific divorce-induced changes in well-being may not generalize to nonmarital dissolutions. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Exposure to Lead (Pb) influences the outcomes of male-male competition during precopulatory intrasexual selection

Male-male competition is a component of Darwin’s theory of precopulatory intrasexual selection, where males compete for access to resources important for reproduction and successful males pass on traits that endow greater competitive ability to their offspring, thereby exaggerating the trait(s) over evolutionary time. Metals, such as lead (Pb) often occur in urban mangrove forests, where shore crabs reside, and being neurotoxic may cause sub-lethal effects on behaviour. In this study, we asked whether exposure to Pb influences the outcomes of male-male competition in the Semaphore crab, Heloecius cordiformis, thereby altering outcomes of intrasexual selection. Crabs were exposed to an environmentally relevant, and a behaviourally relevant, concentration of lead (i.e. Pb, 10 µg/L and 100 µg/L respectively) under laboratory conditions for 96 h and subsequently allowed to compete for burrow ownership in experimental arenas. Exposed crabs (100 µg/L) were less successful than control crabs in chela size-matched paired competitive interactions, spent less time in burrows and predominantly lost burrow ownership. Further, exposure to Pb contamination (both 10 µg/L and 100 µg/L) negated the chela size advantage in size-asymmetric competitive interactions. This contaminant-induced loss of size-related competitive advantage may result in relaxation in selection pressure on body size and smaller male carapace widths and especially male chela lengths in contaminated locations. Assessment of a range of locations in the wild found a consistent pattern of metal-associated size declines in more contaminated locations for males, but not for females.

Retirement through rose-colored glasses: greater positivity bias in retired relative to working older adults

Abstract Retirement has been associated with declines in memory beyond typical age-related memory decline. This may impact the ability to remember distinct events, as older adults (OA) are susceptible to interference in memory across experiences with overlapping features. Impaired hippocampal pattern separation, a computation that allows for the disambiguation of similar experiences as unique events, is thought to underlie age-related impairment in memory. Furthermore, positive experiences tend to be better remembered than neutral or negative experiences in aging. Socioemotional selectivity theory suggests that awareness of a limited remaining lifespan leads OA to prioritize emotionally fulfilling experiences, often leading to a bias towards positive information compared to negative or neutral information. However, the potential role of retirement in contributing to these age-related changes in memory has yet to be examined. Memory measures that tax hippocampal pattern separation may be more sensitive to memory impairment in retirement compared to standard memory measures. Retirement may exacerbate awareness of reduced remaining time, such that retired OA may experience a greater positivity bias in memory than their working peers. Here, we utilized an emotional memory task that taxes hippocampal pattern separation to examine memory in age-matched retired and working OA. We found that retired OA show selective impairments for memories with high interference and a greater positivity bias in memory compared to their working peers. These findings suggest that retirement may accelerate age-related memory changes, including greater susceptibility to interference as well as a bias toward remembering positive relative to neutral information.

Age-inclusive hospitality and tourism: navigating the metaverse travel with avatar

Purpose This study aims to investigate the impact of virtual tours on the engagement and travel intentions of older adults, emphasizing the role of emotional and informative content. It aims to enhance travel confidence and reduce stress among older travelers, fostering inclusive tourism through advanced avatar technology. Design/methodology/approach Using two between-subjects experiments, this research compares the effects of emotion-driven and knowledge-centric virtual tours on older adults. It explores the mediating role of travel confidence and stress reduction, along with the moderating influence of positive psychological cues on engagement and travel intentions. Findings The results highlight the potential of technology in promoting inclusive tourism. Emotionally engaging virtual tours significantly increase travel intentions among older adults by boosting confidence and alleviating stress, with positive psychological cues enhancing these effects. Practical implications This study offers valuable insights for tourism industry stakeholders by suggesting the development of avatar-based virtual tours tailored to the emotional and cognitive needs of older travelers. This approach could create more accessible and satisfying tourism experiences for older travelers. Originality/value This study extends the socioemotional selectivity theory to the realm of metaverse travel, providing a novel perspective on the emotional and cognitive engagement of older adults in the metaverse. This underscores the importance of inclusive technology in addressing the needs of older travelers.

The Effect of Robot Anthropomorphism on Customers' Attention Activation and Satisfaction

ABSTRACTPrior research has predominantly focused on how interacting with anthropomorphic robots might affect customers' psychological processes and behaviors, wherein this stream of research has presented some inconsistent findings regarding its effectiveness in the service context. This research aims at taking a novel angle by illuminating on the arousal‐based reaction among customers, and their subsequent satisfaction. Grounded in selective attention theory, this research develops a model in which robot anthropomorphism activates customers' attention, which in turn cultivates heightened customer satisfaction. Findings across an eye‐tracking experiment (Study 1), a field survey study (Study 2), and a scenario‐based experiment (Study 3) converge to provide support to the hypotheses. The results of our mixed‐method approach shed new light on how robot anthropomorphism might impact customer satisfaction. Importantly, this study contributes to the research of service robot in the consumer psychology literature by disentangling an attention (arousal)‐based mechanism through which robot anthropomorphism might induce positive customer outcomes. Meanwhile, it simultaneously offers timely and crucial managerial implications for practitioners to better understand the underlying arousal‐based influences of digitalizing the service delivery among customers. This research ends with a discussion pertaining to its theoretical and practical implications.

A New Mathetic (The Science of Learning) and Didactic (The Science of Teaching) Concept

The concept of Learngaming integrates Darwin’s natural selection theory into a learning and teaching framework designed to prepare individuals for the demands of the 21st century. It focuses on entrepreneurial learning through play, fostering the development of key skills such as efficiency, flexibility, and creativity. In contrast to traditional educational approaches, which emphasise rote learning and exams, Learngaming promotes active, nonlinear, and collaborative learning environments that reflect the dynamic, digital context of modern life. The methodology uses digital "LEARNGames" to simulate real-world challenges, allowing learners to adapt and thrive in uncertain environments by encouraging risk-taking and instant feedback. This method proves particularly effective in teaching 21st-century skills, as demonstrated in projects with gifted children, where learners showed improved retention and engagement through play-based learning. By shifting from a teacher-centred model to a learner-driven, game-based approach, Learngaming enhances both personal and collective learning outcomes, preparing individuals to succeed in an ever-evolving society.

Exact analytical solution of the equations for a quasiequilibrium two-phase domain: permeability and interdendritic spacing

This study is concerned with the theoretical description of a quasi-stationary process of directional crystallization of binary melts and solutions in the presence of a quasi-equilibrium two-phase region. The quasi-equilibrium process is ensured by the fact that the system supercooling is almost completely compensated by heat released during the phase transformation. Quasi-stationarity of the process determining constancy of the crystallization rate is ensured by given temperature gradients in the solid and liquid phases. The system of heat and mass transfer equations and boundary conditions to them under these assumptions is dependent on a single spatial variable in the reference frame moving with the crystallization rate relative to a laboratory coordinate system. Exact analytical solutions to the formulated problem in parametric form are obtained. The parameter of the solution is the solid phase fraction in a two-phase region. The distributions of temperature and impurity concentration in the solid, liquid and two-phase regions of the crystallizing system, the rate of solidification, and the spatial coordinate in the two-phase region depending on the solid phase fraction in it are found. An algebraic equation for the solid phase fraction at the interface between the solid material and the two-phase region is derived. Exact analytical solutions show that the impurity concentration in the two-phase layer increases as the solid phase fraction increases. Moreover, the solid phase fraction at the interface solid phase — two phase region and its thickness increase as the temperature gradient in the solid phase and the solidification rate increase. The developed theory allows us to determine analytically the permeability of the two-phase region and a characteristic interdendritic spacing in it. Analytical solutions show that the relative permeability in the two-phase region increases from a certain value at the interface with the solid phase to unity at the interface with the liquid phase. The selection theory of stable dendritic growth allows us to determine analytically a characteristic interdendritic distance in the two-phase layer that decreases as the temperature gradient in the solid phase increases. An increase of impurity in the molten phase gives a decrease in the interdendritic spacing within a two-phase region.

The Smirnov Property for Weighted Lebesgue Spaces

We establish lower norm bounds for multivariate functions within weighted Lebesgue spaces, characterised by a summation of functions whose components solve a system of nonlinear integral equations. This problem originates in portfolio selection theory, where these equations allow one to identify mean-variance optimal portfolios, composed of standard European options on several underlying assets. We elaborate on the Smirnov property—an integrability condition for the weights that guarantees the uniqueness of solutions to the system. Sufficient conditions on weights to satisfy this property are provided, and counterexamples are constructed, where either the Smirnov property does not hold or the uniqueness of solutions fails.

Understanding how restoration reduces competition for habitat by combining theory, observation, and experiment.

Habitat selection theory enables inferences about species habitat choice across a range of observed population densities. However, it is relatively uncommon to use habitat selection theory in studies of habitat restoration efficacy to understand the effect of restoration on habitat competition. We combined observational density data and resource selection functions to analyze habitat correlations with both habitat selection theory and a mark-recapture experiment to show how habitat restoration can mitigate competition between species with similar habitat preferences. To restore degraded and channelized riverine habitat for juvenile Chinook salmon (Oncorhynchus tshawytscha) and steelhead trout (Oncorhynchus mykiss) engineered log jams (ELJs) have been installed to create pools to enhance growth and rearing. Application of habitat selection theory first showed that both species share a preference for ELJ-treated habitat over unrestored habitat. Linear models showed that steelhead are generalists with respect to depth in unrestored habitat, whereas both species' abundance varies along a depth gradient in ELJ-treated habitat. Selective versus opportunistic use of deep and shallow ELJ pools was density-dependent. We found a range of densities at which a "ghost of competition" exists, where Chinook are selective on deep ELJ-treated pools and steelhead are selective on shallow pools. A mark-recapture experiment confirmed that steelhead limit Chinook movement into unrestored habitat, but this competitive effect vanished in ELJ-treated habitat where selection occurred with respect to pool depth. The experiment, combined with theory, enabled (1) the identification of a mechanism allowing for shared preference of restored habitat and (2) the description of how restoration can mitigate competition.

Comparative analysis reveals assortative mate preferences in darters independent of sympatry and sex.

A preference for mating with conspecifics over heterospecifics is fundamental to the maintenance of species diversity in sexually reproducing organisms. This type of positive assortative preference results in sexual isolation, and a reduction in gene flow between species due to differences in mate choice. The proximate and ultimate causes of sexual isolation therefore constitute active areas of research in evolutionary biology. Sexual isolation is often stronger between closely related sympatric species as compared to allopatric species because of processes such as reinforcement. In addition, traditional theories of sexual selection suggest that because reproduction is more costly to females, they should be the choosier sex and play a more central role in sexual isolation. We conducted a comparative analysis of assortative mate preferences in males and females of sympatric and allopatric species pairs of darters (fish genus Etheostoma). We performed a meta-analysis of 17 studies, encompassing 21 species, in which assortative preference was measured when fish were (in most cases) allowed only visual information. As expected, we found stronger preferences for conspecifics over heterospecifics across studies and species. However, we did not find an effect of sympatry or sex on the strength of preference for conspecifics, but rather remarkable variation across species. We offer several testable hypotheses to explain the variation we observed in the strength of assortative preference.