Negative Emotional Events that People Ruminate about Feel Closer in Time

Rumination is intrusive, perseverative cognition. We suggest that one psychological consequence of ruminating about negative emotional events is that the events feel as though they happened metaphorically “just yesterday”. Results from three studies showed that ruminating about real world anger provocations, guilt-inducing events, and sad times in the last year made these past events feel as though they happened more recently. The relationship between rumination and reduced temporal psychological distance persisted even when controlling for when the event occurred and the emotional intensity of the event. Moreover, angry rumination was correlated with enhanced approach motivation, which mediated the rumination-distance relationship. The relationship between guilty rumination and distance was mediated by enhanced vividness. Construal level and taking a 3^rd person perspective contributed to the sense of distance when participants were prompted to think about less emotionally charged situations. A meta-analysis of the data showed that the relationship between rumination and reduced distance was significant and twice as large as the same relationship for neutral events. These findings have implications for understanding the role of emotional rumination on memory processes in clinical populations and people prone to rumination. This research suggests that rumination may be a critical mechanism that keeps negative events close in the heart, mind, and time.     

Is Rumination after Bereavement Linked with Loss Avoidance? Evidence from Eye-Tracking

Rumination is a risk factor in adjustment to bereavement. It is associated with and predicts psychopathology after loss. Yet, the function of rumination in bereavement remains unclear. In the past, researchers often assumed rumination to be a maladaptive confrontation process. However, based on cognitive avoidance theories of worry in generalised anxiety disorder (GAD) and rumination after post-traumatic stress disorder (PTSD), others have suggested that rumination may serve to avoid painful aspects of the loss, thereby contributing to complicated grief. To examine if rumination is linked with loss avoidance, an eye-tracking study was conducted with 54 bereaved individuals (27 high and 27 low ruminators). On 24 trials, participants looked for 10 seconds at a picture of the deceased and a picture of a stranger, randomly combined with negative, neutral or loss-related words. High ruminators were expected to show initial vigilance followed by subsequent disengagement for loss stimuli (i.e., picture deceased with a loss word) in the first 1500 ms. Additionally, we expected high ruminators to avoid these loss stimuli and to show attentional preference for non-loss-related negative stimuli (i.e., picture stranger with a negative word) on longer exposure durations (1500–10000 ms). Contrary to expectations, we found no evidence for an effect of rumination on vigilance and disengagement of loss stimuli in the first 1500 ms. However, in the 1500–10000 ms interval, high ruminators showed shorter gaze times for loss stimuli and longer gaze times for negative (and neutral) non-loss-related stimuli, even when controlling for depression and complicated grief symptom levels. Effects of rumination on average fixation times mirrored these findings. This suggests that rumination and loss avoidance are closely associated. A potential clinical implication is that rumination and grief complications after bereavement may be reduced through the use of exposure and acceptance-based therapeutic techniques.     

The form and function of depressive rumination

Rumination is a symptom of depression that refers to intense, distraction-resistant thinking. Although rumination is widely considered maladaptive, the analytical rumination hypothesis (ARH) proposes that rumination is an adaptive cognitive process where depression first promotes rumination on the causes of problems (“causal analysis”), which in turn promotes rumination on solving problems (“problem-solving analysis”). Effective problem-solving then feeds back to reduce depressive symptoms. To test this cyclical model, a scale with both problem-solving and causal analysis components is required. There are two candidates: (1) the widely used Ruminative Responses Scale (RRS); and (2) the Analytical Rumination Questionnaire (ARQ)—a new scale based on the ARH. These instruments were administered to five samples (Total N = 1414) from two different cultures (Canada, Czech Republic) with different clinical statuses (nonclinical, hospitalized). Latent factor analysis of the ARQ supported the existence of both causal analysis and problem-solving analysis factors, making it suitable for testing ARH predictions. Using the ARQ, we found consistent support for the predicted covariance pattern between depression, causal analysis, and problem-solving analysis. However, we found no evidence that either of the RRS factors were related to problem-solving. Moreover, we were systematically unable to detect the predicted covariance pattern between depression and the RRS factors. We conclude that the ability to detect functional relationships between depression and rumination requires the researcher to consider both function (a correct hypothesis for how rumination and depression are adaptively related to each other) and form (valid measures of those constructs). Understanding rumination as a two-stage problem-solving process may help explain why most depressive episodes eventually resolve without treatment.     

Sex-Age Related Rumination Behavior of Père David’s Deer under Constraints of Feeding Habitat and Rainfall

Extensive studies have been conducted on the rumination behavior of domestic herbivores. However, studies on wild animals are limited, particularly wild animals with specific ruminating parameters. In this study, Père David’s deer, a previously extirpated species, was observed to analyze the effects of sex-age, feeding habitat, and rainfall on rumination behavior in the Dafeng Nature Reserve, China. Rumination behavior was investigated based on four parameters: proportion of bedding time spent chewing, bolus processing time (s/bolus), chewing frequency (chews/bolus), and chewing rate (chews/s). Results showed that all three factors affect rumination behavior. The extent of their effects varied based on the four rumination parameters. Chewing rate and frequency decreased based on sex–age levels, i.e., from fawns to juvenile female, juvenile male, adult female, stag, and harem holder. Therefore, body size played a major role in shaping rumination behavior. Deer found in grasslands could chew faster compared with deer found in woodlands. This result might be caused by the effects of dietary composition and sunlight intensity. A deer spends a longer time ruminating while bedding during rainy days compared with rainless days to maximize energy and nutrition intake and compensate for the loss of feeding time during rainy days. Therefore, rumination behavior is plastic and is shaped by intrinsic and extrinsic factors.     

Grief and bereavement: what psychiatrists need to know

This review covers four areas of clinical importance to practicing psychiatrists: a) symptoms and course of uncomplicated (normal) grief; b) differential diagnosis, clinical characteristics and treatment of complicated grief; c) differential diagnosis, clinical characteristics and treatment of grief-related major depression; and d) psychiatrists’ reactions to patient suicides. Psychiatrists often are ill prepared to identify complicated grief and grief-related major depression, and may not always be trained to identify or provide the most appropriate course of treatment. Both conditions overlap with symptoms found in ordinary, uncomplicated grief, and often are written off as “normal” with the faulty assumption that time, strength of character and the natural support system will heal. While uncomplicated grief may be extremely painful, disruptive and consuming, it is usually tolerable and self-limited and does not require formal treatment. However, both complicated grief and grief-related major depression can be persistent and gravely disabling, can dramatically interfere with function and quality of life, and may even be life threatening in the absence of treatment; and both usually respond to targeted psychiatric interventions. In addition, patient suicide has been reported as one of the most frequent and stressful crises experienced by health providers, and psychiatrists are not immune to complicated grief or grief-related depression when they, themselves, become survivors. Thus, it is essential for psychiatrists to recognize their own vulnerabilities to the personal assaults that often accompany such losses, not only for their own mental health and well-being, but also to provide the most sensitive and enlightened care to their patients.     

Monozygotic and dizygotic twins' retrospective and current bereavement-related behaviors: an evolutionary perspective.

The present study compared bereavement responses of 325 monozygotic (MZ) and 176 dizygotic (DZ) adolescent and adult twins following the loss of their co-twins. A subset of twins completed the Grief Experience Inventory using a retrospective time frame, while a second subset completed it using a current time frame. It was hypothesized that MZ twins (in both retrospective and current groups) would report higher levels of grief-related behavior than DZ twins, consistent with Hamilton's (1964) concept of inclusive fitness. Discriminant function and profile analyses yielded supportive findings, but only for the retrospective MZ and DZ twin comparisons. Females in both groups expressed higher levels of bereavement-related behavior than males. Findings are discussed with reference to theoretical aspects of grief and mourning.     

Repeated horizontal gene transfer of GALactose metabolism genes violates Dollo’s law of irreversible loss

Dollo’s law posits that evolutionary losses are irreversible, thereby narrowing the potential paths of evolutionary change. While phenotypic reversals to ancestral states have been observed, little is known about their underlying genetic causes. The genomes of budding yeasts have been shaped by extensive reductive evolution, such as reduced genome sizes and the losses of metabolic capabilities. However, the extent and mechanisms of trait reacquisition after gene loss in yeasts have not been thoroughly studied. Here, through phylogenomic analyses, we reconstructed the evolutionary history of the yeast galactose utilization pathway and observed widespread and repeated losses of the ability to utilize galactose, which occurred concurrently with the losses of GALactose (GAL) utilization genes. Unexpectedly, we detected multiple galactose-utilizing lineages that were deeply embedded within clades that underwent ancient losses of galactose utilization. We show that at least two, and possibly three, lineages reacquired the GAL pathway via yeast-to-yeast horizontal gene transfer. Our results show how trait reacquisition can occur tens of millions of years after an initial loss via horizontal gene transfer from distant relatives. These findings demonstrate that the losses of complex traits and even whole pathways are not always evolutionary dead-ends, highlighting how reversals to ancestral states can occur.     

Reduced plant competition among kin can be explained by Jensen's inequality

Plants often compete with closely related individuals due to limited dispersal, leading to two commonly invoked predictions on competitive outcomes. Kin selection, from evolutionary theory, predicts that competition between relatives will likely be weaker. The niche partitioning hypothesis, from ecological theory, predicts that competition between close relatives will likely be stronger. We tested for evidence consistent with either of these predictions by growing an annual legume in kin and nonkin groups in the greenhouse. We grew plant groups in treatments of symbiotic nitrogen fixing bacteria differing in strain identity and composition to determine if differences in the microbial environment can facilitate or obscure plant competition patterns consistent with kin selection or niche partitioning. Nonkin groups had lower fitness than expected, based on fitness estimates of the same genotypes grown among kin. Higher fitness among kin groups was observed in mixtures of N‐fixing bacteria strains compared to single inoculations of bacteria strains present in the soil, which increased fitness differences between kin and nonkin groups. Lower fitness in nonkin groups was likely caused by increased competitive asymmetry in nonkin groups due to genetic differences in plant size combined with saturating relationships with plant size and fitness‐ i.e. Jensen's inequality. Our study suggests that microbial soil symbionts alter competitive dynamics among kin and nonkin. Our study also suggests that kin groups can have higher fitness, as predicted by kin selection theory, through a commonly heritable trait (plant size), without requiring kin recognition mechanisms.     

Psychobiological and evolutionary perspectives on coping and health characteristics following loss: a twin study.

An analysis of coping, grief and health characteristics is reported for a bereaved monozygotic (MZ) and dizygotic (DZ) same-sex twin sample. The data were examined with reference to psychobiological and evolutionary perspectives on behavior. A Coping Scale, included as part of a comprehensive Twin Loss Survey (TLS), assessed coping with daily responsibilities and activities 1-2 months before the co-twin's death, 1-2 months following the co-twin's death and currently. A Grief Intensity Scale obtained judgments of grief 1-2 months following the loss, and currently. Information on physical symptoms was available from the Somatization Scale of the Grief Experience Inventory. Psychobiological and evolutionary perspectives specified hypotheses for two twin groups: one model was specified to reflect bereavement experiences immediately following loss of the co-twin (retrospective twin group); a second model represented present bereavement response (current twin group). Consistent with psychobiological theory, twins' social closeness showed a positive association with grief intensity which, in turn, affected somatic symptoms and coping efficacy in predicted directions. With respect to evolutionary psychological theory, the effect of zygosity on current grief implicated correlates of genetic relatedness as factors in the bereavement process.     

Validation of the RumiWatch Converter V0.7.4.5 classification accuracy for the automatic monitoring of behavioural characteristics in dairy cows

ABSTRACT

The objective of the present study was to validate the accuracy of algorithms, implemented in the currently available RumiWatch Converter (RWC) version V0.7.4.5 of the RumiWatch System (RWS), for the classification of behavioural characteristics from jaw and head movements which are monitored by a noseband halter comprising a pressure sensor and a triaxial accelerometer. The accurate classification of behavioural characteristics in different time resolutions is critical for the usage of the RWS for scientific and practical purposes as chewing behaviour provides essential indicators for the assessment of diet adequacy in dairy cows. To validate the RWC V0.7.4.5 classification accuracy for behavioural characteristics of rumination, eating, drinking, other activity and ruminating chews per bolus by direct observation as reference method, 14 dairy cows participated in the trial. Concordance between the consolidated 1-min and 1-h classification results was assessed. The RWC V0.7.4.5 classified only rumination and ruminating chews per bolus precisely, whereas an algorithm optimisation for the classification of eating, drinking and other activity is required. Additionally, classification results from the 1-min and 1-h time summaries were not in agreement with each other except for rumination.     

Niche construction,adaptive preferences,and the differences between fitness and utility

A number of scholars have recently defended the claim that there is a close connection between the evolutionary biological notion of fitness and the economic notion of utility: both are said to refer to an organism’s success in dealing with its environment, and both are said to play the same theoretical roles in their respective sciences. However, an analysis of two seemingly disparate but in fact structurally related phenomena—‘niche construction’ (the case where organisms change their environment to make it fit to their needs) and ‘adaptive preferences’ (the case where agents change their wants to make them fit to what the world has given them)—shows that one needs to be very careful about the postulation of this sort of fitness–utility connection. Specifically, I here use the analysis of these two phenomena to establish when connecting fitness and utility is and is not possible.     

Genetic bottlenecks and population passages cause profound fitness differences in RNA viruses.

Repeated clone-to-clone (genetic bottleneck) passages of an RNA phage and vesicular stomatitis virus have been shown previously to result in loss of fitness due to Muller's ratchet. We now demonstrate that Muller's ratchet also operates when genetic bottleneck passages are carried out at 37 rather than 32 degrees C. Thus, these fitness losses do not depend on growth of temperature-sensitive (ts) mutants at lowered temperatures. We also demonstrate that during repeated genetic bottleneck passages, accumulation of deleterious mutations does occur in a stepwise (ratchet-like) manner as originally proposed by Muller. One selected clone which had undergone significant loss of fitness after only 20 genetic bottleneck passages was passaged again in clone-to-clone series. Additional large losses of fitness were observed in five of nine independent bottleneck series; the relative fitnesses of the other four series remained close to the starting fitness. In sharp contrast, when the same selected clone was transferred 20 more times as large populations (10(5) to 10(6) PFU transferred at each passage), significant increases in fitness were observed in all eight passage series. Finally, we selected several clones which had undergone extreme losses of fitness during 20 bottleneck passages. When these low-fitness clones were passaged many times as large virus populations, they always regained very high relative fitness. We conclude that transfer of large populations of RNA viruses regularly selects those genomes within the quasispecies population which have the highest relative fitness, whereas bottleneck transfers have a high probability of leading to loss of fitness by random isolation of genomes carrying debilitating mutations. Both phenomena arise from, and underscore, the extreme mutability and variability of RNA viruses.     

Strong and weak cross-sex correlations govern the quantitative-genetic architecture of social group choice in Drosophila melanogaster

When genotypes differ in niche-constructing traits, genotypes are expected to differ in which environments they experience, providing a novel causal relationship between genotypes, environments, and behavior. Such genetic variation in niche construction (or, more precisely, environment construction) is predicted to be especially important for social environments, yet the quantitative-genetic parameters governing such variation are still poorly understood. Here, we examine genetic variation and cross-sex genetic correlations for social environment-constructing behaviors. We focus on whether genetic variation in patch use—the tendency to spend time near food patches where conspecifics may be present—and group-size preference—the specific group size chosen when individuals are affiliating—is correlated or decoupled across sexes in the fruit fly, Drosophila melanogaster. Across three choice treatments, we find genotype and sex differences in how much time individuals spend near patches, and which group sizes they prefer. We find that the genetic basis of patch use is strongly coupled across sexes, whereas the genetic basis of group-size preference is completely decoupled across sexes. We discuss how these findings augment and complicate our understanding of the evolutionary genetics of social behaviors.     

The distribution of fitness effects in an uncertain world

The distribution of fitness effects (DFE) among new mutations plays a critical role in adaptive evolution and the maintenance of genetic variation. Although fitness landscape models predict several key features of the DFE, most theory to date focuses on predictable environmental conditions, while ignoring stochastic environmental fluctuations that feature prominently in the ecology of many organisms. Here, we derive an extension of Fisher's geometric model that incorporates two common effects of environmental variation: (1) nonadaptive genotype‐by‐environment interactions (G × E), in which the phenotype of a given genotype varies across environmental contexts; and (2) random fluctuation of the fitness optimum, which generates fluctuating selection. We show that both factors cause a mismatch between the DFE within single generations and the distribution of geometric mean fitness effects (averaged over multiple generations) that governs long‐term evolutionary change. Such mismatches permit strong evolutionary constraints—despite an abundance of beneficial fitness variation within single environmental contexts—and to conflicting DFE estimates from direct versus indirect inference methods. Finally, our results suggest an intriguing parallel between the genetics and ecology of evolutionary constraints, with environmental fluctuations and pleiotropy placing qualitatively similar limits on the availability of adaptive genetic variation.     

A generation‐time effect on the rate of molecular evolution in bacteria

Molecular evolutionary rate varies significantly among species and a strict global molecular clock has been rejected across the tree of life. Generation time is one primary life‐history trait that influences the molecular evolutionary rate. Theory predicts that organisms with shorter generation times evolve faster because of the accumulation of more DNA replication errors per unit time. Although the generation‐time effect has been demonstrated consistently in plants and animals, the evidence of its existence in bacteria is lacking. The bacterial phylum Firmicutes offers an excellent system for testing generation‐time effect because some of its members can enter a dormant, nonreproductive endospore state in response to harsh environmental conditions. It follows that spore‐forming bacteria would—with their longer generation times—evolve more slowly than their nonspore‐forming relatives. It is therefore surprising that a previous study found no generation‐time effect in Firmicutes. Using a phylogenetic comparative approach and leveraging on a large number of Firmicutes genomes, we found sporulation significantly reduces the genome‐wide spontaneous DNA mutation rate and protein evolutionary rate. Contrary to the previous study, our results provide strong evidence that the evolutionary rates of bacteria, like those of plants and animals, are influenced by generation time.     

A SHIFT FROM MAGNITUDE TO SIGN EPISTASIS DURING ADAPTIVE EVOLUTION OF A BACTERIAL SOCIAL TRAIT

Although the importance of epistasis in evolution has long been recognized, remarkably little is known about the processes by which epistatic interactions evolve in real time in specific biological systems. Here, we have characterized how the epistatic fitness relationship between a social gene and an adapting genome changes radically over a short evolutionary time frame in the social bacterium Myxococcus xanthus. We show that a highly beneficial effect of this social gene in the ancestral genome is gradually reduced—and ultimately reversed into a deleterious effect—over the course of an experimental adaptive trajectory in which a primitive form of novel cooperation evolved. This reduction and reversal of a positive social allelic effect is driven solely by changes in the genetic context in which the gene is expressed as new mutations are sequentially fixed during adaptive evolution, and explicitly demonstrates a significant evolutionary change in the genetic architecture of an ecologically important social trait.     

Anthropological Genetics: Inferring the History of Our Species Through the Analysis of DNA

The genetic material, deoxyribonucleic acid (DNA), contains information about the evolutionary history of life. Both the relationships amongst organisms and the times of their divergence can be inferred from DNA sequences. Anthropological geneticists use DNA sequences to infer the evolutionary history of humans and their primate relatives. We review the basic methodology used to infer these relationships. We then review the anthropological genetic evidence for modern human origins. We conclude that modern humans evolved recently in Africa and then left to colonize the rest of the world within the last 50,000 years, largely replacing the other human groups that they encountered. Modern humans likely exchanged genes with Neanderthals prior to or early during their expansion out of Africa.     

The contribution of the mitochondrial genome to sex‐specific fitness variance

Maternal inheritance of mitochondrial DNA (mtDNA) facilitates the evolutionary accumulation of mutations with sex‐biased fitness effects. Whereas maternal inheritance closely aligns mtDNA evolution with natural selection in females, it makes it indifferent to evolutionary changes that exclusively benefit males. The constrained response of mtDNA to selection in males can lead to asymmetries in the relative contributions of mitochondrial genes to female versus male fitness variation. Here, we examine the impact of genetic drift and the distribution of fitness effects (DFE) among mutations—including the correlation of mutant fitness effects between the sexes—on mitochondrial genetic variation for fitness. We show how drift, genetic correlations, and skewness of the DFE determine the relative contributions of mitochondrial genes to male versus female fitness variance. When mutant fitness effects are weakly correlated between the sexes, and the effective population size is large, mitochondrial genes should contribute much more to male than to female fitness variance. In contrast, high fitness correlations and small population sizes tend to equalize the contributions of mitochondrial genes to female versus male variance. We discuss implications of these results for the evolution of mitochondrial genome diversity and the genetic architecture of female and male fitness.     

The socio‐genetics of a complex society: female gelada relatedness patterns mirror association patterns in a multilevel society

Multilevel societies with fission–fusion dynamics—arguably the most complex animal societies—are defined by two or more nested levels of organization. The core of these societies are modular social units that regularly fission and fuse with one another. Despite convergent evolution in disparate taxa, we know strikingly little about how such societies form and how fitness benefits operate. Understanding the kinship structure of complex societies could inform us about the origins of the social structure as well as about the potential for individuals in these societies to accrue indirect fitness benefits. Here, we combined genetic and behavioural data on geladas (Theropithecus gelada), an Old World Monkey, to complete the most comprehensive socio‐genetic analysis of a multilevel society to date. In geladas, individuals in the core social ‘units’, associate at different frequencies to form ‘teams’, ‘bands’ and, the largest aggregations, ‘communities’. Units were composed of closely related females, and females remained with their close kin during permanent fissions of units. Interestingly, female–female relatedness also significantly predicted between‐unit, between‐team and between‐band association patterns, while male–male relatedness did not. Thus, it is likely that the socio‐genetic structure of gelada society results from females maintaining associations with their female relatives during successive unit fissions—possibly in an attempt to balance the direct and indirect fitness benefits of group living. Overall, the persistence of associations among related females across generations appears to drive the formation of higher levels of gelada society, suggesting that females seek kin for inclusive fitness benefits at multiple levels of gelada society.