肥胖成因的解释——基于食物奖赏研究的视角

肥胖的形成和发展受生物、心理和社会因素的共同作用,其中食物奖赏对肥胖的产生有重要的作用。食物是一种自然奖赏,它指机体天生对食物的渴望和依赖。食物奖赏包括"wanting"、"liking"以及"learningreinforcement"三个成分,每个成分由相应的神经通路表征。食物奖赏调控机体的摄食行为并以此调控体重变化。目前,关于肥胖与食物奖赏关系的理论模型主要有刺激—敏感化理论、奖赏过度理论以及奖赏不足理论。采用横断面设计、前瞻研究设计和纵向被试内重复测量设计,使用食物图片线索和直接给予美味奶昔的技术方法,人类脑成像研究从不同侧面为以上三个理论模型提供了证据。除此之外,食物奖赏还受基因的调控。目前,研究者关注较多的是多巴胺D2受体基因Taq IA rs1800497的多态性和FTO基因rs9939609的多态性对食物奖赏及体重改变的调控。     

Access to nutritious food,socioeconomic individualism and public health ethics in the USA: a common good approach

Good nutrition plays an important role in the optimal growth, development, health and well-being of individuals in all stages of life. Healthy eating can reduce the risk of chronic diseases, such as heart disease, stroke, diabetes and some types of cancer. However, the capitalist mindset that shapes the food environment has led to the commoditization of food. Food is not just a marketable commodity like any other commodity. Food is different from other commodities on the market in that it is explicitly and intrinsically linked to our human existence. While possessing another commodity allows for social benefits, food ensures survival. Millions of people in United States of America are either malnourished or food insecure. The purpose of this paper is to present a critique of the current food system using four meanings of the common good--as a framework, rhetorical device, ethical concept and practical tool for social justice. The first section of this paper provides a general overview of the notion of the common good. The second section outlines how each of the four meanings of the common good helps us understand public practices, social policies and market values that shape the distal causal factors of nutritious food inaccessibility. We then outline policy and empowerment initiatives for nutritious food access.     

The use of operant technology to measure behavioral priorities in captive animals

Addressing the behavioral priorities of captive animals and the development of practical, objective measures of the value of environmental resources is a principal objective of animal welfare science. In theory, consumer demand approaches derivedfrom human microeconomics should provide validmeasures of the value of environmental resources. In practice, however, a number of empirical and theoretical problems have rendered these measures difficult to interpret in studies with animals. A common approach has been to impose a cost on access to resources and to use time with each resource as a measure of consumption to construct demand curves. This can be recorded easily by automatic means, but in a number of studies, it has been found that animals compensate for increased cost of access with longer visit time. Furthermore, direct observation of the test animals’ behavior has shown that resource interaction is more intense once the animals have overcome higher costs. As a consequence, measures based on time with the resource may underestimate resource consumption at higher access costs, and demand curves derived from these measures may not be a true reflection of the value of different resources. An alternative approach to demand curves isreservation price, which is the maximum price individual animals are prepared to pay to gain access to resources. In studies using this approach, farmed mink (Mustela vison) paid higher prices for food and swimming water than for resources such as tunnels, water bowls, pet toys, and empty compartments. This indicates that the mink placed a higher value on food and swimming water than on other resources.     

Local Food Environments: They’re All Stocked Differently

The obesity epidemic has widened the aims of prevention research to include the influence of local food environments on health outcomes. This mixed methods study extends existing research focused on local food environments by examining whether community members’ find food accessible. Data from food store audits and one-on-one interviews were analyzed. Results reveal that most of the food stores surrounding the three research sites were convenience stores and non-chain grocery stores; interviewees did not perceive these stores to be “real” food stores. Tobacco and alcohol products were more prevalent in the food stores than all varieties of milk, fresh fruits, or fresh vegetables. Food access varied by site in a manner that was designed to appeal to customers’ race, class, gender, or environment. Findings reveal that local food environments are reflections of social hierarchies. Unraveling the politics of space ought to be a part of broader efforts to promote the public’s health.     

The influence of food distribution on the aggressive behaviour of juvenile white-seabream (Diplodus sargus cadenati de la Paz,Bauchot and Daget, 1974)

Experiments were conducted to investigate the effect of differences in the spatial distribution of food on the aggressive behaviour of juvenile white-seabream, Diplodus sargus cadenati, both in the presence and in the absence of food. The groups of fish receiving spatially fixed food displayed less aggression than those receiving spatially variable food. The period (before, during, or after feeding) during which aggressiveness is measured also has influence in the results. During the prefeeding and postfeeding periods (absence of food), groups that were fed with food spatially fixed displayed less aggression than those that received spatially variable food. However, when food was present there were no differences in the number of aggressive acts carried out by fish groups in both environments. The aggressiveness shown by the groups of fish was always more pronounced during the postfeeding period than during the prefeeding period. The dominant fish was more aggressive when food was spatially fixed, and especially when food was present. Therefore, the subordinates were more aggressive when food was spatially variable and particularly when food was present and during the postfeeding period. Aggr. Behav. 24:379–384, 1998. © 1998 Wiley-Liss, Inc.     

A comparison of ready foods to institutional food

This study was conducted as a preliminary investigation of Ready Foods versus Institutional Food in a state residential facility serving approximately 500 mentally retarded residents. One administrative unit of the facility serving approximately 160 residents was used as the setting for the study. Along with residents in this unit, a variety of staff, client advocates, and volunteer workers participated in the investigation. Results were: (1) staff, client advocate, and volunteer worker responses significantly favored Ready Foods; (2) residents selected Ready Foods significantly more than Institutional Food; (3) residents displayed greater overall food waste with the Institutional Food as compared to the Ready Foods; (4) some residents displayed less choking or gagging with ready foods than with Institutional Food; and (5) out of 6 residents who were chronically overweight displayed statistically significant weight gain within one week after beginning Ready Foods and significant weight loss after the return to Institutional Food. Advantages of a Ready Foods System are discussed.     

Sex,skull length,breed, and age predict how dogs look at faces of humans and conspecifics

The gaze of other dogs and humans is informative for dogs, but it has not been explored which factors predict face-directed attention. We used image presentations of unfamiliar human and dog heads, facing the observer (portrait) or facing away (profile), and measured looking time responses. We expected dog portraits to be aversive, human portraits to attract interest, and tested dogs of different sex, skull length and breed function, which in previous work had predicted human-directed attention. Dog portraits attracted longer looking times than human profiles. Mesocephalic dogs looked at portraits longer than at profiles, independent of the species in the image. Overall, brachycephalic dogs and dogs of unspecified breed function (such as mixed breeds) displayed the longest looking times. Among the latter, females observed the images for longer than males, which is in line with human findings on sex differences in processing faces. In a subsequent experiment, we tested whether dog portraits functioned as threatening stimuli. We hypothesized that dogs will avoid food rewards or approach them more slowly in the presence of a dog portrait, but found no effect of image type. In general, older dogs took longer to approach food placed in front of the images and mesocephalic dogs were faster than dogs of other skull length types. The results suggest that short-headed dogs are more attentive to faces, while sex and breed function predict looking times through complex interactions.     

How suboptimal is suboptimal choice?

In a frequently used suboptimal‐choice procedure pigeons choose between an alternative that delivers three food pellets with p = 1.0 and an alternative that delivers ten pellets with p = 0.2. Because pigeons reliably choose the probabilistic (suboptimal) alternative, the procedure has been proposed as a nonhuman analog of human gambling. The present experiments were conducted to evaluate two potential threats to the validity of this procedure. Experiments 1 and 2 evaluated if pigeons obtained food at a lower unit price (i.e., pecks per pellet) on the suboptimal alternative than on the optimal alternative. When pigeons worked under this suboptimal procedure they all preferred the suboptimal alternative despite some pigeons paying a higher price for food on that alternative. In Experiment 2, when the unit price ratio more closely approximated the inverse of the expected value ratio, pigeons continued to prefer the suboptimal alternative despite its economic suboptimality. Experiment 3 evaluated if, in accord with the string‐theory of gambling, the valuation of the suboptimal alternative was increased when pigeons misattributed a subset of the suboptimal no‐food trials to the optimal alternative. When trial sequences were arranged to minimize these possible attribution errors, pigeons still preferred the suboptimal alternative. These data remove two threats to the validity of the suboptimal choice procedure; threats that would have suggested that suboptimal choice reflects economic maximization.     

Umwelt,food, and the limits of control

This paper draws on the work of the early 20th century ethologist Jakob von Uexküll to formulate a notion of food as a process of bodies becoming other bodies. I begin by situating my argument in relation to two strands of critical food research – feminist-inspired work on food and embodiment, and posthumanist approaches that focus on non-humans as mediators of food assemblages. I then discuss Uexküll's work, focusing on three key concepts: umwelt, “the island of the senses” that envelops each being; subjectivity as an intra- and intercorporeal phenomenon; and the variation among umwelten available to humans. These ideas, I contend, illustrate the inherently political nature of ‘food,’ which in turn calls for a realignment of food ethics and critical food scholarship. To illustrate this contention, I draw on my research with the Oklahoma Food Cooperative, considering this socio-ecological experiment as an effort to create a food system in better accord with the affective imperatives (or umwelten) of its constituent components. Throughout the paper, I develop the argument that food systems will always present limits to control by even those actors who seem to enjoy hegemonic positions. Uexküll's work helps us understand these limits in a way that allows critical analysis of dominant food systems and the alternatives proliferating in response to them, but does not prematurely foreclose the actual and virtual possibilities contained in the present heterogeneity of foodways.     

Motion sickness history, food neophobia, and sensation seeking

Motion sickness is believed to be caused by conflicting sensory signals, a situation that mimics the effects of ingesting certain toxins. Thus, one might suspect that individuals who have experienced a relatively high frequency of motion sickness may be particularly vigilant about avoiding anything that produces nausea, induding potentially nauseating toxins. Consequently, they may be more resistant to trying new foods, i.e., be more food neophobic, since unfamiliar foods can have unexpected adverse effects due to toxins or allergens. Likewise, many highly stimulating experiences can trigger motion sickness, so individuals who are more susceptible may be more prone to avoid such experiences, i.e., be less sensation seeking. Finally, it was expected that food neophobia would be more frequent in individuals low on sensation seeking tendencies. Self-reported motion sickness history in 308 adults (M= 18.8 yr.; SD = 1.6) was correlated with scores on the Arnett Inventory of Sensation Seeking and the Food Neophobia Scale. As predicted, greater history of motion sickness was associated with lower Sensation Seeking scores. Food Neophobia was not correlated with motion sickness history but, as expected, was negatively correlated (r = -.42) with scores on Sensation Seeking. Further research is recommended that measures actual sensitivity to motion sickness.     

Dietary variety, energy regulation, and obesity

Increased variety in the food supply may contribute to the development and maintenance of obesity. Thirty-nine studies examining dietary variety, energy intake, and body composition are reviewed. Animal and human studies show that food consumption increases when there is more variety in a meal or diet and that greater dietary variety is associated with increased body weight and fat. A hypothesized mechanism for these findings is sensory-specific satiety, a phenomenon demonstrating greater reductions in hedonic ratings or intake of foods consumed compared with foods not consumed. Nineteen studies documenting change in preference, intake, and hedonic ratings of food after a food has been eaten to satiation in animals and humans are reviewed, and the theory of sensory-specific satiety is examined. The review concludes with the relevance of oral habituation theory as a unifying construct for the effects of variety and sensory-specific satiety, clinical implications of dietary variety and sensory-specific satiety on energy regulation, and suggestions for future research.     

Do Programmers Prefer Predictable Expressions in Code?

Source code is a form of human communication, albeit one where the information shared between the programmers reading and writing the code is constrained by the requirement that the code executes correctly. Programming languages are more syntactically constrained than natural languages, but they are also very expressive, allowing a great many different ways to express even very simple computations. Still, code written by developers is highly predictable, and many programming tools have taken advantage of this phenomenon, relying on language model surprisal as a guiding mechanism. While surprisal has been validated as a measure of cognitive load in natural language, its relation to human cognitive processes in code is still poorly understood. In this paper, we explore the relationship between surprisal and programmer preference at a small granularity—do programmers prefer more predictable expressions in code? Using meaning-preserving transformations, we produce equivalent alternatives to developer-written code expressions and run a corpus study on Java and Python projects. In general, language models rate the code expressions developers choose to write as more predictable than these transformed alternatives. Then, we perform two human subject studies asking participants to choose between two equivalent snippets of Java code with different surprisal scores (one original and transformed). We find that programmers do prefer more predictable variants, and that stronger language models like the transformer align more often and more consistently with these preferences.     

Self-starvation in the rat: running versus eating

Rats given the combination of unrestricted access to an activity wheel and restricted access to food can lose weight to the extent that they will die unless removed from these conditions. Although this has been known for forty years, why this happens has remained unclear. The phenomenon is paradoxical in that one might expect such rats to eat more as their weight decreases, but in fact they eat less than resting controls. This lecture first examines some of the factors than influence whether self-starvation will occur, such as age, time of food access, type of food and ambient temperature. It then compares competing explanations such as circadian adaptation, thermo-regulation and food aversion learning. As so often in psychology, it turns out that self-starvation results from a combination of many separate factors. The general implications of this research are examined, including whether it provides a useful animal model for human anorexia nervosa.     

A New Stigmatized Identity? Comparisons of a “Food Addict” Label With Other Stigmatized Health Conditions

This research assessed public perceptions of a “food addict” label in comparison to stigmatized conditions including obesity, addiction, and disability. Study 1 found this label was perceived similarly to obesity, but more favorably than other addictions, and had an exacerbating effect on weight stigma. Study 2 experimentally replicated the latter effect but demonstrated no weight-related effects for the food addict label. This evidence suggests that food addiction may be less vulnerable to public stigma than other addictions but may increase the stigma associated with obesity. Food addiction as a stigmatized identity is discussed.     

Differential association between food craving,food addiction and eating-related characteristics in persons at risk for eating disorders

IntroductionFood craving is a key feature of eating disorders, but its association with medical and psychological outcome might depend on the type of eating disorder.ObjectivesThis study investigated the factors associated with food craving in individuals at risk for DSM-5 eating disorder.MethodSeventy-six women were recruited from a non-clinical population (n = 372) based on their positive screening (EDDS, QEWP-R) for binge eating disorder (BED; n = 29), anorexia nervosa (AN; n = 28) or bulimia nervosa (BN; n = 19). They completed self-administered questionnaires assessing food craving (FCQ- T-r), Body Mass Index (BMI), eating behaviour (DEBQ), food addiction (YFAS 2.0), and anxiety and depressive symptoms (HADS).ResultsIndividuals at risk for BED or BN had higher food craving than those at risk for AN. Food craving was associated with BMI only in the BED group. Food craving was positively correlated with external eating in all groups, and with emotional eating in the AN and BED groups and correlated with anxiety only in BN. Food addiction prevalence was higher in the BN group than in the AN or BED groups (respectively 94.7%, 46.4% and 65.5%; p < 0.01). In this non-clinical population, we demonstrated that food craving was differentially associated with BMI and eating-related characteristics according to the type of eating disorder.ConclusionThis suggests that food craving is a transdiagnostic dimension that should be differentially targeted depending on the type of eating disorder; future studies should test this hypothesis in clinical populations.     

Self-reports of eating behavior, goals, imagery, and health status: principal components and sex differences

University students (N = 208) completed a questionnaire on four aspects of eating: behavior, goals, imagery, and health status. A principal components analysis of the 18 self-report variables identified six factors: Weight Control Failure, Sensory Awareness of Food and Eating, Stable Eating Pattern, Unrestrained Overeating, "Home Cooking and Good Digestion," and Environmental Indifference. Sex differences in self-reporting were statistically significant on 10 of the 18 variables, with 6 of those significant variables heavily loaded on the first factor: Weight Control Failure. Analysis of these variables suggests that women report eating to be more problematic than do men. Several of the aspects of self-reports are discussed, including the apparent independence of sensory awareness of food and eating from self-reports of behavior, goals, and health status.     

Revising,Correcting, and Transferring Genes

Abstract

The distinction between germline and somatic gene editing is fundamental to the ethics of human gene editing. Multiple conferences of scientists, ethicists, and policymakers, and multiple professional bodies, have called for moratoria on germline gene editing, and editing of human germline cells is considered to be an ethical “red line” that either never should be crossed, or should only be crossed with great caution and care. However, as research on germline gene editing has progressed, it has become clear that not all germline interventions are alike, and that these differences make a significant moral difference, when it comes to ethical questions about research, regulation, clinical application, and medical justification. In this paper, I argue that, rather than lumping all germline interventions together, we should distinguish between revising, correcting, and transferring genes, and I assess the consequences of this move for the ethics of gene editing.     

Fit perceptions in the employment interview: The role of similarity,liking, and expectations

We examined (1) how interviewers construct fit perceptions about applicants and (2) the relationship between these perceptions and actual hiring recommendations. It was hypothesized that actual demographic similarity and human capital similarity would indirectly affect fit perceptions. These fit perceptions would be predicted by the interviewer's perceived similarity to applicants, mediated by two factors: interviewers' liking of the applicant and interviewers' expectations of applicant performance. Actual interviewer‐applicant dyads (N=118) were studied. The results indicated that the relationship between perceived similarity and fit perceptions is mediated by performance expectations but not by liking. This study provides evidence that interviewers are more rational than previous research suggested. However, the fact that human resource interviewers are more likely to perceive applicants as similar to themselves than line interviewers suggests that interviewers' neutrality is questioned.     

The Influence of Television and Film Viewing on Midlife Women's Body Image,Disordered Eating,and Food Choice

A recent trend in screen media is the casting of older women who have bodies that are the shapes and sizes of younger women. These aging beauties can be found in shows such as Cougar Town and Desperate Housewives. It was predicted that heavy viewers of these media would report stronger eating disorder symptomatology, greater body ideal discrepancies, and stricter food choices than light viewers. Participants were 166 midlife women (M: 44.57 years) who completed an online questionnaire that asked about body ideals, disordered eating, food choices, and exposure to aging beauty programming. Results demonstrate that media exposure was associated with stronger reports of disordered eating, greater discrepancies between actual body size and both women's ideal body size as well as perceptions of how others wanted them to look, and stricter food choices when around other people. Ideal self-discrepancies mediate the association between aging beauty media and disordered eating symptomatology. Our study builds on extant work related to media consumption, body concerns, and eating behaviors among a non–college-aged sample.