The Selection of Foods by Rats, Humans, and Other Animals

The brain-body energy conservation model of aging

Aging involves seemingly paradoxical changes in energy metabolism. Molecular damage accumulation increases cellular energy expenditure, yet whole-body energy expenditure remains stable or decreases with age. We resolve this apparent contradiction by positioning the brain as the mediator and broker in the organismal energy economy. As somatic tissues accumulate damage over time, costly intracellular stress responses are activated, causing aging or senescent cells to secrete cytokines that convey increased cellular energy demand (hypermetabolism) to the brain. To conserve energy in the face of a shrinking energy budget, the brain deploys energy conservation responses, which suppress low-priority processes, producing fatigue, physical inactivity, blunted sensory capacities, immune alterations and endocrine 'deficits'. We term this cascade the brain-body energy conservation (BEC) model of aging. The BEC outlines (1) the energetic cost of cellular aging, (2) how brain perception of senescence-associated hypermetabolism may drive the phenotypic manifestations of aging and (3) energetic principles underlying the modifiability of aging trajectories by stressors and geroscience interventions.

Locus Ceruleus Dynamics Are Suppressed during Licking and Enhanced Postlicking Independent of Taste Novelty

Attending to salient sensory attributes of food, such as tastes that are new, displeasing, or unexpected, allows the procurement of nutrients without food poisoning. Exposure to new tastes is known to increase norepinephrine (NE) release in taste processing forebrain areas, yet the central source for this release is unknown. Locus ceruleus norepinephrine neurons (LC-NE) emerge as a candidate in signaling salient information about taste, as other salient sensory stimuli (e.g., visual, auditory, somatosensation) are known to activate LC neurons. To determine if LC neurons are sensitive to features of taste novelty, we used fiber photometry to record LC-NE activity in water-restricted mice that voluntarily licked either novel or familiar substances of differential palatability (saccharine, citric acid). We observed that LC-NE activity was suppressed during lick bursts and transiently activated upon the termination of licking and that these dynamics were independent of the familiarity of the substance consumed. We next recorded LC dynamics during brief and unexpected consumption of tastants and found no increase in LC-NE activity, despite their responsiveness to visual and auditory stimuli, revealing selectivity in LC's responses to salient sensory information. Our findings suggest that LC activity during licking is not influenced by taste novelty, implicating a possible role for non-LC noradrenergic nuclei in signaling critical information about taste.

Flesh Without Blood: The Public Health Benefits of Lab-Grown Meat

Synthetic meat made from animal cells will transform how we eat. It will reduce suffering by eliminating the need to raise and slaughter animals. But it will also have big public health benefits if it becomes widely consumed. In this paper, we discuss how "clean meat" can reduce the risks associated with intensive animal farming, including antibiotic resistance, environmental pollution, and zoonotic viral diseases like influenza and coronavirus. Since the most common objection to clean meat is that some people find it "disgusting" or "unnatural," we explore the psychology of disgust to find possible counter-measures. We argue that the public health benefits of clean meat give us strong moral reasons to promote its development and consumption in a way that the public is likely to support. We end by depicting the change from farmed animals to clean meat as a collective action problem and suggest that social norms rather than coercive laws should be employed to solve the problem.

Evaluating the Presence of Disgust in Animals

The emotion of disgust in humans is widely considered to represent a continuation of the disease-avoidance behavior ubiquitous in animals. The extent to which analogs of human disgust are evident in nonhuman animals, however, remains unclear. The scant research explicitly investigating disgust in animals has predominantly focused on great apes and suggests that disgust might be present in a highly muted form. In this review, we outline the main approaches to disgust. We then briefly discuss disease-avoidance behavior in nonhuman animals, proposing a set of criteria against which evidence for the presence or absence of disgust in animals can be evaluated. The resultant decision tree takes into account other plausible causes of avoidance and aversion when evaluating whether it is likely that the behavior represents disgust. We apply this decision tree to evaluate evidence of disgust-like behavior (e.g., avoidance of carrion and avoidance of feces-contaminated food) in several examples, including nonhuman great apes. Finally, we consider the large disparity between disgust in humans compared to muted disgust in other great apes, examining the possibility that heightened disgust in humans is a relatively recent cultural acquisition.

Distinct Contributions of the Cerebellum and Basal Ganglia to Arithmetic Procedures

Humans exhibit complex mathematical skills attributed to the exceptional enlargement of neocortical regions throughout evolution. In the current work, we initiated a novel exploration of the ancient subcortical neural network essential for mathematical cognition. Using a neuropsychological approach, we report that degeneration of two subcortical structures, the cerebellum and basal ganglia, impairs performance in symbolic arithmetic. We identify distinct computational impairments in male and female participants with cerebellar degeneration (CD) or Parkinson's disease (PD). The CD group exhibited a disproportionate cost when the arithmetic sum increased, suggesting that the cerebellum is critical for iterative procedures required for calculations. The PD group showed a disproportionate cost for equations with increasing addends, suggesting that the basal ganglia are critical for chaining multiple operations. In Experiment 2, the two patient groups exhibited intact practice gains for repeated equations at odds with an alternative hypothesis that these impairments were related to memory retrieval. Notably, we discuss how the counting and chaining operations relate to cerebellar and basal ganglia function in other task domains (e.g., motor processes). Overall, we provide a novel perspective on how the cerebellum and basal ganglia contribute to symbolic arithmetic. Our studies demonstrate the constraints on the computational role of two subcortical regions in higher cognition.

Effects of food deprivation on conditioned orthonasal olfactory preferences with caloric and non-caloric reinforcers

Three experiments were conducted to investigate Conditioned Olfactory Preferences using orthonasal inhalation, which is a less explored perceptual pathway compared to retronasal inhalation. In these experiments, odors were impregnated onto plastic disks to prevent the subjects from consuming or tasting them. The reinforcers used were a sucrose solution (Caloric groups) and a saccharin solution (Non-Caloric groups). The influence of nutritional deprivation was analyzed, with unrestricted access to food throughout the procedure in Experiment 1, food restriction during the conditioning phase in Experiment 2, and limited access to food during the test phase in Experiment 3. The results revealed conditioned preferences using both sucrose and saccharin as reinforcers. Furthermore, dietary restriction reduced the conditioned preference induced by saccharin, but not the preference induced by sucrose. These findings are discussed in light of the potential differences between orthonasal and retronasal presentation of odors during conditioning.

Large Scale Visual Food Recognition

Food recognition plays an important role in food choice and intake, which is essential to the health and well-being of humans. It is thus of importance to the computer vision community, and can further support many food-oriented vision and multimodal tasks, e.g., food detection and segmentation, cross-modal recipe retrieval and generation. Unfortunately, we have witnessed remarkable advancements in generic visual recognition for released large-scale datasets, yet largely lags in the food domain. In this paper, we introduce Food2K, which is the largest food recognition dataset with 2,000 categories and over 1 million images. Compared with existing food recognition datasets, Food2K bypasses them in both categories and images by one order of magnitude, and thus establishes a new challenging benchmark to develop advanced models for food visual representation learning. Furthermore, we propose a deep progressive region enhancement network for food recognition, which mainly consists of two components, namely progressive local feature learning and region feature enhancement. The former adopts improved progressive training to learn diverse and complementary local features, while the latter utilizes self-attention to incorporate richer context with multiple scales into local features for further local feature enhancement. Extensive experiments on Food2K demonstrate the effectiveness of our proposed method. More importantly, we have verified better generalization ability of Food2K in various tasks, including food image recognition, food image retrieval, cross-modal recipe retrieval, food detection and segmentation. Food2K can be further explored to benefit more food-relevant tasks including emerging and more complex ones (e.g., nutritional understanding of food), and the trained models on Food2K can be expected as backbones to improve the performance of more food-relevant tasks. We also hope Food2K can serve as a large scale fine-grained visual recognition benchmark, and contributes to the development of large scale fine-grained visual analysis.

Contributions of Lower Structures to Higher Cognition: Towards a Dynamic Network Model

Researchers often attribute higher cognition to the enlargement of cortical regions throughout evolution, reflecting the belief that humans sit at the top of the cognitive pyramid. Implicitly, this approach assumes that the subcortex is of secondary importance for higher-order cognition. While it is now recognized that subcortical regions can be involved in various cognitive domains, it remains unclear how they contribute to computations essential for higher-level cognitive processes such as endogenous attention and numerical cognition. Herein, we identify three models of subcortical-cortical relations in these cognitive processes: (i) subcortical regions are not involved in higher cognition; (ii) subcortical computations support elemental forms of higher cognition mainly in species without a developed cortex; and (iii) higher cognition depends on a whole-brain dynamic network, requiring integrated cortical and subcortical computations. Based on evolutionary theories and recent data, we propose the SEED hypothesis: the Subcortex is Essential for the Early Development of higher cognition. According to the five principles of the SEED hypothesis, subcortical computations are essential for the emergence of cognitive abilities that enable organisms to adapt to an ever-changing environment. We examine the implications of the SEED hypothesis from a multidisciplinary perspective to understand how the subcortex contributes to various forms of higher cognition.

Consumer Intention towards Buying Edible Beef Offal and the Relevance of Food Neophobia

Enhancing the willingness to eat edible offal can be a valuable strategy to mitigate the greenhouse gas (GHG) emissions related to growing meat production and to provide food with high protein content to a growing global population. Although some edible offal is considered delicacies, we hardly find such foods in Western countries' everyday diet, and their human consumption has decreased during the last decades. This study analyses the consumer purchase intention of BEEF edible offal using an extended version of the Theory of Planned Behaviour (TPB), where food neophobia and food disgust sensitivity play an essential role in determining consumers' willingness to eat beef edible offal. An online survey was conducted among a sample of Italian adult regular meat eaters (n = 720), stratified by age, gender, education and residence. The results showed a direct negative impact of food neophobia on the intention to consume offal. Further, we were able to quantify a negative indirect impact of food neophobia on intention through the mediation of food disgust sensitivity and attitudes, subjective norms and perceived behavioural control, which all exert an essential role in determining the willingness to consume beef edible offal. We found that the mediated impact of food neophobia on the intention to consume beef offal is much higher than the direct impact. In conclusion, recommendations and implications, such as promoting cooking shows with celebrity chefs, new products or new packaging of edible offal, were developed based on the results to increase edible beef consumption.

Human nutritional intelligence underestimated? Exposing sensitivities to food composition in everyday dietary decisions

The social and cultural significance of food is woven into every aspect of our dietary behaviour, and it contributes to our complex interaction with food. To find order within this complexity scientists often look for dietary 'universals' - phenomena or basic principles that guide our food choice and meal size, irrespective of wider context. One such idea is that taste characteristics provide a signal for dietary composition (e.g., sweet taste signals carbohydrate). Others have suggested that behaviour is guided by learning and is based on associations that form between the flavour of a food and its post-ingestive effects. Despite a large body of research, evidence supporting both processes is equivocal, leading some to conclude that humans are largely indifferent to food composition. Here, we argue that human abilities to gauge the nutritional composition or value of food have been underestimated, and that they can be exposed by embracing alternative methods, including cross-cultural comparisons, large nutrition surveys, and the use of virtual portion-selection tools. Our group has focused on assessments of food choice and expected satiety, and how comparisons across everyday foods can reveal non-linear relationships with food energy density, and even the potential for sensitivity to micronutrient composition. We suggest that these abilities might reflect a complex form of social learning, in which flavour-nutrient associations are not only formed but communicated and amplified across individuals in the form of a cuisine. Thus, rather than disregarding sociocultural influences as extraneous, we might reimagine their role as central to a process that creates and imbues a 'collective dietary wisdom.' In turn, this raises questions about whether rapid dietary, technological, and cultural change disrupts a fundamental process, such that it no longer guarantees a 'nutritional intelligence' that confers benefits for health.

Tears for pears: Influence of children’s neophobia on categorization performance and strategy in the food domain

Preschoolers’ neophobic dispositions mainly target fruits and vegetables. They received a great deal of attention in the past decades as these dispositions represent the main psychological barrier to dietary variety. Recently, children’s food neophobia has been found to be negatively correlated with their categorization performance (i.e., the accuracy to discriminate between food categories). We investigated categorization strategies among neophobic children, tendencies to favor one type of error over the other (misses over false alarms), in order to compensate for their poor categorization performance. To capture children’s categorization strategies, we used the Signal Detection Theory framework. A first experiment assessed 120 3-to-6-years old children’ sensitivity to discriminate between foods and nonfoods as well as their decision criterion (i.e., response strategy). In a second experiment, we manipulated the influence of food processing. The hypothesis was that food processing acts as a sign of human interventions that decreases uncertainty about edibility and thus promotes feelings of safety in the food domain. 137 children were tested on a food versus nonfood categorization task contrasting whole and sliced stimuli. In both experiments, increased levels of food neophobia were significantly associated with poorer categorization sensitivity and with a more conservative decision criterion (i.e., favoring “it is inedible” errors). Additionally, results from Experiment 2 revealed that food processing did not influence neophobic children, whereas their neophilic counterparts adopted a more liberal decision criterion for sliced stimuli than for whole stimuli. These findings are the first demonstration of a relationship between a decision criterion and food neophobia in young children. These results have strong implications for theories of food neophobia and laid the groundwork for designing novel types of food education interventions.

Dining with liberals and conservatives: The social underpinnings of food neophobia

Although food and politics seem to be distant domains, socio-political ideology and food neophobia (i.e., reluctance to eat unfamiliar food) may be related. Conservatives’ high threat sensitivity and the inherently threatening nature of novel foods (the existential explanation), along with conservatives’ negative attitudes toward minority outgroups (e.g., foreigners) and the role of the latter in introducing novel foods to a culture (the social explanation), led us to expect that socio-political ideology would predict food neophobia over and above their common roots. Across two correlational and two experimental studies (N = 627), socio-political ideology emerged as a strong predictor of food neophobia. In addition, the findings did not support the existential explanation, while confirming the social explanation of the ideology–food neophobia link: Conservatives seem more neophobic than liberals not because of their higher threat sensitivity but rather because they hold more negative attitudes toward foreigners who are associated with those foods.

Food neophobia and its relationship with dietary variety and quality in Irish adults: Findings from a national cross-sectional study

Food neophobia is characterised by a reluctance to eat novel or unfamiliar foods and has been linked to reduced dietary variety and quality. However, this link has been primarily studied in children. Therefore, we aimed to explore the relationship between food neophobia and dietary variety and quality in adults using a sub-sample of the National Adults Nutrition Survey collected between 2008 and 2010 (n = 1088). Food and nutrient intakes were assessed using a 4-day semi-weighed food diary. Food neophobia was measured using the Food Neophobia Scale (FNS). Dietary variety was assessed in three ways; Total Dietary Variety (TDV), Food-Group Variety (FGV) and Fruit and Vegetable Variety (FVV). Diet quality was assessed using the Mean Adequacy Ratio (MAR) and Nutrient-Rich Food Index (NRF9.3). A multivariate general linear model was used to assess the linear relationships between FNS score and all dietary measures, controlling for age, sex, education level, social class, location and BMI. Food neophobia was found to be inversely associated with TDV, FGV and FVV. In addition, food neophobia was negatively associated with vitamin C, magnesium and fruit and vegetable intakes and positively associated with percentage energy from free sugars. However, food neophobia was not significantly associated with all other nutrients, MAR and NRF9.3. While these results suggest food neophobia may not be a particularly important risk factor for poor nutrient status, adherence to certain dietary recommendations remains low within the Irish population and food neophobia may further inhibit the adaption of healthy and sustainable diets. Future research should seek to understand the implications of food neophobia on dietary behaviour change.

Feather pecking and foraging uncorrelated - the redirection hypothesis revisited

1. Feather pecking (FP) is said to be a redirection of food-related foraging pecks to feathers. The effects of three foraging enrichments on the pecking behaviours of layer pullets in pens and as hens in cages (Gallus gallus domesticus) were studied.2. Treatments included no added enrichment (Control), addition of a mix of wheat and sorghum grains (Grain), a mix of wheat and sorghum grains with lucerne and oaten chaff (Chaff), and lucerne hay (Hay). In pens, Hay was provided in racks, while Grain and Chaff were scattered on the floor. In cages, all treatments were provided in racks. It was predicted that enrichments that encouraged more pecking activity would be most successful at reducing FP.3. Overall pecking activity was similar between all treatments. The Chaff groups tended to FP less than Grain groups, and Hay groups had the least FP. In cages, both Chaff and Hay groups had significantly less FP than either the Grain or Control groups. FP did not reflect stimulus peck rates. Although Chaff groups pecked at their rack significantly less than either Grain or Hay groups, their FP was on a par with the birds in the Hay groups. Feather quality followed these trends.4. The fact that these results were inconsistent with the original hypothesis led to a proposal for a modified hypothesis. Rather than the appetitive component of food searching motivation being redirected to feathers, it is the appetitive component of exploratory motivation, and the ability to reach the goal to update information about the environment is what feeds back to the motivation which leads to FP. This modified hypothesis is consistent with the results of this and many other studies and with modern concepts of motivation, foraging, exploration and food selection.

Practical School Nutrition Program May Reduce Food Neophobia

The study’s purpose was to evaluate an intervention to reduce fruit and vegetable food neophobia and influence attitudes and behaviors among children using a four-month, non-experimental, before-and-after intervention. Participants were children aged 5–11 years in an intervention school (IS) and a control school (CS). Children were offered fruit or vegetable samples weekly utilizing school-specific psychosocial and educational practices to encourage participation. The outcomes of interest included attitudes measured using a written survey-based food neophobia scale (FNS), behavioral observations, and an oral survey. The post-intervention IS FNS score was significantly lower compared to pre-intervention (p = 0.04). Repeated-measures ANOVA revealed a statistically significant overall effect of time (p = 0.006). School type-time interaction was not significant (p = 0.57). Pre-intervention observational data showed the proportions finishing and taking another fruit and vegetable sample were higher in the CS (p < 0.001 for both). Post-intervention, the proportions taking the vegetable (p = 0.007) and the fruit (p < 0.001) were higher in the IS. The percentage tasting the vegetable was higher in the CS (p = 0.009). Offering samples of produce in school lunchrooms may reduce food neophobia. This intervention is an inexpensive program that volunteers can quickly implement.

Arousal influences olfactory abilities in adults with different degree of food neophobia

Food neophobia, i.e., the aversion to novel foods, and olfaction are both factors strongly affecting food choices. Mounting evidence suggests a higher arousal towards food as a key factor underlying the reluctance to eat what is unfamiliar to us. As the role of olfaction behind this phenomenon is poorly understood, we explored the associations between food neophobia and trait anxiety, olfactory functions (odor threshold, discrimination and identification) and retronasal aroma release from a reference food in a healthy cohort of 83 adult volunteers. We grouped participants in Low-Neophobics or neophilics (n = 35), Medium-Neophobics (n = 32) and High-Neophobics (n = 16) according to the widely recognized Food Neophobia Scale. Participants with higher neophobic tendencies were found to have marginally higher trait anxiety levels than neophilics (p = 0.10). A lower global olfactory functioning and odor discrimination abilities characterized High-Neophobics, while Medium-Neophobics showed a higher odor sensitiveness than Low-Neophobics. Lastly, High-Neophobics showed a lower extent of retronasal aroma release, likely due to a shorter duration of oral processing and higher anxiety-related physiological responses (such as breathing rate). In summary, this study supports the assumption that the conflicting relationship that neophobics have with food may be led by higher levels of arousal toward foods, rather than different chemosensory functions.

The role of novelty and fat and sugar concentration in food selection by captive tufted capuchins (Sapajus apella)

Capuchins, like other primates, use feedback from sensory cues and digestion to make decisions about which foods to consume and which to avoid. However, little is known about how capuchins make consumption decisions when simultaneously presented with novel and familiar foods, or how food familiarity and macronutrient concentration together influence food choice, topics with potential implications for developmental and health research. In this study, we evaluated the role of familiarity, as well as fat and sugar concentration, in the food selections of captive tufted capuchins (Sapajus apella). In the first experiment, over 10 sessions, subjects were assigned to either a group that chose between one familiar and one novel food item both high in fat or sugar (high condition), or to a group that chose between one familiar and one novel food item both low in fat or sugar (low condition). In the second experiment, subjects were divided into three groups, familiarized with food over five feeding sessions, and then offered the familiarized food and a novel food that varied in fat or sugar for 10 sessions. When offered foods high in fat, capuchins showed no clear signs of neophobia, forming an initial preference for the novel food, rejecting foods less frequently, and selecting foods faster than when offered foods low in fat. These trends were generally not observed in response to foods with sugar. When presented with options that varied in macronutrient concentration, subjects showed an initial interest in the novel food irrespective of whether it was high in fat or sugar, yet formed a final preference for the higher-concentration item. Findings suggest that the concentration of fat or sugar in novel foods may be an important mediator of exploratory behavior and that capuchins rely on immediate feedback from taste and other sensory cues to make consumption decisions.

Distinct brain representations of processed and unprocessed foods

Among all of the stimuli surrounding us, food is arguably the most rewarding for the essential role it plays in our survival. In previous visual recognition research, it has already been demonstrated that the brain not only differentiates edible stimuli from non-edible stimuli but also is endowed with the ability to detect foods' idiosyncratic properties such as energy content. Given the contribution of the cooked diet to human evolution, in the present study we investigated whether the brain is sensitive to the level of processing food underwent, based solely on its visual appearance. We thus recorded visual evoked potentials (VEPs) from normal-weight healthy volunteers who viewed color images of unprocessed and processed foods equated in caloric content. Results showed that VEPs and underlying neural sources differed as early as 130 ms post-image onset when participants viewed unprocessed versus processed foods, suggesting a within-category early discrimination of food stimuli. Responses to unprocessed foods engaged the inferior frontal and temporal regions and the premotor cortices. In contrast, viewing processed foods led to the recruitment of occipito-temporal cortices bilaterally, consistently with other motivationally relevant stimuli. This is the first evidence of diverging brain responses to food as a function of the transformation undergone during its preparation that provides insights on the spatiotemporal dynamics of food recognition.

A Proximal Perspective on Disgust

The functional basis of disgust in disease avoidance is widely accepted; however, there is disagreement over what disgust is. This is a significant problem, as basic questions about disgust require knowing if single/multiple forms/processes exist. We address this issue with a new model with one form of disgust generated by multiple processes: (a) pure disgust experienced during gastrointestinal illness; (b) somatosensory disgust elicited by specific cues that activate the pure disgust state; (c) anticipatory disgust elicited by associations between distance cues for somatosensory disgust and requiring threat evaluation; (d) simulated disgusts elicited by imagining somatosensory and anticipatory disgust and frequently involving other emotions. Different contamination processes interlink (a–d). The implications of our model for fundamental questions about disgust (e.g., emotion status; continuation into animals) are examined.

Inhibiting gustatory thalamus or medial amygdala has opposing effects on taste neophobia

Taste neophobia is a feeding system defense mechanism that limits consumption of an unknown, and therefore potentially dangerous, edible until the post-ingestive consequences are experienced. We found that transient pharmacological inhibition (induced with the GABA agonists baclofen and muscimol) of the gustatory thalamus (GT; Experiment 1), but not medial amygdala (MeA; Experiment 2), during exposure to a novel saccharin solution attenuated taste neophobia. In Experiment 3 we found that inhibition of MeA neurons (induced with the chemogenetic receptor hM4DGi) enhanced the expression of taste neophobia whereas excitation of MeA neurons (with hM3DGq) had no influence of taste neophobia. Overall, these results refine the temporal involvement of the GT in the occurrence of taste neophobia and support the hypothesis that neuronal excitation in the GT is necessary for taste neophobia. Conversely, we show that chemogenetically, but not pharmacologically, inhibiting MeA neurons is sufficient to exaggerate the expression of taste neophobia.

Selected Psychological Aspects of Meat Consumption-A Short Review

Eating meat is deeply entrenched in Western culture. It is often associated with wealth and a highly nutritional diet; and for many people it is also an established habit that is difficult to change. The second half of the 20th century was a period of rapid growth in meat consumption, which resulted in intensified meat production. At the same time, eating meat has recently become subject to criticism for health-related, environmental or humanitarian reasons. This review aims to signal the potential consequences of a change of diet or switching to diets that are rich/poor in certain ingredients on the functioning of the hormonal and nervous system, which translates into changes in mood and behavior. This paper discusses the psychological phenomena which underlie the difficulty of changing one's food preferences and problems encountered while adding new products to the daily diet. Finally, this study summarizes the limitations of modifying eating habits that have resulted from established attitudes and habits.

Peas, please! Food familiarization through picture books helps parents introduce vegetables into preschoolers' diets

Repeated taste exposure is an established means of increasing children's liking and intake of fruit and vegetables. However, parents find it difficult to offer children disliked foods repeatedly, often giving up after a few attempts. Studies show that familiarizing children to fruit and vegetables through picture books can increase their interest in tasting targeted foods. This study explored whether looking at picture books before providing foods to taste improved the outcomes of a home-delivered taste exposure regime. Parents of 127 toddlers (aged 21-24 months) identified two 'target' foods they wanted their child to eat (1 fruit, 1 vegetable). Families were randomly assigned to one of three groups. Parents and children in two experimental groups looked at books about either the target fruit or vegetable every day for two weeks; the control group did not receive a book. Parents in all three groups were then asked to offer their child both target foods every day during a 2-week taste-exposure phase. Parental ratings of children's liking and consumption of the foods were collected at baseline, immediately following taste-exposure (post-intervention), and 3 months later (follow-up). In all groups, liking of both foods increased following taste exposure and remained above baseline at follow-up (all ps < .001). In addition, compared to the control group who experienced only taste exposure, looking at vegetable books enhanced children's liking of their target vegetable post-intervention (p < .001) and at follow-up (p < .05), and increased consumption of the vegetable at follow-up (p < .01). Exposure to vegetable books was also associated with smaller increases in neophobia and food fussiness over the period of the study compared to controls (ps < .01), suggesting that picture books may have positive, long-term impacts on children's attitudes towards new foods.

Feeding decisions under contamination risk in bonobos

Threats from parasites and pathogens are ubiquitous, and many use pathways that exploit host trophic interactions for their transmission. As such, host organisms have evolved a behavioural immune system to facilitate contamination-risk assessment and avoidance of potential contaminants in various contexts, including feeding. Detecting pathogen threats can rely on different sensory modalities allowing animals to screen for a wide array of contaminants. Here, we present a series of experiments in which bonobos showed clear avoidance of contaminated food items, and were sensitive to risk along a contamination probability gradient. Across experiments, bonobos appeared to use multisensorial cues to inform their feeding decisions. In addition, bonobos showed reduced tactile, gustatory and tool use activities when in the presence of contaminant versus control odours in a challenging foraging context. Our experiments build on previous work conducted in Japanese macaques and chimpanzees aiming at a better understanding of the ways in which the behavioural immune system operates in primates.This article is part of the Theo Murphy meeting issue 'Evolution of pathogen and parasite avoidance behaviours'.

We are what we eat: How food is represented in our mind/brain

Despite the essential role of food in our lives, we have little understanding of the way our knowledge about food is organized in the brain. At birth, human infants exhibit very few food preferences, and do not yet know much about what is edible and what is not. A multisensory learning development will eventually turn young infants into omnivore adults, for whom deciding what to eat becomes an effortful task. Recognizing food constitutes an essential step in this decisional process. In this paper we examine how concepts about food are represented in the human brain. More specifically, we first analyze how brain-damaged patients recognize natural and manufactured food, and then examine these patterns in the light of the sensory-functional hypothesis and the domain-specific hypothesis. Secondly, we discuss how concepts of food are represented depending on whether we embrace the embodied view or the disembodied view. We conclude that research on food recognition and on the organization of knowledge about food must also take into account some aspects specific to food category, the relevance of which has not been sufficiently recognized and investigated to date.

Resource forecasting: Differential effects of glucose taste and ingestion on delay discounting and self-control

We tested a novel hypothesis that glucose taste acts as a signal for resource acquisition, motivating preference for immediate rewards while actual glucose ingestion prompts resource conservation, promoting future-orientated self-regulation. In Study 1, participants were engaged in a delay-discounting task and a grip-control task before and after a beverage intervention (glucose drink, water drink, or glucose mouth-rinse). Glucose ingestion decreased delay discounting, making larger-and-later rewards more attractive. In contrast, glucose rinse increased delay discounting. Water ingestion had none of the effects. In the grip-control task, only glucose ingestion improved the performance. Study 2 using fMRI revealed that glucose rinse and glucose ingestion resulted in distinct brain activational patterns. Compared to glucose rinse, glucose ingestion deactivated a few brain regions (e.g., the anterior cingulate gyrus and inferior frontal gyrus) that are previously shown to be more active when making more difficult intertemporal choices, suggesting that glucose ingestion eases the process of making intertemporal choice. In sum, our behavioral and neuroimaging findings together suggest a dual signaling role of glucose sensation and ingestion in regulating delay discounting and self-control.

Genetic variation in bitter taste receptor gene TAS2R38, PROP taster status and their association with body mass index and food preferences in Indian population

Polymorphisms in bitter taste receptor gene TAS2R38 alter the ability to sense the intensity of bitterness of phenylthiocarbamide (PTC) and 6-n-propylthiouracil (PROP). Genetic variation in sensitivity towards PTC and PROP may affect food preferences and susceptibility to certain diseases. This is the first study aimed at investigating frequency and distribution of TAS2R38 haplotypes in an Indian cohort. Additionally, we studied the association of TAS2R38 and PROP taster status with BMI and food preference. Three hundred and ninety three healthy adults who were 19-55years of age were selected as a convenience sample from 4 geographical regions of India. Single nucleotide polymorphisms (SNPs) of TAS2R38 (rs713598, s1726866 and rs10246939) were analyzed using polymerase chain reaction-restriction fragment length polymorphism. The prevalence of PAV/PAV diplotype was 9.9% and that of AVI/AVI diplotype was 43.76% among this Indian population. PROP status was determined on the basis of its threshold concentration of detecting bitterness, as evaluated by one-solution test. The PROP status revealed 25.95% supertasters, 32.06% medium tasters and 41.98% non-tasters (NT). BMI neither significantly (p>0.05) correlated with TAS2R38 genotypes nor with PROP taster status. Food preferences did not significantly (p>0.05) correlate with TAS2R38 diplotypes or PROP phenotypes.

Temperamental approach/withdrawal and food neophobia in early childhood: Concurrent and longitudinal associations

The purpose of the present study was to investigate whether temperamental approach/withdrawal processes were concurrently and longitudinally associated with parent ratings and behavioral observations of food neophobia at 4.5 years of age. Additionally, maternal feeding practices were examined as potential moderators of the association between toddler temperament and food neophobia. Data were drawn from a longitudinal study following individuals (n = 82) from infancy through early childhood. At 18 months of age, toddlers were observed in an unfamiliar laboratory setting with an experimenter and their reactions were coded. At 4.5 years of age, the children were again observed in an unfamiliar setting and were also offered three novel foods (lychee, nori, and haw jelly). The number of foods they refused to taste was used as a measure of behavioral neophobia. Finally, mothers reported on their child's food neophobia and temperament, as well as their own feeding practices. As expected, temperament was associated with concurrent measures of food neophobia at 4.5 years of age. Also, low approach children who exhibited high negative affect and low positive affect in response to novelty at 18 months of age had higher levels of food neophobia at 4.5 years of age compared to their peers. Furthermore, evidence emerged to show that these neophobic tendencies in low approach children were strengthened by a maternal pressuring feeding style. Collectively, the results of this study emphasize that children who have low levels of temperamental approach are at a heightened risk for developing food neophobia during childhood.

Factors Influencing the Willingness to Taste Unusual Foods

Factors associated with willingness to taste 12 unusual foods were examined among 42 mature university students in a realistic taste testing situation. Low or nonsignificant correlations were found between subjects' willingness to taste the different foods and their scores on personality measures of sensation seeking as well as their ratings of familiarity with each food. Unexpectedly, age was a significant factor, with the older subjects being somewhat more willing to taste the unusual foods. Only a scale of items dealing specifically with food habits was highly correlated with subjects' willingness to try the unusual foods. The results suggest that food adventurousness is best accounted for by highly specific attitudes about food rather than general personality measures.