Food pleasantness affects visual selective attention

Fundamental to adaptive behaviour is the ability to select environmental objects that best satisfy current needs and preferences. Here we investigated whether temporary changes in food preference influence visual selective attention. To this end, we exploited the fact that when a food is eaten to satiety its motivational value and perceived pleasantness decrease relative to other foods not eaten in the meal, an effect termed sensory-specific satiety. A total of 26 hungry participants were fed until sated with one of two palatable foods. Before and after selective satiation, participants rated the pleasantness of the two foods and then viewed the same as stimuli on a computer screen while attention was assessed by a visual probe task. Results showed that the attentional bias for the food eaten decreased markedly from pre- to postsatiety, along with the subjective pleasantness for that food. By contrast, subjective pleasantness and attentional bias for the food not eaten did not show any such decrease. These findings suggest that the allocation of visual selective attention is flexibly and rapidly adjusted to reflect temporary shift in relative preference for different foods.     

Scarce Foods are Perceived as Having More Calories

People vary dramatically in their calorie estimates of food depending on the information available to them. Prior research has focused on information that is normatively relevant to the number of calories a food contains (e.g., fat content, serving size). The current research examines whether information that is normatively irrelevant to the number of calories a food contains—such as its availability—might also shape people's calorie estimates. Three studies found that a food perceived as limited in availability leads people to estimate the food to contain more calories. Serial mediation analyses revealed that this effect occurs because scarce food is seen as more valuable and expensive, which subsequently induces feelings of resource deprivation. This sense of resource deprivation, in turn, leads to motivated perception, whereby higher calorie estimates are the result of people wanting to acquire more resources. The findings provide insight into the psychology of scarcity and underscore the importance of understanding how contextual factors shape people's calorie estimates and the psychological mechanisms that drive them.     

Chimpanzees do not take into account what others can hear in a competitive situation

Chimpanzees (Pan troglodytes) know what others can and cannot see in a competitive situation. Does this reflect a general understanding the perceptions of others? In a study by Hare et al. (2000) pairs of chimpanzees competed over two pieces of food. Subordinate individuals preferred to approach food that was behind a barrier that the dominant could not see, suggesting that chimpanzees can take the visual perspective of others. We extended this paradigm to the auditory modality to investigate whether chimpanzees are sensitive to whether a competitor can hear food rewards being hidden. Results suggested that the chimpanzees did not take what the competitor had heard into account, despite being able to locate the hiding place themselves by the noise.     

Common marmosets (<Emphasis Type="Italic">Callithrix jacchus</Emphasis>) do not utilize social information in three simultaneous social foraging tasks

Social foraging is suggested to increase foraging efficiency, as individuals might benefit from public information acquired by monitoring the foraging activities of other group members. We conducted a series experiments with captive common marmosets (Callithrix jacchus) to investigate to what extent marmosets utilize social information about food location when foraging simultaneously with conspecifics. Subjects were confronted with dominant and subordinate demonstrators in three experiments which differed in the amount of information about food location available to the demonstrators. In all three experiments, the focal subjects’ performance in the social condition was not enhanced in comparison to a non-social control condition. Because we could rule out kleptoparasitism and aggressive displacements as explanations, we argue that the subjects’ tendency for scramble competition by avoiding others and dispersing over the foraging area seems to inhibit or mask the acquisition of social information about the location of rewarded patches.     

Priorities of Global Justice

One-third of all human deaths are due to poverty-related causes, to malnutrition and to diseases that can be prevented or cured cheaply. Yet our politicians, academics, and mass media show little concern for how such poverty might be reduced. They are more interested in possible military interventions to stop human rights violations in developing countries, even though such interventions – at best – produce smaller benefits at greater cost. This Western priority may be rooted in self-interest. But it engenders, and is sustained by, a deeply flawed moral presentation of global economic cooperation. The new global economic order we impose aggravates global inequality and reproduces severe poverty on a massive scale. On any plausible understanding of our moral values, the prevention of such poverty is our foremost responsibility.     

Pilfering ravens, Corvus corax, adjust their behaviour to social context and identity of competitors

Like other corvids, food-storing ravens protect their caches from being pilfered by conspecifics by means of aggression and by re-caching. In the wild and in captivity, potential pilferers rarely approach caches until the storers have left the cache vicinity. When storers are experimentally prevented from leaving, pilferers first search at places other than the cache sites. These behaviours raise the possibility that ravens are capable of withholding intentions and providing false information to avoid provoking the storers' aggression for cache protection. Alternatively, birds may refrain from pilfering to avoid conflicts with dominants. Here we examined whether ravens adjust their pilfer tactics according to social context and type of competitors. We allowed birds that had witnessed a conspecific making caches to pilfer those caches either in private, together with the storer, or together with a conspecific bystander that had not created the caches (non-storer) but had seen them being made. Compared to in-private trials, ravens delayed approaching the caches only in the presence of storers. Furthermore, they quickly engaged in searching away from the caches when together with dominant storers but directly approached the caches when together with dominant non-storers. These findings demonstrate that ravens selectively alter their pilfer behaviour with those individuals that are likely to defend the caches (storers) and support the interpretation that they are deceptively manipulating the others' behaviour.This contribution is part of the special issue “Animal Logics” (Watanabe and Huber 2006).     

Infant food refusal and parental social support

The purpose of this study was to examine the relations between various aspects of social support and maternal and infant outcome variables in a group of families having infants showing food refusal compared to a control group. In the case of early food refusal, the results indicated that access to emotional support and satisfaction with support were related to maternal psychosomatic health. The relationships were interpreted as showing that social support has moderating effects on negative outcomes of food refusal.