“We will work for you” – Social influence may suppress individual food preferences in a communicative situation in dogs

The level of motivation (i.e. incentive power) is thought to be one of the most important factors affecting performance and learning in various tasks. We investigated whether reward quality has an effect on the performance of family dogs in a two-way object choice test in which they can find the hidden food by relying on distal momentary human pointing cues. In three experiments we varied (1) the type of food reward according to the subjects’ own preference; (2) the quality of the reward offered at the same time in the indicated and not-indicated locations; and (3) the order of the high or low quality rewards in consecutive sessions. In Experiment 1, we first tested whether dogs prefer one kind of reward over another. Then one group was tested with the ‘preferred’ food as reward in the indicated bowl, while dogs in the other group received the ‘non-preferred’ food as reward. We did not find any difference between the performance and choice latencies of the two groups. In Experiment 2 for the first group, the indicated bowl contained a piece of carrot and the not-indicated bowl was empty. In the second group the indicated bowl contained carrot, but the not-indicated bowl contained sausage. According to a preliminary preference test, most dogs prefer sausage over carrot invariably. After 20 trials, the two groups performed surprisingly similarly. There was no difference found between groups in the number of correct choices, incorrect choices and non-choices. However, the comparison between the first and last five trials revealed that subjects who found sausage when they chose the not-indicated bowl (did not follow the pointing) chose the non-indicated bowl significantly more often toward the end of their test session. In Experiment 3, each dog received two sessions with 12 pointing trials in each. For the first session, one group was rewarded with sausage and the other with carrot upon choosing the indicated bowl. In the second session, the indicated bowl contained dry dog food for both groups. We found that correct choices and response latencies did not change over two sessions in the ‘sausage’ group. In the ‘carrot’ group, the dogs chose faster in the second session, but their performance did not improve; in fact, they chose the not-indicated bowl more often than the indicated bowl. As a conclusion, we can say that reward quality had some effect on dogs’ choice behavior in these experiments. The drop in their performance was not drastic, taking into account the general refusal to eat one of the ‘rewards’ (carrot) during the preference tests and also during the test trials. It seems that incentive contrast may play a relatively minor role in dog-human social interactions. Appropriate reward quality can be very important in asocial problem solving tasks, but, when interacting with humans, following human signals may override the effect of changed incentive power.     

有“新”同享：共有消费促进对不熟悉产品的选择*

共有消费是多位消费者共同参与并承担开销的一种常见的消费活动。本研究基于风险转移理论, 探究了消费情境(单独消费vs.共有消费)对不熟悉产品偏好的作用机理及边界条件。通过5个实验, 结果发现：相比于单独消费情境下的消费者, 在共有消费情境下的消费者更愿意尝试不熟悉的产品。原因在于共有消费情境会转移消费风险, 使得消费者对不熟悉产品的感知风险降低。但是该效应仅发生于产品风险较低的产品。同时, 当共有消费群体的关系较为疏远时, 该效应会消失甚至逆转。     

A Transformative Eucharistic Vision for the Entire Oikoumene

This article begins from the awareness that in a world of affluence, millions are hungry. It addresses the question as to whether this is merely an economic issue or whether it also poses an ethical and theological dilemma, considering ways in which the situation we are living in challenges our faith in the transformation of bread and wine into the body and blood of Christ. It asks how, in the situation as it is, there is any possibility of believing in such a transformation. Finally it questions whether there is any relationship between hope for the transformation of hunger amidst affluence and belief in the transformation of bread into the body of Christ, and outlines a transformative eucharistic vision for the global Christian Church.     

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.