"ما برای شما کار خواهیم کرد" - نفوذ اجتماعی ممکن است تنظیمات غذایی فرد در یک موقعیت ارتباطی در سگ ها را سرکوب کند

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.

Reward is considered a fundamental factor to the organization of behavior (for a review, see for example Cannon & Bseikri, 2004). Not only the presence and the quantity of the reward, but obviously its quality also can affect behavioral and mental performance. Although there is a vivid debate over the possible beneficial and detrimental effects of extrinsic rewards on human creativity and motivation (Deci et al., 1999 and Eisenberger and Cameron, 1996), the so-called ‘natural rewards’ like food, drink, and positive social interactions are considered almost unequivocally necessary for higher motivation and learning performance in animals. It has been known for some time that positive reinforcement (usually food reward) results in faster learning than punishment in operant conditioning tasks (for example Lawson & Watson, 1963), and that better quality rewards also speed up learning performance (Elliott, 1928). Norway rats (Rattus norvegicus) that developed a particular taste preference through social learning lost their preference faster after being exposed to an alternative food with a different taste, if that food had higher caloric content ( Galef & Whiskin, 2001). Human children also show a preference for calorie rich food. They performed better in a social learning task if their mothers demonstrated the consumption of a ‘nutritious’ food in comparison to the ‘light’ variant of the same product ( Jansen & Tenney, 2001).