Learning food preferences

Zahorik, D.M. 1977. Associative and non-associative factors in learned food preferences. In Learning Mechanisms in Food Selection, eds. L.M. Barker, M.R. Best M. Domjan, pp. 181-200, Baylor University Press, Waco, TX. 

Galef, B. G., Jr., 1977, Mechanisms for the social transmission of food preferences from adult to weanling rats, "Learning Mechanisms in Food Selection," L. M. Barker, M. Best, and M. Domjan, eds., Baylor University Press, Waco Tex. 

It may be hypothesized that the odor of shrews, moles and moonrats is a deterrent to some mammalian predators. Scott and Klimstra (1955), for example, concluded that moles (Scalopus aquaticus) and short-tailed shrews (Blarina brevicauda) were low on the scale of red fox food preferences because captured insectivores were often left uneaten. Shrews release a strong musky scent when disturbed (see Dryden and Conaway, 1967), but the role of scent as an anti-predator ploy is unknown. The deterrent effect of the shrew s scent does not appear to operate until the animal is captured and killed, and so it may be argued that the odor does not prevent predation, On the other hand, prudent predators" may learn to avoid hunting prey which are not edible. Challenging experiments will be required to determine whether red foxes and other carnivores become conditioned to modify their search image for insectivore prey such as moles and shrews. 

Moskowitz HR, Kluter RA, Westerling J and Jacobs HL. (1974) Sugar sweetness and pleasantness evidence for different psychological laws. Science, 184 583-585. Moskowitz H. (2004) From psychophysics to the world. .. data acquired, lessons learned. Food Qual Prefer, 15 633-644. 

Food preferences also can be learned, and, like learned aversions, conditioned preferences can be used to evaluate chemosensory abilities. Typically, preferences are induced by pairing the ingestion of a novel flavor with calories (Bolles et al. 1981 Messier White 1984 Booth 1985 Mehiel Bolles 1984, 1988 Simbayi et al. 1985), recovery from nutritional deficiency (Garcia et al. 1967 Zahorik et al. 1974), and recovery from malaise (Green Garcia 1971 Zahorik 1977 Sherman et al. 1983). The novel flavor is subsequently preferred, as are other flavors that subjects perceive as similar to the conditioned stimulus. However,... 

By the time a child reaches school for the first time, food preferences and a pattern of eating are well established. If this early learning has been good, good habits can be reinforced and knowledge increased in school. If, on the other hand, early learning has been unsatisfactory, some remedial action may be possible. 

Rats learn from group members about new food sources, and clans may develop food traditions. How does one rat transmit to another this information about food. This type of intraspecific communication employs both body and foreign odors. Bennet Galef and coworkers (1985) showed that observer rats who encounter demonstrator rats with food odor on their heads will prefer that food over another when given a choice later. It is important that the food odor is on the head portion of a live rat if it is applied to the rear end of a rat or to the head of a dead rat, it has no effect (Galef and Stein, 1985). 

Adults continue to associate new odors with pleasant and unpleasant situations in social and sex life, work and recreation, and concerning food and drink. The human patterns of odor recognition and preferences do not merely involve the olfactory nerve and its central projections. Learned associations are formed and stored in memoiy. To retrieve odor information, we need affective and cognitive components, as well as verbal descriptors. Without the latter, an odor appears familiar but cannot be labeled, the tip-of-the-nose-phenomenon (Lawless and Engen, 1977). 

Fish from temperate zones have been most studied, and from these we learn that temperature may influence the character of metabolic rhythm both indirectly, through food supply, and directly, through the limited temperature ranges within which one or other vital activity can or cannot occur. It is the response or the preference that fish show to temperature that shapes the rhythmic pattern. This is well shown in two diametrically opposite fish from the Black Sea, the warm-water anchovy and the cold-water sprat (Figure 34). The curves that describe the course of triacyl-glycerol accumulation in these species mirror each other, as the fish oppose one another in their time of spawning. 

Summing up, impairment of DA transmission by DA receptor antagonists and in particular by D1 receptor antagonists impairs the acquisition of place preference conditioned by nondrug rewards (food, water, sucrose and sex). This effect is unrelated to an impairment of the hedonic impact of the rewards, consistent with other evidence, obtained from taste reactivity and consumption studies, that DA is not involved in stimulus-bound hedonia. Therefore, conditioned place-preference studies utilizing conventional rewards support a role of DA in Pavlovian incentive learning. 

Pre-gastric factors can include the appearance of food, its taste and odour, learned preferences, aversions and psychological factors. Mental states such as fear, depression and social interactions can all affect food intake. Such factors are of particular importance to clinicians because they can be manipulated to manage anorectic (anorexigenic) patients. 

Many factors are involved in the control of food intake. Some of the most important factors controlling the amount of food that we eat include environmental factors such as food availability, the characteristics of the food itself (e.g., smell, taste, our eating habits, learned preferences and aversions) as well as other psychological and social factors, including our lifestyle. Although these psychosocial factors are extremely important to the food intake patterns of humans, this section will concentrate on the physiological factors, primarily the role of fat in food intake. 

Sixteen male and sixteen female common marmosets (Callithrix jacchus) weighing 280-380 g had previously been trained to perform a task of visually guided reaching which is sensitive to motivational, attentional and motor disturbances (d Mello et al., 1985). In this task, animals learn to retrieve small items of preferred food from a moving conveyor belt positioned in front of their home cage and performance is gauged by the number of attempts that are made and their effectiveness in retrieving rewards. 

---