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1.
Naive “observer” rats that interact with conspecific “demonstrators” fed a distinctive food increase intake of the food their demonstrators have eaten. Here we found that observer rats that had interacted simultaneously with 2 demonstrator rats, 1 fed a distinctively flavored, protein-poor food, the other a distinctively flavored, protein-rich food, did not prefer the former. Similarly, observer rats ate equal amounts of two distinctively flavored foods after interacting simultaneously with 2 demonstrator rats, 1 that had consumed all food available to it, the other fed from a surplus of the second food. Last, observer rats that had interacted with both a “trustworthy” demonstrator (1 an observer had learned ate only nutritious foods) and an “untrustworthy” demonstrator (1 an observer had learned ate noxious substances) did not prefer unfamiliar foods eaten by trustworthy demonstrators to those eaten by untrustworthy demonstrators. These findings suggest limits on social information observers use in selecting foods. 相似文献
2.
Previous studies have demonstrated that a naive rat (an observer), after interacting with a previously fed conspecific (a demonstrator), will exhibit an enhanced preference for the diet its demonstrator ate. Furthermore, observers poisoned after interacting with demonstrators exhibit an aversion to their respective demonstrators’ diets. In the present paper, we examined the effects, on transmission of information from demonstrator to observer, of introducing delays between the end of demonstrator feeding and initiation of demonstrator-observer interaction. We found that (1) for at least 4 h after ingestion, demonstrator rats emitted diet-related cues sufficient to alter observers’ subsequent diet preferences, and (2) diet-related cues emitted by demonstrators for 1 to 2 h after a meal were adequate conditional stimuli for aversion learning by their observers. 相似文献
3.
Previous studies have shown that interaction of an observer rat with a previously fed conspecific demonstrator enhances the observer’s subsequent preference for the diet its demonstrator ate. The present series of experiments were undertaken to explore both the conditions sufficient to permit demonstrator influence on observer diet preference and the behavioral processes underlying such influence. We found (1) that an observer rat can be influenced in its subsequent diet selection by interaction for as little as 2 min with a demonstrator, (2) that during such brief interactions mouth-to-mouth contact between demonstrator and observer is necessary for demonstrator influence on observer diet preference, (3) that both cues emerging from the digestive tract of a rat fed by intragastric intubation and particles of food clinging to the fur of a demonstrator are sufficient to permit observers to identify their respective demonstrators’ diets, (4) that exposure to a diet is effective in enhancing an observer’s subsequent preference for that diet only if the diet is experienced in the presence of another rat, and (5) that diets experienced on the anterior of a live rat are more effective in altering observers’ subsequent diet preferences than the same diets experienced either on the anterior of a dead rat or the posterior of a live one. 相似文献
4.
Previous studies in our laboratory have demonstrated that a naive rat (an observer), after interacting briefly with a previously fed conspecific (a demonstrator), will exhibit an enhanced preference for the diet its demonstrator had been fed. The present studies were undertaken to determine whether demonstrator-induced alterations in observer diet preference were the result of simple exposure of observers to diet-identifying cues emitted by demonstrators during the period of demonstrator-observer interaction. Our results indicated that observer experience of diet-related cues in the stimulus context provided by the presence of a demonstrator was sufficient to enhance observer preference for a diet, whereas simple exposure to that diet was not. We concluded that demonstrator influence on observer diet preferences was not the consequence of simple exposure of observers to demonstrator-emitted cues reflecting demonstrators’ diet. 相似文献
5.
We fed demonstrator rats diets made by adding three, four, or five different flavorants to powdered Purina Rat Chow. We then allowed each of these demonstrator rats to interact with a naive observer rat for 30 min. We found that (1) observers exhibited enhanced preferences for many of the individual flavorants in the multiflavored diets that their respective demonstrators had eaten and (2) the probability of an observer exhibiting enhanced preference for an individual flavorant in its demonstrator’s diet decreased as the number of flavorants in that diet increased. In Experiment 2, the individual members of pairs of subjects were each fed one of two different four-flavored diets. The subjects in each pair interacted for 30 min, then each chose between two single-flavored diets. One of these single-flavored diets contained a flavorant in the four-flavored food that a subject had itself eaten; the other single-flavored diet contained a flavorant in the four-flavored diet that a subject’s partner had eaten. The subjects showed enhanced preferences for six of eight flavorants in the four-flavored diets that their respective partners had eaten. 相似文献
6.
Bennett G. Galef Brigitte Rudolf Elaine E. Whiskin Elena Choleris Marisa Mainardi Paola Valsecchi 《Learning & behavior》1998,26(4):448-454
In recent experiments in which the social influences on feeding in Mongolian gerbils were investigated, observer gerbils acquired food preferences from conspecific demonstrators only if the demonstrators and observers were either related or familiar. Even then, the effects of demonstrator gerbils on observers’ food choices lasted less than 24 h. In similar experiments with Norway rats, the familiarity/relatedness of demonstrators and observers had little effect on social learning, and the demonstrators’ influence on observers’ food choices lasted many days. We examined the causes of these differences and found that, after observer gerbils interacted with either unfamiliar or familiar conspecific demonstrators that had been fed using procedures typically used to feed demonstrator rats, they showed long-lasting social learning about foods, whereas observer rats interacting with conspecific demonstrators that had been fed as demonstrator gerbils normally are fed showed effects of familiarity/relatedness to demonstrators on their social learning about foods. Procedural differences, rather than species differences, seem to be responsible for reported inconsistencies in social learning about foods by rats and gerbils. 相似文献
7.
Three experiments were undertaken to examine the effects of interactions with demonstrator rats made ill by injection of lithium chloride (LiCl) on the later food choices of their observers. We found that (1) observer rats that had been taught an aversion to an unfamiliar diet exhibited a substantial reduction of that aversion after interacting with poisoned demonstrators that had eaten the diet to which the observers had learned an aversion, (2) exposure of an observer rat to poisoned demonstrator rats that had eaten a diet interfered with later acquisition by the observer of an aversion to the diet that the poisoned demonstrators had eaten, and (3) after interacting with poisoned demonstrators that had eaten one of two diets, observers that ate both diets and were then made ill formed an aversion to whichever diet their respective, poisoned demonstrators had not eaten. The present experiments, like previous studies both in our laboratory and elsewhere, failed to provide any evidence that naive observer rats will learn to avoid a food as a result of interacting with demonstrator rats that had eaten the food and exhibit symptoms of toxicosis. To the contrary, observer rats in the present experiments exhibited an enhanced preference for foods eaten by sick demonstrators. 相似文献
8.
Bennett G. Galef 《Learning & behavior》1987,15(3):327-332
In the present experiments, a naive “observer” rat first interacted with a “demonstrator” rat previously fed a diet unfamiliar to the observer. The observer then sampled two unfamiliar diets, one of which was the diet its demonstrator had eaten. The observer was then injected with LiCl and, following recovery from toxicosis, was offered a choice between the two diets it sampled prior to toxicosis induction. It was found that: (1) each observer rat formed an aversion to whichever diet its demonstrator had not eaten, (2) effects of demonstrators on aversion learning by observers were present even if there was a 7- or 8-day delay between interaction of a demonstrator and observer and diet sampling by the observer, and (3) observers interacting with 3 demonstrators, each fed a different diet, subsequently exhibited a reduced tendency to form an aversion to each of the diets eaten by their demonstrators. Taken together, the results indicate that information acquired from conspecifics as to the diets they have eaten can play an important role in determining the foods to which otherwise naive rats will learn aversions. 相似文献
9.
Following interaction with a “demonstrator” rat, an “observer” rat prefers that diet eaten by its demonstrator prior to their interaction (Galef & Wigmore, 1983). The present series of studies demonstrates that such demonstrator influence on observer diet preference can be found in: (1) first-generation laboratory bred wild rats as well as domesticated rats, (2) food-deprived as well as nondeprived observers, (3) unfamiliar as well as familiar demonstrator-observer pairs, (4) both 21-day-old and adult observers, and (5) rats selecting fluids as well as solids for ingestion. These data indicate that the social transmission of information concerning distant diets is a general and robust phenomenon, observable under a wide variety of experimental conditions. 相似文献
10.
Bennetf G. Galef 《Learning & behavior》1990,18(4):347-351
Rats that (1) either ate a small sample of one or two foods (Diet A or Diet B) or interacted with a demonstrator that had eaten either Diet A or Diet B, (2) ate both Diets A and B in succession, and (3) were made ill preferred whichever of the two foods they or their respective demonstrators had eaten. Although eating a food and interacting with a demonstrator that had eaten that food were each sufficient to enhance preference for the food, eating particles of food clinging to the fur of a demonstrator was not necessary for enhancement of preference for the food that a demonstrator ate. Subjects exposed to demonstrators they could not physically contact still exhibited enhanced preference for the food that their demonstrator had eaten. The data were discussed as indicating that although smelling a diet, eating a diet, and interacting with a demonstrator that had eaten a diet can each enhance preference for that diet, it cannot be inferred that eating a food, smelling a food, and interacting with a demonstrator that has eaten a food each affect diet preference via the same process. 相似文献
11.
Three experiments were conducted to investigate the social learning and transmission of food preferences by excretory marking among adult male Norway rats. The experiments extend our earlier findings that rats prefer to eat from a food bowl marked by the excretory deposits of conspecifics and that this mechanism can result in the communication and social learning of food preferences (Laland & Plotkin, 1991). Here we investigate whether a tradition of food and food site preferences can become established by these means. Experiment 1 established that the residual cues deposited by rats lose their powers of communication as “markers” of food sites over a 72-h period. Experiment 2 showed that while a socially enhanced preference for one flavored diet could be transmitted from one animal to the next along a chain, it was unstable for an alternative diet. This suggests that social transmission may be more stable when it reinforces a prior preference than when it conflicts with one. In Experiment 3, the stability of socially transmitted food preferences was bolstered by the addition of a second process for the communication of diet preferences-namely, gustatory cues on the demonstrator’s breath. This finding suggests that when a socially transmitted trait is mediated by more than one process, the processes may interact, and the diffusion is likely to be more stable. 相似文献
12.
Three experiments were conducted to determine whether a naive observer rat would avoid contact with a shock prod after watching a demonstrator rat contact, be shocked by, and defensively bury the prod. We found that observer rats took longer to contact prods that had delivered a shock to and been buried by a demonstrator rat than to contact prods that had not delivered shock and had not been buried. However, observer rats contacted prods buried by an unseen demonstrator rat or by an unseen experimenter with the same latencies as those for prods they had seen deliver shock to and be buried by a demonstrator rat. In large enclosures, subjects took 1–2 h longer to contact buried prods than to contact unburied prods. We conclude that alteration of the physical environment by individuals receiving noxious stimulation can significantly reduce the probability that conspecifics will contact the noxious stimulus. Observational learning per se, however, need not be involved. 相似文献
13.
Israel Ramirez 《Learning & behavior》1994,22(2):181-187
Rats were trained to associate artificial cherry or grape flavors with 1% starch suspensions. Conditioning was assessed by offering the rats a choice of the cherry versus grape flavors without starch. Conditioned preferences were moderately strong and persistent; 3 days of conditioning produced a preference that did not fully extinguish within 18 days. Food deprivation substantially increased intake of 1% starch suspension, However, the degree of preference conditioned was not influenced by the availability of food during the conditioning period; the rats that had been food deprived during training acquired as strong a preference as did those fed freely during training. The degree of preference obtained was similar in the rats given reinforcing and nonreinforcing fluids simultaneously or sequentially. Starch conditioned a slightly stronger preference than did the same concentration of glucose, even though these substances contain the same amount of calories. A statistically significant, but weak, preference was conditioned by 0.5%, but not by 0.25%, starch. It is proposed that the flavor of starch, independent of its calories, is reinforcing to rats. 相似文献
14.
A rat’s preference for food of a given flavor can be substantially enhanced by allowing it to interact with a conspecificdemonstrator that has recently eaten food of that flavor. The heuristic value of treating such socially induced enhancement of flavor preference as an instance of Pavlovian conditioning was examined in three experiments. Conceiving of the smell of the food as a conditional stimulus and other cues emanating from the demonstrator rat as an unconditional stimulus, we determined whether each of three common Pavlovian phenomena-blocking, overshadowing, and latent inhibition-would occur. Using experimental parameters that readily produce socially induced enhancement of flavor preference, none of the three Pavlovian phenomena were found. 相似文献
15.
In the bidirectional control procedure, observers are exposed to a conspecific demonstrator responding to a manipulandum in one of two directions (e.g., left vs. right). This procedure controls for socially mediated effects (the mere presence of a conspecific) and stimulus enhancement (attention drawn to a manipulandum by its movement), and it has the added advantage of being symmetrical (the two different responses are similar in topography). Imitative learning is demonstrated when the observers make the response in the direction that they observed it being made. Recently, however, it has been suggested that when such evidence is found with a predominantly olfactory animal, such as the rat, it may result artifactually from odor cues left on one side of the manipulandum by the demonstrator. In the present experiment, we found that Japanese quail, for which odor cues are not likely to play a role, also showed significant correspondence between the direction in which the demonstrator and the observer push a screen to gain access to reward. Furthermore, control quail that observed the screen move, when the movement of the screen was not produced by the demonstrator, did not show similar correspondence between the direction of screen movement observed and that performed by the observer. Thus, with the appropriate control, the bidirectional procedure appears to be useful for studying imitation in avian species. 相似文献
16.
Holland PC 《Learning & behavior》2005,33(4):464-478
Rats acquired aversions to food pellets when a previously trained signal for that food was paired with a toxin, but only after
minimal signal—food training. After extensive signal—food training, signal—toxin pairings had no effect on food consumption
even after manipulations that enhanced the associability of the signal. By contrast, conditioned responding to the signal
retained its sensitivity to devaluation of the food reinforcer by food—toxin pairings after extensive training. These results
suggest that the nature of associatively activated event representations changes over the course of training. 相似文献
17.
Rats trained to push a joystick to the left or right for food reward were given two successive tests in which neither response was reinforced. Prior to Test 1, subjects were either confined in the apparatus with a passive conspecific (Group None), or allowed to observe a conspecific demonstrator making 50 nonreinforced responses in the direction that had beeirrewarded during observer training (Group Same) or in the opposite direction (Group Different). In Test 1, Group Same made fewer previously reinforced responses than did Group Different, which made fewer than Group None, and Groups Same and Different each made fewer previously nonreinforced responses than did Group None. In Test 2, Group Same made fewer previously reinforced responses than did Group None. These results indicate that observation of nonreinforced responding can reduce resistance to extinction (Test 1) and spontaneous recovery (Test 2) in rats. 相似文献
18.
Visual cues have an important role in food preference for both rats and humans. Here, we aim to isolate the effects of numerosity, density, and surface area on food preference and running speed in rats, by using a forced-choice maze paradigm. In Experiment 1, rats preferred and ran faster for a group of multiple smaller pellets rather than a single large pellet, corroborating previous research (Capaldi, Miller, & Alptekin Journal of Experimental Psychology: Animal Behavior Processes, 15(1), 75–80, 1989). Further experiments tested the prevailing hypothesis that multiple food pieces are more reinforcing because they occupy a larger surface area. Experiment 2 controlled for numerosity by utilizing a continuous food: mashed potatoes flattened to cover a larger surface area or rounded into a ball. The rats preferred and ran faster for the flattened potatoes, suggesting surface area plays a role in quantity estimations. Finally, in Experiment 3, rats displayed no preference or difference in running speed between a group of scattered and clustered pellets when number of pellets were kept constant. Taken together, these results suggest that density has an important role in food perception—that is, the rewarding effect of higher numerosity or larger surface area is removed when the food does not fill out the entire space. Alternative explanations and implications for human diet are discussed. 相似文献
19.
Bennett G. Galef 《Learning & behavior》1985,13(4):415-418
I examined the capacity of a socially induced enhanced diet preference to reverse the effects of a LiCl-induced diet aversion. I found that rats poisoned after eating a novel diet (Diet NPT) would consume substantial amounts of Diet NPT following interaction with a conspecific that had eaten Diet NPT. Neither rats interacting with a conspecific fed some other diet nor rats exposed to Diet NPT itself exhibited reduced aversion to Diet NPT. This surprising capacity of social interaction to ameliorate even profound toxicosis-induced aversions suggests that social influence may be a major experiential determinant of the diet preferences of free-living rats. 相似文献
20.
Adult male Norway rats were tested in a first experiment to see whether foraging efficiency could be improved by social learning. Observers were placed in one of four conditions in which they were paired with demonstrators that either had or had not been previously trained to dig for buried carrot pieces, and in which the demonstrators either did or did not have carrot buried in the experimental enclosure. Observers in the group with trained demonstrators that did have carrot pieces buried in the experimental area during the observation period subsequently unearthed more buried carrot, did so more rapidly, and were generally more active than were the observers in the other three groups. In a second experiment, chains of transmission were established by allowing each observer to act as a demonstrator for the next naive observer. Enhanced levels of digging behavior were maintained across eight transmission episodes in three transmission groups relative to a no-transmission control group, the performance levels becoming stable after five transmission episodes at a level significantly above that of the control group. The study demonstrates that social learning and transmission mechanisms exist which might result in the diffusion of certain patterns of behavior through populations of Norway rats. 相似文献