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1.
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
2.
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
3.
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
4.
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
5.
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
6.
Immediately after a recently fed rodentdemonstrator interacts with a conspecificobserver, the observer shows a substantially enhanced preference for whatever food its demonstrator ate. Here we show that (1) influence
of a single, 30-min interaction with a demonstrator on an observer’s food preference lasts for at least 1 month, and (2) observers
interacting on 2 successive days with a demonstrator fed a different diet on each day show significantly enhanced preferences
for both diets a month later. Such enduring effects of single, brief interactions between a demonstrator rat and its observer
provide an efficient means for studying physiological and behavioral substrates of long-term memory in rodents. Together with
the results of previous studies of social influences on food choices of rats, the present results also suggest that rats may
use information acquired from conspecifics to identify both toxic and safe foods for many weeks after they have acquired this
information. 相似文献
7.
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
8.
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
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.
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
11.
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
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.
Different types of social relationships can influence individual learning strategies in structured groups of animals. Studies on a number of avian species have suggested that local and/or stimulus enhancement are important ingredients of the respective species’ exploration modes. Our aim was to identify the role of enhancement during object manipulation in different social contexts. We used focal observations to identify a linear dominance hierarchy as well as affiliative relationships between individuals in a group of 14 Goffin’s cockatoos (Cacatua goffiniana, formerly goffini). Thereafter, in an unrewarded object choice task, several pairs of subjects were tested for a possible influence of social enhancement (local vs. stimulus) in three conditions: dominance, affiliation, and kinship. Our results suggest strong individual biases. Whereas previous studies on ravens and kea had indicated that enhancement in a non-food-related task was influenced by the social relationship between a demonstrator and an observer (affiliated – nonaffiliated), we found no such effects in our study group. In this context, Goffin’s cockatoos’ object learning seems to take place more on an individual level, despite their generally high motivation to manipulate nonfood items. 相似文献
14.
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
15.
Bennett G. Galef 《Learning & behavior》1989,17(4):468-474
After interacting with rat demonstrators that had eaten a novel, palatable diet, many observer rats exhibited either attenuation or total blockade of their subsequent acquisition of a lithium-chloride-induced aversion to that diet. In natural circumstances, such social attenuation of aversion learning could prevent new recruits to a population (weanlings or recent immigrants) from learning maladaptive aversions (“food phobias”) to tainted or spoiled samples of normally safe foods that others of their social group were eating. 相似文献
16.
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
17.
Liu WM Lai SJ Lu LZ Shi FX Zhang J Liu Y Yu B Tao ZR Shen JD Li GQ Wang DQ Li JJ Tian Y 《Journal of Zhejiang University. Science. B》2011,12(9):736-743
The effects of different fatty acid (FA) contents in diet on serum parameters, FA compositions of eggs and meat, and liver morphological changes were studied in Shaoxing laying ducks. A total of 264 ducks at 17 weeks were fed a control diet or a diet containing 30 g/kg fish oil (FO), 25 g/kg sunflower oil (SO), or 30 g/kg palm oil with 20 g/kg beef tallow (PBO). Malondialdehyde (MDA) content in the liver and the serum of ducks fed the PBO diet was significantly (P<0.05) higher than that of ducks fed the other diets. Triglyceride (TG) and total cholesterol (TC) levels were significantly lower (P<0.05) in ducks fed the FO diet. Serum TC also was lower in ducks fed the SO diet. Superoxide dismutase (SOD) activity was also affected by diets. The contents of polyunsaturated FAs (PUFAs) in eggs and meat were significantly higher (P<0.001) in ducks fed the FO and SO diets than in ducks fed the control diet. The level of C22:6 (n-3) FA in ducks fed the FO diet was significantly higher than that in ducks fed the other diets. However, the conversion efficiency of the longer-chain C20:5 (n-3) FA was higher than that of C22:6 (n-3). Ducks fed the PBO diet exhibited lipid droplet accumulation in the liver. These results demonstrate that a diet enriched with different FAs has strong effects on serum lipid levels and the deposition of PUFAs into tissue lipids. 相似文献
18.
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
19.
Peter Davies 《牛津教育评论》2019,45(1):1-31
We present an analysis of A-level subject choices at around age 16 for a cohort of students in English schools who completed their studies in 2014. We examined both the National Pupil Database and a unique rich dataset on the subject preferences and subsequent choices between the ages of 16 and 18 (i.e. GCSE and A-level). We found substantive differences between students’ preferences and actual choices of ‘hard’ and ‘soft’ post-16 subjects (i.e. A-level). These differences were strongly associated with falsification of students’ expectations of examination grades taken at age 16 (i.e. GCSE) in the core subjects of English and mathematics. The sizes of these falsification effects were much larger than other significant associations such as gender, ethnicity, and social class. This suggests that subject choices are not rigidly framed by stable individual preferences and they are therefore open to influence from new information, persuasion, and opportunities. 相似文献
20.
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