共查询到20条相似文献，搜索用时 46 毫秒
1.
William H. Overman Carol McLain Gail E. Ormsby Virginia Brooks 《Learning & behavior》1983,11(4):483-488
Squirrel monkeys (Saimiri sciureus) were trained on visual recognition memory tasks in a Wisconsin General Testing Apparatus with a trial-unique procedure that used 250 objects as stimuli. In Experiment 1, acquisition of a trial-unique delayed non-match-to-sample task (DNMS) was compared with acquisition of a trial-unique delayed match-to-sample (DMS) task. The DNMS task was learned in significantly fewer trials and with significantly fewer errors. Two animals in the DNMS group demonstrated highly accurate retention of the DNMS strategy despite an 11-month hiatus in experimental testing. In Experiment 2, the same procedures were used to study the learning of lists of 3, 5, 10, or 20 serially presented items. Although the animals were able to accurately remember lists of up to 20 items, there was no evidence of serial position effects. 相似文献
2.
The effect of stimulus rotation was assessed in four Guinea baboons (Papio papio), using pictures of familiar human faces presented in a computerized go/no-go task. In Experiment 1, 2 baboons were initially trained to discriminate upright faces, and 2 others were trained to discriminate upside-down faces. For the two groups, postlearning discrimination was impaired when the training faces were rotated 180°. In Experiment 2, upright and upside-down priming faces appeared prior to the display of target faces. For the two groups, response times were faster when the prime and the target faces had the same orientations than when they were depicted under different orientations. Finally, Experiments 3 and 4 identified variations in facial contours as the most salient discriminative cue controlling performance in 2 baboons. Altogether, our results provide no evidence that the baboons processed the pictures as representations of faces. It is suggested that the effect of rotation derived from the encoding of the pictorial faces as meaningless mono-oriented shapes, rather than as natural human faces. 相似文献
3.
Three different techniques were employed to analyze the associative structures mediating performance on an instrumental biconditional discrimination. In all three experiments, rats were trained concurrently on two tasks in which different stimuli signaled which one of two responses would be followed by reward. In each task, one response was rewarded in one stimulus and the other response was rewarded in the other stimulus. Correct responses earned pellets in one task and sucrose in the other task. The transfer procedure was used in Experiment 1A to identify whether or not an association developed between a biconditional discriminative stimulus and its instrumental outcome. Evidence was obtained that a biconditional cue elevated preferentially a new response trained with the same outcome. Experiments 1B and 3 examined the potential contribution of this stimulus-outcome association to biconditional performance by training the biconditional cues as signals (S-s) for the nonreinforcement of a different response. There was no evidence that this operation interfered with the ability of a biconditional cue to control performance of its correct response. In Experiments 1B and 2, the value of the instrumental outcome was reduced in an attempt to assess the contribution of stimulus-response associations to performance on the biconditional discrimination. The results of Experiments 1B and 2 reveal that correct responses were depressed following devaluation of the outcome used to train them, suggesting that learning about the response-outcome relation occurs. The implications of these results for binary and hierarchical models of instrumental learning are discussed. 相似文献
4.
Heather Macintosh Schellinck Burton M. Slotnick Richard E. Brown 《Learning & behavior》1997,25(2):193-199
Male Long-Evans rats were trained to discriminate between the urine odors of two congenic strains of rats (PVG and PVG.R1) in an olfactometer on a go/no-go operant task with water reinforcement. These odor donors differ genetically at only one locus of the major histocompatibility complex (MHC). The ability of the subjects to transfer their training to discriminate between novel individuals of the same MHC strain on the same and different diets was then examined. The subjects correctly generalized their original training to new samples from previously undiscriminated individuals of the same MHC type on the same diet without a significant drop in performance. A change in diet disrupted the perception of the MHC-related odor. In a second experiment, rats were trained to discriminate between the odors of pairs of genetically identical PVG or PVG.R1 rats on different diets and were tested for generalization using the odors of rats of the other strain (PVG.R1 or PVG) maintained on the same diet. Changing the strain of the odor donor did not disrupt the learned discrimination. The results of these two experiments confirm the ability of the MHC to generate constant cues in the urine but also reveal that variable diet cues disrupt the perception of these cues. The relationship between the MHC, diet, and other factors in determining individual odors is discussed. 相似文献
5.
In three experiments, pigeons were trained to discriminate between uniform arrays of two elements that differed in color, form, or size. They were then tested with arrays that contained different proportions of the two elements on these dimensions. In all cases, orderly discrimination gradients reflected these proportions. The discrimination readily transferred to new arrays with similar stimuli, but with different total numbers of elements. In Experiment 4, the pigeons were taught to discriminate between two groups of categorical stimuli: pictures of birds and pictures of flowers. A test with different proportions of each again produced a gradient based on relative numerosity. Experiment 5 demonstrated transfer of stimulus control on the numerosity dimension when pigeons were trained with one set of instances from two categories, and then were tested with new instances from the same categories. 相似文献
6.
Honeybees were trained to discriminate between simultaneously presented color-odor compounds, one group with color and odor confounded and a control group with color relevant and odor irrelevant; in subsequent differentially reinforced training with the colors in the absence of the odors, the performance of the two groups was the same (Experiment 1). When, however, response to the colors was measured in a 10-min extinction test, discrimination was found to be poorer after confounded training (Experiment 2), and like results were obtained in an extinction test with the odors after control animals had been trained with odor relevant and color irrelevant, the confounded animals showing poorer discrimination of the odors than the controls (Experiment 3). The results of the first two experiments, in which overshadowing of color by odor was found only with an extinction test, require us to take seriously the possibility that our previous modeling experiments (with probability of correct choice in differentially reinforced training as the measure of performance) may have been insufficiently sensitive to noncontinuity effects. Our first efforts to model extinction suggest, however, that all the results of the present experiments can be understood without sacrifice of the parsimonious independence principle. 相似文献
7.
The ability of visual CSs previously paired with flavored substances to substitute for those substances as conditional discriminative cues was examined in two Pavlovian appetitive conditioning experiments using rat subjects. In Experiment 1, a visual stimulus was first paired with the delivery of a sucrose solution. Then the rats were trained in conditional discrimination tasks in which sucrose delivery alone served as a conditional cue signaling whether or not a subsequent tone would be reinforced with food pellets. Subjects rapidly acquired discriminative performance to the tones, especially in a feature-negative condition in which sucrose delivery signaled when the tone would not be reinforced. In a subsequent test in which neither food nor sucrose was delivered, presentation of the visual CS also controlled discriminative performance to subsequently presented tones. Experiment 2 showed the ability of a visual CS to substitute for a flavored substance as a conditional cue to be highly stimulus specific. Experiment 2 also showed that a flavored substance was less effective as a conditional cue when it was made to be expected by preceding it with a previously associated visual signal than when it was made to be surprising by preceding it with a visual stimulus signaling another flavored liquid. These results indicate that CS-evoked representations of events can substitute for those events themselves in the control of previously established conditional discrimination performance. 相似文献
8.
In two experiments, we examined how preexposure to discriminative stimuli and introduction of a 21-day retention interval
affected the latent inhibition (LI) and perceptual learning (PL) of rats in a choice-maze discrimination task. Experimental
groups were preexposed to three wall patterns, one in each of three arms of a maze. Control groups were preexposed only to
white arms. PL groups were trained to discriminate A versus B, and LI groups, to discriminate A or B versus C. The A and B
patterns shared many elements not shared with the C pattern. In Experiment 1, both at the end of training and after the subsequent
retention interval, the PL groups performed better than controls, whereas the LI groups performed worse. In Experiment 2,
inserting the 21-day retention interval between preexposure and discrimination training disrupted final measures of LI but
not PL performance. Implications for current concepts of PL and LI are discussed. 相似文献
9.
Two experiments are reported comparing performance in dominant and submissive rats as determined by a food-competition procedure. Ss in Experiment I were either trained to criterion or overtrained before being reversed on a visual discrimination task. Although the two groups did not differ significantly in learning the initial task, the dominant Ss were significantly slower on reversal than the submissives. Experiment II, which utilized a tandem runway, showed that when the reinforcer which maintained the running response was not available in the first goalbox, submissive rats responded with a greater increase in running speed in the second runway than dominant rats. These findings were discussed as reflecting motivational differences between dominant and submissive rats. 相似文献
10.
In three experiments, we examined pigeons’ recognition of video images of human faces. In Experiment 1, pigeons were trained
to discriminate between frontal views of human faces in a go/no-go discrimination procedure. They then showed substantial
generalization to novel views, even though human faces change radically as viewpoint changes. In Experiment 2, the pigeons
tested in Experiment 1 failed to transfer to the faces dynamically rotating in depth. In Experiment 3, the pigeons trained
to discriminate the dynamic stimuli showed excellent transfer to the corresponding static views, but responses to the positive
faces decreased at novel viewpoints outside the range spanned by the dynamic stimuli. These results suggest that pigeons are
insensitive to the three-dimensional properties of video images. Consideration is given to the nature of the task, relating
to the identification of three-dimensional objects and to perceptual classifications based on similarity judgments. 相似文献
11.
These experiments examined one way in which the allocation of attentional resources can change performance during a visual discrimination task. Pigeons were trained to discriminate visual forms under conditions that produced dimensional contrast. In three experiments, negative training stimuli differed from positive stimuli either along a primary physical dimension alone or along both a primary dimension and an orthogonal dimension. When a negative stimulus differed from positive stimuli along two dimensions, discrimination of that negative stimulus improved. For one type of visual form, discrimination of the positive stimuli declined with orthogonal variation in a negative stimulus, whereas for other visual forms, there was no decline in performance. These results are consistent with a model of dimensional contrast that suggests that differences in the allocation of attentional resources determine discrimination performance. The results also indicate that the organization of stimulus dimensions plays a crucial role in the allocation of attentional resources in these settings. 相似文献
12.
Within-session changes in responding during delayed matching-to-sample and discrimination procedures
Two experiments examined within-session changes in responding during discrimination procedures. In Experiment 1, rate of responding changed significantly within sessions during symbolic delayed matching-to-sample tasks when the delay between the stimulus and the choice period was short (1–5 sec), but not when it was long (8–12 sec). The percentage of responses that were correct did not change within sessions. In Experiment 2, response rates increased and then decreased within sessions during both S1 and S2 when successive discrimination procedures provided high, but not low, rates of reinforcement. Discrimination ratios sometimes increased within sessions. These results question two potential definitions of attention as explanations for within-session changes in response rates. They are more compatible with explanations based on concepts such as arousal, satiation, habituation, and interfering responses. 相似文献
13.
Heather Macintosh Schellinck Richard E. Brown Burton M. Slotnick 《Learning & behavior》1991,19(3):223-233
To determine the influence of genetic and microbiological factors in producing individually unique urine odors, we used a go/no-go operant task to assess the ability of eight male Long-Evans rats to discriminate between urine odors from the following pairs of male rats: (1) two outbred Long-Evans rats, (2) individual conventionally housed rats differing genetically only at the major histocompatibility complex (PVG vs. PVG.R1), (3) individual PVG versus PVG.R1 rats born by cesarean section and raised in germfree conditions, and (4) conventionally housed, genetically identical individuals of the PVG or PVG.R1 strains. Discriminable differences were present between the urine odors used in all four tasks. Analysis of the errors to a criterion of 85% correct discrimination responses revealed different learning patterns in each task. When bacteria were not present in genetically different rats (Task 3) and when bacteria were present but there were no genetic differences between rats (Task 4), the discrimination was the most difficult. The easiest discrimination involved the presence of bacteria and a genetic difference at the major histocompatibility complex (Task 2). These results indicate that, although bacteria are not necessary for the production of discriminable odor differences, they do influence the discriminability of the urine odors of rats. 相似文献
14.
The Dynamics of Preschoolers' Categorization Choices 总被引：1，自引：0，他引：1
The present research explored the effects of stimulus and task factors on preschoolers' (Experiments 1 and 3) and adults' (Experiment 2) tendency to categorize according to taxonomic relations, when those relations conflict with appearances. In Experiment 1, we examined the effects of and interactions among ( a ) available information, operationalized by using more- or less-informative stimulus types (objects vs. line drawings) and by the presence or absence of labeling, and ( b ) task constraints, operationalized by comparing sorting questions with inductive inferences questions. When provided with information that constrained the categorization decision, either through the availability of labels or a combination of enhanced physical informativeness of objects and an inference question, preschoolers reliably based their categorization decisions on taxonomic relations between physically dissimilar items. In Experiment 2, stimulus type (objects vs. line drawings) was shown to have a similar effect on adults. In Experiment 3, we examined the effects of stimulus type on preschoolers' inductive inferences and accuracy of naming. The effects in the two tasks were closely related, suggesting that the amount of available information affects different responses in similar ways. These data demonstrate the interactive effects of available information and task constraints on categorization decisions. 相似文献
15.
In two experiments, we investigated the impact of odor preexposure treatments on the acquisition of an olfactory discrimination in dogs. In the first experiment, four groups of dogs were each given five days’ odor-exposure treatment prior to discrimination training. Dogs in the exposure group were exposed to anise extract (S+) for 30 min daily. Dogs in the Pavlovian-relevant pairing group received six daily delayed-conditioning trials to the same S+. The Pavlovian-irrelevant pairing group received conditioning trials to almond extract (S'). Dogs in the control group received no pretreatment. All of the dogs were then trained to detect S+ from a background pine odor (an AX-vs.-X discrimination). The Pavlovian-relevant pairing group acquired the odor discrimination significantly faster than all of the other exposure and control groups, and the remaining groups acquired the discrimination at the same rate as the no-exposure control group. In a second experiment, we extended these results to a within-subjects design using an AX-versus-BX discrimination. Six dogs were simultaneously trained on two different odor discriminations, one discrimination in which the S+ was previously Pavlovian conditioned, and one discrimination in which the S+ was novel. All of the dogs learned the odor discrimination with the previously conditioned S+ faster than they learned the novel odor discrimination, replicating the results of Experiment 1, and demonstrating that familiarity in the form of Pavlovian conditioning enhances odor-discrimination training. The potential mechanisms of the facilitated transfer of a Pavlovian conditioned stimulus to discrimination training are discussed. 相似文献
16.
Thomas H. Turney 《Learning & behavior》1976,4(4):363-366
Long-Evans rats were trained on an easy simultaneous discrimination problem and then transferred to a hard discrimination problem. The discriminanda were different orientations of stripes. In Experiment I, transfer was intradimensional with stimulus generalization controlled. The easy-to-hard effect was not found. In Experiment II transfer was intradimensional and either compatible (nonreversal) or incompatible (reversal). With compatible transfer, rats trained on a prior easy problem learned the hard problem faster than rats trained only on the hard problem. Persistent negative transfer was found with incompatible transfer. Attention was not supported as underlying the easy-to-hard effect. Explanations based on specific sources of intradimensional transfer, such as stimulus generalization or adaptation level, are suggested. 相似文献
17.
Visual illusions are objects that are made up of elements that are arranged in such a way as to result in erroneous perception of the objects’ physical properties. Visual illusions are used to study visual perception in humans and nonhuman animals, since they provide insight into the psychological and cognitive processes underlying the perceptual system. In a set of three experiments, we examined whether dogs were able to learn a relational discrimination and to perceive the Müller-Lyer illusion. In Experiment 1, dogs were trained to discriminate line lengths using a two-alternative forced choice procedure on a touchscreen. Upon learning the discrimination, dogs’ generalization to novel exemplars and the threshold of their abilities were tested. In the second experiment, dogs were presented with the Müller-Lyer illusion as test trials, alongside additional test trials that controlled for overall stimulus size. Dogs appeared to perceive the illusion; however, control trials revealed that they were using global size to solve the task. Experiment 3 presented modified stimuli that have been known to enhance perception of the illusion in other species. However, the dogs’ performance remained the same. These findings reveal evidence of relational learning in dogs. However, their failure to perceive the illusion emphasizes the importance of using a full array of control trials when examining these paradigms, and it suggests that visual acuity may play a crucial role in this perceptual phenomenon. 相似文献
18.
In multiple fixed interval (FI) schedules, rats are trained to discriminate different FIs that are signaled by different stimuli. After extensive training, the different stimuli often acquire control over performance, observed by an earlier increase in responding for stimuli that signal shorter FIs, as compared with stimuli that signal longer FIs. The order in which the different FIs are trained, either intermixed across cycles or in blocks of several cycles, may seem irrelevant given that average performance at asymptote may be similar. In this study, rats were trained in two procedures with multiple FIs presented intermixed within sessions or in blocks of one interval per session. Similar performance was observed at asymptote, but an inspection of early cycles in each session revealed that different stimuli acquired control over performance only when trained intermixed within each session. Although the stimuli reliably signaled the upcoming FI, when trained in successive blocks of 60 cycles, rats rapidly adjusted performance early in the sessions on the basis of the temporal aspects of the task, and not on the basis of the stimulus presented in the current cycle. These results are discussed in terms of overshadowing of the stimuli by temporal cues and in terms of conditions under which a stimulus acquires control over performance. 相似文献
19.
An attempt was madeto manipulate the strength of internal stimulus representations by exposing pigeons to brief delays between sample offset and comparison onset in a delayed conditional discrimination. In Experiment 1, pigeons were first trained on delayed conditional discrimination with either short (0.5-sec) delays or no delays. When delays were increased by 2.0 sec, birds trained with a delay performed at a higher level than did birds trained with no delays. In Experiment 2, subjects were first trained on a delayed simple discrimination. Following a circle stimulus, responses to a white key were reinforced; however, following a dot stimulus, responses to the white key were not reinforced. The pigeons were then trained on a delayed conditional discrimination involving hue samples and line-orientation comparisons with differential outcomes. Choice of vertical following red yielded food; choice of horizontal following green yielded no food. Mixed delays were then introduced to birds in Group Delay, whereas birds in the control group received overtraining. When tested on a delayed simple discrimination with hue stimuli (red and green initial stimuli followed by white response stimulus), pigeons in Group Delay tended to perform at a higher level than did birds in the control group (i.e., although the birds in both groups responded more following red than following green, birds in Group Delay did this to a greater extent than did birds in the control group). Thus, experience with delays appears to strengthen stimulus representations established during training. 相似文献
20.
Shigeru Watanabe 《Learning & behavior》1997,25(2):185-192
Pigeons were trained on two visual discrimination tasks. One task was discrimination between real objects and their photographs. Training stimuli consisted of real food (grains), photographs of food, and nonedible junk objects and their photographs. The other task was discrimination between food and nonfood using the same stimuli as those in the first task. The pigeons learned either task and showed generalization of these classifications to novel stimuli. These results suggest that pigeons can either discriminate or integrate real stimuli and their photographs. Bilateral ectostriatal lesions caused deficits in food versus nonfood discrimination, but not in object versus picture discrimination. This dissociation suggests different brain mechanisms between the two visual discriminations using the same stimuli. 相似文献