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1.
In the present experiment, we investigated whether pigeons rely exclusively on elemental information or whether they are also able to exploit configural information in apeople-present/people-absent discrimination task. Six pigeons were trained in a go/no-go procedure to discriminate between 800 color photographs characterized by the presence or absence of people. Thepeople-present stimuli were designated as positive, and thepeople-absent stimuli were designated as negative. After training and a subsequent generalization test, the pigeons were presented with both familiar and novel people-present stimuli containing human figures that were distorted in one of seven different ways. All the pigeons learned the initial discrimination and also showed generalization to novel stimuli. In the subsequent test, performance on all types of distorted stimuli was diminished in comparison with that on the intact original pictures from which they had been derived. At the same time, however, peck rates clearly exceeded the level of responding found for regular people-absent stimuli. This result strongly suggests that responding was controlled by both the constituting target components and their spatial relations and, therefore, points to the dual importance of elemental and configural information.  相似文献   

2.
FourCebus albifrons monkeys received 24 sessions of multiple avoidance-punishment conditioning of the skin conductance response (SCR) with no discriminative stimuli, followed by 24 additional sessions with visual discriminative stimuli identifying the avoidance and punishment components. Four other monkeys that had previously been conditioned with the discriminative stimuli were given 24 additional sessions without them. Yoked controls were run with this group and received the electric shock noncontingently. The presence of the discriminative stimuli clearly facilitated acquisition and maintenance of higher SCR frequencies in avoidance as compared with punishment. Acquisition was retarded with the stimuli absent, and higher overall response levels resulted. Adding the stimuli improved differentiation and resulted in lower overall rates. Removing the stimuli likewise resulted in higher response frequency. When the stimuli were absent initially, higher shock frequencies were administered, and when they were removed, shock frequency increased. The yoked controls increased in response frequency but did not differentiate between the avoidance and punishment conditions. Overall, the presence of the stimuli appeared to facilitate differentiation and reduce trauma, as compared with when they were absent.  相似文献   

3.
The delayed matching-to-sample (DMTS) task was used in three experiments to investigate how pigeons code information about sample stimuli. In all experiments, each trial consisted of a signaled presentation of a sample stimulus for a fixed duration followed, after some delay, by the presentation of three comparison stimuli. After incorrect first choices, the bird was allowed a second choice between the remaining two stimuli. It was found, in Experiment 1, that the probability of a second choice error declined with increasing sample duration. This result is consistent with a gradual short-term memory encoding process but not with a simple two-state all-or-none process. In the second experiment, it was found that the distribution of first-choice errors was affected by the particular sample occurring on a trial. This result is inconsistent with a two-stage discrete state memory/attention model based on the assumption that encoding of the sample and attention to the comparison stimuli are both independent all-or-none processes. The third experiment involved symbolic DMTS, in which the sample stimuli varied along a dimension different from that along which the comparison stimuli varied. With increasing delay between sample and comparison stimulus presentations, the pigeons were more likely to confuse test stimuli than to confuse sample stimuli. The results of these experiments lead to the conclusion that pigeon DMTS performance depends on a gradual encoding process in which a representation isomorphic with the test stimuli is generated and maintained.  相似文献   

4.
In their everyday communication, parents do not only speak but also sing with their infants. However, it remains unclear whether infants' can discriminate speech from song or prefer one over the other. The present study examined the ability of 6‐ to 10‐month‐old infants (N = 66) from English‐speaking households in London, Ontario, Canada to discriminate between auditory stimuli of native Russian‐speaking and native English‐speaking mothers speaking or singing to their infants. Infants listened significantly longer to the sung stimuli compared to the spoken stimuli. This is the first study to demonstrate that, even in the absence of other multimodal cues, infant listeners are able to discriminate between sung and spoken stimuli, and furthermore, prefer to listen to sung stimuli over spoken stimuli.  相似文献   

5.
Three experiments demonstrated Pavlovian appetitive discrimination learning in the marine mollusc,Aplysia californica. In each experiment, subjects were exposed to two conditioned stimuli; one stimulus (CS+) was paired with food presentations and the other stimulus (CS?) was never followed by food. In Experiments 1 and 3 different chemosensory stimuli were used, and in Experiment 2 different tactile stimuli were used. For both types of conditioned stimuli, bite responses occurred significantly more often to the CS+ than to the CS?. Experiment 2 also showed thatAplysia could learn a reversal of this discrimination. Experiment 3 showed that nonreinforced presentations of CS+ resulted in a decline in the frequency of conditioned biting. The implications of these results for neurobiological analyses of learning are discussed.  相似文献   

6.
Introduction: Multi-sensory storytelling (MSST) is a storytelling method designed for individuals with profound intellectual and multiple disabilities (PIMD). It is essential that listeners be alert during MSST, so that they become familiar with their personalised stories. Repetition and the presentation of stimuli are likely to affect the alertness of listeners during MSST. Previous studies have only examined the overall level of alertness during MSST. This study focuses on changes in alertness over time during storytelling. Method: In this study, 27 direct support people read an MSST book 20 times with a person with PIMD. The 1st, 5th, 10th and 20th storytelling sessions were recorded. The relation between alertness and the active presentation of stimuli is analyzed using a time-window sequential analysis. We examined changes in alertness levels by comparing the four different storytelling sessions. Results: Higher levels of active alertness were observed when stimuli were actively presented. Alertness was not constant within storytelling sessions, and was related to the presentation of stimuli. Actively presented stimuli were associated with larger fluctuations in alertness. Discussion: Storytellers should present stimuli actively and for longer periods, in order to increase the alertness of listeners during storytelling.  相似文献   

7.

Current approaches emphasize the control exercised over behavior by various internal stimuli arising from goal events such as reward and nonreward. In contrast, certain earlier views emphasized the behavioral control exercised by internal stimuli arising from responding. The purpose of the three experiments reported here was to determine if stimuli arising both from goal events and from response events control instrumental behavior, and, if so, how much behavioral control is exercised by each. In the three experiments reported, rats received partial reinforcement in a runway either at a 24-h ITI or at both a 24-h ITI and a shorter ITI (2 min, 15 min, 30 min, or 1 h), with extinction always occurring at the shorter ITI. The results suggest that both goal-produced and response-produced internal stimuli control behavior simultaneously. Too, it was found that at ITIs as long as 30 min, response-produced cues regulate responding about as strongly as goal-produced cues.

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8.
Many attitudes are acquired in early childhood. However, due to a lack of experimental research, little is known about the processes of how they are acquired. Two experiments were therefore conducted with 153 German kindergarten children aged 3–6 years that provide first evidence for childhood attitude formation in terms of evaluative conditioning. Specifically, it was found that children preferred novel stimuli previously paired with liked stimuli over novel stimuli previously paired with disliked stimuli. This effect occurred independently of age, generalized toward similar novel stimuli, and did not depend on children's recollection of how stimuli were paired. The findings are discussed in terms of the processes underlying childhood attitude formation, and implications for related research areas are highlighted.  相似文献   

9.
Two pigeons matched to sample in a three-key operant conditioning chamber. In Experiment I, two different kinds of samples were presented on the center key.Element samples were members of one of two sample sets — colors (a red or blue disk) or lines (a vertical or horizontal orientation of a set of white lines). These samples were followed by their respective sample sets on the side keys as comparison stimuli.Compound samples consisted of a set of lines superimposed on a colored disk. Following these samples, either sample set could appear as comparison stimuli. Matching to compound samples was less accurate than matching to element samples. One interpretation is that sharing of attention among elements of a compound sample weakened stimulus control by each element. A different interpretation is that an element sample controlled matching better because it was physically identical to a comparison stimulus whereas a compound sample was not. Experiments II–IV evaluated this “generalization decrement” alternative by testing element- vs. compound sample control with both element and compound comparison stimuli. Irrelevant elements were added to form compound comparison stimuli, some of which were physically identical to a preceding compound sample, but never identical to an element sample. In all experiments, the addition of irrelevant elements of comparison stimuli reduced sample control. However, the generalization decrement hypothesis failed to predict how differences in performance maintained by element and compound samples were affected by different tests of sample control. Matching accuracy appeared to be independently determined by the number of elements in a sample and whether irrelevant elements were present during tests of sample control.  相似文献   

10.
Short-term memory (STM) for haptic information was examined in a delayed matching-to-sample (DMTS) task. Three rhesus monkeys were tested in DMTS with all possible combinations of different-size spheres and cubes as the sample and comparison stimuli. The results showed that the decrease in percentage correct as a function of the retention intervals was relatively independent of the size and shape of the sample and comparison stimuli. In general, at each retention interval, percentage correct was higher when the (1) comparison stimuli differed in both size and shape than when the comparison stimuli differed in only size or shape, (2) size differences between the comparison stimuli increased, and (3) samples were spheres rather than cubes. This pattern of results suggests that dimensions of the haptic stimuli influenced discrimination but had little effect on the animals’ STM. In Experiment 2, the same three monkeys responded to the sample and comparison stimuli with the same hand or responded to the sample with one hand and the comparison stimuli with the opposite hand. The decrease in percentage correct across retention intervals was comparable for all possible hand combinations. These results suggest that the loss of information from STM is comparable when the sample and comparison stimuli are both felt with the same hand or with opposite hands.  相似文献   

11.
Play-solicitation and social investigatory behaviors were observed in male and female juvenile rats exposed to playful and nonplayful juvenile social stimuli. A nonplayful state was induced by treatment with scopolamine HBr. In Experiment 1, the play-solicitation behavior of males exposed to nonplayful stimuli was reliably greater than that of females; social investigation did not differ by gender. In Experiment 2, males and females were exposed to nonplayful male and female stimuli. Male subjects engaged in more soliciting than did female subjects, and male social stimuli were subjected to more soliciting than were female social stimuli. Experiment 3 compared the influence of varying social deprivation intervals on play soliciting by male juveniles. Although social investigation did not vary reliably with interval of social deprivation, play soliciting increased reliably with longer intervals of isolation. In Experiment 4, play-soliciting behavior of males exposed to nonplayful males correlated positively and reliably with play fighting behavior upon exposure to normally playful males. The results support the proposal that some specific behaviors functionally provoke interactive play fighting.  相似文献   

12.
Within-trial contrast has been proposed as a mechanism underlying preferences for stimuli that follow relatively more aversive events over stimuli that follow less aversive events. In this study, we manipulated deprivation level to test within-trial contrast predictions. In Experiment 1, pigeons encountered two discriminative stimuli, one presented when they were deprived and the other when they were prefed. When later given a choice between the two stimuli, pigeons strongly preferred the stimulus encountered when deprived, independently of their deprivation level at test. In Experiment 2, pigeons learned two simultaneous discriminations, one when deprived and the other when prefed. Here, subsequent tests between the two S+ or the two S− stimuli revealed no consistent preferences. These contrasting findings suggest that differential aversiveness is necessary but not sufficient to induce preferences via within-trial contrast.  相似文献   

13.
Rats received pairings of two stimuli with reward noncontingently in the Skinner box. During noncontingent pairings, the bar was immobilized. For Group CC 100% of the presentations of both stimuli were rewarded (S1 ±, S2 ±), for Group PP 50% of the presentations of each stimulus were rewarded (S1, ±, S2±), and for Group PC one stimulus was followed by reward on 50% of its presentations, while the second stimulus was followed by reward on 100% of its presentations (S1 ±, S2 ±). A fourth group received the stimuli and reward nonpaired. In a subsequent rewarded test phase, the response facilitating effects of the stimuli were evaluated. In the test phase all groups that received reward paired with S1, and S2 performed better in the presence of S1 and S2 than the group for which the stimuli were not paired with reward. For groups that received the stimuli paired with reward, a difference due to schedule of reward occurred when schedule of reward was varied within Ss (Group PC), but not when varied between Ss (Group PP vs Group CC). The specific form of this finding was that Group PC’s performance in the presence of S2 ± was more vigorous than its performance in the presence of S1 ± and was more vigorous than the performance of Groups PP and CC to S2. Group PC’s performance to S1 ± did not differ from that of Groups PP and CC to S1.  相似文献   

14.
Coding strategies developed in the acquisition of delayed conditional discriminations can be assessed by independently manipulating sample and comparison memory load. Two stimulus dimensions that can affect memory load were examined: Number of stimuli in the sample and comparison sets (two vs. four) was manipulated between groups in a 2×2 design, and discriminability of sample and comparison stimuli (hues vs. lines) was manipulated between counterbalancing subgroups and within subjects. The results indicated large effects of sample discriminability but not of comparison discriminability, evidence for retrospective coding. There was also a significant effect of number of stimuli in the comparison set (although only with hard-to-discriminate samples) but not of number of stimuli in the sample set, evidence for prospective coding. These findings suggest evidence for retrospective coding with easy-to-discriminate samples, independently of number of stimuli in the comparison set, and evidence for prospective coding with hard-to-discriminate samples.  相似文献   

15.
Peking ducklings were reared for 1–2 weeks with either 9 or 12 companions, which were either conspecifics or imprinting stimuli (blocks of foam rubber). They were then tested for their tendency to distress call as the number of companions was reduced systematically. Consistent with prior research, ducklings reared with conspecifics modulated their distress calling as a function of both the number of companions with which they were reared and the number of companions with which they were tested. In contrast, ducklings reared with moving imprinting stimuli gave few if any distress calls, regardless of the number of stimuli with which they were reared or tested, as long as at least one imprinting stimulus was present. The difference in responding did not reflect just a lack of attachment to the imprinting stimuli, since when all stimuli were removed these ducklings gave as many distress calls as the ducklings that had all their conspecifics removed. Finally, ducklings reared with stationary imprinting stimuli displayed an erratic pattern of distress calling when the number of test stimuli was manipulated. These latter ducklings appeared to be less strongly imprinted than the ducklings reared with either conspecifics or moving imprinting stimuli. Implications for understanding duckling perception of brood size and thenature of sibling vs. filial imprinting are examined.  相似文献   

16.
This paper follows on from an earlier companion paper (McLaren & Mackintosh, 2000), in which we further developed the elemental associative theory put forward in McLaren, Kaye, and Mackintosh (1989). Here, we begin by explicating the idea that stimuli can be represented as patterns of activation distributed across a set of units and that different stimuli activate partially overlapping sets (the degree of overlap being proportional to the similarity of the stimuli). A consequence of this view is that the overall level of activity of some of the units representing a stimulus may be dependent on the nature of the other stimuli present at the same time. This allows an elemental analysis in which provision for the representation of configurations of stimuli is made. A selective review of studies of generalization and discrimination learning, including peak shift, transfer along a continuum, configural discrimination, and summation, suggests that the principles embodied in this class of theory deserve careful consideration and will form part of any successful model of associative learning in humans or animals. There are some phenomena that require an elemental/associative explanation.  相似文献   

17.
Stumptailed monkeys (Macaca arctoides) were given two two-choice line-discrimination problems in which the lines were presented either alone or embedded in a patterned context that was the same in all cases. When the stimuli were a left- and a right-tilting line, the addition of the context significantly improved performance, as measured by frequency of correct choice responses. It also decreased choice response latency, duration of visual fixations, and frequency of scanning back and forth between the two stimuli. When the stimuli were a horizontal and a vertical line, the addition of the context had the opposite effect on all the performance measures. These results are very similar to those found with adult and infant humans when given the same stimuli. They suggest that the pattern perception of monkeys, like that of humans, involves top-down or holistic processing of incoming visual information.  相似文献   

18.
Aitken (1999) argues that, in a simultaneous discrimination, reports of the transfer of value from the positive to the negative stimulus can be more readily explained in terms of an artifact produced by the procedure in which differential inhibition accrues to the negative test stimuli during training, together with stimulus generalization (similarity between the positive and negative stimuli). We argue that (1) there is little evidence for differential inhibition, and it often occurs in the wrong direction; (2) value transfer can be demonstrated when differential value is established to the positive stimuli afterdiscrimination training, when differential inhibition is not likely to be a factor; and (3) on both logical and empirical grounds, stimulus similarity does not provide an adequate account of the transfer of value from the positive to the negative stimulus (i.e., the strongest evidence for value transfer occurs when there is least stimulus similarity). We propose that value transfer occurs whenever there is relatively little experience with the negative stimuli. However, when there is extended experience with the negative stimuli, contrast will be found.  相似文献   

19.
In three experiments, we examined how matching-to-sample by pigeons is affected by discrimination versus nondifferential training between the matching stimuli. In Experiment 1A, pigeons responding differentially to the sample stimuli off-baseline acquired accurate matching performances more rapidly than did pigeons responding nondifferentially to those same stimuli. In Experiment 1B, tests involving reversal of the off-baseline requirements demonstrated that the birds were primarily controlled in their matching choices by the sample stimuli. The results of Experiment 2 showed that off-baseline nondifferential training did not retard acquisition relative to comparable training between stimuli unrelated to the matching task. Together, these results suggest that discrimination training can facilitate matching acquisition by enhancing attention to the sample stimuli.  相似文献   

20.
A bottlenose dolphin was trained to discriminate two simultaneously presented stimuli differing in numerosity (defined by the number of constituent elements). After responding correctly to stimuli consisting of three-dimensional objects, the dolphin transferred to two-dimensional stimuli. Initially, a variety of stimulus parameters covaried with the numerosity feature. By systematically controlling for these stimulus parameters, it was demonstrated that some of these attributes, such as element configuration and overall brightness, affected the animal’s discrimination performance. However, after all the confounding parameters were under control, the dolphin was able to discriminate the stimuli exclusively on the basis of the numerosity feature. The animal then achieved a successful transfer to novel numerosities, both intervening numerosities and numerosities outside the former range. These findings provide substantial evidence that the dolphin could base his behavior on the numerosity of a set independently of its other attributes and that he represented ordinal relations among numerosities.  相似文献   

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