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1.
We examine some implications of an attentional model designed to explain dimensional contrast. Pigeons were trained to discriminate rectangular forms under conditions that produced positive dimensional contrast. In two experiments, the spacing of training stimuli was manipulated in ways that should have changed the allocation of attention. Experiment 1 compared the effect of an increased spacing between negative and positive stimuli with the effect of a decreased overall range of positive stimuli. Both manipulations increased the quality of discrimination performance. Experiment 2 demonstrated that dimensional contrast continued to occur under conditions that minimized the difficulty of the task. Results from these experiments were consistent with quantitative predictions of the attentional model concerning the interaction of discriminability factors and factors related to the allocation of attentional resources. 相似文献
2.
In two experiments, a maintained generalization procedure was employed to examine stimulus control of pigeons’ responses to a visual wavelength continuum. For both experiments, pigeons’ responses were periodically reinforced during wavelength values from one end of a continuum, while responses during other stimulus values were extinguished. In Experiment 1, the set of positive stimulus values remained constant, while the spacing of the set of negative stimuli varied. In Experiment 2, the set of negative stimulus values remained constant, while the spacing of positive stimuli varied. Positive dimensional contrast effects were obtained in both experiments. In general, the results indicated that variation in the spacing of negative stimuli had little effect on positive dimensional contrast. However, variation in the spacing of positive stimuli produced changes in the peak of the dimensional contrast gradient, without apparent change in the magnitude of the effect. 相似文献
3.
The influence of dimensional organization on pigeon texture perception was examined in a simultaneous conditional discrimination procedure. Six experienced pigeons were reinforced for pecking at a small block oftarget elements randomly located within a larger array ofdistractor elements in each texture stimulus. Target/distractor differences in color, size, orientation, and combinations of these dimensions were examined. In Experiment 1, the influence of target/distractor similarity on performance was investigated by using different forms of unidimensional and conjunctively organized texture stimuli made of two and three dimensions. Targets infeature displays, in which the two regions consistently differed along a single dimension, were located more accurately than targets inconjunctive displays, where a combination of values from all dimensions defined each region. In Experiment 2, a tradeoff between response speed and accuracy was found in the pigeons’ processing of conjunctive displays. In Experiment 3, the number of distractors differentially influenced the localization of feature and conjunctive targets. Overall, the pigeons’ reactions to these feature and conjunctive stimuli paralleled those of humans, suggesting that functionally equivalent mechanisms may mediate the perceptual grouping, search, and discrimination of textured multidimensional stimuli in both species. 相似文献
4.
The advantage in learning after an intradimensional shift rather than an extradimensional shift has been widely used as a behavioural marker of attentional changes during discrimination learning in different fields of neuroscientific study. However, some of the factors assumed to guide these attentional changes have not been completely disentangled by previous research. In two predictive-learning experiments, we investigated the importance of stimulus relevance and of stimulus-outcome correlation for the modulation of attention. In each experiment, participants were trained on two discrimination problems given in successive order. Each problem required participants to differentiate stimuli varying on two dimensions. We found that acquisition of the second discrimination was influenced by whether its relevant dimension (Exp. 1) or its irrelevant dimension (Exp. 2) had previously been trained as relevant and uncorrelated or as irrelevant and uncorrelated. We also observed that acquisition of the second discrimination was independent of whether its relevant dimension (Exp. 1) or its irrelevant dimension (Exp. 2) had previously been trained as relevant and uncorrelated or as relevant and correlated. Our results indicated that the modulation of attention is guided by stimulus relevance and not by stimulus-outcome correlation. 相似文献
5.
Pigeons received variable-interval (VI) reinforcement for keypecking during randomized presentations of seven line-orientation stimuli forming a continuum ranging from horizontal (0 deg) to vertical (90 deg). Each line presentation lasted for 30 sec and was preceded and followed by 30-sec time-outs. After responding stabilized, only responding in the two extreme stimuli (0 and 90 deg) was reinforced. As discrimination training proceeded, strong behavioral contrast and dimensional contrast effects appeared. However, only marginal local effects (local contrast and local dimensional effects), exerted by one line-orientation component upon a second, appeared, indicating that behavioral and dimensional contrast may be independent of parallel local effects. An attempt was made to apply Blough’s (1975) quantitative model of operant generalization and discrimination to the present discrimination procedure. However, this model did not predict the generalization gradient shape that was experimentally obtained. This experiment also yielded two serendipitous findings: (1) Positive behavioral contrast appeared in an extinction-related stimulus (time-out) when other stimuli were switched from reinforcement to extinction (hitherto, positive behavioral contrast had been observed only in responding to a reinforcementrelated stimulus when other stimuli were switched from reinforcement to extinction), and (2) final responding was higher in the presence of an extinction stimulus that had always been an extinction stimulus than it was in the presence of other extinction stimuli that had previously been paired with VI reinforcement. 相似文献
6.
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
7.
Pigeons were trained to discriminate visual flicker-rate stimuli using two types of instrumental choice procedures. One experiment used a free-operant concurrent schedule with multiple schedule components. Two additional experiments used a two-alternative, discrete-trial procedure. In all experiments, the range of training stimuli was manipulated across conditions. Results from all three experiments showed typical range effects on discrimination performance. That is, performance declined with increases in the overall range of variation of training stimuli. These range effects occurred with either continuous response rate measures or discrete choice measures. Moreover, range effects appeared with relatively high or low levels of overall discrimination accuracy and with either symmetrical or asymmetrical extensions of stimulus range. The results of these experiments suggest that increasing stimulus range influences both perceptual sensitivity and bias to response alternatives. 相似文献
8.
Pigeons’ responses on an operant key were reinforced according to either multiple variable-interval variable-interval or multiple variable-interval extinction schedules. The multiple-schedule components were signaled by line-tilt stimuli on a second key (signal key). Signal-key responses never produced reinforcement, and operant-key responses were not reinforced if they followed within 1 sec of a signal-key response. Behavioral contrast was not observed on the operant key, although there was a small, but reliable, increase in signal-key responding in the variable-interval component of the multiple variable-interval extinction condition. Generalization tests were interspersed between sessions of multiple variable-interval extinction training. Generalization gradients along the line-tilt dimension exhibited peak shift for both operant-key and signal-key responding following intradimensional (line tilt) discrimination training. Line-tilt generalization gradients following interdimensional discrimination did not exhibit peak shift. Gradients following intradimensional discrimination were sharper than gradients following interdimensional discrimination for both operant-key and signal-key responding. It was concluded that dimensional stimulus control of topographically tagged responding maintained by the stimulusreinforcer relation parallels that maintained by the response-reinforcer relation. 相似文献
9.
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
10.
Isaac Behar 《Learning & behavior》1974,2(1):49-53
Relative performance on color and form dimensions during acquisition of two-cue problems by learning-set-sophisticated rhesus monkeys was evaluated with differential reinforcement. Six animals received 24 two-choice problems, each generated from three planometric stimuli, a reference stimulus, an alternate stimulus identical in color but differing in form, and one identical in form but differing in color. The reference stimulus appeared on every trial of a problem and was paired with one or the other alternate on a given trial On half of the problems, the reference stimulus was positive and on the remainder was negative. Acquisition was nearly equivalent on both cue dimensions with positive reference stimuli, but only one dimension was learned with negative reference stimuli. Results were interpreted as unfavorable to attention theory. 相似文献
11.
Advocates of modality preference posit that individuals have a dominant sense and that when new material is presented in this preferred modality, learning is enhanced. Despite the widespread belief in this position, there is little supporting evidence. In the present study, the authors implemented a Morse code–like recall task to examine whether visual and auditory recall is moderated by modality preference. When the perceptual discriminability of visual and auditory stimuli was controlled for, there was no significant relation between (a) modality preference and (b) visual and auditory recall. The nature of the task did however effect performance. When a temporal discrimination between stimuli was required, recall for auditory stimuli was superior to recall of visual stimuli. In contrast, when the task involved a spatial discrimination, the opposite effect was observed. It is not surprising that in each recall task, sequences with a discernible pattern were recalled more accurately than were sequences that lacked any obvious pattern. The authors concluded that the ability to recall simple material is determined more by the type of stimulus than by the preferences of the individual. 相似文献
12.
Impaired visual attention in children with dyslexia 总被引：2，自引：0，他引：2
Reading involves the correct and rapid identification of visual stimuli with letters and words. The processing of visual stimuli depends not only on the integrity of the peripheral and central visual system but also on the attentional systems involved. In the present study, a cue-target visual attention task was administered to a population-based sample of 25 children with dyslexia from 10 to 12 years of age. A control group matched for group size, age, and gender was obtained from the same general population. A two-stage screening process involved a spelling task of regular words followed by a battery of five single-word reading tasks. The cue-target task involved both a computer-controlled stimulus presentation and a computer-controlled measurement of reaction time. The data were analyzed by visual field, cue condition (valid, invalid, and no cue), and cue-target interval (CTI). The results showed a general pattern of slower responses in the dyslexia group compared to the control group. The dyslexia group also had longer reaction times in the short CTI condition (covert shift of attention) and in the long CTI condition (overt shift of attention). The findings may reflect a general attentional deficit to visual stimuli in dyslexia, possibly related to problems with the recruitment of necessary cognitive resources for the performance of complex reaction time tasks and for fluent reading. 相似文献
13.
We report the first successful demonstration of a simultaneous, two-itemsame-different (S/D) discrimination by 6 pigeons, in which nonpictorial color and shape stimuli were used. This study was conducted because
the majority of recently successful demonstrations of S/D discrimination in pigeons have employed displays with more than
two items. Two pairs of stimulus items were simultaneously presented on a touch screen equipped computer monitor. Pigeons
were reinforced for consistently pecking at either thesame (i.e., identical) or thedifferent (i.e., nonidentical) pair of items. These pairs were created from combinations of simple colored shapes drawn from a pool
of six colors and six shapes. After acquiring the discrimination with item pairs that differed redundantly in both the shape
and the color dimensions, the pigeons were tested for transfer to items that varied in only one of these dimensions. Although
both dimensions contributed to the discrimination, greater control was exhibited by the color dimension. Most important, the
discrimination transferred in tests with novel colored, shaped, and sized items, suggesting that the mechanisms involved were
not stimulus specific but were more generalized in nature. These results suggest that the capacity to judge S/D relations
is present in pigeons even when only two stimuli are used to implement this contrast. 相似文献
14.
An information-processing analysis of children's accuracy in predicting the appearance of rotated stimuli 总被引：2，自引：0，他引：2
Children's ability to discriminate reflections and rotations of visual stimuli was examined using a kinetic imagery task. It was hypothesized that success would be related to the number and placement of orientation markers on the stimuli, as well as whether or not reflections had to be discriminated from simple rotations. 40 4- and 5-year-old children were directed to imagine how a stimulus would look if rotated to a specified location and asked to indicate the appearance of the reoriented stimulus by selecting the correct option from a number of foils. 48 of the items required only discrimination of a reoriented stimulus. The other 48 also required discrimination of a reflection of the reoriented stimulus. Stimuli differed in the number of orientation cues on the edges of the figures. Results revealed that prediction accuracy was associated with the existence of orientation markers on the stimuli, as well as age, sex, type of discrimination, and several interactions among the variables. Findings were discussed in comparison to a priori predictions based on an analysis of how children might use orientation information when performing mental rotation tasks. 相似文献
15.
After training with a variable-interval schedule of positive reinforcement, pigeons were tested for stimulus generalization along the hue dimension. For one group, the stimulus was located on the response key. For a second group, the stimulus was located on a surface adjacent to the response key. The stimulus-on-key group produced the typical steep gradients normally found with hue stimuli; the stimulus-off-key group produced flat gradients. After discrimination training between the presence and absence of the hue stimulus, both groups produced decremental gradients. In a second experiment, naive pigeons were trained to peck a transparent key with the stimulus surface located approximately 3.8 cm behind the key. When tested for generalization, the hue gradients were decremental. The results suggest that location of the stimulus in the line of sight with pecking is a necessary condition for stimulus control by hue after nondifferential training. 相似文献
16.
Geoffrey Hall 《Learning & behavior》1980,8(2):282-286
Two experiments demonstrated that pigeons can solve a simultaneous discrimination in which on half the trials the positive and an ambiguous cue (A) are presented and on half the trials choice is between A and the negative stimulus. In Experiment 1, where a relatively nondistinctive A cue was used, performance on the former type of trial was superior to that shown on the latter. In Experiment 2, where a distinctive A cue was provided, this pattern of results was reversed. These findings are interpreted in terms of an approach-avoidance explanation first proposed by Leary (1958). Experiment 3 tested and confirmed a central prediction of this explanation by showing that in an orthodox simultaneous discrimination, occasional reinforcements of the negative stimulus produce less accurate performance than do nonreinforcements of the positive. 相似文献
17.
Pigeons were trained to discriminate between arrays containing equal numbers of two different elements as S+, and arrays which contained more elements of one kind than the other as S?. They were then tested with the full range of the proportions of the two elements. This resulted in behavioral contrast and peak shift, as the pigeons responded more to arrays containing more positive than negative elements than they did to the positive training arrays. These findings were obtained with elements that differed in color (blue vs. red dots) and with elements that differed in orientation (horizontal vs. vertical rectangles). The results indicate that the stimulus control exerted by the derived dimension of relative numerosity involves the same processes as the fundamental dimensions that characterize simple stimulus elements. 相似文献
18.
Infants must learn about many cognitive domains (e.g., language, music) from auditory statistics, yet capacity limits on their cognitive resources restrict the quantity that they can encode. Previous research has established that infants can attend to only a subset of available acoustic input. Yet few previous studies have directly examined infant auditory attention, and none have directly tested theorized mechanisms of attentional selection based on stimulus complexity. This work utilizes model‐based behavioral methods that were recently developed to examine visual attention in infants (e.g., Kidd, Piantadosi, & Aslin, 2012). The present results demonstrate that 7‐ to 8‐month‐old infants selectively attend to nonsocial auditory stimuli that are intermediately predictable/complex with respect to their current implicit beliefs and expectations. These findings provide evidence of a broad principle of infant attention across modalities and suggest that sound‐to‐sound transitional statistics heavily influence the allocation of auditory attention in human infants. 相似文献
19.
In Experiment 1, six groups of pigeons (n=8) were tested for wavelength generalization either immediately or 24 h after learning a successive discrimination, with 550 nm reinforced and a black vertical line extinguished. The groups differed in the stimulus present during single stimulus pretraining, which was 550 nm (pretrain S+), the vertical Une (pretrain S?), or a neutral dim white light (pretrain Sn), respectively. The three immediate generalization gradients were steep and indistinguishable, reflecting only the immediately preceding discrimination training condition. The three delay gradients were flatter, with the flattening particularly marked in the pretrain S? group. This was interpreted as proactive interference (PI) resulting from the memory that both the 550-nm and the line stimuli had previously been reinforced. In Experiment 2, two (TD) groups of pigeons (n=16) were given single stimulus training with a 555-nm keylight followed by eight sessions of discrimination training with two line angles, then one session of non-differential (ND) training with the same two lines, and then a wavelength generalization test either immediately or after a 24-h delay. Two other (hold) groups (n=16) received similar training, except for the TD Une angle training sessions, in these hold groups, the wavelength gradient was flatter in a delayed test; in the TD groups it was steeper, indicating PI from the prior TD training. These two experiments suggest that the “attentional sets,” which purportedly result from TD and ND training, may fruitfully be viewed as target memories subject to the principles of interference theory. 相似文献
20.
Individual Differences in Infant Visual Attention: Are Short Lookers Faster Processors or Feature Processors? 总被引：2，自引：1，他引：2
John Colombo D. Wayne Mitchell Jeffrey T. Coldren Laura J. Freeseman 《Child development》1991,62(6):1247-1257
Individual differences in the duration of infants' visual fixations are reliable and stable and have been linked to differential cognitive performance; short-looking infants typically perform better than long-looking infants. 4 experiments tested the possibility of whether short lookers' superiority on perceptual-cognitive tasks is attributable to attention to the featural details of visual stimuli, or simply to differences in the speed or efficiency of visual processing. To do this, the performance of long- and short-looking 4-month-olds was examined on separate discrimination tasks that could be solved only by processing either featural or global information. The global task was easier than the featural task, but as the amount of time allotted for infants to solve either type of task was decreased, short lookers' performance was superior to that of long lookers. These results thus lend support to a speed or efficiency of stimulus processing interpretation of infant fixation duration. 相似文献