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1.
Pigeons trained in a conditional discrimination procedure to respond to a visual array made a left or right choice, depending
on which of two numbers of elements (i.e., anchor numerosities) the array contained. They were then tested with novel arrays
at these anchor numerosities, as well as at interpolated and extrapolated numerosities. Various control conditions showed
that the birds’ discrimination performance was primarily based on stimulus numerosity, and not on other factors, such as brightness
or area. Results from a series of tests, spanning a wide range of numerosities, conformed to scalar principles. Psychometric
functions showed superposition, indicating that Weber’s law applies to numerosity discrimination. The subjective midpoint
between anchor values was at the geometric mean. Variability about this bisection point increased in proportion to the numerical
value of the mean. 相似文献
2.
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
3.
Pigeons were trained in a conditional discrimination paradigm to differentiate successively presented visual arrays according to the relative number of their elements. Transfer tests with novel stimuli demonstrated that they discriminated the categories of “many” (6 or 7) from “few” (1 or 2) items. In further tests, other new stimuli were introduced that consisted not only of these training numerosities, but also of the intervening ones (3, 4, and 5). Variations in the birds’ discrimination performance corresponded to the order of stimuli on a numerosity dimension. This serial ordering was maintained when other factors such as brightness, size, shape, area, and contour of the elements were systematically controlled across tests. Smaller numerosities were somewhat better discriminated than those at the higher end of this test range. 相似文献
4.
Jacky Emmerton 《Learning & behavior》1998,26(3):243-256
Two experiments are described in which pigeons were trained in a simultaneous conditioning procedure to discriminate small arrays of dots that differed in numerosity. The birds successfully learned to choose the array of each pair that contained fewer dots when these choices were reinforced and choices of the array with more dots led to timeout. For the majority of numerosity values tested, discrimination performance for a fixed S+ value was better when the numerical difference between S+ and S-values was larger rather than smaller. This effect was seen in the first experiment when the numerical difference value was shifted between training trials and novel test trials. In the second experiment, too, performance level depended on the size of the numerosity difference when the birds were concurrently trained with two difference values that varied across trials within sessions. However, discrimination accuracy was influenced secondarily by variations in the density, or interdot spacing, of the stimulus arrays. In order to explain the latter finding, it is suggested that a tendency to “scan” a lowdensity array incompletely might alter the probability of accepting it as the smaller numerosity (S+) stimulus. This would increase error rates with S? arrays in which the dots are more widely spaced. 相似文献
5.
Five-year-old children categorized as skilled versus unskilled counters were given verbal estimation and number word comprehension tasks with numerosities 20-120. Skilled counters showed a linear relation between number words and nonsymbolic numerosities. Unskilled counters showed the same linear relation for smaller numbers to which they could count, but not for larger number words. Further tasks indicated that unskilled counters failed even to correctly order large number words differing by a 2 : 1 ratio, whereas they performed well on this task with smaller numbers, and performed well on a nonsymbolic ordering task with the same numerosities. These findings provide evidence that large, approximate numerosity representations become linked to number words around the time that children learn to count to those words reliably. 相似文献
6.
Jacky Emmerton 《Learning & behavior》2001,29(1):21-35
Pigeons were trained to discriminate the proportion of red to green color in paired stimulus displays. Initially, the stimuli were horizontal bars composed of continuous blocks of color that varied from being all red versus all green to .5 proportions of these two colors. Discrimination accuracy decreased as a function of the disparity in the proportions of the two colors. This relationship was maintained when the stimulus configurations were altered in various ways. Tests with horizontal bars indicated that the pigeons could utilize differences in the lengths (or areas) of one of the colors when choosing between stimuli. They did not rely only on this type of cue to assess proportion disparities but rather on multiple stimulus parameters. Also, the form of the discrimination function suggests that the pigeons distinguished ratio differences, so that Weber’s law applies to this type of discrimination. 相似文献
7.
8.
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
9.
Rosemary A. Rosser Sally Stevens Ensing John Mazzeo 《Contemporary educational psychology》1985,10(2):95-103
Children's ability to discriminate reflections and rotations of visual stimuli was examined within the confines of a mental rotation task. It was hypothesized that success would be affected by both characteristics of the stimulus and by the subtlety of the discrimination required. Forty 3- to 4-year-old children were directed to mentally rotate a stimulus a given number of degrees and to discriminate the appearance of the rotated stimulus from among a set of alternatives. Four stimuli differing in the number of visual orientation cues were utilized across 24 trials. A significant effect was found for number of orientation cues, and data indicated the difficulty children experienced detecting reflections, a task which bears close resemblance to the yes/no option in prototypic rotation studies. Children were only successful with a limited range of stimuli when discrimination of a reflected foil was not required. Results are discussed in light of discrepant findings about children's kinetic imagery ability and the advisability of using this particular paradigm with young Children. 相似文献
10.
Infants'' Detection of Correlations among Feature Categories 总被引：2，自引：0，他引：2
Barbara Younger 《Child development》1990,61(3):614-620
The present study demonstrates that the infant's ability to detect correlations among attributes extends to correlations among feature categories of the type we might expect to be useful in forming natural object categories. 48 10- and 13-month-old infants were tested using an infant-control habituation procedure. Infants initially were exposed to as many as 12 different animals. 2 attributes were perfectly correlated within the set of habituation stimuli. For example, animals with feathered tails had ears, and animals with furry tails had antlers. The appearance of the correlated features varied across the set of 12 animals. Infants' sensitivity to the pattern of correlation existing within the habituation set was demonstrated by their responses to new stimuli following habituation. Infants generalized habituation to a new animal that preserved the experienced pattern of correlation, but showed an increase in looking to a stimulus that contained a novel combination of the same features. 相似文献
11.
We explored response rate as a possible mediator of learned stimulus equivalence. Five pigeons were trained to discriminate
four clip art pictures presented during a 10-sec discrete-trial fixed interval (FI) schedule: two paired with a one-pellet
reinforcer, which supported a low rate of responding, and two paired with a nine-pellet reinforcer, which supported a high
rate of responding. After subjects associated one stimulus from each of these pairs with a discriminative choice response,
researchers presented two new clip art stimuli during a 10-sec FI: one trained with a differential reinforcement of low rate
schedule (DRL) after the FI and the other trained with a differential reinforcement of high rate schedule (DRH) after the
FI. Each of the stimuli that were withheld during choice training was later shown to see if the choice responses would transfer
to these stimuli. The results suggest that response rate alone does not mediate learned stimulus equivalence. 相似文献
12.
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
13.
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
14.
To examine the relationship between visual attention in infancy and the stimulus variables of contour and numerosity, 2- and 4-month-old infants were placed in 3 experimental conditions. In the first condition, the patterns shown to the infants varied in amount of contour but had an equal number of elements; in the second, they varied in numerosity but had an equal amount of contour; and in the third, the patterns varied in both numerosity and contour. The results showed that contour and numerosity acting in tandem are responsible for the age-complexity shift observed in previous investigations of infant attention. 相似文献
15.
A bottlenosed dolphin (Tursiops truncatus) with good underwater and aerial visual acuity was tested in visual matching-to-sample (MTS) paradigms. Attempts to train visual identity MTS directly, using two simple two-dimensional patterns as sample stimuli and as alternatives (comparison stimuli), met with little success, in keeping with previously observed difficulties of this auditory-specialized species for learning complex tasks utilizing simple visual materials. Pairing of each visual sample with a unique sound, to produce a compound auditory-visual sample, while retaining the two visual alternatives, resulted in the dolphin’s learning both auditory-visual symbolic matching and visual-visual identity matching. At 0-sec delay, performance with the auditory element of the sample alone was equivalent (76%) to performance with the visual element alone; performance with the compound was distinctly better (95%–98% correct). Testing with longer delays using the visual element alone resulted in successful matching through to a maximum delay of 34 sec. These results provided the first demonstration of delayed MTS in a dolphin using visual materials, and complemented other data showing the ready capability of this species for delayedauditory MTS. It appeared that the dolphin solved the visual MTS task by forming auditory codes to represent the visual materials, and that these auditory codes were eventually replaced with purely visual codes. 相似文献
16.
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
17.
In each of two experiments, different groups of pigeons were required to discriminate between one of two basic kinds of stimulus differences: stimulus quality or stimulus location. For stimulus-quality groups, a key was illuminated by one of two colors on trials ending with food delivery and by the other color on trials ending with no food. For stimulus-location groups, a key was illuminated at one of two locations on trials ending with food delivery and at the other location on trials ending with no food. The birds began to respond differentially to the stimuli (i.e., peck the keys on food trials and not peck the keys on no-food trials) earlier in acquisiton if the stimulus qualities served as the signals for trial outcomes than if the stimulus locations served as those signals. The results from both experiments are consistent with predictions from a hypothesis regarding interactions among the qualities and locations of stimuli and responses (the “quality-location hypothesis”). Furthermore, the present results support other recent demonstrations of the important role that spatial relations among stimuli can play in classical conditioning. 相似文献
18.
Infant response to stimuli of similar hue and dissimilar shape: tracing the origins of the categorization of objects by hue 总被引：3，自引：0，他引：3
This study confirms that infants, like older children, are capable of responding "categorically" to stimuli of different shape if these are similar in hue. 24 infants (mean age 20.0 weeks) were familiarized to a stimulus in 1 hue (dominant wavelength 515 nm) and in either of 2 different shapes (face of a bear or a rabbit) and then presented with 4 main test comparisons in which the familiar stimulus was paired with a novel stimulus in either the familiar or the alternate (novel) shape and in a novel hue from the same or a different category (dominant wavelengths being 548 and 482 nm, respectively, and equally different from the familiar hue). Infants displayed a preference for the novel stimuli only in the new-category hue. Control tasks with a further 40 infants (same mean age as experimental group) eliminated alternative explanations of this pattern of response in terms of differential brightness of the hues, hue preferences, or inability to discriminate the shapes. 相似文献
19.
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
20.
We trained 7 pigeons to discriminate visual displays of 16same items from displays of 16different items. The specific stimulus features of the items and the relations among the items could serve as discriminative stimuli.
Unlike in most studies of same-different discrimination behavior, we gave a small number of probe tests during each session
of acquisition to measure the time-course of control by the learning of specific stimulus features and relational cues. Both
the specific stimulus features and relational cues exerted reliable stimulus control, with the specific stimulus features
exerting more control during the final three fourths of same-different learning. These findings replicate research suggesting
that pigeons encode both the specific stimulus features and relational cues, and for the first time document the time-course
of control by each kind of cue. 相似文献