首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
In 3 experiments, the attentional responses of 4-month-old infants to frequency-modulated (FM) sweeps corresponding to the frequency range of adult-to-infant and adult-to-adult intonation patterns were assessed. In Experiment 1, infants were observed to discriminate "exaggerated" (i.e., adult-to-infant) FM sweeps from "normal" (i.e., adult-to-adult) FM sweeps in a habituation-dishabituation paradigm but did not selectively attend to one over the other. In Experiment 2, where the same stimuli were used in a paired-comparison paradigm, again no differential attention was observed. In Experiment 3, the most exaggerated sweep was paired against a continuous, monotonic pure tone, but again no difference in salience was observed. These data suggest that the extent of modulation or intonation of an auditory stimulus per se does not constitute a salient cue for infants' attention to sound.  相似文献   

2.
Two experiments demonstrate that 5‐month‐olds are sensitive to local redundancy in visual‐temporal sequences. In Experiment 1, 20 infants saw 2 separate sequences of looming colored shapes that possessed the same elements but contrasting transitional probabilities. One sequence was random whereas the other was based on bigrams. Without any prior exposure, infants looked longer at the random sequence. In Experiment 2, 17 infants looked equally long at bigram‐ and trigram‐based sequences. However, an analysis of local redundancy revealed that in both experiments disengagement from the sequences was governed by local repetitions rather than by global sequence statistics. This finding suggests that a spontaneous sensitivity to stimulus complexity helps orient infants to sequences they can learn from.  相似文献   

3.
Extinction-induced attenuation of single-phase and two-phase blocking was examined with rats in a conditioned lick-suppression task. In Experiment 1, which compared the effectiveness of single- and two-phase blocking, it was found that single-phase blocking was facilitated by the initiation of training with an A-US trial rather than an AX-US trial. Single-phase (but not two-phase) blocking was attenuated as a result of 200 extinction trials with the blocking stimulus (Experiment 2). Experiment 3 revealed recovery from two-phase blocking after 800 extinction trials with the blocking stimulus. Recovery from both types of blocking was specific to the blocked CS trained in compound with the extinguished stimulus (Experiment 4). This is the first article to report that the blocking deficit can be reversed by extinguishing the blocking stimulus. These results are discussed in light of acquisition models (i.e., retrospective revaluation) and expression models (i.e., the comparator hypothesis).  相似文献   

4.
In the present study, we examined whether the presentation of postevent cues would bias recognition in a visual delayed matching-to-sample task with pigeons. Postevent cues were either consistent with the original target stimulus (i.e., they were the same as the correct choice option at recognition), inconsistent (i.e., they were the same as the incorrect recognition option), or neutral (i.e., they were different from both the correct and the incorrect recognition options). In Experiment 1, a single colored light served as the target stimulus. In Experiment 2, the target stimulus was one of three lights presented in a sequence. Both experiments demonstrated that recognition choices were biased toward the option corresponding to the postevent cue, but only if the cue occurred at the end of the delay interval. The present results mirror those found using the misinformation paradigm with human subjects.  相似文献   

5.
When rats learn to anticipate a sequence of stimulus events, such as a serial pattern of different food quantities, they are sensitive to the rule-based formal structure relating the magnitude of successive stimuli. Earlier research has shown that if formal structure is simple (e.g., if a single “less than” rule relates the size of each successive quantity), patterns are learned faster than if formal structure is complex (e.g., if two or more rules such as “less than” and “greater than” relate successive pattern quantities). Two experiments tested the hypothesis that pattern length modulates the role of pattern complexity. We predicted that pattern length and pattern complexity interact in determining pattern difficulty. That is to say, long complex patterns should be learned more slowly than short complex patterns. However, long simple patterns should be learned faster than short simple patterns. In Experiment 1, rats ran a straight runway to receive repeated sequences of food quantities. The long-monotonic group received a formally simple 18-10-6-3-1-0 pattern, in which each number represents a quantity of food pellets. The long-nonmonotonic group received a formally complex 10-1-3-6-18-0 pattern. Similarly, the short-monotonic and short-nonmonotonic groups received 18-1-0 and 1-18-0 patterns. Pattern tracking—fast and slow running in anticipation of large and small quantities of food, respectively—was taken as an index of pattern learning. In Experiment 2, comparable patterns were used, but rats leverpressed in a discrete-trial procedure; response latencies measured pattern tracking. In both experiments, rats learned formally simple patterns faster than they did formally complex patterns. In Experiments 1 and 2, but less clearly in Experiment 2, the predicted interaction was obtained. The results support and generalize the idea that rats encode and use some representation of the formal rule structure of serial patterns as they learn them.  相似文献   

6.
The present research used a preferential‐reaching task to examine whether 9‐ and 11‐month‐olds (n = 144) could infer the relative weights of two objects resting on a soft, compressible platform. Experiment 1 established that infants reached preferentially for the lighter of 2 boxes. In Experiments 2–4, infants saw 2 boxes identical except in weight resting on a cotton wool platform. Infants reached prospectively for the lighter box, but only when their initial exploratory activities provided critical information. At 11 months, infants succeeded as long as they first determined that the platform was compressible; at 9 months, infants succeeded only if they also explored the boxes and thus had advance knowledge that they differed in weight.  相似文献   

7.
Two experiments examined perceptual colocation of visual and tactile stimuli in young infants. Experiment 1 compared 4- (n = 15) and 6-month-old (n = 12) infants’ visual preferences for visual-tactile stimulus pairs presented across the same or different feet. The 4- and 6-month-olds showed, respectively, preferences for colocated and noncolocated conditions, demonstrating sensitivity to visual-tactile colocation on their feet. This extends previous findings of visual-tactile perceptual colocation on the hands in older infants. Control conditions excluded the possibility that both 6- (Experiment 1), and 4-month-olds (Experiment 2, n = 12) perceived colocation on the basis of an undifferentiated supramodal coding of spatial distance between stimuli. Bimodal perception of visual-tactile colocation is available by 4 months of age, that is, prior to the development of skilled reaching.  相似文献   

8.
Two experiments explored how infants learn to form an abstract categorical representation of support (i.e., on) when habituated to few (i.e., 2) or many (i.e., 6) examples of the relation. When habituated to 2 pairs of objects in a support relation, 14-month-olds, but not 10-month-olds, formed the abstract spatial category (i.e., generalized the relation to novel objects). When habituated to 6 object pairs in a support relation, infants did not attend to the relation. The results indicate that infants learn to form an abstract spatial category of support between 10 and 14 months and that having fewer object pairs depicting this relation facilitates their acquisition of the abstract categorical representation.  相似文献   

9.
In two experiments, rats solved two concurrent discrimination problems in which one stimulus (i.e., a facilitator) signaled the reinforcement of another stimulus (i.e., a target). Then a transfer test assessed the capacity of facilitators trained in one problem to promote responding to targets trained in the other. Experiment 1 found that a facilitator promoted as much responding to such a transfer target as to the target with which it was originally trained. Transfer was not obtained with a pseudofacilitator that was uninformative, in training, about the reinforcement of its target. Experiment 2 manipulated the stimulus modality of the targets and facilitators. Its results indicated that transfer performance was not due to generalization between training and transfer targets or facilitators. These results parallel those from comparable autoshaping paradigms with pigeons, and they agree with the view that facilitators promote responding by lowering the threshold for activation of the US representation.  相似文献   

10.
We explored infants' ability to perceive stationary, partially occluded objects as connected units (Experiments 1 and 2) with specific appearances (Experiment 3). In each experiment, the infants saw 2 test events involving what appeared to adults to be a tall rectangular object whose middle portion was hidden behind a narrow screen. During the test events, the screen alternately uncovered and covered the object. In Experiments 1 and 2, removal of the screen revealed either a single, connected rectangle (complete object event) or an interrupted rectangle with a gap where the screen had been (broken object event). In Experiment 3, removal of the screen revealed either a rectangle (rectangle event) or a cross-shaped object (cross-shape event). The pattern of infants' looking times at these events suggest that they perceive the unity of the partially occluded object by 6.5 months of age but did not perceive the form of the hidden part of the object until 8 months. The results of baseline control conditions support this interpretation.  相似文献   

11.
We report an investigation of the development of visual expectancies in 3.5-month-old infants. One of the infant's eyes was videorecorded as the infant watched a series of slides that were presented noncontingent on behavior. Babies were presented an alternating and an irregular series of 30 slides with a 700-msec onset duration separated by an interstimulus interval (ISI). The ISI for the alternating series was 1,100 msec, whereas the slides for the irregular series were separated by 900, 1,100, or 1,300 msec, randomly ordered. One-half of the babies saw the irregular series first, and one-half saw the regular series first. Babies in both groups provided evidence that they developed expectations for the visual events in the alternating series. Their reaction times (RTs) declined significantly from 3-5 "baseline" presentations, and their RTs were reliably faster during the alternating than the irregular series. Additionally, babies in the alternating-late group had significantly more stimulus anticipations during the alternating than during the irregular series. These findings indicate that 3.5-month-olds can detect regularity in a spatiotemporal series, will develop expectancies for events in the series, and will act on the basis of those expectancies even when those actions have no effect on the stimulus events. We believe that infants are motivated to develop expectations for noncontrollable spatiotemporal events, because these expectations permit them to bring their visual behavior under partial internal control.  相似文献   

12.
This study examined how timing (i.e., relative maturity) and rate (i.e., how quickly infants attain proficiency) of A‐not‐B performance were related to changes in brain activity from age 6 to 12 months. A‐not‐B performance and resting EEG (electroencephalography) were measured monthly from age 6 to 12 months in 28 infants and were modeled using logistic and linear growth curve models. Infants with faster performance rates reached performance milestones earlier. Infants with faster rates of increase in A‐not‐B performance had lower occipital power at 6 months and greater linear increases in occipital power. The results underscore the importance of considering nonlinear change processes for studying infants’ cognitive development as well as how these changes are related to trajectories of EEG power.  相似文献   

13.
Fundamental to amassing a lexicon of relational terms (i.e., verbs, prepositions) is the ability to abstract and categorize spatial relations such as a figure (e.g., boy) moving along a path (e.g., around the barn). Three studies examine how infants learn to categorize path over changes in manner, or how an action is performed (e.g., running vs. crawling). Experiment 1 (n = 60) finds that 10‐ to 12‐month‐old English‐learning infants categorize a figure’s path. In Experiment 2 (n = 27) categorization is disrupted when the ground object is removed, suggesting the relation between figure and ground defines the path. Experiment 3 (n = 24) shows that language may be a mechanism guiding category formation. These studies suggest that English‐learning infants can categorize path, a component lexicalized in the world’s languages.  相似文献   

14.
This study investigated the possible effects of first language (L1) orthographic characteristics on word recognition in English as a second language (ESL). Case alternation was used to examine the impact of visually distorted words of different types on fluent ESL readers' word recognition in naming. Visual distortion of word shape (i.e., cAsE aLtErNaTiOn) was utilized because, although visually distorted words have lost word-shape cues, they preserve the cue value of words (i.e., spelling patterns). It, therefore, was hypothesized that if one is sensitive to alphabetic orthography, or if one's inner mechanism of processing an alphabetic word is efficient, then the visual disruption of word-shape cues should not affect one's sensitivity to sequences of letters in words. In other words, this study focused on the magnitude of the effect of case alternation in word recognition as an index of the sensitivity to alphabetic words. Results showed that the magnitude of the case alternation effect in a naming task was significantly larger for the ESL participants whose L1 is not alphabetic (i.e., Chinese and Japanese) than the ESL participants whose L1 is alphabetic (i.e., Iranians -- Persian as L1). This result seems to indicate that the Persian speakers, due to the facilitating influence of their L1 orthography, were less influenced by case alternation than the Chinese and Japanese speakers, whose L1 orthographies are not alphabetic. This finding suggests that the first language orthographic features affect the orthographic coding mechanisms (i.e., word recognition mechanisms) in a second language.  相似文献   

15.
Are humans unique in their ability to interpret exogenous events as causes? We addressed this question by observing the behavior of rats for indications of causal learning. Within an operant motor–sensory preconditioning paradigm, associative surgical techniques revealed that rats attempted to control an outcome (i.e., a potential effect) by manipulating a potential exogenous cause (i.e., an intervention). Rats were able to generate an innocuous auditory stimulus. This stimulus was then paired with an aversive stimulus. The animals subsequently avoided potential generation of the predictive cue, but not if the aversive stimulus was subsequently devalued or the predictive cue was extinguished (Exp. 1). In Experiment 2, we demonstrated that the aversive stimulus we used was in fact aversive, that it was subject to devaluation, that the cue–aversive stimulus pairings did make the cue a conditioned stimulus, and that the cue was subject to extinction. In Experiments 3 and 4, we established that the decrease in leverpressing observed in Experiment 1 was goal-directed instrumental behavior rather than purely a product of Pavlovian conditioning. To the extent that interventions suggest causal reasoning, it appears that causal reasoning can be based on associations between contiguous exogenous events. Thus, contiguity appears capable of establishing causal relationships between exogenous events. Our results challenge the widely held view that causal learning is uniquely human, and suggest that causal learning is explicable in an associative framework.  相似文献   

16.
Sprague-Dawley rat pups aged 14 or 18 days were trained on a patterned (single) alternation schedule with either an 8- or a 105-sec intertriai interval (ITI). At the 8-sec ITI, alternation learning was obtained at both ages, but the older age group learned more rapidly. There was no evidence of response alternation at the 105-sec ITI at either age. Continuously reinforced (CRF) and partially reinforced (PRF) groups trained and extinguished along with the patterned alternation (PA) group at the 105-sec ITI showed a robust partial reinforcement extinction effect (PREE) at both ages. Moreover, there was no difference in the rate of extinction of the PRF and PA groups at either age (i.e., no effect of N-length). A PREE can therefore be obtained in infant rats under conditions that apparently preclude the formation of sequential associations. The implications of this finding for the ontogeny of instrumental learning and extinction are discussed.  相似文献   

17.
Using speech sounds to guide word learning: the case of bilingual infants   总被引:1,自引:0,他引:1  
Despite the prevalence of bilingualism, language acquisition research has focused on monolingual infants. Monolinguals cannot learn minimally different words (e.g., "bih" and "dih") in a laboratory task until 17 months of age (J. F. Werker, C. T. Fennell, K. M. Corcoran, & C. L. Stager, 2002). This study was extended to 14- to 20-month-old bilingual infants: a heterogeneous sample (English and another language; N = 48) and two homogeneous samples (28 English-Chinese and 25 English-French infants). In all samples, bilinguals did not learn similar-sounding words until 20 months, indicating that they use relevant language sounds (i.e., consonants) to direct word learning developmentally later than monolinguals, possibly due to the increased cognitive load of learning two languages. However, this developmental pattern may be adaptive for bilingual word learning.  相似文献   

18.
19.
The visual behavior of infants in the paired-comparison paradigm was assessed with multiple discrimination tasks week-to-week at 4 and 7 months and longitudinally from 4 to 7 months. Results indicated that although task-to-task reliability was extremely variable and typically low, most measures of infants' attention averaged across multiple tasks were reliable from 1 week to the next as well as relatively stable over the longer longitudinal period. Across all groups, infants who had shorter fixations (i.e., more fixations per fixed-exposure period) during the familiarization phase showed higher novelty preferences. While infants' shift rate during test phases was a reliable individual characteristic at 7 months, it was not at 4 months; rather, data suggested that the difficulty of the stimulus discrimination may be related to young infants' shift rate.  相似文献   

20.
Developmental psychophysiologists have long been interested in a means for evaluating infants at risk for cognitive disabilities. The current research addressed the utility of a noninvasive measure of cardiac vagal tone in predicting developmental outcome. At 40 weeks conceptional age, 3 min of resting EKG were recorded from 80 infants. Four groups of infants were evaluated: prematures who had no medical complications in the postnatal period; prematures who experienced respiratory distress syndrome during the postnatal period; term infants who experienced birth asphyxia during labor and/or postdelivery; and healthy term infants. The mental scale of the Bayley Scales of Mental Development was administered at 8 and 12 months conceptional age. Heart period data were analyzed to derive mean heart period, heart period variability, and estimates of vagal tone for each subject. Analyses of the relationship between the heart period variables and 8- and 12-month outcome (i.e., Bayley Scales) indicated that infants with high vagal tone at 40 weeks conceptional age always had positive developmental outcome at both eight and 12 months of age. Infants with low vagal tone had varied outcomes. Measures of medical complications and other measures of heart period variability were not related to developmental outcome. The results suggest that measurement of cardiac vagal tone may provide an important means for assessing risk in birth stressed populations.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号