Psychophysical design influences frequency discrimination performance in young children

We investigated how different psychophysical procedures affect frequency discrimination performance in children. Four studies used a design in which listeners heard two tone pairs and had to identify whether the first or second pair contained a higher frequency target tone. Thresholds for 6- and 7-year-olds were higher than those for 8- and 9-year-olds and adults. Two manipulations led to lower (better) thresholds in young children: (a) moving the standard comparison tone before the target tone and (b) using three target comparison tone pairs. It is suggested that young children benefit from designs that help cue them to when they need to attend to a target tone. The two-interval, forced-choice procedure that is widely used in studies of developmental disorders led to variable performance even in adults and did not give a realistic picture of the perceptual capabilities of children under 8 years of age.     

The right hemispheric dominance for face perception in preschool children depends on the visual discrimination level

The developmental origin of human adults’ right hemispheric dominance in response to face stimuli remains unclear, in particular because young infants’ right hemispheric advantage in face‐selective response is no longer present in preschool children, before written language acquisition. Here we used fast periodic visual stimulation (FPVS) with scalp electroencephalography (EEG) to test 52 preschool children (5.5 years old) at two different levels of face discrimination: discrimination of faces against objects, measuring face‐selectivity, or discrimination between individual faces. While the contrast between faces and nonface objects elicits strictly bilateral occipital responses in children, strengthening previous observations, discrimination of individual faces in the same children reveals a strong right hemispheric lateralization over the occipitotemporal cortex. Picture‐plane inversion of the face stimuli significantly decreases the individual discrimination response, although to a much smaller extent than in older children and adults tested with the same paradigm. However, there is only a nonsignificant trend for a decrease in right hemispheric lateralization with inversion. There is no relationship between the right hemispheric lateralization in individual face discrimination and preschool levels of readings abilities. The observed difference in the right hemispheric lateralization obtained in the same population of children with two different paradigms measuring neural responses to faces indicates that the level of visual discrimination is a key factor to consider when making inferences about the development of hemispheric lateralization of face perception in the human brain.     

Numerosity discrimination in preschool children

We used a numerical bisection procedure to examine preschool children's sensitivity to the numerical attributes of stimuli. In Experiment 1 children performed two tasks. In the Cups Task they earned coins for choosing a green cup after two drumbeats and a blue cup after eight drumbeats. In the Gloves Task they earned coins for raising a red glove on their left hand after two drumbeats and a yellow glove on their right hand after eight drumbeats. Then in each task a psychometric function was obtained by presenting intermediate numerosities and recording the percentage of trials in which children chose the "many" option. In Experiment 2 children's performance in a '2 vs. 8' discrimination was compared with their performance in a "4 vs. 16" discrimination. Results showed that the individual psychometric functions were of two types, one in which the percentage of "many" choices increased gradually with stimulus numerosity and another in which it increased abruptly, in a step-like manner. Although the average point of subjective equality was close to the geometric mean of the anchor numerosities and the average functions for "2 vs. 8" and "4 vs. 16" superimposed when plotted on a common scale (the scalar property), the individual data were highly variable both across tasks (Cups and Gloves) and numerosity ranges ('2 vs. 8' and '4 vs. 16'). It is suggested that between- and within-subjects variability in the psychometric function is related to children's verbalizations about the sample stimulus.     

Dynamic locomotor imagery in athletes with severe visual impairments

Motor imagery is a mental process not accompanied by movement and widely studied in healthy subjects, related to hand movements in terms of timing. This study compared static and dynamic motor imagery analyzing temporal and spatial features in different locomotor conditions in three different groups of subjects: high-skilled athletes with visual impairments, a group of sighted unprofessional athletes and a control group of sighted subjects. We found that dynamic motor imagery resulted in timely closer to real performance than static motor imagery. The discrepancies between dynamic motor imagery and real condition, in fact, resulted limited to uncommon locomotion, such as lateral walking. Motor imagery resulted closer to real performance in terms of timing than in terms of step length, with the exception of athletes with visual impairments that, differently from the other groups, did not show any significant differences between the numbers of imagined and performed steps. It opens a new question about the relationship between temporal and spatial imagination of locomotion.     

Teaching early braille literacy skills within a stimulus equivalence paradigm to children with degenerative visual impairments

Despite the need for braille literacy, there has been little attempt to systematically evaluate braille-instruction programs. The current study evaluated an instructive procedure for teaching early braille-reading skills with 4 school-aged children with degenerative visual impairments. Following a series of pretests, braille instruction involved providing a sample braille letter and teaching the selection of the corresponding printed letter from a comparison array. Concomitant with increases in the accuracy of this skill, we assessed and captured the formation of equivalence classes through tests of symmetry and transitivity among the printed letters, the corresponding braille letters, and their spoken names.     

Using conditional discrimination training to produce emergent relations between coins and their values in children with autism

The current study evaluated the effects of conditional discrimination (listener) training with coins on the emergence of novel stimulus relations, textual behavior, tacts, and intraverbals. Two preschoolers with autism were taught 3 relations among coins, their names, and values. After initial training, 4 relations emerged for the first participant and 7 for the second participant, suggesting that this technology can be incorporated into educational curricula for teaching prerequisite money skills to children with autism.     

流动儿童歧视知觉与心理健康关系的元分析

本研究基于心理健康双因素模型,通过运用元分析技术探讨流动儿童歧视知觉与各项心理健康指标的关系,以及调节变量对二者关系的影响,以期为提升流动儿童心理健康提供有效借鉴。经过文献检索和筛选,共纳入原始文献30篇,含49个独立样本,被试总数达到40351名。根据同质性检验结果,选择随机效应模型分析发现,流动儿童歧视知觉与积极心理健康指标存在中等程度的负相关(r=-0.323,95%CI为[-0.378,-0.266]),与消极心理健康指标存在中等程度的正相关(r=0.41,95%CI为[0.36,0.458])。流动儿童歧视知觉测量工具、学龄段对流动儿童歧视知觉与积极心理健康的关系存在显著的调节效应,而对流动儿童歧视知觉与消极心理健康的关系不存在显著的调节效应。同时,元回归分析结果发现,性别对二者的关系不存在显著的调节效应。后续研究应该进一步探索流动儿童歧视知觉与心理健康间的调节变量,结合中国流动儿童心理发展特点,探索提升流动儿童心理健康水平的新路径。     

Stagewise multidimensional visual discrimination by pigeons

We trained six pigeons in a stagewise Multiple Necessary Cues (MNC) go/no‐go task to document the dynamics of discrimination learning involving increasingly complex visual stimuli. The compound stimuli were composed from four dimensions, each of which could assume either of two extreme values or their intermediate value: Shape, Size, Line Orientation, and Brightness. Starting with a stimulus composed entirely from intermediate values, we replaced those values with each of the two extreme dimensional values in four successive stages, thereby increasing the stimulus set from 2 in Stage 1 to 16 in Stage 4. In each stage, only one combination of values signaled food (S⁺), whereas the remaining combinations did not (S^?s). We calculated the rate of pecking during the first 15 s of each stimulus presentation and, in any given stage, training continued until the rate of responding to all of the S^?s was less than 20% of the rate of responding to the S⁺. All pigeons successfully acquired the final discrimination, suggesting that they attended to all of the dimensions relevant for the discrimination. We also replicated the key results of prior MNC studies: (1) the number of extreme dimensional values in each stage was positively related to the amount of training required for pigeons to acquire the discrimination; (2) attentional tradeoffs were most often observed when three or four dimensions were being trained; and (3) throughout training, the number of dimensional values in the S^?s that differed from the S⁺ was positively related to their discriminability from S⁺.     

Simultaneous visual discrimination in Asian elephants

Two experiments explored the behavior of 20 Asian elephants (Elephas aximus) in simultaneous visual discrimination tasks. In Experiment 1, 7 Burmese logging elephants acquired a white+/black- discrimination, reaching criterion in a mean of 2.6 sessions and 117 discrete trials, whereas 4 elephants acquired a black+/white- discrimination in 5.3 sessions and 293 trials. One elephant failed to reach criterion in the white+/black- task in 9 sessions and 549 trials, and 2 elephants failed to reach criterion in the black+/white- task in 9 sessions and 452 trials. In Experiment 2, 3 elephants learned a large/small transposition problem, reaching criterion within a mean of 1.7 sessions and 58 trials. Four elephants failed to reach criterion in 4.8 sessions and 193 trials. Data from both the black/white and large/small discriminations showed a surprising age effect, suggesting that elephants beyond the age of 20 to 30 years either may be unable to acquire these visual discriminations or may require an inordinate number of trials to do so. Overall, our results cannot be readily reconciled with the widespread view that elephants possess exceptional intelligence.     

Conditional discrimination after errorless and trial-and-error training.

Children were trained on a visual discrimination by stimulus shaping, stimulus fading, or trial-and-error. Those who did not acquire the conditional discrimination received a second, different training. More children initially trained by stimulus shaping acquired the conditional discrimination than did those initially trained with stimulus fading or trial-and-error. After a history of fading or trial-and-error training, children were less likely to acquire the conditional discrimination even after the more successful procedure of shaping was later used.     

Comparison of two discrimination methods in teaching Chinese children with autism

In teaching conditional discriminations to children with autism spectrum disorder (ASD), practitioners may progress from simple to conditional discriminations or may teach conditional discriminations from the onset of instruction. Some research indicates that teaching simple discriminations first may be unnecessary and that teaching may more efficiently focus on conditional discriminations exclusively. This study replicated comparisons of simple-to-conditional and conditional-only discrimination training methods in teaching audio-visual conditional discriminations to Chinese preschoolers with ASD. Results indicated the conditional-only training method appeared to be more efficient in teaching these skills.     

Using a combined blocking procedure to teach color discrimination to a child with autism

A combined blocking procedure was used to teach a child with autism to select two colors on request. First, two color cards were placed at fixed locations on a table and the experimenter repeatedly requested the child to touch one of the colors. After 10 consecutive correct selections, the child was asked to touch the other color. Blocks of trials with each color were systematically thinned until requests were presented randomly with few errors. Subsequently, the location of the selection cards was systematically alternated until the child was able to touch the correct card when both requests and card positions were presented in random fashion.     

Programming generalization of social skills in preschool children with hearing impairments.

The efficacy of a social skills training package in producing stimulus generalization, both with and without the systematic application of generalization programming techniques, was evaluated with 5 preschool children with hearing impairments. The evaluation was conducted within a multiple baseline design. Generalization probes were conducted daily. The social skills training package was implemented in a training setting and produced high, stable rates of social interaction in that setting. However, generalization of the social skills to new teachers, peers, and play activities did not occur until generalization programming strategies were applied in the original training setting. Using sufficient stimulus exemplars and contacting natural consequences appeared to be the key strategies for promoting generalization of social interaction. In addition, the use of supplementary procedures (e.g., a fluency criterion and treatment integrity checks) may have contributed to stimulus generalization.     

Prenominal adjective order and visual discrimination in children

Preschool and third-grade children heard prenominal adjective phrases describing an object. Each phrase contained an article, two adjectives and a head noun. The phrases were constructed with either normal or inverted adjective order. Either after a one second delay or immediately following phrase presentation, Subjects were shown pictures of two objects. One of the objects (target) depicted the object described in the noun phrase. The other object differed from the target along the dimensions of color, size, or both color and size. The Subject's task was to select the target object. It was predicted that adjective order would influence perceptual strategies used by the Subjects in the visual discrimination task. Analysis of response time scores showed that adjective order interacted with the relevant discriminative stimuli in the discrimination task. These results were interpreted as support for hypotheses that suggest that linguistic organization can constrain conceptual processing involving nonlinguistic information. The effects of the delay condition provided additional evidence for these hypotheses plus support for an arousal hypothesis.     

The symmetry of visual fields in chromatic discrimination

Both classical and recent reports suggest a right-hemisphere superiority for color discrimination. Testing highly-trained normal subjects and taking care to eliminate asymmetries from the testing situation, we found no significant differences between left and right hemifields or between upper and lower hemifields. This was the case for both of the cardinal axes of color space. In addition, there was no difference according to whether the discriminanda were delivered to the same or to different hemispheres, and we note that the same number of synapses may lie between the retina and the site of comparison whether or not the stimuli are delivered to the same hemisphere.     

Simple discrimination training with differential responses to establish functional and equivalence classes with preschool children

The present study assessed whether simple discrimination training with differential responses would produce functional and equivalence classes with preschool children. In Experiment 1, we exposed 10 children to simple successive discrimination training in which they had to press different buttons (selection‐based responses). Response 1 (R1) was reinforced only in the presence of A1, B1, or C1, and Response 2 (R2) was reinforced only in the presence of A2, B2, or C2. We assessed the formation of functional classes by training new selection responses in the presence of one member of each class (A1‐R3, A2‐R4) and testing to see if these responses would occur in the presence of other members. Eight children responded consistently with functional class formation. Four of these eight children also responded consistently with the formation of equivalence classes. Experiment 2 investigated whether differential motor responses (i.e., gestures) would improve equivalence class yields. Three of six children showed both functional and equivalence class formation. In general, the results indicate that the simple discrimination procedure with differential responses yielded functional and equivalence class formation.     

Age slowing down in detection and visual discrimination under varying presentation times

The reaction time has been described as a measure of perception, decision making, and other cognitive processes. The aim of this work is to examine age‐related changes in executive functions in terms of demand load under varying presentation times. Two tasks were employed where a signal detection and a discrimination task were performed by young and older university students. Furthermore, a characterization of the response time distribution by an ex‐Gaussian fit was carried out. The results indicated that the older participants were slower than the younger ones in signal detection and discrimination. Moreover, the differences between both processes for the older participants were higher, and they also showed a higher distribution average except for the lower and higher presentation time. The results suggest a general slowdown in both tasks for age under different presentation times, except for the cases where presentation times were lower and higher. Moreover, if these parameters are understood to be a reflection of executive functions, these findings are consistent with the common view that age‐related cognitive deficits show a decline in this function.     

Simple and conditional visual discrimination with wheel running as reinforcement in rats.

Three experiments explored whether access to wheel running is sufficient as reinforcement to establish and maintain simple and conditional visual discriminations in nondeprived rats. In Experiment 1, 2 rats learned to press a lit key to produce access to running; responding was virtually absent when the key was dark, but latencies to respond were longer than for customary food and water reinforcers. Increases in the intertrial interval did not improve the discrimination performance. In Experiment 2, 3 rats acquired a go-left/go-right discrimination with a trial-initiating response and reached an accuracy that exceeded 80%; when two keys showed a steady light, pressing the left key produced access to running whereas pressing the right key produced access to running when both keys showed blinking light. Latencies to respond to the lights shortened when the trial-initiation response was introduced and became much shorter than in Experiment 1. In Experiment 3, 1 rat acquired a conditional discrimination task (matching to sample) with steady versus blinking lights at an accuracy exceeding 80%. A trial-initiation response allowed self-paced trials as in Experiment 2. When the rat was exposed to the task for 19 successive 24-hr periods with access to food and water, the discrimination performance settled in a typical circadian pattern and peak accuracy exceeded 90%. When the trial-initiation response was under extinction, without access to running, the circadian activity pattern determined the time of spontaneous recovery. The experiments demonstrate that wheel-running reinforcement can be used to establish and maintain simple and conditional visual discriminations in nondeprived rats.