The effectiveness of fading in programming a simultaneous form discrimination for retarded children

A non-verbal teaching program, combined with reinforcement and extinction (Program Group), was compared with reinforcement and extinction alone (Test Group) in teaching retarded children to discriminate circles from ellipses. In the Program Group, fading techniques were used to transfer stimulus control from “bright vs. dark” to “form vs. no-form” and then to “circle vs. ellipse”. The Test Group had the task of learning the circle-ellipse discrimination with no prior teaching program. With the program, seven of 10 children learned the circle-ellipse discrimination. Without the program, one of nine learned. The eight Test-Group children who failed to learn circle vs. ellipse were then given the opportunity to learn the form no-form discrimination by reinforcement and extinction alone, without fading. Six of the eight learned, but only three of these six then learned circle vs. ellipse on a second test. All seven Program-Group children who had learned form vs. no-form also learned the circle-ellipse discrimination by means of fading; each of the seven made fewer errors than any of the three who succeeded on the second test. Children who failed to learn circle vs. ellipse adopted response patterns incompatible with the development of appropriate stimulus control.     

Shape constancy and theory of mind: is there a link?

In three experiments, children aged between 4 and 7 years viewed a circular disc oriented at a slant. The disc was made of luminous material and situated in a darkened chamber. Children of all ages exaggerated the circularity of the disc when they knew that the object was really a circle (the circle task), and the effect was greatest in the younger members of the sample. Crucially, however, a group of children in Experiment 3 who viewed an identical shape that they knew emanated from an actual ellipse did not exaggerate circularity. In the second experiment, children tackled three standard theory of mind tasks in addition to the circle task mentioned above. A significant correlation emerged (even with age partialed) between the extent of exaggeration made by those who knew that the shape was a circle and ability to pass the theory of mind tests. It seems knowledge of reality contaminates judgements of appearance in the circle task. This might be the same bias that features in realist errors in theory of mind tasks.     

Effects of error and errorless discrimination acquisition on reversal learning

The effectiveness of trial-and-error, graded-choice, and verbal-instruction procedures on the acquisition and maintenance of a two-choice simultaneous color discrimination in an intradimensional double-reversal learning situation was studied using 18 first-grade children. After acquiring a red-green discrimination during one 70-trial session, the discriminative roles of the stimuli were reversed for 30 trials, followed by a second reversal for 30 trials. Children in the graded-choice and verbal-instruction groups acquired and maintained the discriminations with fewer errors than children who learned by trial and error. The importance of the results in terms of two-stage discrimination learning theories is pointed out and similarities between errorless learning and overtraining are discussed.     

Information producing responses in normal and retarded children.

Normal and retarded children were given trials on several discriminations which varied in difficulty. On standard discrimination trials the retarded subjects did not differ from the MA control subjects in the number of errors made but both groups made more errors than the CA control group. On other trials if subjects were not sure which stimulus was correct they were allowed to press an information key which made the discrimination easier. The retarded subjects made significantly more informational key responses than either of the control groups. These results confirmed the findings of prior investigations dealing with outerdirectedness in an experimental situation which did not allow distractibility to be a significant factor.     

Ellipses on the surface of a picture

Shapes on the surface of a perspective picture may be misperceived. Subjects picked a match for an ellipse depicting the circular top of a cylinder. The top was depicted as tilted forward from 5 degrees to 85 degrees, generating a series of ellipses on the picture surface. The matches were biased towards a circle over a wide range of midrange tilts, which suggests that, influenced by features of perspective, they were seen as in-between the shape on the surface and the shape they depicted.     

An analysis of confusion errors in many-to-one matching with temporal and nontemporal samples

In experiment 1, pigeons were trained to match temporal (2, 8, and 10 s of houselight) and location (feeder light, left key, center key illumination) samples to color comparison stimuli. Red choices were correct following the 2-s and feeder light, orange choices were correct following the 8-s and center key, and green choices were correct following the 10-s and left key. Samples that were harder to discriminate (8- vs 10-s, and left vs center key) were mapped onto comparisons that were easy to discriminate (orange vs green), while samples that were easier to discriminate (2- vs 8-s, and feeder light vs left key) were mapped onto comparisons that were hard to discriminate(red vs orange). The pattern of errors for temporal and location samples indicated that these samples were not represented by a common code even though they were associated with the same comparison stimuli. In experiment 2, the same pigeons were trained with visual samples in which samples that were hard to discriminate (triangle vs circle) were mapped onto comparisons that were easy to discriminate (orange vs green), while samples that were easy to discriminate(plus vs triangle) were mapped onto comparisons that were hard to discriminate (red vs orange). Following acquisition of the visual discrimination, the temporal samples were re-introduced and many-to-one training was continued. During delay testing, the pattern of errors for temporal and visual samples was equivalent and consistent with the hypothesis that visual samples were being coded in terms of the duration appropriate for the temporal sample with which it shared a common comparison response. Data from no-sample test sessions ruled out a simple response bias explanation of the data. The properties of common codes for temporal and nontemporal events can be somewhat flexible and more complicated than previously envisaged. Received: 21 January 1998 / Accepted after revision: 5 April 1998     

Coordination dynamics of elliptic shape drawing: effects of orientation and eccentricity

The aim of the present study was to show the effect of orientation on producing ellipses of various eccentricities. Ten right-handed adults were required to reproduce eight series of 84 ellipses on a graphic tablet at spontaneous speed. The ellipses displayed seven eccentricities, corresponding to the Lissajous plot produced by two orthogonal harmonic oscillators whose relative phase (RP) varied from 0° (a line) to 90° (a circle), and twelve orientations, the long axis of the ellipses aligned in a direction ranging from three to nine o’clock with respect to the body transverse plane. Results confirmed the participant’s preference for two eccentricities, 0° and 45°, that is, a line and an ellipse of intermediate eccentricity, respectively. Except for the circle, insensitive to orientation by definition, orientation became a cogent constraint: In the 10:30 o’clock direction, line drawing (0° RP) increased in variability and the intermediate ellipse (45° RP) was attracted towards a circle (90° RP). These findings suggest an interaction between orientation effects, putatively due to differences in the motion of the wrist and fingers, and eccentricity effects, which may pertain to preferences arising from the non-linear coupling between the effectors.     

The effects of a graduated stimulus change on the acquisition of a simple discrimination in severely retarded boys

Methods were compared for teaching severely retarded boys to discriminate the position of a 0.75-in. black square and to press the response key closest to it. Seven boys were given trial-and-error training; one learned the task. The six boys who did not learn were presented with a program of graduated stimulus changes. All but one acquired the performance, and he was under appropriate control during the program. When he reached the criterion stimuli, he reverted to a position-based response learned during trial-and-error training. Six similar subjects were presented with graduated stimulus training alone. All six learned the criterion discrimination with few or no errors. Both groups were tested for retention of the criterion performance 35 days after training was completed. Two boys who had near-perfect criterion discrimination performances showed no signs of retention after 35 days. These boys had a history of trial-and-error training.     

Global and local processing in adult humans (Homo sapiens), 5-year-old children (Homo sapiens), and adult cotton-top tamarins (Saguinus oedipus)

This study compared adults (Homo sapiens), young children (Homo sapiens), and adult tamarins (Saguinus oedipus) while they discriminated global and local properties of stimuli. Subjects were trained to discriminate a circle made of circle elements from a square made of square elements and were tested with circles made of squares and squares made of circles. Adult humans showed a global bias in testing that was unaffected by the density of the elements in the stimuli. Children showed a global bias with dense displays but discriminated by both local and global properties with sparse displays. Adult tamarins' biases matched those of the children. The striking similarity between the perceptual processing of adult monkeys and humans diagnosed with autism and the difference between this and normatively developing human perception is discussed.     

Quokkas (Setonix brachyurus) demonstrate tactile discrimination learning and serial-reversal learning

Two male quokkas (Setonix brachyurus: a herbivorous macropod marsupial) were trained to discriminate pairs of stimuli in the laboratory. Quokkas indicated their choice by pulling on 1 of 2 simultaneously presented cords. The quokkas' discrimination abilities were tested on 6 tactile and 6 visual discrimination tasks. Correct responses were rewarded with food. For both quokkas, all tactile tasks were learned to a criterion of 75% correct in up to 4 20-trial sessions. No visual task maintained criterion performance in 4 sessions. One tactile discrimination was reversed 10 times. After the 1st reversal, the error rate declined sharply and fell to a level well below the initial discrimination.     

Conditional discrimination in young children: the roles of associative and relational processing

Two experiments examined conditional discrimination in 4- to 6-year-olds. Children learned to choose one of two objects (e.g., circle) when the background was, say, red and to choose the other object (e.g., triangle) when the background was, say, blue. Awareness was assessed and interpreted as a marker of relational processing. In Experiment 1, most 4- and 5-year-olds did not reach the learning criterion. Children in Experiment 2 solved simpler reversal learning problems before the conditional discrimination problems. Most 4- to 6-year-olds reached criterion, but they did not necessarily demonstrate awareness, suggesting that reversal learning and conditional discrimination can be acquired through associative or relational processing. Relational processing increased with age and was used more on simpler problems. Fluid intelligence predicted Problem 2 performance in children who used relational (not associative) processing on Problem 1. Prior experience with simpler problems and awareness of relational structure are influential in children's conditional discrimination.     

Accuracy in discriminating blood glucose levels in a sample of children with type 1 diabetes

The present study explores accuracy in estimating blood glucose levels (BGL) in children with type 1 diabetes and analyzes the kinds of symptoms and cues which they use to estimate their BGL. Forty two children with type 1 diabetes completed a SI/IC-3 scale consisting of 28 items (22 symptoms and 6 feelings), indicating those which they perceived at the time and their intensity. They estimated their BGL and gave reasons for their estimation, before having a blood glucose level analysis performed. The results indicated great variability in the accuracy of estimating BGL. They showed failures in the correct discrimination of symptoms of hypoglycemia as well as the presence of false beliefs regarding indicative symptoms of hyperglycemia, and the absence of symptoms as an indicator for euglycemia, beliefs which provoke different and frequent errors in the estimation of BGL. Correct use of external signs is shown to be related to correct estimations of normal BGL, as well as hypoglycemia and hyperglycemia. We discuss the implications these results could have on designing psychological intervention procedures for diabetics in the form of training programs to discriminate BGL accurately, taking into account these findings and previous studies completed in the same field.     

Touch screen assays of behavioural flexibility and error characteristics in Eastern grey squirrels (<Emphasis Type="Italic">Sciurus carolinensis</Emphasis>)

Behavioural flexibility allows animals to adjust their behaviours according to changing environmental demands. Such flexibility is frequently assessed by the discrimination–reversal learning task. We examined grey squirrels’ behavioural flexibility, using a simultaneous colour discrimination–reversal learning task on a touch screen. Squirrels were trained to select their non-preferred colour in the discrimination phase, and their preferred colour was rewarded in a subsequent reversal phase. We used error rates to divide learning in each phase into three stages (perseveration, chance level and ‘learned’) and examined response inhibition and head-switching during each stage. We found consistent behavioural patterns were associated with each learning stage: in the perseveration stage, at the beginning of each training phase, squirrels showed comparable response latencies to correct and incorrect stimuli, along with a low level of head-switching. They quickly overcame perseveration, typically in one to three training blocks. In the chance-level stage, response latencies to both stimuli were low, but during initial discrimination squirrels showed more head-switches than in the previous stage. This suggests that squirrels were learning the current reward contingency by responding rapidly to a stimulus, but with increased attention to both stimuli. In the learned stage, response latencies to the correct stimulus and the number of head-switches were at their highest, whereas incorrect response latencies were at their lowest, and differed significantly from correct response latencies. These results suggest increased response inhibition and attention allowed the squirrels to minimise errors. They also suggest that errors in the ‘learned’ stage were related to impulsive emission of the pre-potent or previously learned responses.     

An experimental study of the correlates and consequences of perceiving oneself to be the target of gender discrimination

An experimental methodology was used to test hypotheses concerning the effects of contextual, cognitive-developmental, and individual difference factors on children’s views of whether they have been the target of gender discrimination and the possible consequent effect of such views on two forms of state self-esteem: performance and social acceptance. Children (N = 108, 5-11 years of age) completed theory of mind and gender attitude measures and a drawing task. Next, children received feedback that was designed to appear either gender biased (discrimination condition) or nonbiased (control condition). Children’s attributions for the feedback and state self-esteem were assessed. As expected, children reported having been the target of gender discrimination more often in the discrimination condition than in the control condition. Older and more cognitively advanced children made fewer attributions to discrimination than their peers. Perceptions of discrimination were associated with higher performance state self-esteem and, among egalitarian children, lower social state self-esteem.     

Three experiences affecting spatial discrimination learning by ambulatory children

Children 1 and 3 years of age were given a two-choice spatial discrimination task. They were placed in front of a barrier and encouraged to walk around it; one route around the barrier was blocked. Three experiments studied the effects of different types of experience with this spatial problem. The first examined trial and error experience, in which the child was allowed to walk the route he or she had chosen. Although most children readily learned to choose the open route, the pattern of choices indicated that 3-year-olds were more likely to achieve a learning criterion after an error than 1-year-olds. A second experiment looked at the effects of showing the children the layout of the problem prior to trial and error experience. The 3-year-olds were again more likely than the 1-year-olds to achieve criterion after an error; furthermore, they were likely to know the correct route on the first trial. The third experiment let the children watch their parents take the correct route. This procedure eliminated age differences in performance. The initial choices of the 1-year-olds indicated that they were likely to know the correct route, and if they did not, they were just as likely to learn from their mistakes as the 3-year-olds. The data were interpreted within a mathematical model of learning. Based upon these analyses, we propose two developmental trends. One involves a growth in sensitivity to the consequences of a choice of route. The other is a progression from social learning to more independent and ideational methods of spatial problem solving.     

The sources of developmental differences in children's incidental processing during discrimination trials

Crane and Ross reported that second graders learned more than sixth graders about attributes made relevant after solution of a discrimination task. Here two experiments are reported that enlighten the sources of this developmental difference. Both make use of an experimental technique whereby children verbalize their hypotheses during solution of a discrimination problem. The results indicate that ten-year-olds do not learn about incidental attributes that they tested while irrelevant in the pre-solution period, but that five-year-olds and seven-year-olds do. Children of all three ages process incidental information about attributes that they did not sample pre-solution. With some qualification, the incidentally processed information is retained throughout a five-minute delay interval. The results bear on developmental trends in the distribution of attention and on theoretical accounts of incidental learning in discrimination tasks.     

Training letter discrimination in four-year-old children

Four-year-old children were tested on letter discrimination. Subjects in two experimental groups went through an experimental training program on a match-to-sample apparatus. Subjects in the experimental-critical group were given reinforcers for responding to features of the stimuli thought critical for discriminating letters while subjects in the experimental-noncritical group were given reinforcers for responding to non-critical features. Subjects went through the training program daily until they reached criterion; then they were posttested on letters. Subjects in a control group received no training but were posttested. Subjects in all groups made fewer errors on the posttest. Subjects in the experimental-critical group made significantly fewer posttest errors than subjects in the experimental-noncritical group, lending support to the hypothesis that reinforcement of discriminative responding to critical features of letter-like stimuli results in greater improvement in letter discrimination than reinforcement of discriminative responding to noncritical features of stimuli. Analysis of confusion matrices provided tentative indications of the nature of letter confusions in 4-yr-old children.     

Scene and Object Vision in Rats

Dark Agouti rats learned to discriminate large visual displays ('scenes') in a computercontrolled Y-maze. Each scene comprised several shapes ('objects') against a contrasting background. The constant-negative paradigm was used; in each problem, one constant scene was presented on every trial together with a trial-unique variable scene, and rats were rewarded for approaching the variable scene. By varying the manner in which variables differed from the constant, we investigated what aspects of scenes and the objects comprising them were salient. In Experiment 1, rats discriminated constant scenes more easily if they contained four objects rather than six, and they showed a slight attentional bias towards the lower halves of the screens. That bias disappeared in Experiment 2. Experiments 3 and 4 showed that rats could discriminate scenes even if the objects that comprised them were closely matched in position, luminance, and area. Therefore, they encoded the form of individual objects. Rats perceived shapes of the same class (e.g. two ellipses) as more similar than shapes from different classes (e.g. ellipse and polygon) regardless of whether they also differed in area. This paradigm is suitable for studying the neuropsychology of perceiving spatial relationships in multi-object scenes and of identifying visual objects.     

From sharing to dividing: young children’s understanding of division

Children have particular difficulty with division problems, as compared to sharing problems. An inability to discriminate between the dividend, divisor and quotient might contribute to their difficulty with division. This study investigates whether young children (5–9 years) were able to discriminate between the divisor and quotient in simple division problems that were modeled for them. Children were presented with partitive and quotitive division problems in which the dividend was grouped either by the divisor or by the quotient. The children showed a very different pattern of results in the partitive and quotitive problems; they found it easier to identify the answer (quotient) when the dividend was grouped by the divisor in partitive problems and by the quotient in quotitive problems. It is argued that children rely on a schema of action of creating ‘portions’ when they first learn about division, and that the ‘portions’ produced by sharing are different in partitive and quotitive problems. We discuss this finding in terms of the importance of problem representation, children’s schemas of action and mental models.     

Programming stimuli in matching to sample

In these investigations, a “teaching machine” was used to train pre-school and first-grade children in a series of progressively difficult discrimination tasks, leading up to matching to sample. Such training was much more efficient than training in the final discrimination alone. The errors the subjects made were found to be a functon both of the differences between consecutive discriminations (the “size of the steps” in the program) and the length of training on each discrimination. Theoretical and practical implications of these findings are discussed.