Discrimination of spatially confusable letters by young children

A study of the ability of young children to discriminate spatially confusable letters using four different methods of discrimination (matching, copying, naming, and writing to dictation) was carried out. The subjects were 31 English children whose ages ranged from 5 years 6 months to 6 years 10 months. The test material consisted of 10 spatially confusable letters, i.e., letters whose differential features depend upon their spatial orientation: p, q, d, b, u, and n, and to a lesser extent h and y and w and m. The results show that the accuracy of discrimination of spatially confusable letters is dependent upon the method of assessment employed. The highest accuracy is achieved when the method requires copying confusable letters from a given sample, followed by the method that requires matching a given letter with other possible alternatives. Naming the confusable letters and writing them in response to dictation are the most difficult tasks to perform. The results also indicate that there is a significant correlation between individual performances in the matching, naming, and writing to dictation tests; but in the copying task individual performances varied independently of the performances in the other tests. Some theoretical implications of the findings are discussed.     

Discrimination of small shapes by the rat

Three experiments on small shape discrimination are described. The first investigates the discrimination of square from circle, a discrimination claimed by Lashley to be extremely difficult for the rat and which has since become a matter of theoretical interest. The second and third test a prediction from the writer's theory of shape recognition; the prediction is refuted.     

Discrimination of faces by young infants

An experiment was conducted to obtain normative data concerning discrimination between human faces by infants under 6 months of age and to determine the information base required for this performance. Infants were habituated to a specific face and recovery of attention was monitored to a novel face, where one or more features was common to both faces. Results suggested that discrimination between photographs of adult, female faces is possible from 5 weeks of age, with critical information probably lying in the hair-face outline while internal features were relatively unimportant until the 19th week.     

Discrimination by young infants of stimuli presented discontinuously

Four experiments are reported showing that young infants can pick up visual information from very brief displays. Pattern, edge orientation, and form can be discriminated when stimuli are presented for repeated exposures of only 300 ms.     

Discrimination of picture requests for missing items among young children with developmental disabilities

Two experiments were conducted to assess discrimination of picture requests for missing items among young children with developmental disabilities. In Experiment 1, three children were first taught to request one object when it was missing from a set of two related leisure items. In Experiment 2, two children were taught to request one object belonging to a set of three leisure items. In both studies the requesting response consisted of pointing to a photograph of the missing item. After acquisition of the initial request, discrimination of picture requests was assessed when the second item (Experiment 1) and second or third item (Experiment 2) was missing. Requests for the untrained items emerged in the presence of natural maintaining contingencies and in the absence of instructional prompts for all but the third child in Experiment 1. This child required continued intervention on the initial request. The results suggest that for some children a sequence of intervention and the programming of natural maintaining contingencies may prove effective in promoting the discrimination of picture requests for missing items among young children with developmental disabilities.     

When causality shapes the experience of time: Evidence for temporal binding in young children

It is well established that the temporal proximity of two events is a fundamental cue to causality. Recent research with adults has shown that this relation is bidirectional: events that are believed to be causally related are perceived as occurring closer together in time—the so‐called temporal binding effect. Here, we examined the developmental origins of temporal binding. Participants predicted when an event that was either caused by a button press, or preceded by a non‐causal signal, would occur. We demonstrate for the first time that children as young as 4 years are susceptible to temporal binding. Binding occurred both when the button press was executed via intentional action, and when a machine caused it. These results suggest binding is a fundamental, early developing property of perception and grounded in causal knowledge. A video abstract of this article can be viewed at https://www.youtube.com/watch?v=EQC_MqjxZQQ     

Intermanual transfer of mirror-image discrimination by monkeys

Mirror image equivalence has been studied in four monkeys during inter-manual transfer of tactile discrimination learning. The tasks were designed to progressively reduce the possibility that discrimination would be based on use of the thumb. On three of the four tasks there were consistently significant mirror reversals. The findings support the supposition that mirror inversion occurs during the formation of memory traces, and specifically when the trace is laid down in a second cerebral hemisphere.     

Discrimination training of mirror-image stimuli with a delayed-prompt technique: some critical dimensions of extra-stimulus prompts

Research on fading and delay procedures has shown that extra-stimulus prompts frequently fail to help children learn difficult discriminations. The present study analyzed two delay conditions for an extra-stimulus prompt to help preschoolers discriminate mirror-image stimuli as a function of the configurations and locations of the prompts. All subjects were selected on their ability to discriminate the task stimuli in the presence of a third stimulus, a replica of the S+ and an arrow pointing to that stimulus; and on their inability to do so without these stimuli. Experiments 1 and 2 compared these prompt configurations (S+ replica, arrow) when presented equidistant from the task stimuli. Experiment 3 analyzed the contribution of the replica configuration in terms of its location, in between stimuli or immediately above the S+. Experiment 4 investigated the extent to which the results of the previous experiments could be influenced by the methodology for the assessment of prompt control. The results consistently demonstrated that most subjects did not learn the task unless the extra-stimulus prompt had the same configuration as the S+ and was located equidistant from both task stimuli.     

Representation of object orientation in children: Evidence from mirror-image confusions

Although many cognitive functions require information about the orientations of objects, little is known about representation or processing of object orientation. Mirror-image confusion provides a potential clue. This phenomenon is typically characterized as a tendency to confuse images related by left–right reflection (reflection across an extrinsic vertical axis). However, in most previous studies the stimuli were inadequate for identifying a specific mirror-image (or other) relationship as the cause of the observed confusions. Using stimuli constructed to resolve this problem, Gregory and McCloskey (2010) found that adults’ errors were primarily reflections across an object axis, and not left–right reflections. The present study demonstrates that young children's orientation errors include both object–axis reflections and left–right reflections. We argue that children and adults represent object orientation in the same coordinate-system format (McCloskey, 2009), with orientation errors resulting from difficulty encoding or retaining one (adults) or two (children) specific components of the posited representations.     

Discrimination of small numerosities in young chicks

Chicks were trained to discriminate small sets of identical elements. They were then tested for choices (unrewarded) between sets of similar numerosities, when continuous physical variables such as spatial distribution, contour length, and overall surface were equalized. In all conditions chicks discriminated one versus two and two versus three stimulus sets. Similar results were obtained when elements were presented under conditions of partial occlusion. In contrast, with sets of four versus five, four versus six, and three versus four elements chicks seemed unable to discriminate on the basis of number, although nonnumerical discrimination based on perceptual cues was observed. This adds to increasing evidence for discrimination of small numerosities of up to three elements in human infants and nonhuman animals.