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.     

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.     

The effects of modifying color-meaning concepts on racial concept attitudes in five- and eight-year-old children

Williams and Edwards (1969) found that changing the positive and negative evaluations given to color concepts by preschool children through reinforcement procedures over two sessions reduced their racial concept attitude scores measured during a third session. The present study replicated their negative reinforcement and control procedures with 5-year-old children, and extended their research to include 8-year-old children. The present results replicated the original findings and in fact showed a larger change in racial attitude scores. While the color-meaning concepts were modified to a greater extent in the older children, the effect of the negative reinforcement procedure on racial attitude scores was similar for the two age groups.     

Fading procedures and conditional discrimination in children

A discrimination reversal task followed by a conditional discrimination problem was administered to children (age range 36 to 107 months). A fading procedure was used during the discrimination reversal training of some subjects and other subjects were trained by a traditional procedure. More subjects trained by the fading procedure performed without errors during training and more subjects in the traditional group solved the conditional discrimination problem.     

Visual size difference discrimination: Effect of disc size and retinal locus

Ability to discriminate between the sizes of two adjacently presented discs of light is considered both as a function of the size of the discs and the retinal locus of their presentation. Ss were required to report whether a comparison disc was seen as larger or the same size as a standard disc when the two were presented briefly together. Results showed that the and required for 50% difference discrimination was independent of the size of the disc and was constant at about 30 sec of arc. For peripheral presentations, the jnd was found to increase in a linear manner with increasing eccentricity of presentation. Comparisons are drawn between the results obtained and peripheral visual acuity data and it is speculated that similar processes are involved in both situations.     

Distance discrimination and observer strategy in judgments of relative size

Six paid Ss participated in an experiment designed to assess the effects of observer strategy and the detectability of a distance cue on judgments of relative size. Ss viewed stimulus pairs through a 21-in. tunnel at one end of an 8-ft table. The Standard stimulus, 94 in. from S, was individually paired with three larger and two smaller comparison stimuli 96 in. from S. A slit of light on the table 95 in. from S and 90 deg to his line of sight served as distance cue. Increases in distance detection improved accuracy of relative size judgments when the comparison stimulus was larger than the Standard stimulus, but decreased accuracy when the comparison stimulus was smaller. Magnitude of this effect varied directly with Ss’ post-experimental reports of judgmental strategy. These findings confirm the importance of distance discrimination in judgments of actual size and the necessity to control perceiver characteristics in the study of size-distance relationships.     

An analysis of emergent simple discrimination in children

In Experiment 1 eight five-year-old children received an arbitrary matching-to-sample task with sample stimuli A1 and A2 and comparison stimuli B1 and B2. This task was mixed with a simple, two-choice discrimination task with stimuli A1 and A2. In subsequent tests with B1 and B2 presented alone, the number of responses to B1 was greater when it had been paired with the correct stimulus of the simple discrimination task than when it had been paired with the incorrect stimulus. In Experiment 2 incorrect comparisons were omitted during the matching-to-sample task. Eight children were taught to point to either A1 or A2 first, and to either B1 or B2 second. Eight other children were taught to point to either B1 or B2 first, and to either A1 or A2 second. The effect of Experiment 1 was replicated with the first but not with the second group. The results of both experiments suggest that the functions of S+ and S- in a simple discrimination task can transfer to test stimuli if the training stimuli precede the test stimuli during paired presentations.     

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.     

Stimulus interaction and transfer of discrimination in children

Two discrimination learning experiments on third- and fourth-grade children are reported. In Expt I, Ss received either simultaneous or successive pretraining followed by simultaneous or successive transfer tasks in which an irrelevant dimension was varied either between or within settings. With the incorporation of a response-produced cues proposal, a modified version of the Hull-Spence theory (C. C. Spiker, Psychological Review, 1970, 77, 496–515) accounted for 81.2% of the variance of the group means and provided a satisfactory method of both quantifying and manipulating the mechanisms of associative transfer, even when the dimensions of pretraining and transfer differed. Because simultaneously pretrained Ss performed more as was expected than did successively pretrained Ss, it was hypothesized that Ss have an extraexperimental tendency to respond to dimensions varying within settings. This hypothesis was supported by the results of Expt II, in which an extensive shaping procedure was used for simultaneous, successive or control pretraining tasks followed by a successive transfer task in which the arrangement of two irrelevant dimensions was manipulated.