Deborah G. Kemler

Developmental trends in free classification: Evidence for a new conceptualization of perceptual development☆

Two studies are reported to explore the hypothesis that young children perceive integrally some stimuli that older children perceive separably. In both, kinder-garteners, second graders, and fifth graders (approximately 5, 8, and 11 years old) are required to classify sets of stimuli that vary in size and brightness. Triads are used in Experiment 1 and tetrads are used in Experiment 2. Also, in Experiment 2, second classifications, judgments of which classification is “best,” and verbal justifications for classifications are obtained. The general finding is that the kinder-garten data systematically implicate integrality of size and brightness while the fifth-grade data systematically implicate separability of size and brightness. The second-grade data are more ambiguous. Issues related to refining the developmental hypothesis and to extending its supportive data base are considered in a final discussion.

Holistic and analytic modes of processing: The multiple determinants of perceptual analysis

With the use of the criterion of privileged axes, a set of experimental studies establishes that analytic processing of saturation and brightness, prototypical integral dimensions, does sometimes occur. Still, it is less frequent and less successful than analytic processing of separable dimensions. The studies identify several factors that influence whether or not analytic processing occurs. Among them are the following: (a) stimulus factors, in addition to the choice of dimensions (e.g., the magnitude of dimensional differences); (b) task factors (e.g., the degree to which analytic processing is encouraged by instructions or by implicit task demands, the amount of time available for processing); and (c) subject factors (e.g., the amount of experience that the perceiver has had with the stimuli in tasks that encourage stimulus analysis).

Is there a developmental trend from integrality to separability in perception

Abstract Some previous literature suggests that young children perceive in an integral, holistic fashion stimuli that older children perceive in a separable, dimensionalized mode. A prediction from a strong form of this position is that younger children actually may perform more rapidly a speeded classification task that requires “condensation” than a task that requires “filtering” (if the similarity relations among the wholes favor the former task). Older children should be able to take advantage of the simple unidimensional basis of the filtering task and thus accomplish it much more rapidly than the condensation task. The results are only partially in accord with the predictions. Kindergarteners (5 years of age), on size-and-brightness stimuli, show no speed advantage on either task, while second (8 years) and fifth (11 years) graders clearly show more rapid filtering. Therefore, the developmental hypothesis is in need of some revision and elaboration. Some stimuli are less separable for younger than for older children, but even five year olds can access their dimensional structure under some conditions.

Overcoming Stroop Interference: The Effects Of Practice On Distractor Potency

With practice, do distracting stimuli lose their ability to distract? In a series of experiments, subjects practiced counting digits, a task subject to Stroop-type interference, and then were tested in a variety of transfer conditions. The results indicate that digits do lose their ability to distract as a result of practice but that this loss is highly specific; practice in ignoring one pair of distractors (2 and 4) does not improve later performance when ignoring a different pair (1 and 3). However, this practice effect does transfer to distractor stimuli having the same meaning as the stimuli ignored in practice (TWO and FOUR, but not TO and FOR). The results can be explained either in terms of active learning to suppress distraction or in terms of habituation of competing responses.

The Ability For Dimensional Analysis In Preschool And Retarded-Children: Evidence From Comparison, Conservation, And Prediction Tasks

Abstract Previous findings of a developmental trend from holistic to analytic modes of processing yield to two possible interpretations—the ability to analyze into dimensions increases with age, or a production deficiency for the strategy of analyzing decreases with age. In the three studies reported here an attempt is made to elucidate which of these interpretations is the more correct by investigating the performance of preschoolers and retarded children in three tasks, all of which require dimensional analysis. The three tasks involve (a) same-different comparisons of selected dimensions of stimuli, (b) judgments of whether dimensions are conserved through transformations of objects, and (c) predictions of the outcomes of transformations that selectively modify dimensions of objects. Normal 3-year-old children and mildly retarded preadolescents make many errors on all three tasks and the patterns of these errors are predictable from holistic processing. Older groups of normal preschoolers, 4.5 to 5 years old, perform very well on the tasks, although they show some hints of remaining analytic deficits. It seems likely that the ability to analyze does undergo development in the preschool years, but that the production-deficiency interpretation also has merit, particularly for explaining developmental trends within the elementary school range.

The Sources of Developmental Differences in Children's Incidental Processing during Discrimination Trials.

Abstract 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.

A developmental study of facilitation by mnemonic instruction

Abstract First- and fourth-grade children, as well as adults, were given mnemonic instructions to image or to verbalize a sentence in order to study either a sentence or a noun pair provided aurally. Uninstructed control subjects also were included at each age level. A test of cued recall evaluated the amount of facilitation by mnemonic instruction in each of the groups. Both types of instruction enhanced childrens memory, most notably when verbal pairs served as stimuli. However, whereas first graders under imagery instruction were inferior on pairs relative to sentence stimuli, fourth graders and adults recalled the two stimulus types equivalently. Also, whereas first graders performed at the same level on sentences and pairs under the verbalization instruction, fourth graders were superior on the pairs. These results indicate that greater requirements for subject-generated mediation to some degree penalized the younger subjects and benefited the older ones.

A Developmental Comparison of Two Types of Visual Mnemonics.

Abstract The effectiveness of two kinds of visual mnemonics (mental imagery instructions and picture presentation) was evaluated by comparison to an uninstructed control condition. Subjects were included from three age groups: first grade, fourth grade, and adult. Three types of memory tests (free recall, cued recall, and recognition) were used to assess performance. While both mental imagery and picture mnemonics reliably facilitated cued recall and recognition for first- and fourth-grade subjects, there were no reliable differences between the adult groups. In contrast, only adults showed significant facilitation under free-recall testing. Qualitative analyses of memory gave no indication that the kinds of information stored under the three instruction conditions are different.

Selective attention and dimensional learning: A logical analysis of two-stage attention theories

The argument of the present paper is that attention theories (e.g., Sutherland & Mackintosh, 1972) make logically independent assumptions of selective attention and dimensional learning. The separability of these assumptions is illustrated by a model that assumes dimensional learning but no selective attention. The model successfully predicts the results of discriminative shift studies (e.g. ID vs ED shift comparisons) and supports the conclusion that a selective attention mechanism is not necessary to explain the results of such studies.