Automatic and conscious processing in retarded and nonretarded adolescents

Educable mentally retarded and nonretarded adolescents participated in incidental learning tasks that emphasized the utilization of processes that were consciously controlled but not deliberately aimed at memory (Experiment 1). Retarded individuals' performance on a standard recognition test was equivalent to that of nonretarded subjects following phonetic encoding and nonstrategic encoding, but was deficient following semantic encoding. Retarded subjects also demonstrated a lower level of performance on a rhyme recognition task. In Experiment 2, retarded subjects provided a pattern of responding identical to that of nonretarded subjects on a picture-word interference task designed to assess automatic processing. The two groups produced equivalent levels of semantic activation. It was argued that the results of the two experiments indicate deficient semantic processing on the part of retarded individuals relative to that of nonretarded individuals that cannot be accommodated by a structural-deficiency model, a developmental-lag model, or a hypothesis that predicts intelligence-related differences only when the task involves the use of deliberate mnemonic strategies.     

A follow-up developmental study of hypothesis behavior among mentally retarded and nonretarded children

To clarify the roles of IQ and mental age (MA) in hypothesis behavior, MA-matched subjects at three levels of IQ (70, 100, and 130) and three levels of MA ($\text{5}\text{1}\text{2}\text{, 7}\text{1}\text{2}\text{,}\text{and}\text{9}\text{1}\text{2}\text{years}$) received blank-trial discrimination learning problems using procedures designed to discourage position-oriented responding. With position responding discouraged, earlier findings were contradicted in that no hypothesis measure showed a main effect of IQ. This suggest that previously reported IQ group differences in hypothesis behavior may not reflect cognitive deficits inherently linked to low IQ, but instead may reflect the influence of specific methodological factors. The finding and interpretation are consistent with Zigler's (American Journal of Mental Deficiency, 1969, 73, 536–556) “developmental” theory of retardation and inconsistent with the general “difference” position. In additional findings, the predictions that subjects at all three MA levels would use hypotheses, and that retarded children from special-education classes would use hypotheses more often than retarded children “mainstreamed” in classes for the nonretarded were confirmed.     

GENERALIZATION AND TRANSFER BETWEEN COMPREHENSION AND PRODUCTION: A COMPARISON OF RETARDED AND NONRETARDED PERSONS

The study compared the acquisition, generalization, transfer, and maintenance of language comprehension and production responses by persons at two IQ levels: mentally retarded (N = 10) and nonretarded (N = 10). The two levels of the IQ Level factor were combined factorially with two levels of a Training Condition factor: Comprehension-Production and Production Only. Participants in the former groups were trained sequentially to (a) comprehend coin labels by pointing, and then (b) produce verbally the correct coin label. Participants in the Production Only groups were trained on the latter response only. A three-factor mixed design with one repeated measure plus a multiple baseline across coin responses was employed. Results indicated that both mentally retarded and nonretarded subjects attained a high level of acquisition and maintained their performance on 1- and 4-week follow-up tests. No difference occurred between mentally retarded and nonretarded participants in magnitude of acquisition, but the mentally retarded groups took approximately three times as many trials to complete training. Data also suggested, contrary to past research, that generalization from comprehension to production was bidirectional, with no difference in magnitude between mentally retarded and nonretarded subjects. Transfer from comprehension to production occurred in both nonretarded and retarded subjects; comprehension training facilitated a savings of trials in production training. These results show that language differences between retarded and nonretarded persons are quantitative rather than qualitative as some past research may have suggested.     

Tic-Tac-Toe performance as a function of maturational level of retarded adolescents and nonretarded children

Two groups of retarded adolescents, differing from each other primarily in IQ (and mental age), were compared with two groups of nonretarded children, differing from each other in chronological age (and mental age), on a modified tic-tac-toe game. The mental ages of the retarded and nonretarded groups were approximately the same. It was found that the slope of performance improvement with increasing maturational level was the same for both subject groups, but the performance of the retarded adolescents was approximately 1.5 years behind mental age expectations, as derived from the performance levels of the normal children. These findings support previous suggestions of a major retardate deficit in tasks requiring logical foresight.     

Étude des stratégies d’adultes présentant un retard mental dans la résolution de la Twenty Questions Task

A Twenty Questions problem solving Task was given to 30 mentally retarded adults, 30 mentally nonretarded adults matched on chronological age, and 12 mentally nonretarded children matched on cognitive efficiency. Four strategies were identified on the basis of a subject-by-subject analysis. Results showed group differences of frequency in the use of the strategies. Moreover, results indicated that the more frequent strategy used by the mentally retarded adults is the one which consists in identifying the categories without using them to efficiently reduce the problem space. The interpretation of the results as reflecting a conceptual deficit or a chronicle cognitive sub-functioning of the mentally retarded adults depicted in the literature is discussed.     

Social problem solving and mother-child interactions of educable mentally retarded children

Mothers of retarded children and nonretarded children were observed and videotaped as they interacted with their own child in a seminaturalistic situation, requiring teaching, cooperation, and free play. The child's social problem-solving abilities were assessed independently. The Vineland scale was employed to provide some convergent evidence of social problem-solving as a component of social competence. Twelve educable mentally retarded and 19 nonretarded 10-year-old children and their mothers comprised the sample. For the mentally retarded group, it was found that the higher maternal directiveness, the lower the child's social problem-solving skills. Mothers who often gave the child opportunity for decision-making and social influence had children with higher problem-solving skills. The retarded children produced significantly fewer different strategies for solving social problems, but gave a wider range of strategies than has been found in previous research. There was some support that social problem-solving skills are related to social maturity.     

Control in memory for movement cues by mentally retarded children

The study was designed to determine the desirability of providing external prompts (1) to use a mnemonic to enhance accuracy of recall and (2) to use response 'priming' in memory for spatial location by mentally retarded persons. Two groups of 40 mentally retarded boys and girls and two groups of 40 MA-matched nonretarded children were compared for accuracy in the recall of movement on an arm-positioning task. No differences were found between mentally retarded subjects and MA-matched subjects treated under the same conditions. However, all groups were unable to make spontaneous control adjustments to accommodate the covert manipulations made just prior to recall. By providing response primes, appropriate performance adjustments were made by all groups, resulting in a significant improvement in accuracy of recall. These findings serve to reaffirm earlier reports showing remarkable similarity between the mentally retarded and MA-matched nonretarded subjects.     

Influence of item identification on the memory performance of mentally retarded and nonretarded adults

The role of item identification in the memory performance of mentally retarded and nonretarded adults was examined by varying the identification and memory parameters of a sequential same-different task. In Study 1, retarded subjects' identification ability was demonstrated to be less efficient than nonretarded subjects' ability. In Study 2, target duration and interstimulus interval were varied. Memory performance differed between groups, and the memory deficit for retarded subjects was demonstrated to be independent of their identification deficit. The target durations in Study 2 were relatively brief, and in Study 3, the target duration was increased to insure that all subjects could identify the target. Mentally retarded subjects were demonstrated to have a memory deficit. The results were discussed in terms of possible sources of the memory deficit.     

Performance of retarded adolescents and nonretarded children on one- and two-bit logical problems

Groups of adolescents of retarded and borderline intelligence, ranging in IQ from 44 to 80 and in mean MA (mental age) from 8 to 12 yr, and groups of nonretarded children ranging in mean MA from 6 to 12 yr, were given logical problem solving tasks. In the nonretarded groups, on a one-bit problem only the kindergarten children (mean MA = 6 yr) failed to perform above chance, and were not tested further. On a two-bit problem, only the first graders (mean MA = 7 yr) failed to perform above chance.Conversely, in the low IQ groups, only the borderline group (mean MA = 12 yr) performed reliably above chance on the one-bit problem, and none performed above chance on the two-bit problem. There is a profound deficiency in low IQ individuals on certain tasks requiring logic and foresight, and MA markedly over-estimates their performance relative to the performance of nonretarded individuals.     

Forgetting in retarded and nonretarded persons under conditions of minimal strategy use

Short-term memory processes of mentally retarded (mild, moderate, and severe) and nonretarded persons were compared in a delayed matching-to-sample task that minimized the use of verbal rehearsal. In addition to trials with delays up to 20 s, the inclusion of trials on which the sample and comparison stimuli occurred simultaneously made it possible to isolate memory and discriminability. Forgetting was most pronounced between the simultaneous and 0-s conditions, and nonretarded subjects forgot less than retarded subjects between these conditions. There were no group differences beyond the 0-s delay. Ease of strategy use failed to account for individual differences, and reported strategy use was not related systematically to performance. These findings are incompatible with the hypothesis that normal-retarded differences occur only on tasks involving effortful cognitive strategies. Differences between nonretarded and retarded groups in this study may be due to a failure in automatic encoding processes in retarded persons.     

Comparison of selected gait parameters of trainable mentally retarded and nonretarded males

Although there were no significant differences in the single support phase of gait for 6 trainable mentally retarded boys (Mean age 9.6 yr.) and 6 nonretarded boys (Mean age 9.5 yr.), total gait time and time in double support were significantly different for the two groups, supporting previous research which showed gait was was deficient in trainable mentally retarded individuals.     

Memory for Objects and Faces by the Mentally Retarded and Nonretarded

Visual recognition skills of 26 mentally retarded high school students were compared with the skills of two groups of nonretarded students. All groups were taught to recognize 32 target faces and objects and were retested 1 week, 1 month, and 2 months later. The counterintuitive findings were that there were no significant differences between the retarded and nonretarded groups in memory for faces on any of the retest trials. All groups remembered faces significantly better than they did objects and remembered more of the pictures at 1 week than they did at 1 month or at 2 months. There was no significant loss over time in memory for faces. Relative to nonretarded subjects, the retarded subjects exhibited deficits in encoding and remembering objects but showed no such deficits in encoding and remembering faces. The results suggest that different configurational features may be used to encode objects as opposed to faces.     

The Ability to Encode Facial and Emotional Expressions by Educable Mentally Retarded and Nonretarded Children

The object of the present study was to investigate whether 20 educable mentally retarded (EMR) children matched for verbal mental age on the Peabody Picture Vocabulary Test (PPVT; Dunn, 1965) with 20 nonretarded (NR) controls were adept in identifying emotional facial expressions and producing the equivalent word adjectives. I also reassessed the relationship between the phase of identifying facial expressions (i.e., happy, sad, angry, and scared) and the phase of producing emotional word adjectives, consisting of 16 emotional linguistic constructions (4 short stories for each of the adjectives) between higher in verbal ability educable mentally retarded (HEMR) children and higher in verbal ability nonretarded controls (HNRC) and between low in verbal ability educable mentally retarded (LEMR) children and low in verbal ability nonretarded controls (LNRC). There were no significant differences between EMR and NR children in general, despite the fact that EMR children had deficits in receptive linguistic competence.     

Anderson's Overlap-Hypothesis and the Discontinuities of Growth

Role-taking ability and level of moral development were measured in three groups of boys and girls including 16 moderately retarded adolescents (mean chronological age 15; mean mental age 9), 16 nonretarded adolescents matched for chronological age, and 16 nonretarded children matched for mental age. The mentally retarded adolescents scored significantly lower on role-taking ability and moral development than the adolescents matched for chronological age. They did not differ from children of their same mental age in role-taking ability; and they tended to score lower in moral development. The results supplied qualified support for Kohlberg's theory of moral development.     

Behavioral expectations of retarded and nonretarded children

Two experiments were conducted to examine the effect of the mental retardation (MR) label on impression formation among retarded and nonretarded children and adolescents. The first experiment, conducted with nonretarded children in a mainstreamed school, indicated that they have pessimistic expectations of retarded children with regard to cognitive and ability-related behaviorsand, to a lesser extent, social behaviors (i.e., getting married). However, their reactions were not as pessimistic nor as “patronizing” as were those demonstrated by college students in previous research. In the second experiment, mentally retarded adolescents indicated that they also have negative behavioral expectations of retarded children, however, their self expectations were negative only for social behaviors. The results suggest that, among retarded persons, the expectations associated with the MR label are negative for social behavior, but apparently less pessimistic for cognitive and ability related tasks.     

The ability to encode facial and emotional expressions by educable mentally retarded and nonretarded children.

The object of the present study was to investigate whether 20 educable mentally retarded (EMR) children matched for verbal mental age on the Peabody Picture Vocabulary Test (PPVT; Dunn, 1965) with 20 nonretarded (NR) controls were adept in identifying emotional facial expressions and producing the equivalent word adjectives. I also reassessed the relationship between the phase of identifying facial expressions (i.e., happy, sad, angry, and scared) and the phase of producing emotional word adjectives, consisting of 16 emotional linguistic constructions (4 short stories for each of the adjectives) between higher in verbal ability educable mentally retarded (HEMR) children and higher in verbal ability nonretarded controls (HNRC) and between low in verbal ability educable mentally retarded (LEMR) children and low in verbal ability nonretarded controls (LNRC). There were no significant differences between EMR and NR children in general, despite the fact that EMR children had deficits in receptive linguistic competence.     

Mnemonic strategy instruction in coding, processing, and recall of movement-related cues by mentally retarded children

The purpose of study was to examine the differential coding and processing characteristics of two movement cue types in the investigation of the short-term memory of mentally retarded and nonretarded children. The central focus of the study was to determine the effects of formal instruction in the use of a mnemonic versus no instruction with both types of cues in a memory for movement paradigm. The investigation was conducted across two experiments. The main conclusion drawn from Exp. 1 was that movement 'location' cues were coded, processed, and retained by both the mentally retarded and the nonretarded children, but only the former required instruction in the use of a mnemonic to achieve accurate recall. Exp. 2 was fundamentally a replication of Exp. 1 with the exception that movement 'extent' cues were maintained reliable. The results were similar but not exactly the same as those of Exp. 1. Only the mentally retarded children given mnemonic instruction appeared to code, process, and retain movement 'extent' cues over time. The net result of the two experiments was that formal instruction in the use of a mnemonic was of benefit to the mentally retarded subjects and was not necessary for nonretarded subjects to achieve the same level of movement accuracy.     

Mental retardation and perception of global motion

We have found that mildly mentally retarded adults are impaired in their perception of global stereoscopic forms (Fox & Oross, 1988) in ways that cannot be attributed to peripheral visual deficits or failures to comprehend. To assess the generality of that result, we measured the ability of mentally retarded adults to perceive kinematographic forms. Mentally retarded and nonretarded adults were presented with a two-choice, forced-choice detection task requiring the location of a target's spatial position. The discriminability of the forms was varied by systematic reductions in both element density and temporal correlation. We found that, relative to nonretarded adults, mentally retarded adults exhibited large qualitative deficits in their ability to discriminate these kinematographic forms when either density or correlation was reduced. After considering a number of alternative interpretations of these data based on factors such as peripheral visual impairment and a failure to attend, we could find none more compelling than a perceptual interpretation, which posits a deficit within the short-range motion system.     

Developmental auditory agnosia in the severely retarded: A further investigation

The hypotheses were investigated that (a) ability to recognize the auditory perceptual stimuli for familiar events is a developmental correlate to language acquisition and (b) the low functioning mentally handicapped suffer from auditory agnosia and are impaired in this ability. The subjects were 42 nonretarded children of ages 3 through 6 and 53 severely and moderately retarded, noninstitutionalized students. The retarded subjects were matched by mental age to the chronological age of the nonretarded children. The stimuli were 49 environmental sounds; the task consisted of sound-and-picture matching-to-sample. Group membership and developmental age were the factors in an analysis of variance design. The results revealed a strong effect of developmental age (p <. 0001). The effect of group was not significant, indicating that auditory agnosia may not be common among the lower functioning retarded. The assumption that agnosia may be a major factor underlying the language disability of the severely retarded was reexamined. It was suggested that the severely retarded achieve the requisite perceptual-semantic knowledge base for language too late, after the critical age for spontaneous and efficient language learning has passed.