Effects of an intervention program for pregnant adolescents: Educational outcomes at two years postpartum

Examined postpartum effects of a school-based intervention program for pregnant adolescents. Interviews were conducted with 102 innercity black, low-income, school-aged mothers who had attended the program, and their academic and medical records were reviewed. For teenagers who had been poor students prior to becoming pregnant, a strong linear effect was found for duration of program attendance: with sufficient time in the program, poorer students became indistinguishable from better students in educational success. Most of the better students were educationally successful at 2 years postpartum, independent of their length of time in the program. For all students, longer durations of postnatal intervention were predictive of lower likelihood of subsequent childbearing. Numerous academic, medical, social, and demographic variables were ruled out as possible confounding factors that might have produced the positive educational outcomes for poorer students. The results suggest that adolescents who appear to have minimal academic promise prior to their pregnancy are nevertheless very responsive to school-based intervention.     

The specificity of the effects of stimulant medication on classroom learning-related measures of cognitive processing for Attention Deficit Disorder children

There appear to be beneficial effects of stimulant medication on daily classroom measures of cognitive functioning for Attention Deficit Disorder (ADD) children, but the specificity and origin of such effects is unclear. Consistent with previous results, 0.3 mg/kg methylphenidate improved ADD children's performance on a classroom reading comprehension measure. Using the Posner letting-matching task and four additional measures of phonological processing, we attempted to isolate the effects of methylphenidate to parameter estimates of (a) selective attention, (b) the basic cognitive process of retrieving name codes from permanent memory, and (c) a constant term that represented nonspecific aspects of information processing. Responses to the letter-matching stimuli were faster and more accurate with medication compared to placebo. The improvement in performance was isolated to the parameter estimate that reflected nonspecific aspects of information processing. A lack of medication effect on the other measures of phonological processing supported the Posner task findings in indicating that methylphenidate appears to exert beneficial effects on academic processing through general rather than specific aspects of information processing.     

Rhythmic motor behavior of preambulatory motor impaired,down syndrome and nondisabled children: A comparative analysis

The developmental course of rhythmic motor behavior was followed longitudinally for three groups of preambulatory children — normally developing, Down syndrome, and those with profound motor impairment. The groups differed in chronological age but were comparable with respect to motor age. The motor impaired subjects displayed significantly less rhythmic motor behavior than the nondisabled and Down syndrome groups. In comparing particular subtypes of rhythmic motor behavior, differences were found in both the average number of bouts and duration of subtypes among the groups. Longitudinal analyses of the data over the entire observation period revealed that the rhythmic motor behavior of the children with Down syndrome was more similar to that exhibited by the nondisabled children than was the rhythmic motor behavior of the children with motor impairment. However, there was considerable variability among the groups in several particular subtypes.This research was supported by grants from the National Institute of Child Health and Human Development (HD 17650 and HD 07226).The authors acknowledge the assistance of Robert E. Arendt, Grant Youngquist, Michael Hohn, and Charles Lowitzer in obtaining the observational data and thank the families of the subjects for their enthusiasm and dedication to the project.This study was presented at the 23rd Annual Gatlinburg Conference on Research and Theory in Mental Retardation and Developmental Disabilities, April 21, 1990.     

Automatic processes in lexical access and spreading activation.

The semantic priming effect can be reduced or eliminated depending on how the prime word is processed. The experiments reported here investigate this prime task effect. Two experiments used identity and semantic priming tasks to determine whether the prime word is encoded at a lexical level under letter-search conditions. When the prime task was naming, both identity and semantic priming occurred; however, when a letter-search task was performed on the prime word, only identity priming occurred, thus supporting the argument that the search task affects activation of semantic associates rather than lexical access of the prime word. Another experiment demonstrated that this identity priming was the result of lexical processes rather than of letter-by-letter priming. A cross-modal priming technique demonstrated that the letter-search prime task does not actively suppress activation of semantic associates. The implications of these results for automaticity and for proposed mechanisms of priming are discussed.     

Selective impairment of grammatical morphology due to induced stress in normal listeners: implications for aphasia

The traditional clinical picture for English nonfluent aphasics has generally presented the deficit as one of total loss of control over grammatical morphology, with some sparing of word order. This is at odds with recent research involving nonfluent aphasic speakers of highly inflected languages, which has shown that agrammatic performance is characterized by morphological substitution rather than omission errors. If the deficit associated with focal brain damage cannot be adequately accounted for in syndrome-specific ways, we may need to look for language-specific processing explanations. One such explanation has to do with language-specific response to global processing difficulty. The current experiment is designed to study the effects of a stress-related limitation on morphological processing. Normal speakers of a language with a relatively rich morphological system (German) are compared with those of a comparatively impoverished system (English) on different forms of a sentence comprehension task. In one form, "clean" stimuli permit full reliance on all available cues to meaning in each language. In another test, a low-level noise mask partially obscured the stimulus sentences. English speakers, who rely almost exclusively on word order cues, were not affected by the noise manipulation. German speakers relied heavily on morphological and semantic information rather than on word order under "clean" conditions. However, under noise Germans made significantly less use of grammatical morphology, with a trend toward compensatory reliance on word order. The results indicate that a global reduction in processing capacity can affect some aspects of language more than others and suggest that such factors must be taken into account in trying to understand specific impairment of morphology in aphasia.     

Repetition blindness depends on perceptual capture and token individuation failure

A visual prime succeeded by a brief target produces a paradox. Namely, target repetition yields poorer identification accuracy and shorter duration judgments than unrelated prime-target pairs. Experiment 1 manipulated stimulus onset asynchrony to learn when repetition blindness is maximized. Experiments 2 and 3 manipulated expectancy of repetitions through changes in the proportion of repeated trials and instructions, respectively. Results indicate that repetition blindness is influenced by subject strategies and that the change is not mediated by response bias. Experiment 4 showed that increasing the spatial distance between prime and target reduced but did not eliminate repetition blindness. The current data support joint explanation of repetition blindness in terms of perceptual capture (prime-target fusion) and token individuation failure (problems in encoding episodic reoccurrences of an event).     

Scratching as a behavioral index of anxiety in macaque mothers.

The aim of this study was to assess the validity of the notion that anxiety influences maternal style in monkeys. To this end, we investigated the correlations between measures of the quality of mother-infant relationship and scratching, a behavior pattern that reflects a state of anxiety. The subjects were seven group-living macaque mothers and their infants observed during the first 12 weeks postpartum. Postpartum scratching by the mothers was positively correlated with both maternal possessiveness and maternal warmth, two composite measures of the quality of mother-infant relationship that reflect a possessive and attentive maternal style. Evaluation of the correlations between maternal rank and scratching before and after parturition indicated that interactions with their infants, not those with other group companions, were the main source of anxiety for the mothers. These results support the notion that anxiety influences maternal style in monkeys and suggest that studies aimed at investigating physiological and social correlates of maternal emotionality in nonhuman primates could use scratching as a useful and simple behavioral measure.     

Visual detectability gradients: effect of high-speed visual experience.

The detectability of a target pattern presented briefly with a number of similar nontarget patterns varies as a function of the spatial location of the target. Previous work attributes these detectability gradients to a visual search process--a non-eye movement serial scan--that examines a decaying neural representation of the image. (Heron, 1957; Efron, Yund, & Nichols, 1987, 1990a,b,c; Yund, Efron, & Nichols, 1990a,b,c). The results reported in the companion paper (Ostrosky-Solis, Efron, & Yund, 1991) indicated that literacy did not affect overall performance levels but did influence scanning behavior: "...reading, or learning to read, caused the scanning mechanisms of literate subjects to adopt more consistent scan paths, from subject to subject, than they would have adopted without this reading experience." The purpose of the present experiment was to determine the effect on this scanning mechanism, if any, of an entirely different type of visual experience--the high-speed visual processing required of tennis players. Unlike reading which requires the linguistic interpretation of a highly structured visual input, tennis skill requires rapid target detection and tracking in three-dimensional visual space as well as large scale visual-motor coordination. As in the previous experiments, subjects were required to detect a vertical stripe pattern among a number of similar non-target patterns. The experiment was performed on a group of 52 tennis players and on an age- and sex-matched group of 52 non-tennis players. The overall accuracy of target detection was greater among the tennis players than among the non-tennis players and, of more interest, there was a significant difference in the detectability gradients. The detection advantage of the tennis group seemed to reach its maximum in the first half of the scan and then to deteriorate as the scan proceeded. These results indicate that visual experience other than reading can affect the habitual activity of the scanning mechanism.     

Incidental memory for format of presentation of number stimuli: Evidence from monolinguals and bilinguals

Are numerical stimuli represented in an abstract code or is information about surface format preserved in memory? Three experiments bearing on this issue are reported. All used an incidental recall procedure. Two experiments examined memory for numeral versus word format in monolinguals and the third examined memory for words in the first versus second language of Spanish-English bilinguals. Across all studies, memory for format of number presentation was above chance and was as high as 76% under certain conditions. Implications for number representation are discussed.