Lawrence V. Harper

Epigenetic Inheritance and the Intergenerational Transfer of Experience

Currently, behavioral development is thought to result from the interplay among genetic inheritance, congenital characteristics, cultural contexts, and parental practices as they directly impact the individual. Evolutionary ecology points to another contributor, epigenetic inheritance, the transmission to offspring of parental phenotypic responses to environmental challenges-even when the young do not experience the challenges themselves. Genetic inheritance is not altered, gene expression is. Organismic pathways for such transmission exist. Maternal stress during the latter half of a daughters gestation may affect not only the daughters but also grand-offsprings physical growth. The author argues that temperamental variation may be influenced in the same way. Implications for theory and research design are presented along with testable predictions.

Teacher–child and child–child interactions in inclusive preschool settings: do adults inhibit peer interactions?

Abstract We conducted real-time analyses of the videotaped free play of 24, 3–4-year-olds, half of whom had disabilities, in four University-sponsored, inclusive, child-centered preschool classrooms. There were 7–10, 20-minute observations for each child. Despite significant differences related to child condition in the frequencies of interactions with peers and one-on-one with adults, the same pattern obtained for both groups: Across observations, the proportions of time that each child spent interacting with peers and with adults were negatively correlated for 21 of the 24 children. Analyses of event-sequences revealed that adults were more likely than expected by chance to initiate interactions with a child when s/he was alone and less likely to do so when s/he was interacting with a peer. Within-child patterns of choices also indicated that, after an adult had initiated an interaction with them, the children were less likely to initiate an interaction with a peer and more likely than expected to initiate another interaction with an adult. Additional, exploratory analyses yielded results consistent with the view that some kinds of exchanges with adults may interfere with peer interactions. Implications both for theory and for planning curricula are discussed.

Offspring Effects upon Parents

The idea that offspring affect the behavior of their caregivers is not new. Early concepts of instinct portrayed the activities of animals as mechanical reactions to external stimulation—including stimuli emanating from the young; the Darwinian revolution simply provided a secular explanation for their origins.

Caregiver and Peer Responses to Children with Language and Motor Disabilities in Inclusive Preschool Programs.

Abstract The free-play social behaviors of 24 children with special needs in two discovery-oriented, inclusive preschool programs were compared with their typically-developing classmates who were matched by age and sex. Children who, for various reasons, used little or no productive language spent more time in solitary pursuits, seldom initiated interactions and, when they did, used a different entry strategy than any other group. Children who were incapable of independent locomotion were largely dependent on adults for initiating changes in their activities and for social exchanges. Although they received more adult support than children developing typically, perhaps because of limited sample size, children with disabilities who were capable of independent locomotion and displayed sufficient language to make their needs and intents clear did not differ significantly from the children who were developing typically. Adults’ behavior varied according to child condition and activity. From observing a single, 20-minute videotape of free play, naive observers agreed with our classifications of over 78% of the children.

Longitudinal Change of Ear Advantage for Receptive Language Function in 2½ - to 9-Year-Old Children

In Study I, 24 children at the average ages of 41.1 and 46.1 mo. were presented dichotic digits while another 27 children were tested at average ages of 40.0, 49.6, and 54.6 mo. In Study II, 40 children were tested at average ages of 50.7 and again at 91.8 mo. No significant change in right-ear advantage (REA) appeared across 4- or 9-mo. intervals; however, significant increases were found over the 14-mo. (Study I) and 41-mo. (Study II) intervals. There were no significant effects of sex or phenotypic or family history of handedness.

Lateral specialization and social-verbal development in preschool children

Forty-two 2 1/2- to 5 1/2-year-old childrens social and verbal behaviors were observed during free play in a preschool. A test measuring lateral specialization of verbal function and a standardized psychometric test of verbal ability were also administered. Analysis of variance indicated that the right ear (left hemisphere) is predominant in processing verbal stimuli in children as young as 2 1/2. Multiple regression analyses revealed significant relations between the right ear accuracy score for dichotically presented verbal stimuli and both psychometrically measured verbal ability and a social-verbal factor score derived from play behavior. After the increase related to age was statistically partialled out from both verbal ability and social-verbal scores, verbal expression, length of verbal utterances, time spent in conversation, and peer social interactions increased and parallel play decreased as a function of right ear (left hemisphere) accuracy for verbal stimuli. The relationship between left ear (right hemisphere) accuracy scores for verbal stimuli and social-verbal behavior, however, was not linear. Very high and very low levels of left ear recall predicted an increase in the frequency of parallel play and low social-verbal behavior while moderate levels of left ear accuracy scores predicted the reverse.

Hemispheric Asymmetry Profiles During Beginning Reading: Effects of Reading Level and Word Type

We evaluated how right- and the left-temporal lobe activation of first (1st LR), second (2ndLR), and third (3rdLR) level readers (N = 60; Age = 6–9 years) varied with reading level, word characteristics, and cognitive abilities by using electroencephalogram measurements while the children read high-frequency/high-imageability, high-frequency/low-imageability, and nonsense words. The ANOVA showed significant interaction effects: 1stLR had greater right-hemispheric activation than 3rdLR, who had greater left-hemispheric activation; for nonsense words, 1stLR had lower left-hemisphere activation than that of 2ndLR and 3rdLR. The electroencephalogram (EEG) measure of hemispheric asymmetry indicated a developmental effect on lateralized activity in the temporal lobes of beginning readers during word reading.

Stability and Ear Advantage for Dichotically Presented Environmental Sound Stimuli: Development during Early Childhood

55 right-handed children with no family history of left-handedness received two dichotic presentations of environmental sounds. The mean test-retest interval was 9 days. Raw accuracy scores yielded acceptable temporal stability (rs>.72). The expected consistent left-ear advantage for environmental sound stimuli was only evident in younger and less mature children. Five- and 6-yr.-old children, particularly those with strong right-hand preferences, had a right-ear advantage for the stimuli. Their computed laterality coefficients showed low and nonsignificant test-retest reliabilities, however. Three- and 4-yr.-old children, particularly those with weak hand preferences, had a left-ear advantage for the same stimuli. Of the 3- and 4-yr.-old children who did not have strong right-hand preferences, 92% demonstrated consistent ear advantages across testing sessions and their laterality coefficient test-retest correlations were significant. In contrast, only 47% of the strongly right-handed 3- and 4-yr.-old children and 71% of the strongly right-handed 5- and 6-yr.-old children had consistent ear advantages for the same stimuli. It is suggested that the 3- and 4-yr.-old children processed these stimuli according to endogenous, stimulus-specific brain mechanisms and that learned processing strategies overrode these mechanisms for the 5-and 6-yr.-old children.

Speech self-monitoring in preschoolers: the effects of delayed auditory feedback on recitation.

39 3- to 6-yr.-old children counted to 10 or recited the alphabet with normal auditory feedback, and delays of 150, 350, and 550 msec. There were no age differences. In addition to affecting rate of speech, delay differentially influenced the prosody, intelligibility, and content of utterances. For both tasks and all delay intervals, delay slowed speaking and produced more prosodic disturbances than no delay. More disturbances of intelligibility occurred at the 350- and 550-msec. delays than under no or 150-msec. delay. Disturbances in the content of counting were greater than in the no-delay condition but did not differ across delays. For alphabet recitation, disturbances in content under delay were greater than under no delay and were greater at 350 and 550 msec. than at 150 msec. Thirty-four children lost track of what they were doing; 10 articulated confusion. Children as young as 3 years of age concurrently self-monitor their speech for content.

Pathways by which the interplay of organismic and environmental factors lead to phenotypic variation within and across generations.

The range of responses made to environmental exigencies by animals, including humans, may be impacted by the experiences of their progenitors. In mammals, pathways have been documented ranging from transactions between a mother and her developing fetus in the womb through continuity of parenting practices and cultural inheritance. In addition, phenotypic plasticity may be constrained by factors transmitted by the gametes that are involved in the regulation of gene expression rather than modifications to the genome itself. Possible mediators for this kind of inheritance are examined, and the conditions that might have led to the evolution of such transmission are considered. Anticipatory adjustments to possible environmental exigencies are likely to occur when such conditions recur regularly, but intermittently across generations and endure for substantial periods of time, and when adjusting to them after the fact is likely to be biologically costly, even life-threatening. It appears that physical growth and responses to nutrient availability are domains in which anticipatory, epigenetically inherited adjustments occur. In addition, given the fact that humans have oppressed one another repeatedly and for relatively long periods of time, such behavioral tendencies as boldness or innovativeness may be behavioral traits subject to such effects. The implications of these factors for research and policy are discussed.