Infants' responses to mothers' imitative behaviors

Several investigators have suggested that young infants' smiles and vocalizations following their mothers' imitative behaviors might reflect infant recognition that the mother's behavior is imitative or at least contingent. This study investigated whether infants smile and vocalize more frequently subsequent to maternal imitative than non-imitative behavior during both spontaneous and imitative face-to-face interactions. Fourteen 3 1/2-month-old infants and their mothers were videotaped in these two face-to-face interaction situations. The infants vocalized more frequently during the imitative situation and infant vocalizations plus simultaneous smiling, and vocalizations occurred more often following maternal imitative than non-imitative behavior. Although these data suggest that infant vocalizations and simultaneous smiles and vocalizations may reflect the infants' recognition of maternal imitative behavior, they do not establish definitively that it is the imitation per se vs. the contingency aspect that is recognized by the infant.     

Developmental effects of an intervention for preterm infants of teenage mothers

Since preterm infants and infants born to teenage mothers are noted to be at risk for developmental delays, a group of infants who were both preterm and born to teenage mothers was provided a sensorimotor exercise intervention program for the first year of infancy. The development of these infants was compared to the development of preterm infants without intervention and term infants of teenage mothers as well as term and preterm infants of adult mothers to determine the degree to which developmental delays were prevented. The intervention infants showed more optimal growth, cognitive development, temperament and play behaviors during interactions with their mothers across the first year of development.     

Play behaviors of handicapped preschool children in the presence and absence of nonhandicapped peers

Sixteen minimally handicapped children and 18 nonhandicapped children were observed playing as separate classes and as a combined group on their preschool playground. Play behaviors directed toward self, toys, teachers, and peers were recorded using a time sampling procedure. Repeated measures analyses revealed that: (1) handicapped children engaged in less peer-directed and more teacher-directed behaviors than the similar chronological age but developmentally more advanced normal children; (2) a comparison between a subsample of normal and handicapped children who were approximately equivalent on developmental age suggested that the normal children only vocalized more often; (3) when integrated with the normal children, handicapped children engaged in more peer-directed and less teacher-directed behaviors than when playing in the non-integrated situation; (4) during the combined group play situation, normal children directed more behaviors to their own classmates while handicapped children directed approximately equal amounts of behavior to their own classmates and to their normal peers. These results suggest that the normal children were not negatively affected and the handicapped children were positively affected by the integrated play situation.     

Perceptual-motor sequence learning of general regularities and specific sequences.

Participants viewed digit strings and typed them on a computer keyboard. When they used the same key configuration across training and test, they typed test strings that adhered to the same sequence rule as training strings faster than test strings that adhered to the opposite rule (general-regularity [GR] learning), and they typed test strings that were processed repeatedly during training faster than test strings that were not (specific-sequence [SS] learning). However, when they used different key configurations at training and at test, GR learning, but not SS learning, was observed. Conversely, when they did not type but spoke the strings aloud during training, SS learning, but not GR learning, was observed. Results suggest that in addition to declarative memory for specific sequences, relatively independent subsystems underlie procedural learning of perceptual-motor sequence components (producing GR effects) and sequence wholes (producing SS effects).     

Reevaluating evaluative conditioning: a nonassociative explanation of conditioning effects in the visual evaluative conditioning paradigm.

In 2 studies, the authors investigated whether evaluative conditioning (EC) is an associative phenomenon. Experiment 1 compared a standard EC paradigm with nonpaired and no-treatment control conditions. EC effects were obtained only when the conditioned stimulus (CS) and unconditioned stimulus (UCS) were rated as perceptually similar. However, similar EC effects were obtained in both control groups. An earlier failure to obtain EC effects was reanalyzed in Experiment 2. Conditioning-like effects were found when comparing a CS with the most perceptually similar UCSs used in the procedure but not when analyzing a CS rating with respect to the UCS with which it was paired during conditioning. The implications are that EC effects found in many studies are not due to associative learning and that the special characteristics of EC (conditioning without awareness and resistance to extinction) are probably nonassociative artifacts of the EC paradigm.     

Changes in imitative behavior during early infancy

Changes in imitative behavior and attentiveness were observed in 40 infants when they were 2 to 6 months of age. The facial expressions happy, sad, and surprised were modeled in a trials-to-criterion procedure, and the infants' looking time and mouth movements were recorded by an observer who was unaware of the face being modeled. In addition, the observer recorded her guess as to the expression being modeled by the corresponding expression on the infant's face and rated the infant's expressivity. The results suggested that looking time, correspondence between the mouth expression of the infant and the mouth expression modeled, accuracy of the observer's guess, and expressivity ratings decreased from 2 to 3 and 4 to 6 months. Although matching of mouth movements with the modeled mouth movements and accuracy of guesses were greater than chance over the 2 to 6 month-period, the decreases in these measures suggest that imitative behavior declined across early infancy. The decrease in looking time suggests that imitative behavior and attentiveness may be related and highlights the limitation of this paradigm for assessing the development of imitation during early infancy.     

Prenatal cortisol, prematurity and low birthweight

Three hundred depressed pregnant women were recruited at approximately 20 weeks gestation. They were then divided by a median split into high and low urinary cortisol level groups. The high cortisol group had higher CES-D depression scores and higher inhibition (BIS) scores prenatally. Their fetuses had smaller head circumference, abdominal circumference, biparietal diameter and fetal weight. The high cortisol group neonates were shorter gestational age and lower birthweight and they had lower Brazelton habituation and higher Brazelton reflex scores. Discriminant function analyses suggested that cortisol levels more accurately classified short gestation and low birthweight groups than CES-D depression scores.     

Happy faces are habituated more slowly by infants of depressed mothers

Three-month-old infants of depressed (n=16) and non-depressed mothers (n=16) were habituated to video clips of a female model reciting phrases while posing happy or sad facial/vocal expressions and dishabituated to the alternate expressions. Overall, infants of depressed mothers took longer to habituate the video clips compared to infants of non-depressed mothers, and those assigned to habituate the sad video clips displayed a novelty response or dishabituated to the happy expressions. These findings suggest that 3-month-old infants of depressed mothers discriminate sad from happy expressions, however, they do not appear to perceive sad expressions as novel.     

Newborns of depressed mothers who received moderate versus light pressure massage during pregnancy

Sixty-four neonates (M age=6.8 days) of depressed mothers who received moderate pressure massage versus light pressure massage therapy during pregnancy (month 5 through month 8) were compared on their behaviors during 15-min observations and on their performance on the Brazelton Neonatal Behavior Assessment Scale. The group of neonates whose mothers received moderate pressure massage spent a greater percent of the observation time smiling and vocalizing, and they received better scores on the orientation, motor, excitability, and depression clusters of the Brazelton scale.     

Greater arousal and less attentiveness to face/voice stimuli by neonates of depressed mothers on the Brazelton Neonatal Behavioral Assessment Scale

Neonates born to depressed (n = 44) versus non-depressed (n = 43) mothers were compared on individual items of the Brazelton Neonatal Behavioral Assessment Scale (NBAS). The neonates of depressed mothers received lower scores on orienting to the live face/voice stimulus and on the alertness items, suggesting they were less attentive. They also scored less optimally on the cuddliness and hand-to-mouth activity items, suggesting they were more aroused. These data lend support to the model that infants of depressed mothers are more aroused and less attentive.