Three-month-olds' visual preference for faces and its underlying visual processing mechanisms

This study was aimed at investigating the face preference phenomenon and its underlying mechanisms at 3 months of age. Using an eye-tracker apparatus, Experiment 1 demonstrated that 3-month-olds prefer natural face images to unnatural ones, replicating and extending previous evidence obtained with schematic facelike stimuli. Experiments 2 and 3 showed that the general mechanisms that induce face preference in newborns could not explain the same phenomenon at 3 months of age, when infants are attracted by perceptual cues more specific to faces. This suggests that signs of a process of cognitive specialization are already present in 3-month-olds' visual behavior toward faces.     

Immediate Effect of Training at the Onset of Reaching in Preterm Infants: Randomized Clinical Trial

The authors' aim was to investigate the immediate effect of a single specific training session (serial varied practice), of short duration on the kinematic parameters of reaching, in the period of the emergence of the skill in preterm and low birth weight infants. The study included 16 infants of both sexes, born at a mean gestational age of 32.13 (±1.36) weeks and mean birth weight of 1720.94 (±358.46) g. The infants were randomly divided into 2 groups: experimental and control. The experimental group was given a 5-min training session in reaching, while the control group received no training. The results showed significant differences in peak velocity in the intra (Z = –2.10, p = .036) and intergroup (U = 9.00, p = .016) evaluations, which decreased in the experimental group after training. Cohen's d test for clinical relevance suggested that the specific, short duration training proved effective in promoting slower reaches, with greater adjustment and lower number of units of movement. These results are positive for preterm infants given that these parameters more closely resemble the typical development of mature reaching behaviors in term infants, which suggests that this protocol of reaching training (serial varied practice) could be used as an evidence-based intervention strategy.     

Early Development of Head Movements Between Birth and 4 Months of Age: A Longitudinal Study

The control of head posture and movement play a significant role in the early development of motor skills. However, a detailed kinematic study charting this development is currently lacking. Hence, the authors performed a longitudinal study of 18 infants between birth and 4 months charting changes in head posture and movements when tracking a visual object. The results showed that beyond 2 months, the head was more often held at the body midline and this was accompanied by an increase in the number, extent, and speed of head movement. Further, it was found that head movements were organized into movement units. Movement units initially increased in number, but after 3 months decreased in number and increased in duration, especially after peak velocity. This more symmetrical profile velocity points to more controlled head movements after 3 months of age.     

Early control of reaching: effects of experience and body orientation

Although research suggests that experience may be a better indicator of the acquisition of certain abilities by infants than age, little work addresses this issue in the development of reaching movements in particular. This longitudinal study fills this gap by verifying the effect of practice time on more- and less-skilled reachers of the same age group in different body orientations. Less- (n=6) and more-skilled (n=4) reachers were evaluated at the acquisition of reaching and again after 1 month of spontaneous practice. Kinematic analyses examined 3D wrist motion during reaching trials in supine (0 degrees ), reclined (45 degrees ) and seated (70 degrees ) orientations. The results indicated that skill level was a relevant factor in dealing with gravitational constraints imposed by different body orientations. Time of practice affected the way less- and more-skilled reachers explored and adapted the kinematic parameters of reaching to constraints imposed by body orientations. These findings suggest that not only age, but also experience and body orientations are important constraints that should be taken into account when examining infant reaching development.     

Proximal and distal adjustments of reaching behavior in preterm infants

The authors aimed to investigate proximal and distal adjustments of reaching behavior and grasping in 5-, 6-, and 7-month-old preterm infants. Nine low-risk preterm and 10 full-term infants participated. Both groups showed the predominance of unimanual reaching, an age-related increase in the frequency of vertical-oriented and open hand movement, and also an increase in successful grasping from 6 to 7 months. The frequency of open hand was higher in the preterm group at 6 months. Intrinsic restrictions imposed by prematurity did not seem to have impaired reaching performance of preterm infants throughout the months of age.     

Spatio-temporal parameters in infant's reaching movements are influenced by body orientation

Many studies have demonstrated that the seated position is more effective in promoting reaching movements when compared with supine. The aim of this longitudinal study was to verify the effect of seated and supine positions on spatio-temporal parameters of reaching in 4-6-month-old infants. Four infants were observed during reaching trials in both positions. A total of 235 reaches were analyzed by using the 3D movement reconstruction. Our results showed that frequency of reaching and straightness index increased over age. Significant differences between the positions were observed at 4 months, when the frequency increased and the duration and deceleration time decreased in the seated position. There were no significant differences at 5 and 6 months. These findings suggest that young infants are able to change kinematical parameters of reaching to adapt themselves to intrinsic and extrinsic constraints (i.e. age and position).     

Motor acquisition rate in Brazilian infants

This study used the Alberta Infant Motor Scale (AIMS) with the aim of characterizing motor acquisition rate in 70 healthy 0–6‐month‐old Brazilian infants, as well as comparing both emergence (initial age) and establishment (final age) of each skill between the study sample and the AIMS normative data. New motor skills were continuously acquired from 0 to 6 months of age by the Brazilian infants, but their acquisition rate was non‐linear. When compared to the AIMS sample, Brazilian infants achieved lower percentiles, and their initial age to acquire skills requiring greater antigravity demand was higher. In contrast, Brazilian infants stopped exhibiting primitive patterns earlier, and their final age to acquire antigravity skills was lower. These differences in motor development are suggested to be a consequence of different parental practices and not necessarily indicate motor delay. Thus, the AIMS normative values should be adapted to cultural particularities so as to avoid that infants are misclassified as at risk for motor delay. Furthermore, an adequate assessment of motor development should consider not only the age at which a skill is emerged, but also the age at which such a skill is established in the infant's motor repertoire. Copyright © 2009 John Wiley & Sons, Ltd.     

Reliability of the M-FLEX™: equipment to measure palmar grasp strength in infants

The palmar grasp behavior investigation is frequent in evaluation routine of infants. The aim of this study was to determine the reliability of an instrument for measuring palmar grasp strength in infants from birth to four months of age. Thirty-nine healthy infants from both sexes from birth to four months of age were evaluated and divided into three groups (“SC”, “FR”, “BL”) according to the city they came from. The equipment under test is called M-FLEX^®, which provides maximum grasp strength (FMAX), mean grasp strength (FMEAN) and grasp time (GRT) values. The repeatability and reproducibility of measures produced by the M-FLEX™ were verified. Three measurements were obtained (M1, M2, M3) from both hands, with the infant's face turned to the right. To calculate the repeatability, the three measures were compared to themselves in each group. For reproducibility, the difference between the averages of M1 of the three variables provided by M-FLEX™ was verified in the three sampling sites. The statistical tests used were ANOVA, Pearson's correlation and calculation of the intra-class correlation coefficient (ICC) with their respective confidence intervals (CI). The M-FLEX™ proved to be an outfit that provides measures capable of characterizing the palmar grasp phenomenon in infants.     

Early development of object unity: evidence for perceptual completion in newborns

The present study aimed to investigate whether perceptual completion is available at birth, in the absence of any visual experience. An extremely underspecified kinetic visual display composed of four spatially separated fragments arranged to give rise to an illusory rectangle that occluded a vertical rod (illusory condition) or rotated so as not to elicit perceptual grouping (control condition) was constructed. After newborns' ability to detect the particular kind of rod-and-box display used in the present study had been probed (Experiment 1), they were habituated to the illusory rod-and-box display (Experiment 2), to the control display that did not contain illusory contours (Experiment 3), and to a standard real rod-and-box display akin to those used in previous infants' studies (Experiment 4). Newborns perceived the rod as a connected unit either in the illusory condition (Experiment 2) or in the real condition (Experiment 4), as documented by a preference for a broken rod over a complete rod during the test phase, but not when the occluder was absent (Experiment 3). In all experiments newborns showed no preference between the two test stimuli (control condition), avoiding the possibility that newborns have a spontaneous preference for one test display over the other. Overall, the results of the present study provide evidence that the ability to achieve object unity (1) stems from intrinsic properties of the human perceptual system and (2) is operative from birth, given the right conditions.