HAPTIC PERCEPTION IN INFANTS USERS OF ERGONOMIC PACIFIERS

Abstract

Infants haptically react to changes in object characteristics (Rochat, 1987; Streri, Lhote, & Dutilleul, 2000), being able to explore the space and be sensitive to different orientations of a rod by the hands (Gentaz & Streri 2002). One-year-old babies show haptic recognition memory after a short period of haptic familiarization, manipulating novel objects differently from familiar ones (Gottfried and Rose, 1980).

Non-nutritive sucking (NNS) is defined as sucking without the delivery of fluid, is a naturally occurring phenomenon recognized as a pacifying mechanism for preterm and term infants. Thumb sucking and other sucking movements have been seen in human foetuses as early as the 12th week of gestation (Hepper, Shahidullah, & White, 1991).

During familiarization to hard nipples, two-month-old infants revealed decreasing of the amount of irregular mouthing oral activity, while the amount of NNS increased, supporting the hypothesis that information about the object is detected during mouthing rather than during NNS (Pêcheux, Lepecq & Salzarulo, 1988).

Oral exploration and mouthing increases up to the age of seven months and then declines until the age of eleven months, while manual skills progress and diversify between the ages of five and eleven months (Ruff, Saltarelli, Capozzoli & Dubiner, 1992).

The purposes of this paper are to verify if infants detect different spatial orientations of pacifier in the mouth; and if so, to describe infants' motor behaviors when constrained with different spatial orientations of an ergonomic pacifier in the mouth.

The sample consisted of 10 infants (decimal age: 271,6 ± 60,8 days, minimum: 191 days, maximum: 352 days), 5 females, belonging to two kindergartens, users of ergonomic pacifiers (sucking ratio: 1,1 ± 0,8). Informed consent was obtained. The assent was assumed if the baby did not avoid the pacifier of the experimenter and did not cry, sleep or reject the experimenter's presence. The babies' pacifier was used.

Pacifiers were placed by the same experimenter in the babies' mouths in three positions relative to the standard orientation: (i) rotated 90 degrees clockwise; ii) rotated 90 degrees counterclockwise; iii) rotated 180 degrees. The conditions were alternated between the babies. Data were collected with the infant awakened and in a good mood, using their reclined chair at approximately 110-130 degrees (Harrison et al., 1999), in a place with few objects and minimal noise, with the recording of the camera diagonally, at the level of the mouth. The pacifier was presented at the eye level of the child's midline and at approximately 50 cm (eg, Banks, 1980). Each infant made 1 trial in each condition.

When confronted with pacifiers' spatial constraints, all infants presented active behaviors, divisible in 3 categories: i) relocated the pacifier to the standard spatial position, through 3 possible ways- turning it with the mouth; or, grasping it and turning it with the hand; or, spitting it and putting it in the mouth; ii) relocated the pacifier, but to 180 degrees relative to the standard spatial position, through the same actions named in i); and, iii) pacifier rejection, by the ways of spitting it or bitting it. No association was found between decimal age and frequency of behaviors occurrence. No gender differences were found in the frequency of behaviors occurrence. Successful mouth turning behavior occurred 11 times (in 30 possible trials), while successful grasp turning occurred 2 times. In some cases, infants made successive actions to relocate the pacifier, e.g., in the counter clockwise condition, a male infant with 221 days of age grasped and rotated the pacifier and, also, rotated it with the mouth, and a female infant with 303 days of age spit it, grasped and putted it in the mouth, and then rotated it with the mouth. In an open question made to parents, asking them to report play behaviors of their infants with the pacifier, answers obtained reported behaviors as dislocates it to front and rear with the mouth, makes it tremble with the mouth, grasp it and look at it, bitts it, turns it with the mouth, take it off and put it in.

The results reveal that these infants have detected the incorrect position of the pacifier in the mouth, supporting the hypothesis that information about the object is detected during mouthing (Pêcheux, Lepecq & Salzarulo, 1988). An equifinality principle was present in their motor actions, i.e., they had variations of a motor solutions for the same need, e.g., rotating the pacifier in both directions, clockwise and counter clockwise; or, different solutions for the same need, e.g., rotating the pacifier with the mouth or with the hand. Some infants revealed the capability to try to solve their problem through successive motor actions, meaning that a perception-action cycle was present, i.e., after perceptual detection of incorrect pacifier position a motor action was made, and if pacifier position detected was again incorrect a new motor action was done. All these actions reveal that infants detect and search for the ergonomic affordance of the pacifier, to have it comfortably inside the mouth (cf., Rochat, 1987). The occurrence of this perception-action cycle proves that mouth haptic perception is present, is used by infants to solve a spatial problem through motor actions, and that the pacifiers, as implements, are used for functional play (parents reports).