Modulation of manual activity by vision in human newborns

How do human newborns come to understand the multimodal environment?

For a long time, newborns were considered as human beings devoid of perceptual abilities who had to learn with effort everything about their physical and social environment. Extensive empirical evidence gathered in the last decades has systematically invalidated this notion. Despite the relatively immature state of their sensory modalities, newborns have perceptions that are acquired, and are triggered by, their contact with the environment. More recently, the study of the fetal origins of the sensory modes has revealed that in utero all the senses prepare to operate, except for the vision mode, which is only functional starting from the first minutes after birth. This discrepancy between the maturation of the different senses leads to the question of how human newborns come to understand our multimodal and complex environment. More precisely, how the visual mode interacts with the tactile and auditory modes from birth. After having defined the tools that newborns use to interact with other sensory modalities, we review studies across different fields of research such as the intermodal transfer between touch and vision, auditory-visual speech perception, and the existence of links between the dimensions of space, time, and number. Overall, evidence from these studies supports the idea that human newborns are spontaneously driven, and cognitively equipped, to link information collected by the different sensory modes in order to create a representation of a stable world.

Roughness perception: A multisensory/crossmodal perspective

Roughness is a perceptual attribute typically associated with certain stimuli that are presented in one of the spatial senses. In auditory research, the term is typically used to describe the harsh effects that are induced by particular sound qualities (i.e., dissonance) and human/animal vocalizations (e.g., screams, distress cries). In the tactile domain, roughness is a crucial factor determining the perceptual features of a surface. The same feature can also be ascertained visually, by means of the extraction of pattern features that determine the haptic quality of surfaces, such as grain size and density. By contrast, the term roughness has rarely been applied to the description of those stimuli perceived via the chemical senses. In this review, we take a critical look at the putative meaning(s) of the term roughness, when used in both unisensory and multisensory contexts, in an attempt to answer two key questions: (1) Is the use of the term 'roughness' the same in each modality when considered individually? and (2) Do crossmodal correspondences involving roughness match distinct perceptual features or (at least on certain occasions) do they merely pick-up on an amodal property? We start by examining the use of the term in the auditory domain. Next, we summarize the ways in which the term roughness has been used in the literature on tactile and visual perception, and in the domain of olfaction and gustation. Then, we move on to the crossmodal context, reviewing the literature on the perception of roughness in the audiovisual, audiotactile, and auditory-gustatory/olfactory domains. Finally, we highlight some limitations of the reviewed literature and we outline a number of key directions for future empirical research in roughness perception.

Interweaving social and manipulative development in early infancy: Some direction for infant caregiving

Early infancy has been neglect not having the best opportunities to promote social motor and cognitive development. The maturational concept considering young infants as passive beings provide a misguided view of the developmental process. The human infant is an active being from the very beginning of life. In the social and physical world, they can, by observing and imitating, perform complex actions involving different motor behaviours. In the present review we argue that imitation and manipulative actions are integrated in Expressive Action System (Reed, 1996) where baby-caregiver social interaction is the link between the use and exploration of objects in the world. We present evidence that neonatal imitation and manipulation activities are connected and thus, we propose stimulation practices based in seminal experimental designs where infants should be positioned in favourable postures to observe others acting in the world. This will have an impact on the way that early infants understand the social world and the chain of actions possible in this environment.

Body perception: intersensory origins of self and other perception in newborns

Self-perception involves integrating changes in visual, tactile, and proprioceptive stimulation from self-motion and discriminating these changes from those of other objects. Recent evidence suggests even newborns discriminate synchronous from asynchronous visual-tactile stimulation to their own body, a foundation for self-perception.

Haptic processing in newborns of depressed and nondepressed mothers

This study was conducted to compare how newborns of depressed mothers and newborns of nondepressed mothers gather tactile information about texture. Spontaneous manual activity on objects with a smooth or rough texture was recorded in 20 newborns born of mothers with a high risk of depression or a low risk of depression. An important result of the present study is that texture-based modulation of hand-pressing frequency was observed in both neonates born of depressed mothers and neonates born of nondepressed mothers. Moreover, hand-pressing frequency did not depend on the pressure exerted on the object, since all neonates displayed comparable pressure on the held object. Lastly, the results revealed that newborns of depressed mothers held the rough object twice as long as newborns of nondepressed mothers. These results are analyzed in reference to deregulated biochemical functions in neonates born of mothers with a high risk of depression.

The haptic abilities of the human newborn

Abstract. How do human babies gain knowledge by touch? This review presents information on the haptic abilities of human newborns and preterm infants which sheds light on this question. How do full-term and preterm newborns perceive information and form a perceptual representation of objects extracted from the hands alone? How do full-term newborns transfer this information to vision in an intermodal process? Using a habituation/dishabituation procedure, experiments have revealed that preterm and full-term newborns are able to discriminate object shapes in the manual, as well as in the visual modalities for full-term newborns. These abilities are a prerequisite for the establishment of relations between haptic and visual sensory information in cross-modal transfer tasks. We discuss several experiments performed using an intersensory successive preference procedure which provide evidence for cross-modal recognition from touch to vision from birth in full-term newborns. The links, however, are limited, partial, and not always reciprocal. We discuss these results in the light of recent theories on visual-haptic links.

Perception of object shape and texture in human newborns: evidence from cross-modal transfer tasks

The present research investigates newborn infants' perceptions of the shape and texture of objects through studies of the bi-directionality of cross-modal transfer between vision and touch. Using an intersensory procedure, four experiments were performed in newborns to study their ability to transfer shape and texture information from vision to touch and from touch to vision. The results showed that cross-modal transfer of shape is not bi-directional at birth. Newborns visually recognized a shape previously held but they failed to tactually recognize a shape previously seen. In contrast, a bi-directional cross-modal transfer of texture was observed. Taken together, the results suggest that newborn infants, like older children and adults, gather information differently in the visual and tactile modes, for different object properties. The findings provide evidence for continuity in the development of mechanisms for perceiving object properties.

WEIGHT PERCEPTION IN NEONATE INFANTS

A recent research revealed the capacity of the newborn to haptically detect, the weight of an object [12]. In this research, we tried to determine the means by which newborn infants, not having yet exploratory procedures, are able to treat this object property. We support the assumption that tactile perceptive capacities of the newborn infants derive from a fundamental property of the sensorimotor system: its primary variability. After a period of habituation with a heavy or light object, an object of new weight is presented (period test). Three parameters of the sensorimotor activity were analyzed during these two periods: holding times, amplitude of the pressure exerted on the object and frequency of the pressure. Analyses of these parameters demonstrate the neonate's capacity to discriminate objects weight.