Neurobehavioural Development in Infancy

Infant neurobehavior and development comprise behaviours produced by neurophysiological and psychological processes that mediate babies' internal processes and interactions with the outside environment. Neurobehavior should ideally develop adaptability within circumstances that challenge babies daily. We begin with a very restricted description of neurobehavior, followed by the argument that understanding neurobehavioral development requires a larger biosocial perspective.

Although this may surprise some readers, we contend that neurobehavior is not self-contained, predetermined, or simply unfolding under the supervision of genetic maturational processes. We consider neurobehavior integrated into constant, bidirectional, dynamic regulation interactions between babies and carers.

Infant Neurobehavioural Capacities

In the past, babies were thought to be reflexive. Infant neurobehavioral conduct was patterned after spinal frog behaviour, in which reactions to stimuli were supposed to be fixed, under stimulus control, and automated; however, the model was severely incorrect. The newborn's brain and physiology generate four categories of complex neurobehavioral behaviour −

  • Attention − The visual and auditory capacity to process information, such as monitoring objects and distinguishing faces;

  • Arousal − The expression and intensity of emotions ranging from sleep to alert to distress, as well as its modulation through self-soothing of discomfort;

  • Action − Fine and gross motor abilities for acting in the world of things and people, such as protective "reflexes" and reaching for an item;

  • Affective, social processes − Communicative, emotional displays, smiling

On the other hand, understanding baby neurobehavior necessitates acknowledging that the quality of neurobehavior is mediated by state - the organization of neurophysiological (heart rate, breathing, EEG) and behavioural systems (tone, movements) through time. Six states have been identified and are now used to understand infant neurobehavior: two sleep states (States 1 and 2, REM sleep), one semi-awake/transitional state (State 3), two awake or alert states (States 4 and 5, active alert), and a distressed state (State 6).

Recognizing the mediating function of state threw the spinal frog model out the window when baby reflexes (e.g., knee jerk, sucking) were discovered to vary in intensity, strength, and quality depending on the child's state; that is, they were barely single synapse spinal reflexes.

Each condition influences the quality of a baby's neurobehavior and its effect on reflexes. States influence the repertoire of complex motor and sensory/perceptual processes in infants and even determine various infant response modalities; for example, facial brightening and alerting to visual stimuli only occur during the awake states; startles occur in States 1,4,5,6, but rarely in States 2 or 3; movements are smooth in State 4 but jerky and uncoordinated in State 6, uncoordinated in State 3, and largely absent in State 2.

Furthermore, babies acquire information in various states and adjust their behaviours differently. Cuddling and head tilting to sound occur primarily in States 4 and 5, may occur in States 3 but not in States 2, and habituation can occur in States 1, 2, and 4.

Mutual Regulation Model

Although we see newborns as capable individuals with a remarkable capacity to self-regulate and behave in the environment, we must acknowledge that their skills are restricted and undeveloped. Unless newborns obtain external help to scaffold their organization, the quality of their neurobehavior declines. Infants, for example, can limit heat loss by assuming a foetal posture or increasing activity. However, they may require carer ventral touch to establish thermal homeostasis. Similarly, newborns may interpret inputs when aware, although this is an energy-intensive and sometimes fleeting condition.

They can better maintain neurobehavioral alert states with postural support and calming from their careers. Overall, newborns actively control their neurobehavioral systems to maintain homeostasis and neurobehavioral coherence, particularly when assisted by a career. External supports like these are sometimes disregarded, although they are crucial to the quality of expression and development of newborn neurobehavior.

The Mutual Regulation Model (MRM) is proposed for describing extrinsic supports that contribute to organized newborn neurobehavior. It has been demonstrated that babies and adults cooperatively control their behaviour, emotion, and communication during social interactions and share objectives to achieve well-organized physiological, behavioural, and interpersonal states. According to the MRM, these processes are cooperatively governed by newborns who use intrinsic self-organized capacities in conjunction with regulatory input from carers.

The success or failure of mutual regulation to maintain infants' neurobehavioral coherence and engagement with others is thus dependent on both infant and carer capacities: the infant's physiological and central nervous system integrity, the infant's ability to express the status of these systems to the carer, and the caregiver's ability to read and act on the infant's messages. These processes are dynamic in that they constantly impact and modify one another; they are mutually controlled.

Culture and Infant Neurobehavioural Development

When child neurobehavior is seen to be highly linked with the behaviours of another person, a more extensive understanding of neurobehavioral organization is necessary. It must be viewed as a socially managed process, not just a biological one. The brain and the physiological mechanisms that drive neurobehavior are imbued with culture as a social activity. This viewpoint is required because carers' implicit and explicit views of baby capacities, as well as their attention and actions with their infant, are influenced by culture. This is seen in how the carer reacts to the infant's demands in the present.

Thus, cultural caregiving practises impact the development of newborns' central nervous systems and infants' reactions to the specific limits imposed by the cultural environment. However, biological factors, maturation, and the effects of biological perturbations (e.g., illness, malnutrition) have traditionally overshadowed the role of culture on neurobehavioural development, in part because they frequently demonstrate causal and immediate effects on physiological and behavioural changes; the assumption is that these factors are the primary determinants of neurobehavioural development.

The MRM, on the other hand, contends that prenatal and postnatal events shape functional and structural aspects of neurodevelopment, placing culture considerably closer to neurobehavioral development.

Although studying cultural effects is difficult in comparison to factors that can be manipulated (e.g., NICU care) or that already vary within a community (e.g., toxicant exposure), characterizations of infant development from various cultural groups, as well as research on gene-environment interaction and epigenetic processes, support the interdependence of biology and culture.

For example, the Peruvian Quechua's different caregiving practises impact the biological and behavioural processes underpinning baby neurobehavioral development. The Manta pouch is a culturally constructed care-taking technique used by Peruvian Quechua living at high altitudes (4250 m) to 'house' their children - a layered arrangement of cloths and blankets that snugly wrap around and surround the infant.


Only considering biological elements in neurobehavioral development is an incomplete picture of neurobehavioral development. A broader perspective on neurobehavioral development is required to understand the complexities of the processes that occur across time. As it absorbs external inputs, the infant state recognizes the general organization of the newborn's physiological and behavioural systems.

Through the MRM lens, the carer and newborn work together to sustain infant neurobehavioral coherence and organization. Social input influences the organization of neurobehavioral behaviour in the present. Most importantly, babies unable to engage in acceptable social interactions within their culture will not grow normally. Fortunately, when carers perform well in their contexts, excellent parenting naturally flows, assisting newborns in developing into culturally suitable creatures.

Updated on: 10-May-2023


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