Post content

Summary of the scientific evidence on the nature and determinants of child development and their implications for programmatic interventions with young children

Working group: Sally M. Grantham-McGregor (Chairman), Ernesto Pollitt, Theodore D. Wachs, Samuel T. Meisels, and Keith G. Scott

Food and Nutrition Bulletin, vol. 20, no. 10, 1999, The United Nations University

Introductory Statement

Although in recent years there has been a dramatic decrease in child mortality in low-income countries, many surviving children continue to have poor psychosocial and cognitive development. There are extremely limited data on the size of the problem, but it is likely that millions of young children are failing to reach their potential in development. They subsequently are unable to benefit fully from schooling and to become productive citizens. This failure has implications both for the individuals and for national development.

A workshop held in 1991 in Jamaica [1] concluded that there was substantial evidence that poor health and nutrition detrimentally affected children’s development. However, good health and nutrition alone were insufficient to promote optimal child development, and quality of the psychosocial environment was also important. It was the need to look at the children’s development in a holistic way and take an integrated approach to child services that stimulated the subcommittee on Nutrition and Mental Health of the Institute of Child Health, London University, and UNICEF, New York to plan another workshop. The aim of the event was to sensitize senior managers and policy makers to the need for development of programmes that integrated child development, health, and nutrition activities.

The resulting workshop was held at Wye College, Kent, in the United Kingdom, on April 4-8, 1998, and was attended by researchers active in the field of nutrition and child development, UNICEF programme officers from regional and country offices, and representatives from other international agencies and non-governmental organizations. The papers in this issue were presented at the workshop. These papers review the nature of child development and factors that affect it, including health, nutrition, and the environment. The problems in measuring child development and identifying at-risk children are discussed. Case studies of integrated programmes and studies from developing countries are also included. Finally, the economic implications of such programmes are considered.

Following the Wye meeting, a small group of researchers met at UNICEF’s request in New York and wrote a short summary of the scientific evidence on the nature and determinants of child development and their implications for interventions. This summary can be found in this issue after this introductory statement. It is hoped that this issue will contribute to further work on designing and implementing integrated programmes for the promotion of child development in developing countries.

Several people contributed to the planning of the meetings, including David Alnwick, Roger Shrimpton, Ludmila Lhotska, and Marjorie Newman-Williams from UNICEF, and Andrew Tomkins from the Centre for International Child Health, University College, London. Ernesto Pollitt from the University of California, Davis, was particularly helpful in planning the scientific programme. The meeting was funded by UNICEF with a contribution from the International Union of Nutritional Sciences

Sally Grantham-McGregor Editor

At the request of UNICEF, a summary was prepared of the scientific evidence on the nature and determinants of child development and their implications for programmatic interventions with young children. This summary is given below and reflects the views of the authors. We have included well-established points that we think are important as well as adding information that is new both theoretically and empirically

The size of the problem

No figures exist on the number of children with developmental delays (lags in mental, motor, social, and emotional development compared with reference criteria) as a result of poor health and nutrition and poor environments. However, 39% of children under five years of age in low-income countries are growth retarded. Growth retardation is a marker for both disadvantaged environments and developmental risk, and hence it is likely that at least this proportion of children will have poor developmental outcomes. The size of the problem is obviously enormous, but more data are urgently required

The nature of early childhood development

Child development is multidimensional. These dimensions, which are interdependent, include social, emotional, cognitive, and motor performance, as well as patterns of behaviour and health and nutritional status.

The optimal development of children refers to their ability to acquire culturally relevant skills and behaviours that allow them to function effectively in their current context as well as adapt successfully when their current context changes.

Development is multidetermined, varying as a function of nutritional and biomedical status, genetic inheritance, and social and cultural context.

Undernutrition, poor health, and non-optimal caregiving affect a broad range of outcomes, including cognitive, motor, psychosocial, and affective development. For example, children are naturally motivated to explore and to attempt to master their environment. Under nutrition, poor health, and non-optimal caregiving tend to reduce these motivations, which may inhibit development.

The early years of life are essential as the foundation for later development. However, the impact of past and concurrent under nutrition, poor health, and nonoptimal caregiving is not confined to these years. Children’s development is essentially cumulative in nature.

Some developmental trajectories can be made better or worse as a function of influences encountered past the early years

Determinants of child development

The number of risk factors has a cumulative or interactive impact on child development.

The effect of risk factors varies with the age of the child, and their effects, or the results of interventions, may have delayed and not immediate impact.

When resources are limited, the highest-risk individuals in a population should be targeted for intervention. However, it is important to realize that the highest-risk individuals in a population may occur relatively infrequently. Focusing solely on these individuals may not have a large impact on the community. Further, some communities may have such a high prevalence of multiple risk factors (e.g., orphaned children, famine, widespread maternal illiteracy) that the whole population should be targeted. Risk can be assessed at both the individual and the community or ecological level (table 1).

It is important to understand the prevalence of risk and protective factors in a population in order to plan effective resource utilization. Thus, the first step in planning any programme of services should be to conduct an assessment of the prevalence of protective and risk factors.

Programmatic actions

Programme characteristics and content.

The timing, duration, and breadth of an intervention modify its effect. Generally, the earlier and the longer the interventions, the larger the developmental benefits. This is true for both the initial and the later size of the effect as well as for its duration. If timing and duration are held constant, multifocal interventions (e.g., health, nutrition, and optimal child care) will yield larger and more sustained benefits than unifocal interventions (e.g., supplementary feeding). This statement is particularly valid when the interventions begin past the child’s postnatal growth spurt of the brain. Short-term and unifocal interventions that begin during the later pre-school period will do little to repair the damage from a history of malnutrition, poor health, and less than optimal caretaking. The merit of late interventions, even during the school years, is to prevent or remedy the adverse effects of concurrent health and nutrition problems that often interfere with learning and performance.

The more frequent the contact and the more intense the intervention, the more likely the children will benefit. Ideally, there should be an integration of maternal and child health services and early childhood development programmes.

Interventions may not benefit all domains of development. As programmes are implemented in communities, they should be monitored carefully. Before going to scale these programmes should be expanded in a staged manner, and it is critical to take into account culture, ecology, language, and demographic factors, among others, and to devise interventions that reflect these variables. Rather than simply adopting already existing approaches, there is an urgent need for evaluations of varied approaches to intervention and methods of delivering these services.

Recommendations of programme type (e.g., homebased, centre-based, or a combination) are dependent on the availability of several critical variables, such as responsible caregivers in the home, safety of the home, quality of caregiving in the centre, and stability, support, and training of caregivers in the centre. In general, centre-based programmes are not recommended for children from birth to three years of age except when the child is an orphan, the mother is in full-time employment, there is no suitable adult caregiver in the home, or there is extreme family disruption or child abuse and neglect.

Actions taken to facilitate child development in addition to nutrition and health interventions should contain at a minimum the following: age-appropriate responses of adults; stable relationships with adult caregivers; supporting the child’s development of language through labelling, encouraging the child’s vocalizations, expanding, explaining, and two-way conversations; providing an environment for the child to explore safely; providing interesting play materials and books that reflect the child’s everyday experiences; warm, affectionate behaviour and positive affect; sensitive and responsive behaviour to the child’s signals; play activities with peers and adults.

Many children with disabilities can respond productively to the same developmental interventions as children without disabilities and should be included in such intervention efforts. Children who have been injured as a result of war are also included among those with disabilities.


Actions should be taken to strengthen the parent’s or caregiver’s sense of effectiveness as a promoter of child development.

Interventions with parental and non-parental caregivers are needed to help them use developmental materials appropriately, to provide challenging activities at the appropriate level of difficulty in which the child can be successful, to become increasingly involved with their children, to respond verbally to the child’s vocalizations, to be responsive to the child’s emotional needs, and to avoid physical punishment as a standard child-rearing practice.

Parents or caregivers should be taught how to integrate child development activities into activities of daily living as much as possible. Involving other family members in these activities has the potential to increase their impact.


Another critical element of programme expansion is systematic and continuous training and supervision for both professional and paraprofessional staff. The success of the programme is highly dependent on the preparation and supervision of staff at all levels. Paraprofessionals need to be given field-based training to be closely affiliated with the communities in which they work, and should have credibility with the families in their communities. Health and medical professionals should receive inservice training to enable them to appreciate and provide necessary support for paraprofessionals and professionals working in child development activities.

Evaluation and assessment

Larger-scale studies of effectiveness with careful evaluation of process and impact need to be conducted.

All programme evaluations should begin by specifying programme objectives and documenting that programme activities are delivered.

Adaptation of existing direct (developmental scales and cognitive tests) and indirect (e. g., parent’s report) assessments of child development in children 18 months to 6 years of age (focusing on psychomotor, gross motor, reasoning, language, and adaptive tasks, including social and emotional behaviour) can be used to evaluate programme success when the programmes are intended to promote and enhance these outcomes. .

There is need for an investment of resources to develop new instruments and improve existing instruments intended to assess children’s cognitive and noncognitive development below the age of three years. This is particularly true for large-scale evaluations of programme interventions. Further research on the use of parental reports and other approaches, including brief observations, is needed.

Process measures of developmental interventions are critical for continuous improvement of programmes and for providing assessment of the strengths and weaknesses of programme practices (e.g., children’s and parent’s responsiveness to the intervention, children’s level of development and change over time, parental level of participation, and factors that inhibit participation). Such process measures can also serve the function of teachmg parents and other caregivers about their children and providing them with information about how to modify their behaviour with their children. Simple checklists, combined with training and supervision, can be used for this purpose

TABLE 1. Examples of community or ecological risk factors and individual risk factors

Community or ecological  Individual
  •     Poor sanitation
  •     Famine
  •     Endemic violence
  •     Endemic poverty
  •     Lack of accessible services: pre-schools, schools, libraries, health services
  •     AIDS epidemic
  •     Lack of commitment to child development
  •     Population traditionally discriminates against refugees
  •  Repeated infections
  • Undernutrition
  • Abuse and neglect
  • Very low family income
  • Low birthweight
  • Unstable caretaking
  • Low maternal education
  • Large family size
  • Short spacing between births
  • Orphans
  • Young sibling caregiver
  • Low levels of developmentally enhancing parenting practices
  • Developmental disabilities or severe physical injury