Naomi Richman

The Prevalence of Language Delay in a Population of Three-year-old Children and its Association with General Retardation

Using a simple assessment of language and a behaviour screening questionnaire, a one‐in‐four random sample of a total population of three‐year‐olds was screened for the presence of language delay and behaviour problems. A full psycho‐developmental assessment was carried out in children with suspected language delay or a behaviour problem, and in a group of control children, and the sensitivity and specificity of the language screening‐test was examined.

Individual differences at birth.

‘Each individual is endowed .from the beginning with its own peculiar difpositions and tendencies.”. The question of how these differences affect the infant’s experiences, his perception of the world and his interactions with others is basic to the consideration of the growth of individual behavioural and cognitive styles, and of early emotional reactions and relationships2. Although it is taken for granted that early experiences are of major importance for emotional development, we can still only speculate about the shortor long-term effects of innate dispositions and their mediating influences on experience. Individual differences have been demonstrated at various levels of organisation of behaviour using many measurements of response. Variables such as maturity at birth, the infant’s state (alertness, time after last feed and so and the effects of parental handling in all but the very young infant4! 5 , ought to be controlled in such studies, but they are not always taken into account. Studies have varied from the somewhat global aspects of behaviour (such as mood, rhythmicity, activity level, and intensity of response)6 to specific autonomic nervous system changes (such as variations in heart-rate in response to changing stimuli)’. In early infancy, individual differences have been described in the frequency and duration of spontaneous crying, in how readily infants can be soothed and for how long, and in how much they engage in spontaneous oral activity like sucking and mouthing2. In a group of 37 infants followed for 18 months, nine were found to be ‘non-cuddlers’, 19 ‘cuddlers’, and nine ‘intermediate’8. The ‘non-cuddlers’ were more active and restless and were intolerant of close physical contact, whilst the ‘cuddlers’ actively sought physical contact. These differences did not seem to be associated with different parental handling. By measuring responses to carefully controlled stimuli, it has also been possible to demonstrate differences in sensitivity to varying perceptual modalitieseJO. In particular, there has been increasing interest in individual differences in attention. It has become apparent that preferences for novel stimuli can be seen in very young infantsll, and that from these preferences something can be learnt about how the infant organises and assimilates information. L E W I S ~ ~ has defined attention as ‘the process by which an organism directs his sensory and elaborating (cognitive) systems’. Three attributes of attending show individual variations which should be predictive of differences in learning: (1) the ability to sustain attention; (2) attention differentiation, or the ease with which discrimination can be made between different but closely similar stimuli; and (3) attention distribution, or how quickly the infant habituates, i.e. stops attending to a particular stimulus which is repeatedly presented. A possible assumption is that habituation occurs when the information has been processed and assimilated and has become part of the infant’s internal representation or schema. Thus, rapid habituation would imply the ability to make that particular stimulus meaningful. Four-month-old infants-36 boys and 36 girls-were presented with familiar and similar but novel stimuli in the form of small pictures13. Three habituation groups were found: (1) ‘short-lookers’, who did not look very long at the stimuli even when initially presented but who responded positively to each presentation; (2) ‘rapid habituators’, who responded only to the first discrepancy; and (3) ‘slow habituators’, who showed only minimal response to any of the discrepancies. It is difficult to say how innate these differences are, even in four-month-old children, because of the influences of environmental factors. For instance, differential attention to novel and familiar stimuli in infants aged two to three months