In the first 3 years of life recall is via preverbal memory (sometimes called eidetic memory), which allows early events to be recalled visually but not in words. Preverbal memory is very accurate but is largely lost around the age of 3 years as language develops. This form of memory remains longer in children who have delayed language development. The loss of this early form of memory explains why adults do not usually have conscious memories from the first 3 years of life. It is only around the age of 3 years that experiences begin to be memorized in ‘explicit memory’, which is accessed by verbal recall.⁽¹⁾ Memories laid down in explicit memory are organized according to hierarchical cognitive structures formed by the child’s past experiences of the world. In young children, this organization is rudimentary. This means that new memories are stored with little selection or adaptation to reflect preconceptions, and in younger children the retrieval of stored memories from poorly organized mental representations is difficult. External prompts and cues help children recall more fully but in court witnesses are not generally allowed to be ‘led’ by questioning. Younger children are more likely than older children to forget information over time. By the age of 12 years, children are generally considered to have the same capacities to lay down memories and recall information as adults.

Surprisingly, children’s immature memories can sometimes actually improve the quality of information provided in witness statements. For example, events may be memorized without being influenced by the prejudices that affect adult perceptions, and seemingly trivial details may be memorized by a child whose primitive cognitive schemas allow incoming sensory information to be memorized unselectively.⁽²⁾ However, cognitive immaturity more often acts as a barrier to children giving their testimonies fully and accurately, especially when they are asked to talk about what they remember, rather than being allowed to communicate by behaviour or play.

By the age of 6 years, many children are using the syntax and grammar of adults in their spoken language. However, their vocabulary is still limited and they are easily confused by sophisticated or complex speech. A particularly important aspect of language development for child witnesses is the role played by children and adults in conversational partnerships. Children are used to being co-operative partners when talking with adults. They attempt to please by providing answers to questions, even if they do not know the answer or have not understood the question.⁽³⁾ Young children rarely answer ‘I don’t know’ to a question they are uncertain about and prefer to give a false ‘yes’ or ‘no’. This willingness to provide an answer is probably encouraged by the frequent experience of being ‘tested’ by adults who already know the answers to the question (for example, ‘Look at this picture! Can you see the duck?’ or ‘How many sweets am I holding?’). As children expect adults to know the answers to their questions, and if a question is repeated, children may change the answer they gave in the assumption that the questioner feels it to be wrong. The readiness of young children to please adults in conversation no doubt adds to their suggestibility.

The suggestibility of children as witnesses has been a major concern in legal arenas. Modern research does not endorse the stereotype of the child witness as being highly suggestible. However, there is clear evidence that both children and adults are prone to suggestion at times, and that pre-school children are particularly vulnerable to this. The necessity to avoid suggesting information or answers to a child has led to the development of guidelines for interviewing child witnesses in several jurisdictions.

According to Kohlberg’s seminal description of children’s moral development, children below 10 years of age operate with ‘preconventional morality’ and evaluate events according to whether the child themselves will gain reward or avoid punishment. Only after this age do children develop ‘conventional morality’ and begin to be motivated by the approval of other people and society. Therefore, only older child witnesses have a full understanding of their moral obligations in court. However, young children, who may hold concrete worldviews such as ‘bad people must be punished’ as moral imperatives, may be strongly motivated to tell the truth in court.

Contrary to popular belief, children above the age of 3 years have no more difficulty than adults in distinguishing fact from fantasy. Neither do children tell more lies than adults (although children’s lies are more often unconvincing and therefore more easily discovered). Children and adults are motivated to lie for similar reasons.⁽⁴⁾ The two motives for lying, which may particularly influence child witnesses asked to testify in cases of child abuse, are fear of personal recrimination and a wish to protect those to whom a child feels loyal.

Before 8 years of age, children do not generally have a clear sense of time. Young children therefore often have a muddled recollection of the timing of events and they may have difficulty saying how many times an event occurred. Similarly, children below this age have short attention spans, and readily become bored or overwhelmed by prolonged questioning. Both of these developmental limitations can cause difficulties in the preparation of witness statements when a child appears in court.