<P> Explicit memory becomes much better over the developmental years . However, there are small effects of age on implicit memory, which could be because implicit memory involves more basic processes than declarative memory which would make it less affected by a child's developing cognitive skills and abilities . </P> <P> Infants who are 5 months or older are able to use emotions to influence their memories . However, at this age, infants will be more likely to remember things that were characterized by positive emotions . The way that researchers study the memory capabilities of infants in this age range is through measuring eye movements between test images presented . After doing this initial round of testing, the researchers would conduct follow - up tests both 5 minutes later and one day later . The follow - up tests shown to the infants included two geometric shapes: one from the original test, and a new shape . The researchers were able to record how long the infants looked at the images in the follow - up tests and measured how long the infants stared at each shape . The infants were more likely to gaze at the geometric shapes from the original tests if they had been paired with positive voices than if they had been paired with neutral or negative voices . This study indicated that infants at this age would be able to better remember shapes and patterns of things if they were associated with positive emotions because positivity would increase the infants' interest and attention . </P> <P> Infants at as early as 7 - months - old can conceptually differentiate between categories such as animals and vehicles . Although infants' concepts may be crude by adult standards, they still allow infants to make meaningful semantic distinctions . An example is that infants can differentiate between items belonging to a kitchen and those items belonging to a bathroom . At the very least, these categories lay a foundation for early knowledge development, organizing information in storage and influence future encoding . Infants from 16 months old are able to draw on their semantic knowledge in generalization and inference . This knowledge can also be used by older toddlers, 24 - month - olds, to facilitate acquisition and retention of new information . Their knowledge of causal ordering of events can be used to help to recall the sequence of events . </P> <P> Knowledge itself will not alter retention performance, rather how well that knowledge is structured will alter performance . Better retention was shown with information that had greater cohesion and more elaborative elements . Familiarity and repetition of an experience can also influence the organization of information in storage for preschoolers and older children . Children who experienced an event twice recalled the event better 3 months later than did children who only experienced it once and showed equally good recall at 3 months compared to recall at 2 weeks after experiences . </P>

When does a child develop long term memory