Abstract: Gestures are hand movements which are generated during communication or cognitive process and don't act on the object directly. It has the mixed characteristics of concreteness and abstractness. On a continuum from action to abstraction, gestures are more abstract than action but still less abstract than verbal language. Gestures have the power not only to reflect the individual's cognitive level, but also to change the individual's cognitive level, and as a result, thus facilitating the learning of new knowledge. The classification of gestures is mainly divided from the perspectives of the source of gestures, the content of gestures, the intention of gestures, the matching between gestures and speech. According to the source of gestures, gestures can be divided into producing gestures and observing gestures. In terms of the content of gestures, the classic classification is McNeill's (1992) elaboration on gesture's classification, which divides gestures into four types: iconic gestures, deictic gestures, beat gestures and metaphoric gestures. The previous researches on children's gestures mainly employ two experimental paradigms: laboratory experimental method and scenario experimental method. Between them, most of the studies use the laboratory experimental method, while a small number of studies use scenario experimental method, which is mostly used for the study of infant's gestures development. In the aspect of the development of gestures, deictic gestures, iconic gestures, beat gestures and metaphoric gestures spontaneously occur at different time points in the process of children's growth. Deictic gestures appear earliest and usually appear at around 12 months old, while metaphoric gestures appear the latest and usually appear after the children enter primary school. The developmental trends of different types of gestures are also distinguish. It is important to note that the advantage effect of gestures may occur earlier than the children's spontaneous occurrence of gestures. Therefore, encouraging young children to use gestures may promote the development of gestures' spontaneous occurrence. What's more, encouraging particular types of gestures can even introduce new ideas into children's repertoire. Both producing gestures and observing gestures can facilitate children's vocabulary learning, speech expression, mathematical problem-solving, spatial learning and memory. That is to say, the self-producing gestures group perform better on the task than the non-producing gestures group, and the observing other people's gestures group perform better on the task than the non-observing gestures group. However, the influence of gestures on speech comprehension has not reached a consistent conclusion, mainly because speech comprehension is affected by many factors, it needs to be considered in consideration of factors such as the type of gestures, difficulty level of tasks, and children's age. In the process of children's cognitive development, adults should pay attention to the phenomenon of “gesture-speech mismatches” which can give teachers and parents insight into the children's cutting-edge thoughts, and actively guide the “implicit thoughts” expressed by gestures, so as to facilitate positive results of children's learning and acquisition of new knowledge. Future research should continue to explore the following aspects. Firstly, factors such as culture and socio-economic status can be considered to investigate whether the occurrence time and developmental trends of gestures could be affected by these factors. The second is to compare the advantage effect of producing gestures and observing gestures in various learning fields. The third is to pay attention to the use of gestures among special children. The last is to focus on the advantage effect of gestures in the classroom teaching and family education.

Key words: children's gestures, developmental trends, advantage effect