The Importance of Joint Attention

Language is one of the most important aspects of child development in the early years. There is one key aspect of language development during early childhood, joint attention. Joint Attention is important in a wide variety of abilities in later development including recognition memory, intelligence (as measured by IQ), learning abilities (Striano et al., 2006; Smith & Ulvund, 2003; Baldwin, 1995). It is a form of creating a shared referential object which allows for the input of new information in the contexts of interests (Tomasello & Farrar, 1986). This places joint attention as a self-organizing system allowing for information processing in support of social learning (Mundy, 2003). As such joint attention possesses a close link to language development and learning as whole. Today we will discuss the various models of joint attention and how these relate to later language development.

Firstly, it is important to understand what joint attention is. Joint attention refers to a skill in child development (Mundy et al., 2009). It is comprised of two factors: responding to joint attention (RJA) and initiating joint attention (IJA). RJA is an infant's capacity to identify and follow others' gaze direction. IJA is the infant's ability to form these shared gaze direction at a point of reference with other individuals. Multiple studies have evidenced the importance of joint attention on aspects of development such as reward mechanisms and motivation (Dawson, 2008). However, joint attention is often seen as key in pre-verbal development (Dawson et al., 2004).

One key model is the parallel- and distributed-processing model (PDPM) of joint attention outlined by Mundy et al. (2009) providing a multi-disciplinary approach to joint attention. This model implements neurology to provide a distributed model between the posterior and anterior regions of the brain. The posterior regions of the brain have been suggested to regulate involuntary attention leading to turning towards meaningful stimuli, relating to RJA. Whereas the IJA relates to the anterior attention network, which is related to cognitive processing, regulation of self-initiated goal directed action, representation, and reward modulation functions (Mundy et al., 2009). One major assumption of the PDPM is that "the integrated processing of internal information about our own visual attention with posterior processing of information about the visual attention of other people" (Mundy & Newell, 2007). The distributed nature of joint attention further contributes to the learning ability of joint attention, as Otten et al. (2001) evidence that learning across varied neural networks leads to deeper encoding. The development of joint attention is key in the later development of Theory of Mind (Mundy et al., 2009) as infants develop through the basic "learning to" period of joint attention, through the "learning from" period and into Theory of Mind. "Learning to" period is the stage where strategies of overt visual self-attention and processing of other's attention is reinforced. "Learning from" period is controlled attention which allows for full symbolic development of social cognition.

There is a core difference in the development of RJA and IJA functions. This difference is explained neurologically as the anterior attention network develops later on than the posterior systems (Mundy et al., 2007). Specifically, IJA is associated with frontal-cortical activity (Mundy et al., 2000) whilst RJA is related to parietal and temporal cortical processes (Materna et al., 2008). These posterior systems (RJA) regulate involuntary attention and facing towards biologically meaningful stimuli, beginning in the first three months of life. These systems also relate to control of orienting and development of cognitive representations of the world through sense (Fuster, 2006; Cavana & Trimble, 2006). On the other hand IJA is supported by the development of the anterior attention network, made up of the anterior cingulate, medial superior frontal cortex, anterior prefrontal cortex, basal ganglia and orbital frontal cortex (Fuster, 2006; Long & Hikosaka, 2006). This network relates to cognitive processing, representation and regulation of self-initiated goal directed action. These functions be assumed to enable intentional gaze alternation between peers and events of interest (Mundy, 2003). This neural mapping of self-other representations that Decety & Grezes (2006) suggest is essential to social cognition. This is then consistent with the "gateway" hypothesis which suggests a primary function of the rostal medial frontal cortex is to switch attention between self-generated and perceptual information for adequate social-cognitive performance (Gilber & Burgess, 2008). 

The importance of joint attention in language exists within it's social relevance. Kristen et al. (2011) discusses joint attention's relevance within mental state language, the discussion of the mind and it's processes, which has been further linked to Theory of Mind (Ruffman et al., 2003). This was shown through improved performance in mental state language at 24 and 36 months being correlated to joint attention abilities at 12, 15, and 18 months (Kristen et al., 2011). On the other hand, Brookes & Meltzoff (2015) suggest that general language abilities may act as a bridging effect between joint attention and Theory of Mind, as such mental state language could play a vital role in both social cognition and Vygotskian language development.

Vygotskian language development possesses close links to joint attention and the effect they have on wider language development. Vygotsky's ideas of proximal and interpsychological development rely on social environment  and forming positive interactions towards actual and intrapsychological development (Vygotsky, 1978). This is particularly relevant to RJA where infant's respond and learn from adults and peers about their own environment and language. This then shifts within the 'producing new cultural tools' stage the infant takes responsibility for participating and producing cultural products with others, or IJA. This again supports the chronological difference between IJA and RJA as this follows the stages Vygotsky (1978) outlined.

These ideas were summarised by in Tomasello's 1988 paper who directly links later language ability to earlier joint attention. Alongside this he proposed a five-stage developmental sequence where children are able to develop both language and joint attention abilities in concordance. Firstly, is the primary intersubjectivity stage where attention can be given to people or objects, but not both. Secondly, the secondary intersubjectivity stage introduces active manipulation of adults to increase joint attention, particularly IJA. This is followed by the holophrastic speech stage, which is characterised by simple one-word speech utterances. The holophrastic prediction stage is when infant's begin assuming a shared focus on objects, often making linguistic comments. Finally, the conversational stage where children can understand a shared topic and form responses in the form of a conversation. Tomasello (1988) highlights that the linguistic areas most influenced by joint attention are those of the lexical, syntactical, and conversational. This was summarised when he stated "linguistic symbols both lead to and are dependent upon the efficient social coordination of covert mental attention to common and abstract representations among people" (Tomasello et al., 2005).

These ideas of joint attention's influence in linguistic ability is further supported by Hirotani et al. (2009) showing that joint attention possess direct links to the ability to learn new words. This is further supported by Morales et al. (2000) who provide further evidence that RJA at 6, 8, 10, 12 and 18 months were positively correlated with vocabulary acquisition. However, this correlated drops once infants reach 21 months. This suggests a critical period in which joint attention possesses a significant influence over vocabulary acquisition. These findings provide further questions on which aspects of vocabulary are best influenced by joint attention, as it may be hypothesised that these skills only benefit vocabulary and not wider linguistic ability.