A parallel and distributed-processing model of joint attention, social cognition and autism

Abstract

The impaired development of joint attention is a cardinal feature of autism. Therefore, understanding the nature of joint attention is central to research on this disorder. Joint attention may be best defined in terms of an information-processing system that begins to develop by 4-6 months of age. This system integrates the parallel processing of internal information about one's own visual attention with external information about the visual attention of other people. This type of joint encoding of information about self and other attention requires the activation of a distributed anterior and posterior cortical attention network. Genetic regulation, in conjunction with self-organizing behavioral activity, guides the development of functional connectivity in this network. With practice in infancy the joint processing of self-other attention becomes automatically engaged as an executive function. It can be argued that this executive joint attention is fundamental to human learning as well as the development of symbolic thought, social cognition and social competence throughout the life span. One advantage of this parallel and distributed-processing model of joint attention is that it directly connects theory on social pathology to a range of phenomena in autism associated with neural connectivity, constructivist and connectionist models of cognitive development, early intervention, activity-dependent gene expression and atypical ocular motor control.

Figure 1

Illustrations of different types of infant social attention coordination behaviors: a) Responding to Joint Attention-RJA involving following and other persons gaze and pointing gesture; b) Initiating Joint Attention-IJA involving a conventional gesture ‘pointing’ to share attention regarding a room poster, c_1,2,3) IJA involving alternating eye contact to share attention with respect to a toy, d) Initiating Behavior Request involving pointing to elicit aid in obtaining an out of reach object, and e) Responding to Behavior Requests involving following an adult’s open-palm “give it to me” gesture.

Figure 2

Illustration of the moderating affect of mental age on diagnostic group differences on RJA versus IJA reported in Mundy et al., (1994).

Figure 3

Illustration from Baldwin (1995) depicting the referential mapping problem encountered by infants in incidental social word learning situations.

Figure 4

Illustration from Mundy & Newell (2007) depicting the lateral (top) and medial (bottom) illustrations of Brodmann’s cytoarchitectonic areas of the cerebral cortex associated with Initiating Joint Attention and the anterior attention system, as well as RJA and the posterior attention systems. The former include areas 8 (frontal eye fields) 9 (prefrontal association cortex), 24 (anterior cingulate), 11 and 47 (orbital prefrontal association cortex). The latter include areas 7 (precuneous, posterior parietal association area), 22, 41, and 42 (superior temporal cortex) and 39 and 40 (parietal, temporal, occipital association cortex).

Figure 5

An illustration of the distributed information processing system model of joint attention and social cognition, from Mundy & Newell (2007). In this model, different types of lines depict the multiple paths of joint attention development from. The posterior attention system path associated with RJA development is illustrated with a dotted line and the anterior attention system path associated with IJA development is illustrated with a dashed line . The central solid line in the figure depicts the developments of other processes during infancy that influence joint attention development such as representational ability, speed of processing, motivation and the executive attention control, as well as each other during infancy. The diagonal arrows connect all paths throughout early development. This reflects the dynamic and coactive nature of joint attention development whereby the maturation of attention, cognitive and affective systems interact in reciprocal cause and effect relations with experience, including the experiences children create for themselves through their own actions. Finally, the development of integrated self and other attention processing is considered to be a social attention executive function of the anterior system that emerges in the 4 to 9 months period. This is represented by the box. The capacity to integrate and share overt aspects of attention provides a foundation for the ability to share covert aspects of attention, such as representations, and social cognition.

Figure 6

An illustration of the continuous nature of joint attention development. Development is modeled as a spiral in which the initial acquisition of the capacity for integrated processing of information about self and other attention (joint attention) remains an active but deeper layer of cognitive activity throughout life that supports symbolic thought, language and cultural social exchange. Numbers of the spiral bands represent changing phases of development. The letters on each side of the spiral bands represent change and continuity in multiple developmental factors which may impact joint attention development, such as speed of information processing, representational development, and memory.

Figure 7

In the first year the development of joint attention involves the “learning to” integration of executive, motivation and imitation processes to support the routine, rapid and efficient (error free) execution of patterns of behavior that enable infants to coordination processing of overt aspects of visual self attention with processing of the social attention of other people. In the latter part of the first year and the second year infants can better monitor their own experiences and integrate it with information about the social partners during joint attention events. This provides a critical multi-modality source of information to the infants about the convergence and divergence of self and others experience and behavior during sharing information in social interactions. Theoretically, this provides the stage for the “learning from” phase of joint attention development. In this stage infants can control their attention to self organize and optimize information processing in social learning opportunities. The integration of anterior and posterior self-other attention processing (Fig. 5) provides a neural network that enriches encoding in social learning. The internalization of the overt joint processing of attention to the covert joint processing of attention to representations is part of an executive system that facilitates symbolic development and the social cognition. Indeed both symbolic thought and social cognition may be characterized by a transition from learning to socially coordinate overt attention to the capacity to socially coordinate covert mental representations of the attention of self and others.