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Brain networks for processing social signals of emotions: early development and the emergence of individual differences

Final Report Summary - EARLYDEV (Brain networks for processing social signals of emotions: early development and the emergence of individual differences)

An important challenge for brain and behavioral sciences is to explicate the early developmental bases of human cognitive and behavioral traits, including traits that predispose some individuals to emotional and social disorders. The present project (EarlyDev) combined the methods of molecular genetics, neurosciences, and behavioral assessments to examine early-developing cognitive traits in human infants (for example, infants’ well-documented tendency to look at others’ faces), to examine whether there are stable individual variations in these traits, and to examine whether individual variations in these traits predict infants' later developmental outcomes. EarlyDev also sought to examine whether there is a causal relationship between infants’ early-emerging attentional processes and their behavioral development (that is, whether attention provides a foundation for the development of other cognitive and social skills).

EarlyDev team comprised of researchers with expertise in developmental psychology, computer science and programming, molecular genetics, and electrophysiology. During the 5-year project, the team collected large amount of DNA, electrophysiological, and behavioral (eye movement) data from 5- to 12-month-old children of families who volunteered in participating in EarlyDev studies in purpose-built infant laboratories in Finland or in other collaborating research centers in South Africa and Malawi. A total of 1003 children participated in different sub-studies of EarlyDev and related projects and a total 1375 visits to infant laboratories were completed. Some of the children who participated in the study as infants were later invited for follow-up assessments at the age of 13, 24 or 48 months.

Over the course of the 5-year project, the project team developed and published new techniques that were designed to be suitable for the special requirements of analyzing electrophysiological and eye-tracking data from infants. Project results demonstrated that, by 7 months of age, infants have developed distinct mechanisms for coding visual information from non-face objects and faces and exhibit a strong interest to look at socially communicative cues on faces, such as facial expressions. Through combined analysis of data on infants’ brain activity (electroencephalography) and eye movements, project studies further showed that integrated activity of frontal and posterior brain regions appears to mediate infants' early-developing ability to "prioritize" attention to faces and "suppress" attention to other competing visual inputs. Certain inherited genetic variations in brain serotonin system were associated with the strength of this tendency to look at faces in infants, and the individual variations that were found in this tendency at 5 to 9 months of age were moderately stable across short time intervals in infancy (but not over a longer time interval in early childhood).

Establishing the potentially important causal role of early-developing attention skills in behavioral development, EarlyDev results demonstrated that experimentally induced improvements in attention in infants led to changes in infants’ responsiveness to adults’ communicative cues in naturalistic settings (for example, infants who were trained to attend to visual stimuli by using gaze-interactive games were more likely to respond to adults’ pointing gestures in a naturalistic session). EarlyDev results also showed that subtle individual differences in attention to faces at 7 months of age predict the development of more complex emotional and social traits later in childhood. Infants who were relatively more attentive to faces displaying salient emotional expressions at 7 months of age were more likely to develop a supportive attachment relationship to their caregiver by 13 months of age, and infants who paid more attention to faces at 7 months were less likely to express problems of social behavior (i.e. lack of empathy) at 48 months of age.

Project results were presented to scientific communities in 11 international conferences in Europe and USA, such as meetings of the societies of research on the development of children (International Congress of Infant Studies and Society for Research in Child Development). Project results were also disseminated to academic audiences in invited talks in Europe, USA, and Africa, and to general public through newspaper and television interviews, as well as presentations and demonstrations to high-school students. Project results have so far been published in 1 review article, 3 peer-reviewed technical reports, and 7 empirical articles in international peer-reviewed journals on child development (Infancy, Child Development, Journal of Child Psychology and Psychiatry, and Archives of Disease in Childhood). The techniques developed in the project and reports of projects results can be freely accessed from

In future, the techniques and data from this project can be used to further examine and characterize typical phenotypic variations in early-developing neurocognitive processes in infants, to examine the stability of these variations over time, and to identify variations that present a risk for the development of certain behavioral problems (for example, problems of empathy and prosocial behavior). The results of this project and future projects using similar approaches may ultimately help researchers to identify the first signs of certain cognitive and behavioral traits in humans, as they emerge in infancy, and to model the developmental pathways that lead from these first signs to longer-term individual variations in psychological health and well being.