Johnson and Morton (1991. Biology and Cognitive Development: The Case of Face Recognition. Blackwell, Oxford) used Gabriel Horn's work on the filial imprinting model to inspire a two-process theory of the development of face processing in humans. In this paper we review evidence accrued over the past two decades from infants and adults, and from other primates, that informs this two-process model. While work with newborns and infants has been broadly consistent with predictions from the model, further refinements and questions have been raised. With regard to adults, we discuss more recent evidence on the extension of the model to eye contact detection, and to subcortical face processing, reviewing functional imaging and patient studies. We conclude with discussion of outstanding caveats and future directions of research in this field.

Socioeconomic status (SES) impacts on both structural and functional brain development in childhood, but how early its effects can be demonstrated is unknown. In this study we measured resting baseline EEG activity in the gamma frequency range in awake 6–9‐month‐olds from areas of East London with high socioeconomic deprivation. Between‐subject comparisons of infants from low‐ and high‐income families revealed significantly lower frontal gamma power in infants from low‐income homes. Similar power differences were found when comparing infants according to maternal occupation, with lower occupational status groups yielding lower power. Infant sleep, maternal education, length of gestation, and birth weight, as well as smoke exposure and bilingualism, did not explain these differences. Our results show that the effects of socioeconomic disparities on brain activity can already be detected in early infancy, potentially pointing to very early risk for language and attention difficulties. This is the first study to reveal region‐selective differences in functional brain development associated with early infancy in low‐income families.

It has been suggested that poor habituation to stimuli might explain atypical sensory behaviours in autism. We investigated habituation to repeated sounds using an oddball paradigm in 9-month-old infants with an older sibling with autism and hence at high risk for developing autism. Auditory-evoked responses to repeated sounds in control infants (at low risk of developing autism) decreased over time, demonstrating habituation, and their responses to deviant sounds were larger than responses to standard sounds, indicating discrimination. In contrast, neural responses in infants at high risk showed less habituation and a reduced sensitivity to changes in frequency. Reduced sensory habituation may be present at a younger age than the emergence of autistic behaviour in some individuals, and we propose that this could play a role in the over responsiveness to some stimuli and undersensitivity to others observed in autism.

Recent advances in neuroimaging methods have provided new ways of unravelling the complex interplay between genetic and environmental factors that influence functional brain development in the critical first years of life. This has allowed new insights into the effects that early adverse experience can exert on the brain later in life. We review recent progress in the characterization of those effects and underlying mechanisms through which adverse environment influences the neurocognitive development. Socioeconomic background may have a profound effect on structural and functional brain development, especially in the domains of language and prefrontal executive control. These effects are mediated by several factors: diet, quality of parental care, impoverished environment, prenatal exposure to toxic substances and so on. Other circumstances such as perinatal brain injury, early sensory deprivation or limb malformation may result in atypical functional organization of the brain and lasting cognitive impairment of certain functions. Early experience of maltreatment or institutionalized care may alter the development of the social brain, contributing to negative mental health outcomes, which may be partially reversed through early intervention programmes. Subsequent models of psychiatric disorder should take into account early risk factors and embrace developmental models at multiple levels of biological organization. There is a continuing need for the study of optimal environmental input during sensitive periods in brain development.

Investigation into the earliest signs of autism in infants has become a significant sub-field of autism research. This work invokes specific ethical concerns such as use of ‘at-risk’ language, communicating study findings to parents and the future perspective of enrolled infants when they reach adulthood. This study aimed to ground this research field in an understanding of the perspectives of members of the autism community. Following focus groups to identify topics, an online survey was distributed to autistic adults, parents of children with autism and practitioners in health and education settings across 11 European countries. Survey respondents (n = 2317) were positively disposed towards early autism research, and there was significant overlap in their priorities for the field and preferred language to describe infant research participants. However, there were also differences including overall less favourable endorsement of early autism research by autistic adults relative to other groups and a dislike of the phrase ‘at-risk’ to describe infant participants, in all groups except healthcare practitioners. The findings overall indicate that the autism community in Europe is supportive of early autism research. Researchers should endeavour to maintain this by continuing to take community perspectives into account.

Human faces under natural illumination, and human eyes in their unique morphology, include specific contrast polarity relations that face-detection mechanisms could capitalise on. Newborns have been shown to preferentially orient to simple face-like patterns only when they contain face- or gaze-relevant contrast. We investigated whether human adults show similar preferential orienting towards schematic face-like stimuli, and whether this effect depends on the contrast polarity of the stimuli. In two experiments we demonstrate that upright schematic face-like patterns elicit faster eye movements in adult humans than inverted ones, and that this occurs only if they contain face- or gaze-relevant contrast information in the whole stimulus or in the eye region only. These results suggest that primitive mechanisms underlying the orienting bias towards faces and eyes influence and modulate social cognition not just in infants but in adults as well.