The immune-response perspective in cognitive development is intended to explore how certain environmental proteins and genetic factors affect neuro-cognitive development and mental health thereafter. Specifically, naturally occurring proteins are known to cause severe and pervasive immune responses. More specifically, environmental antigenic/allergenic proteins may trigger IgE mediated reaction antibodies that influence cross-react immune responses to homologous exogenous/endogenous proteins. Repeated exposure to antigenic/allergenic proteins has been shown to cause an increased incidence of sensitisation, adverse allergic reactions, and even death through anaphylactic shock.