The response to 'new security' risks requires significant changes in public behaviour, and the legitimization of unpopular government policies. Public Educating (public information/public education) is one means to achieve this. The need is reflected in initiatives such as environmental education, development education, health promotion, and the Public Understanding of Science. Current strategies are often based on commercial advertising, but mass communications theory does not directly encompass influencing perception , which is necessary to create awareness of the new 'invisible' risks. Recent evolutionary brain science is providing fresh and relevant insights into our species perception deficits, which can inform a more effective approach to Public Educating. This paper first places risk within the context of the post-Cold War 'global security' agenda. It proposes a theoretical framework - 'brain lag' - to explain perceptual deficits in relation to this agenda, which draws on theories of information, adaptation and denial, and an understanding of the human senses including time-scale-latency. Fundamental areas of evolutionary perception are proposed which are relevant across the agenda: fear and disgust, number perception, and cheating. This leads to a core concept for Public Educating about new security risks, 'enhanced difference', and a set of hypotheses that can be applied to text or image.