[1] She specialises in the archaeology of Scotland, particularly the Picts and their neighbours in the early medieval period.
Foster studied at University College London and graduated in 1984 with a degree in medieval archaeology.
She completed her doctoral studies under Leslie Alcock at the University of Glasgow.
She was awarded her PhD in 1990 with a thesis entitled Aspects of the Later Atlantic Iron Age.
[2] Foster previously chaired the National Committee on Carved Stones in Scotland[3] and served as a trustee of the Society of Antiquaries of Scotland and the Kilmartin Glen Museum Company.