Since completion of her Phd Dr Matthews has worked on fossil small mammals and, more recently, frogs, from archaeological and palaeontological sites from the south and west coasts of South Africa, and the interior, dating to the Pleistocene and Holocene. One focus of research has been to elucidate Quaternary palaeoenvironments and ecologies, and investigate climatic change over time using fossil micromammal and frog assemblages as environmental proxies. Another is to research the evolution of micromammals and frogs during the Quaternary, and map changes in distribution, which has relevance to the development and use of climatic modelling.