David Prytherch

Haptic discrimination of different types of pencils during writing

Professional artists seem to develop a preference for certain types of pencils and paper (Akyuz 1995). While theaesthetic outcome may be the obvious reason for this preference, haptic feedback may also play a role in selecting media (Prytherch and Jerrard 2001, 2003). This suggestion implies that artists may be sensitive to vibrotactile signals resulting from the interaction between pencil and paper during drawing. Tribological tests showed that H-range leads generate more resistance than B-range pencils when writing on a standard 80 g/m 2 paper. Moreover, a constant stimulus 2IFC procedure showed that Fine Arts students found it easier to discriminate between H-range and HB than B-range and an HB. This suggests that the human haptic system may be sensitive to the vibrotactile signals generated by the differences in resistance resulting from the interaction of leads with the papers textured surface. Implications for pencil manufacturing and simulations of virtual writing are discussed. Statement of Relevance: The study assesses the tactile sensitivity of Fine Artists to the physical properties of the interaction between different types of lead and a standard printing paper. The results may help in designing more responsive drawing instruments as well as more realistic virtual drawing interfaces.

Whose Questionnaire is It, Anyway?

This chapter focuses on the adoption and adaptation of methodologies drawn from research in psychology for the evaluation of user response as a manifestation of the mental processes of perception, cognition and emotion. The authors present robust alternative conceptualizations of evaluative methodologies which allow the surfacing of views, feelings and opinions of individual users producing a richer, more informative texture for user centered evaluation of software. This differs from more usual user questionnaire systems such as the Questionnaire of User Interface Satisfaction (QUIS). (Norman et al, 1989) The authors present two different example methodologies so that the reader can firstly, review the methods as a theoretical exercise and secondly, applying similar adaptation principles, derive methods appropriate to their own research or practical context.