THE WHORFIAN HYPOTHESIS AND NUMERICAL COGNITION - IS 24 PROCESSED IN THE SAME WAY AS 4-AND-20

Recent theoretical developments have redefined a Whorfian effect as a processing difference due to the language of the individual, and no lo nger as a marker for or against linguistic determinism. Within this fr amework, Whorfian effects can be used to investigate whether a particu lar part of the cognitive system is penetrable by language processes o r forms an encapsulated module, provided the experimenter ensures that the target language difference is not caused by peripheral input or o utput processes. In this article, we examine the possibility of a Whor fian effect in numerical cognition by making use of the: fact that in the Dutch number naming system the order of tens and units is reversed (i.e. 24 is read 'four-and-twenty'). In a first experiment, we asked native French- and Dutch-speaking students to name the solution of add ition problems with a two-digit and a single-digit operand (e.g. 20 4 = ?, 24 + 1 = ?). The order of the operands was manipulated (20 + 4 vs. 4 + 20) as well as the presentation modality (Arabic vs. verbal). Three language differences emerged from this study. Experiment 2, howe ver, showed that these differences were all due to input or output pro cesses rather than differences in the addition operation (i.e. the dif ferences between Dutch and French disappeared when subjects were asked to type the answer rather than pronounce it). On the basis of these f indings, we question the idea that mathematical operations are based o n verbal processes. (C) 1998 Elsevier Science B.V.