The University of Arizona


Zachary Brooks


Do second languages speakers (L2) of any language make decisions that are measurably different from first language speakers (L1)? One way to explore this question is through the expression of probability. Probability can be expressed numerically (“75%”) or verbally (“probable”) and both numerical and verbal probability expressions have been studied extensively in medical, legal, and management contexts. In terms of utilization, verbal probability expressions are preferred more than numerical probability expressions despite their lack of precision because of their ease of use (Kuipers, Moskowitz, Kassirer, 1988), their ability to express a wider range of possibilities (Zwick, 1987), and the fact that using verbal probabilities rather than numerical probabilities costs decisionmakers very little in terms of accuracy (Hamm, 1991a; Wallsten, Budescu, & Erev, 1988). Decision making research to date, however, has assumed that participants in these studies speak the same language(s). Using verbal probabilities to investigate possible decision-making variability between L1 vs. L2 speakers is a way to explore: 1) If there are differences in decision making between L1 and L2 speakers: 2) If there are differences, are they significant: 3) If there are differences, do native speakers assign higher or lower probabilities than non-native speakers for the same event? In this study, findings from 180 L1 and L2 subjects are reported. Subjects were provided the same verbal probability expressions (VPEs) and asked to assign numbers to ten VPEs – “rare,” “very unlikely,” “unlikely,” “likely,” “possible,” “probable,” “good chance,” “frequent,” “usually,” and “very probable” (Theil, 2002). Within subject and between subject tests were conducted and results show dissimilarities between L1 and L2 speakers’ numerical valuations.

Keywords: bilingual, second language, decision making, verbal probabilities

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