The Effect of Reading Direction Habit on Numerical Processing

The Hebrew Academy of Language in Israel has ruled that numerical ranges shall be written from right-to-left (lower number on right, higher number on left), consistent with language direction. This pilot study investigated the effect of that rule on human performance in a simulated directional sign-reading task. Right-to-left text, followed by single digit number sets depicting a range of values were presented to sixteen native Hebrew speakers, who were asked to report whether an additional number presented separately appeared within that range. Number sets following the Hebrew text were presented from left-to-right and from right-to-left. No significant differences were found in response times between left-to-right and right-to-left conditions. However, a significant main effect of direction was found for percent errors, which were significantly higher for right-to-left than for left-to-right number sets. The rule requiring number sets to appear from right-to-left is called into question, and implications for numerical range information display in right-to-left languages are suggested. The authors are currently engaged in more extensive research aimed at expanding the findings of this pilot study.