Eye movements when reading Arabic numbers in sentences

We examined eye movements in 49 adults as they read aloud or silently rounded and non-rounded Arabic numbers embedded in texts. We compared the patterns of eye movements to those obtained when participants read words and pseudowords matched in length to the numbers. The results revealed that non-rounded numbers elicited more fixations, longer fixation durations, and an increased number of saccades with shorter amplitudes compared to words, with pseudowords and rounded numbers falling in between. This reflects the cognitively demanding step-by-step processing required for number reading. However, this effect was moderated for non-rounded numbers in silent reading, suggesting that without oralization requirement, participants engaged in a more superficial reading. This interpretation was further supported by a higher error rate on a comprehension task administered after reading when the questions were related to the magnitude of the numbers read. Additionally, participants made more leftward saccades when reading numbers compared to words and pseudowords, indicating that despite numbers being oralized from left to right, they must be, to some extent, scanned from right to left to determine the value and therefore the denomination of the various digits. These findings shed light on the cognitive mechanisms underlying number reading.