Numerical comparison of two-digit numbers: How differences at encoding can involve differences in processing

Abstract

The study of two-digit numbers processing has recently gathered a growing interest. Here, we examine whether differences at encoding of two-digit oral verbal numerals induce differences in the type of processing involved. Twenty-four participants were submitted to a comparison task to 55. Differences at encoding were introduced by the use of dichotic listening and synchronous (synchronous condition) or asynchronous presentation (tens-first and units-first conditions) of the two-digit numerals' components. Our results showed that differences at the encoding stage of two-digit numerals involve: (1) different comparison processes (tens-first and units-first conditions: parallel comparison; synchronous condition: parallel and holistic comparison); and (2) differences in the weight of the tens- and units-effects. Therefore, attentional mechanisms determining at the encoding stage how much attention is paid to the two-digit numerals' components might account for the different types of processing found with two-digit numbers.

Keywords:

• Compatibility effect
• Distance effect
• Numerical processing
• Tens- and units-effect
• Two-digit numbers

Acknowledgements

JC is Postdoctoral Researcher at the Belgian National Fund for Scientific Research (http://www1.frs-fnrs.be). VC is a Research Fellow at the Belgian National Fund for Scientific Research.

Notes

¹The SiCE corresponds to the difference between the congruent and the incongruent conditions in a Stroop-like numerical task, in which participants have to undertake a physical comparison task on Arabic numbers varying along both the physical and numerical dimensions. In other words, the SiCE corresponds to an interference effect that is assumed to reflect the automatic processing of the irrelevant numerical dimension.