The number decision task: investigation of the representation of multi-digit numbers

Sass, Katharina, Theissen, Lena, Muente, Thomas F., Habel, Ute and van der Lugt, Arie (2013) The number decision task: investigation of the representation of multi-digit numbers. Acta Neurobiologiae Experimentalis, 73 2: 289-303.

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Author Sass, Katharina
Theissen, Lena
Muente, Thomas F.
Habel, Ute
van der Lugt, Arie
Title The number decision task: investigation of the representation of multi-digit numbers
Journal name Acta Neurobiologiae Experimentalis   Check publisher's open access policy
ISSN 0065-1400
Publication date 2013-01-01
Sub-type Article (original research)
Open Access Status File (Publisher version)
Volume 73
Issue 2
Start page 289
End page 303
Total pages 15
Place of publication Warsaw, Poland
Publisher Polska Akademia Nauk, Instytut Biologii Doswiadczalnej im. M. Nenckiego [Nencki Institute of Experimental Biology, Polish Academy of Sciences]
Language eng
Formatted abstract
The ability to process multi-digit numbers is an essential skill which we investigated using a number decision task. Subjects were asked to decide whether a target number (e.g., 649) is too small or too large to be the mean between two delimiter numbers that constituted the interval (e.g., 567 and 715). Three-digit numbers were presented vertically with (1) growing interval sizes (i.e., distance between the two delimiters; e.g., interval size between 567 and 715 is 148) and target gap to the mean (e.g., the gap between the ‘real’ mean 641 and the target 649 is 8) and (2) growing interval sizes with constant gap to the mean (i.e., for each interval size the gap between target and mean was held constant). The results showed that target gap to the mean “masked” the influence of interval sizes, i.e., subjects’ performance improved with increasing interval sizes (distance effect). This effect was reversed when constant target gaps to the mean and growing interval sizes were presented. These results were replicated presenting the numbers horizontally and with two-digit numbers. Additionally, a significant influence of decade but no effect of unit compatibility on reaction times and error rates, on number magnitude (size effect) and response format was found. Overall, we showed that the number decision task is an efficient tool to investigate multidigit number representation and the results from the experiments revealed evidence for a hybrid model of multi-digit number representation in which numbers are represented as a whole but also on separate mental number lines that interact with each other.
Keyword Number representation
Number decision task
Hybrid model
Multi-digit numbers
Distance effect
Size effect
Bisection task
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2014 Collection
School of Psychology Publications
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