Strategic Use of Number Representation is Independent of Test Instruction in Random Number Generation

Abstract

The effects of different instructions on verbal random number generation were examined in 40 healthy students who attempted to generate random sequences of the digits 1 to 6. Two groups of 20 received different instructions with alternative numerical representations. The Symbolic group (Arabic digits) was instructed to randomize while continuously using the analogy of selecting and replacing numbered balls from a hat, whereas the Nonsymbolic group (arrays of dots) was instructed to imagine repeatedly throwing a die. Participants asked for self-reports on their strategies reported spontaneously occurring visuospatial imagination of a mental number line (42%), or imagining throwing a die (23%). Individual number representation was not affected by the initial instruction. There were no differences in randomization performance by group. Comprehensive understanding of the nature of the randomization task requires considering individual differences in construction of mental models.

Gravity modulates behaviour control strategy

“…Our results suggests a gravitational bias on the spatial distribution of numbers. The random number generation task has been previously adopted to investigate the properties of the non-verbal mental number line (Loetscher & Brugger 2007;Strenge & Rogge, 2010). Loetscher, Schwarz, Schubiger and Brugger (2008) found that actively turning the head to the left or right biased participants' responses towards smaller or larger numbers respectively.…”

“…Small numbers are associated with the left side of space, while larger numbers are associated with the right side (Dehaene, 1992). Results indicated a spatial-numerical interaction in random number generation: numbers were spontaneously remapped to spatial locations along a number line (Loetscher & Brugger 2007;Strenge & Rogge, 2010). Additionally, participants seem to mentally visualize the order of digits to facilitate the process of number generation (Towse 1998;Towse & Neil, 1998).…”