Grouping strategies in number estimation extend the subitizing range

In the calculation folder: each file contains a matrix called “MATR”. Each row of the matrix “MATR” is a trial. The columns contain the following information: 1st: Number of trial 2nd: Subject response 4th: Response time 5th: first number 6th: math symbol (1=*; 2= +; 3= –) 7th: second number 8th: third number In the calculation folder: each file contains a matrix called “matr”. Each row of the matrix “matr” is a trial. The columns contain the following information: 1st: subject response in the numerosity task 2nd: the presented numerosity 3rd: subject response in the numerosity task 4th: zero 5th: stimulus duration 6th: Response time in the numerosity task 7th: Grouped (1) or random (2) presentation 8th: 1 9th: 1 10th: Number of items of the upper-left quadrant 11th: Number of items of the lower-left quadrant 12th: Number of items of the upper-right quadrant 13th: Number of items of the lower - right quadrant 14th: odd shape presented (1=diamond; 2=triangle; 3=circle) 15th: subject response in the shape task 16th: 0.2 in the single task response time in the shape task when dual task 17th: single (0) or dual (1) task 18th: time stimulus on 19th: time stimulus off