Table 5 
Concept of invariance: 
Solution probabilities at age seven 
by social class in six categories 
Urban sample 
Socio-economic Status 
Task 
INA/B101 Task A: Two Dimensional Space 
INA/B102 Task B: Number 
INA/B103 Task C: Substance 
INA/B104 Task D: Continuous Quantity 
INA/B105 Task E: Weight 
INA/B106 Task F: Discontinuous Quantity 
INA/B107 Task Al: Area 1 
INA/B108 Task AII: Area 2 
INA/B109 Task AIII: Area 3 
INA/B110 Task Bl: Length 1 
INA/BI11 Task BII: Length 2 
INA/B112 Task BIII: Length 3 
Socio-Economic Status 
Task 
INA/B101 Task A: Two Dimensional Space 
INA/B102 Task B: Number 
INA/B103 Task C: Substance 
INA/B104 Task D: Continuous Quantity 
INA/B105 Task E: Weight 
INA/B106 Task F: Discontinuous Quantity 
INA/B107 Task Al: Area 1 
INA/B108 Task All: Area 2 
INA/B109 Task AIII: Area 3 
INA/BI10 Task Bl: Length 1 
INA/BII1 Task BII: Length 2 
INA/B112 Task BIII: Length 3 
low/low (SES 1) 
Judgment 
Justification 
— 
0.611 
0.389 
0.833 
0.889 
0.611 
0.667 
0.556 
0.611 
0.444 
0.389 
0.556 
0.667 
0.722 
0.833 
0.611 
0.611 
0.500 
0.444 
0.500 
0.500 
0.444 
0.444 
0.444 
0.667 
middle/low 
(SES 3) 
Justification 
Judgment 
0.667 
0.833 
0.778 
0.889 
0.500 
0.611 
0.500 
0.667 
0.611 
0.667 
0.833 
0.667 
0.889 
0.833 
0.833 
0.778 
0.778 
0.667 
0.611 
0.667 
0.611 
0.667 
0.556 
0.722 
lowfhigh (SES 2) 
N. 
Judgment 
N 
Justification 
27 
0.593 
18 0.926 
0.852 
18 0.963 
27 
27 
0.593 
18 0.778 
27 
18 0.630 
0.519 
27 
0.593 
18 0.667 
27 
0.704 
18 0.778 
18 0.778 
0.741 
27 
27 
0.556 
18 0.630 
27 
0.519 
18 0.556 
0.630 
18 0.704 
27 
27 
0.630 
18 0.667 
0.593 
27 
18 0.741 
middle/high (SES 4) 
Judgment 
Justification N 
N 
 
18 
20 
0.950 
0.750 
18 
0.900 
 
0.900 
20 
20 
18 0.900 
0.650 
0.650 
0.850 
18 
20 
20 
0.700 
18 0.850 
0.800 20 
18 0.900 
0.900 20 
18 0.900 
18 0.700 
0.650 20 
0.600 20 
18 0.600 
0.750 20 
18 0.900 
18 0.900 
0.700 20 
18 0.850 0.800 20 
21