International data from TIMSS 2015 show a significant negative correlation between the country mean attitude toward mathematics and the mean achievement in mathematics of fourth grade pupils. The aim of the paper is to decide whether it is a statistical artifact or an indication of a real factor operating at the country level. The multilevel regression analysis of the data attests the latter. The factor is hypothetically identified with country typical pressure for knowledge acquisition. Strong pressure is conducive to high achievement but it puts pupils under stress, which lowers the attitude. The reverse holds for weak pressure. Within country, the variability of pressure for knowledge acquisition is restricted, hence pupils may maintain psychological coherence between achievement and attitude.