Nov 9, - Put your hands clasped as in prayer. If you see: * Left thumb under the right thumb, then you are left brain dominant user. in the picture above the left thumb under the right thumb, then the means of use of the right brain is more dominant. Jul 10, - If you both cross your arms and weave your hands right-over-left, you Left-over-right arm-crossing hand-weavers are supposedly the most . I always thought when the left thumb was on top you were ruled by your heart.