Vygotsky argued that good instruction should be pitched:

1. Vygotsky placed instruction inside the zone of proximal development. 2. Work the child can already do alone teaches little new. 3. Work far beyond the child's reach cannot be done even with help. 4. So effective instruction is slightly ahead of the child's current level. **Why not the others:** Exactly at the child's level sounds sensible but leaves the child doing only what she can already manage alone. _Source: Wikipedia, "Constructivism (philosophy of education)", section "Social constructivism" (revision 1378243907)_