_Satisfactory._ "Stone is harder." "Egg is softer." "Egg breaks easier." "Egg breaks and stone doesn't." "Stone is heavier." "Egg is white and stone is not." "Egg has a shell and stone does not." "Eggs have a white and a yellow in them." "You put eggs in a pudding." "An egg is rounder than a stone." We may also accept statements which are only qualifiedly true; as, "You can break an egg, but not a stone." Likewise double but incomplete comparisons are satisfactory; as, "An egg you fry and a stone you throw," "A stone is tough and an egg you eat," etc. A little over three fourths of the comparisons made by children of 6, 7, and 8 years are in terms of hardness. The other responses are widely scattered. _Unsatisfactory._ "A stone is bigger (or smaller) than an egg." "A stone is square and an egg is round." "An egg is yellow and a stone is white." "Stones are red (or black, etc.) and eggs are white." "An egg is to eat and a stone is to plant." "An egg is round and a stone is sometimes round." It will be noted that the above responses are partly true and partly false. The error they contain renders them unacceptable. Most of the failures are due to misstatements as to size, shape, or color, but occasionally one meets a bizarre answer. _Wood and glass_ _Satisfactory._ "Glass breaks easier than wood." "Glass breaks and wood does not." "Wood is stronger than glass." "Glass you can see through and wood you can't." "Glass cuts you and wood doesn't." "You get splinters from wood and you don't from glass." "Glass melts and wood doesn't." "Wood burns and glass doesn't." "Wood has bark and glass hasn't." "Wood grows and glass doesn't." "Glass is heavier than wood." "Glass glistens in the sun and wood does not." An incomplete double comparison is also counted satisfactory; as, "Wood you can burn and glass you can see through." _Unsatisfactory._ "Wood is black and glass is white." (Color differences are always unsatisfactory in this comparison unless transparency is also mentioned.) "Glass is square and wood is round." "Glass is bigger than wood" (or _vice versa_). "Wood is oblong and glass is square." "Glass is thin and wood is thick." "Wood is made out of trees and glass out of windows." "There is no glass in wood." The two most frequent types of failures are misstatements regarding color and thickness. The other failures are widely scattered.