to recognize that his or her dog is a Labrador, that a Labrador is a dog, and that a dog is an animal, and draw conclusions from the information available, as well as apply all these processes to hypothetical situations. The abstract quality of the adolescent's thought at the formal operational level is evident in the adolescent's verbal problem solving ability. The logical quality of the adolescent's thought is when children are more likely to solve problems in a trial-and-error fashion. Adolescents begin to think more as a scientist thinks, devising plans to solve problems and systematically test opinions. They use hypothetical-deductive reasoning, which means that they develop hypotheses or best guesses, and systematically deduce, or conclude, which is the best path to follow in solving the problem. During this stage the adolescent is able to understand love, logical proofs and values. During this stage the young person begins to entertain possibilities for the future and is fascinated with what they can be. Adolescents also are changing cognitively by the way that they think about social matters. One thing that brings about a change is egocentrism. This happens by heightening self-consciousness and giving adolescents an idea of who they are through their personal uniqueness and invincibility. Adolescent egocentrism can be dissected into two types of social thinking: imaginary audience and personal fable. Imaginary audience consists of an adolescent believing that others are watching them and the things they do. Personal fable is not the same thing as imaginary audience but is often confused with imaginary audience. Personal fable consists of believing that you are exceptional in some way. These types of social thinking begin in the concrete stage but carry on to the formal operational stage of development. Testing for concrete operations Piagetian tests are well known and practiced to test for concrete operations. The most prevalent tests are those for conservation. There are some important aspects that the experimenter must take into account when performing experiments with these children. One example of an experiment for testing conservation is the water level task. An experimenter will have two glasses that are the same size, fill them to the same level with liquid, and make sure the child understands that both of the glasses have the same amount of water in them. Then, the experimenter will pour the liquid from one of the small glasses into a tall, thin glass. The