ShuiEro ... from vague up to sometimes ;) crystal clear drop by drop ...

The concept that all living animals can be arranged along a continuous "phylogenetic scale" with man at the top is inconsistent with contemporary views of animal evolution. Nevertheless, this arbitrary hierarchy continues to influence researchers in the field of animal behavior who seek to make inferences about the evolutionary development of a particular type of behavior. Comparative psychologists have failed to distinguish between data obtained from living representatives of a common evolutionary lineage and data from animals which represent divergent lineages. Only the former can provide a foundation for inferences about the phylogenetic development of behavior patterns. The latter can provide information only about general mechanisms of adaptation and survival, which are not necessarily relevant to any specific evolutionary lineage. The widespread failure of comparative psychologists to take into account the zoological model of animal evolution when selecting animals for study and when interpreting behavioral similarities and differences has greatly hampered the development of generalizations with any predictive value. (42 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)