In recent years the exploration of the brain has shown some of those systems which are involved in the production and maintenance of certain motivational states. In rats, Olds and Milner demonstrated rewarding effects of stimulating certain systems; in cats, Delgado, Robert, and Miller, and Delgado, Rosvold, and Looney showed punishing effects from stimulating other zones. Brady et al. confirmed Olds and Milner in the cat and monkey. We have confirmed both effects in the monkey, and have investigated in some detail the reward and the punishment effects in various loci. We have found also the same effects from a few loci in the porpoise's (dolphin) brain; this animal's brain is as large as the human one and hence is of interest A number of workers have been doing exploratory studies on healthy intact human individuals in isolation from other persons and from their usual levels of exchange with the physical environment; by such means one may investigate positive and negative motivations in more or less pure culture in the subjective psychological sphere. Such research is full of technical problems and pitfalls; it shows that in these special conditions some minds tend to disguise the presently acting true motives and to project them in multitudinuous forms into the minimally stimulating and non-reactive reality. Some useful data are also derived from autobiographical accounts written by those who have been exposed to isolation at sea or in the polar regions; the dominance of the positive or of the negative motivations can be seen operating especially clearly in such accounts. Such exploratory studies are slowly adding to an understanding of positive and negative motivations and offer powerful tools for further studies.Abstract Teaser