Terminology: why do psychologists use "positive" and "negative"? In a lot of places in psychology - for example in operant conditioning and in describing symptoms of psychological disorders - various things are described as "positive" and "negative". Positive rewards/punishments or positive symptoms are things that are added or given to an individual, whereas negative rewards/punishments or symptoms are things that are taken away or that disappear. 

This terminology seems confusing - both the word "positive" and the word "negative" have other connotations in areas that psychology is concerned with, for example in describing mood. Using this particular terminology for things like the symptoms of psychological disorders, instead of less ambiguous words with more direct meanings like "additive" or "subtractive", seems confusing. Is there a particular reason why the words "positive" and "negative" continue to be used in a scientific sense over such less ambiguous alternatives?
They are used in conditioning because those terms were originally used by Skinner, and after some shuffling around ("negative reinforcement" used to be used to describe what is now called "punishment" or more specifically "positive punishment") became standard terms. Dinsmoor (2004) covers a bit of the history and cites the relevant source literature.

For the positive and negative symptoms of schizophrenia, that goes back earlier, to Bleuler who was also the first person to use the term "schizophrenia" in 1908 to describe the disease known by that name today. The 1908 use of schizophrenia was at a conference, but there are also published books and articles by him later that use the terms, I've included a reference to one from 1912 below.

It isn't all that uncommon for scientific terms to differ from their lay usage; language is also mutable, so even carefully chosen terminology can drift away from the meaning in broader society. I'm not suggesting that is what happened in this case, but I just want to emphasize that it is typically more important to use terms consistently in science. Changing terminology that has been used for a long time is difficult, potentially confusing, and makes it harder to connect older literature to newer work.



Ashok, A. H., Baugh, J., &amp; Yeragani, V. K. (2012). Paul Eugen Bleuler and the origin of the term schizophrenia (SCHIZOPRENIEGRUPPE). Indian journal of psychiatry, 54(1), 95. Available from: http://www.indianjpsychiatry.org/text.asp?2012/54/1/95/94660

Bleuler, E., &amp; White, W. A. (1912). The theory of schizophrenic negativism. Journal of Nervous and Mental Disease, 39(1), 50-57, 133-139, 195-202, 274-279. doi: 10.1097/00005053-191201000-00009

Dinsmoor, J. A. (2004). The etymology of basic concepts in the experimental analysis of behavior. Journal of the Experimental Analysis of Behavior, 82(3), 311-316. doi: 10.1901/jeab.2004.82-311 pdf: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1285013/pdf/15693525.pdf