understimulate

under- +‎ stimulate

understimulate (third-person singular simple present understimulates, present participle understimulating, simple past and past participle understimulated)

1. (transitive) To stimulate too little or infrequently; to provide with insufficient stimulation.
   • 1992, Robert Paul Liberman, Handbook of psychiatric rehabilitation

     Thus, as Wing and Brown (1970) observed, an understimulating "back ward" may lead to withdrawal and a lack of external social stimulation and support.

• overstimulate