Is it farther or further?
reinforcer re·in·forc·er (rē'ĭn-fôr'sər)
A stimulus, such as a reward, that in operant conditioning maintains or strengthens a desired response.
reinforce re·in·force (rē'ĭn-fôrs')
v. re·in·forced, re·in·forc·ing, re·in·forc·es
To give more force or effectiveness to something; strengthen.
To reward an individual, especially an experimental subject, with a reinforcer subsequent to a desired response or performance.
To stimulate a response by means of a reinforcer.