The photo-lickerandum: A device for detecting the licking response,with capability for near-instantaneous programming of variable quantum reinforcement

A combined operandum-feeder is described that eliminates the necessity of passing an electrical sensing current through S while detecting and reinforcing tongue-licking responses. A glass nozzle for dispensing liquid reinforcers is situated just above a small separation in a loop of photo-conducting Sterite tubing; licks at a tiny area below the nozzle break a light beam and are detected via a photo-resistor and associated circuitry. Data are presented from a study in which rats worked at the operandum on a mult FR 40 ext schedule; performance and records are comparable to those obtained via conventional electronic sensing. Applications of the photo-lickerandum and an associated variable-quantum reinforcing system are suggested.