Bar pressing in the rat as a function of variable visual stimulation

Differential reinforcing effects of steady and flickering light on bar pressing in the rat

“…Rats show a significant increase over their normal operant level of bar pressing in a Skinner box if a dim light onset is made contingent upon this response (e.g., Kish, 1955)_ In apreviousexperiment (Williams& Lowe, 1967), it was found that after an adaptation period of 10 daily \.2-h sessions in a dark box flickering light rather than a steady light produced a greater rate of bar pressing as measured over five daily \.2-h experimental sessions. This result was interpreted in favor of the notion that stimulus change represents the crucial reinforcing event in this situation (cf.…”

“…had previously been farniliarized with the dark experimental box, and similarly Lowe & Williams (1968) showed that a longer period of adaptation to the dark experimental box also increased the light reinforcemen t effect. The present experiment is, therefore, a repetition of the initial study (Williams & Lowe, 1967), using a shorter pretest period, 15 min instead of 10 x 30 min. While it may be expected that the overall effectiveness of both flicke ring and steady light may be reduced following this shorter baseline session, there is no reason to predict from stimulus change theory any alteration in the relative effectiveness of the two types of response-<:ontingent light as reinforcers.…”

Sensory reinforcement and response facilitation

“…For example, they will learn a task in order to produce variable visual stimulation (e.g., Butler, 1954;Williams & Lowe, 1967). This "sensory reinforcement" effect is apparently unrelated to such organic drive states as hunger and thirst, and has been demonstrated in several species under various conditions, although visual stimulation has been the most effective reinforcer.…”