Michael C. Choban

The effects of inescapable shock on the retention of a previously learned response in an appetitive situation with delay of reinforcement

During Phase 1 of this experiment, all rats received a delay of (food) reward in a straight alley. During Phase 2, rats received escapable, inescapable, or no footshock in an operant chamber. The results, which supported a motivational interpretation of learned helplessness, showed that only inescapable shock reduced speed in a response previously attained (running in the straight alley; Phase 3).

DELAY OF REINFORCEMENT EFFECTS WITHOUT GOAL-BOX CONFINEMENT

24 male albino rats were randomly assigned to one of three groups, immediate reinforcement, moderate delay, or long delay. Group Immediate (n = 8) received food reinforcement immediately upon entering the goal box and were then placed in a waiting cage. For Group Moderate Delay (n = 8), goal-box confinement was eliminated by placement in a waiting cage rather than confinement in the goal box. Group Long Delay (n = 8) also had goal-box confinement eliminated with placement in a waiting cage for the 30-sec. delay of reinforcement. After acquisition trials, Group Immediate ran significantly faster than both Groups Moderate and Long Delay, but there was no significant difference in speeds between Group Moderate and Group Long Delay. Apparently, previous findings of a delay of reinforcement effect were at least partly associated with timing of presentation rather than goal-box confinement.

Effects of word repetition and presentation rate on the frequency of verbal transformations: Support for habituation

A verbal transformation (VT) is any perceptible change that subjects hear when the same word is repeated several times. Habituation was studied by investigating whether more VTs would occur during the second 3 min of word repetition. We also attempted to replicate the finding of Snyder, Calef, Choban, and Greller (1992) that a familiar word presentation style (a word spoken relatively “normally”) resulted in more VTs than did an unfamiliar word presentation style (a word spoken slowly). Thirty-two psychology students listened to six neutral words repeated for 6 min with approximately 3 sec between words. Subjects reported significantly more VTs during the second as opposed to the first 3 min of word repetition only during normal presentation, supporting a habituation explanation that an increase in VTs following the continuous repetition of a word could be an example of habituation. We replicated the findings of Snyder et al. (1992) only during the second 3 min.

The effects of noncontingent reinforcement on the behavior of a previously learned running response

During Phase 1, all rats received a delay of food reward following a traversal of a straight alley. During Phase 2, rats received contingent (CR), noncontingent (NCR), or no food reward (NR) in an operant chamber. During the 1st day of Phase 3 (running in the straight alley), no differences in speeds occurred between groups receiving contingent and noncontingent food. However, during the 3rd day of Phase 3, Group NCR ran significantly slower than Groups CR and NR, suggesting that noncontingent reinforcement does not interfere with the retention of prior learning, but may impair the further learning of a response partially learned prior to receiving uncontrollability (response-independent rewards).

Frequency of verbal transformations as a function of word-presentation styles

The “arousal” hypothesis was studied by investigating whether a familiar presentation style (a word spoken relatively “normally”) would result in more verbal transformations (VTs) than would an unfamiliar presentation style (a word spoken slowly). A VT is any perceptual change that subjects hear when the same word is repeated several times. Forty-three students in an introductory psychology class listened to six neutral words (bedroom, telephone, door, people, subjects, television) repeated for 6 min with approximately 3 sec between each word. Subjects produced significantly more VTs when the word was spoken normally (familiar) as opposed to slowly (unfamiliar). In addition, the sequence of the presentation styles had no effect. The results are explained in terms of arousal, habituation, word clarity, and attention.

Effects of unsolvable anagrams on retention

During Phase 1, 51 college students received 40 nonsense syllables to memorize (free recall). During Phase 2, 17 students received unsolvable anagrams (Group USA), 17 students received solvable anagrams (Group SA), and 17 received a blank piece of paper on which to write an autobiographical essay (Group E). During Phase 3, Group USA recalled significantly fewer Phase 1 nonsense syllables than did Groups SA and E, both of which recalled approximately the same number of nonsense syllables. The results support previous animal research, which shows that uncontrollable tasks interfere with the retention of a previously learned response.

Perseveration of the partial reinforcement effect in extinction with rats over two phases of extinction and two stages of continuous reinforcement.

One group of 10 male albino rats was given partial reinforcement while the other 10 rats received continuous reinforcement in a straight alley. Subjects then experienced five consecutive stages of Extinction 1, Continuous Reinforcement 1, Extinction 2, Continuous Reinforcement 2, and finally, Extinction 3. Analysis showed the partial reinforcement effect in extinction was sustained over two stages of extinction and two stages of continuous reinforcement, since subjects receiving partial reinforcement ran faster than rats given continuous reinforcement throughout all three of the extinction periods. The results seem to support those of Amsels (1967) and Capaldis (1967) theoretical formulations of the partial reinforcement effect in extinction.

Effects of Preshift Small Magnitude of Reward Received during Goalbox Placements on the Negative Contrast Effect

During preshift, one experimental group of rats was given a large magnitude of food reward following a traversal of a straight alley and during a goalbox placement, while the other experimental group was given a small reward during goalbox placement and a large reward following a run. During postshift, all experimental groups were given a small reward of food following a traversal down the runway and during a goalbox placement. A control group was maintained on small reward during placements and following a traversal throughout the study. Only the group who received preshift large reward during placement and following a runway response ran slower to small reward during postshift than the control group maintained on small reward (negative contrast effect).

DELAY OF REINFORCEMENT EFFECTS: TIMING OF REINFORCEMENT OR NARROW GOAL-BOX CONFINEMENT

The present experiment investigated whether narrow goal-box confinement in studies of delay of reinforcement in the runway may have had aversive or punishing effects. Analysis showed no difference in performance between groups of rats who were either confined in a narrow goal-box or a large compartment while receiving their delay of reinforcement. The results suggest that narrow goal-box confinement does not have aversive characteristics.

Effects of Delay of Reinforcement with Reduction of Confinement in the Goal-Box and Elimination of Handling Immediately following Runway Traversal

24 male rats were randomly assigned into one of three groups. The first group was immediately reinforced with food pellets upon entering a wide goal-box area after running down a straight alley. The second group was reinforced with food pellets 10 sec. after they placed their noses above the goal cup. A third group was reinforced 30 sec. after they placed their noses above the goal cup. All animals were given a total of 72 trials (four trials per day). The results indicated that rats given immediate reinforcement ran faster than those with a 10-sec. delay which were faster than those with a 30-sec. delay. These findings suggest that the results of the previous studies were due to delay of reinforcement effects and not confinement in the goal-box or handling following a run.