Carl D. Williams

Effect of induced stress on convergent and divergent thinking.

Measures of convergent and divergent thinking were obtained from college students before and after the presentation of either a disturbing motion picture film or a benign control film. Induced stress was found to inhibit divergent thinking but to have no effect on convergent thinking. The data suggest that certain intellectual abilities are influenced more readily than others by psychological stress.

Motivational Correlations of Strategy Choices in the Prisoner's Dilemma Game

The purpose of the present study was to investigate the relationship between the motivational dimensions assessed by the Motivation Analysis Test and prisoners dilemma game behavior as measured both by the number of competitive strategy choices and the two-stage stochastic variables labelled trustworthiness, forgiveness, repentance, and trust by Rapoport.

Event Patterns in Sequential Choice Behavior

A procedure for identifying classes of effective event patterns in the sequential prediction task was applied to responses to 1 fully random and 13 semirandom schedules of binary events. The assumption that subjects respond to homogeneous and heterogeneous event patterns of fixed length led to more accurate prediction of behavior on 13 of the 14 schedules than the assumption that they respond to homogeneous event patterns of variable length. The event patterns responded to were a function of maximum run length; there was a regression toward simpler patterns as task complexity increased and a tendency to encode patterns as combinations rather than as permutations; and the fully random schedule did possess discriminative properties.

A Three-Element Model for Binary Prediction

600 Ss received 1 of 4 100-trial, 2-alternative, 50%-event sequences. A model incorporating logical, experiential, and error components provided a better description of choice behavior on these four event schedules than an alternative model. The data suggest that each element of the model presented in this paper plays an important role in choice behavior.

Paranormal belief, experience, and the Keirsey Temperament Sorter.

121 college students completed the Anomalous Experience Inventory and the Keirsey Temperament Sorter. Multiple regression analyses provided significant models predicting both Paranormal Experience and Belief; the main predictors were the other subscales of the Anomalous Experience Inventory with the Keirsey variables playing only a minor role.

Humphreys' “Acquisition and Extinction of Verbal Expectations” Revisited: Evidence for a Partial Reinforcement Hump Effect

The present study employed the sequential prediction task to determine whether the partial reinforcement hump effect—a rise in the dependent variable curve following partial reinforcement—is a reliable phenomenon. 210 college students received one of seven sequences in which two events occurred equally often for 100 trials and in which the maximum run length was 2, 3, 4, 5, 6, 7, or 8, followed by 30 trials during which one event was always correct. A hump appeared in the post-acquisition curves of all seven groups. The location of the hump was a function of the maximum run length during Trials 1–100. These results provide strong support for an expectancy interpretation of the partial reinforcement extinction effect.

Extinction of human eyelid conditioning as a function of components of a masking procedure

Eyelid conditioning and extinction procedures were embedded in a masking probability learning task. On non-CS trials interspersed with extinction trials, a 100% masking (100% M) group received the US along with the masking stimuli, whereas a masking + free-shock (M + FS) group received US-alone presentations. A control (C) group received the same stimuli as did Group 100% M but with neutral instructions. Group 100% M revealed more, but Group M + FS revealed less, resistance to extinction than did Group C. Only the M + FS group extinguished completely.

Warning signal as a component of a compound stimulus in human eyelid conditioning

One hundred human Ss conditioned and extinguished in a parallel fashion to both the warning signal of a masking probability learning task and the programmed CS. Acquisition and extinction curves were similar for early and nonearly responders though early responders had a higher response rate during acquisition.

The Partial Reinforcement Hump in A Two-Choice Sequential Prediction Task With Alternatives of Unequal Frequency

Four hundred college students received one of five sequences in which one of two events occurred on either 60%, 70%, 80%, 90%, or 95% of 100 trials followed by 30 trials during which one event was always correct. A partial reinforcement hump—a rise and decline in the dependent variable curve following partial reinforcement—appeared in the postacquisition curves of two of the five groups. In the other three groups, a large fall-off in the curve occurred where a large drop in the curve should occur if postacquisition choices are controlled by the cognitive processes posited to produce the partial reinforcement hump. These results are consistent with the general expectancy position.