The surreptitious observation design: an experimental paradigm for distinguishing artifact from essence in hypnosis

Administered a hypnotic induction and 5 standard hypnotic suggestions twice via audiotape to a group of high-hypnotizable subjects and a group of low-hypnotizable simulators. During the first administration, subjects were led to believe that they were alone. However, their behavior was surreptitiously recorded on videotape and observed on a video monitor. The second administration occurred in the presence of an experimenter who had not been informed of group assignment. When unaware that they were being observed, simulators were significantly less responsive to suggestions than they were when openly observed. In contrast, the behavior of nonsimulating subjects was not affected by the presence of an experimenter. These data indicate that the responses of highly hypnotizable subjects to standard hypnotic suggestions cannot be accounted for in terms of simple compliance with experimental demand.     

Logic, reasoning, and verbal behavior

This paper analyzes the traditional concepts of logic and reasoning from the perspective of radical behaviorism and in the terms of Skinner's treatment of verbal behavior. The topics covered in this analysis include the proposition, premises and conclusions, logicality and rules, and deductive and inductive reasoning.     

Continuous versus discrete dimensions of reinforcement schedules: An integrative analysis

An approach to reinforcement-schedule contingencies is presented that accommodates continuous as well as discrete effective dimensions of responses and reinforcers. College students' wheel turning was reinforced by projected reading material according to four schedule contingencies that incorporated either a discontinuous (count) or continuous (duration) dimension of the response and the reinforcer. The contingencies arranged a 1:1 correspondence between (a) response count and consequent stimulus count, (b) response duration and stimulus count, (c) response count and stimulus duration, and (d) response duration and stimulus duration. Contingencies incorporating response count produced moderate to high rates of very short-duration responses. Contingencies incorporating response duration produced very low-rate, long-duration responding. The dimension of the reinforcer had minimal or no additional effect. We suggest that incorporating duration and other continuous dimensions into schedule contingencies may improve our understanding of both laboratory and nonlaboratory behavior.     

Involuntary attentional capture by abrupt onsets

The extent to which brief abrupt-onset visual stimuli involuntarily capture spatial attention was examined in five experiments. The paradigm used was intended to maximize the opportunity and incentive for subjects to ignore abrupt-onset distractor stimuli in nontarget locations. Subjects made a speeded two-choice response to a target letter appearing in one of four boxes. An abrupt-onset visual stimulus, easily discriminable from the target, was flashed briefly prior to the presentation of a target. In separate blocks, the flash stimulus marked the box in which the target would subsequently appear (SAME), a different box (DIFF), fixation (CENTER), or all four boxes (ALL). Prior to each block, subjects were informed of the flash-target relationship. In all five experiments, response time was elevated in the DIFF, CENTER, and ALL conditions. The interference effect was larger for the DIFF condition and persisted for longer flash-target SOAs. These results suggest that, under appropriate conditions, spatial attention can be involuntarily drawn to abrupt-onset events despite the intention of subjects’ to ignore them.     

Spontaneous attention to primed and nonprimed inputs

The literature is ambiguous with respect to whether attention is drawn spontaneously to expected or unexpected items in mixed arrays. Several studies from our own laboratory indicate that even though expected words are more localizable than unexpected words in unmixed four-word arrays, showing a baseline advantage for expected words, unexpected words are sometimes more localizable than their expected companions in mixed arrays, suggesting that unexpected words attract attention (see, e.g., Johnston & Schwarting, 1996). By contrast, Dark, Vochatzer, and VanVoorhis (1996) observed that expected words were more reportable than their unexpected companions in mixed, two-word arrays. However, because the Dark et al. research did not include arrays in which both words were expected, it is not clear whether their findings reflect an attentional effect over and above a baseline advantage of expected words. The present study added some additional controls in order to assess this possibility. The superior reportability of expected words was even greater in mixed arrays than in unmixed arrays, suggesting that expected words in mixed arrays attract attention. Following Johnston and Hawley (1994), the conflicting effects of expectancy on spontaneous attention are taken as further evidence that the mind/brain system is biased simultaneously toward both what it most expects and what it least expects to perceive.     

Second-order schedules: a comparison of chained, brief-stimulus, and tandem procedures

Pigeons were exposed to seven types of two-component schedules, each component a 2-min fixed-interval schedule. Food presentation occurred at the completion of the second component under all conditions. The seven types of schedules were: (1) a chained schedule in which completion of the first component produced the discriminative stimulus associated with the second component; (2) a chained schedule to which was added the brief presentation of a food-paired stimulus at the completion of the first component; (3) a chained schedule to which was added the brief presentation of a stimulus not paired with food at the completion of the first component; (4) a multiple schedule in which food presentation occurred at the completion of both components; (5) a tandem schedule in which completion of the first component initiated the second component, with no changes in exteroceptive stimuli; (6) a food-paired brief-stimulus schedule in which the brief presentation of a food-paired stimulus was made at the completion of the first component and no other changes in stimuli occurred; and (7) a brief-stimulus schedule in which the brief presentation of a stimulus not paired with food was made at the completion of the first component and no other changes in stimuli occurred. Positively accelerated patterns of responding developed in the first component under three conditions: (1) the chained schedule with the added food-paired brief stimulus; (2) the multiple schedule; and (3) the food-paired brief-stimulus schedule. Response rates were low in the first component, with few instances of positively accelerated patterns, under two conditions: (1) the chained schedule; and (2) the chained schedule with the added nonpaired brief stimulus. The results suggest that a briefly presented food-paired stimulus may function as a more effective conditioned reinforcer than does the presentation of a discriminative stimulus.     

The analysis of performance criteria defining course grades as a determinant of college student academic performance

A series of five experimental conditions were designed to investigate the influence of minimum performance criteria and grade labels on college student academic performance. A college course in abnormal psychology was taught in an individualized manner so that each student could perform on each unit of subject matter in individual performance sessions whenever he wished. In each of the five experiments the minimum performance criteria that had to be attained before progressing to the next unit were varied during the quarter and the resulting changes in performance were recorded. In Experiment I there were no criteria; in Experiments II, III, and IV three levels of criteria (High, Medium, and Low) were varied but all of the criteria defined a course grade of "A". In Experiment V, the three criteria defined course grades of A, B, and C. The results showed that the criteria controlled performance to a high degree, so that regardless of what quality of performance had been demonstrated previously or was being produced currently, performance was immediately changed to attain new criteria put into effect. Students in Experiment I produced very poor performance compared to the other conditions.     

Modification of consonant speech-sound articulation in young children

A series of three experiments was performed in a classroom setting with small groups of young children with severe articulation problems. Variations on a basic token reinforcement procedure were demonstrated in each experiment. A combined multiple baseline/reversal design showed effective experimenter control of rates of correct and incorrect consonant sound articulation in all cases. In addition, the data in each experiment showed the problems of obtaining stimulus generalization of the high rates of correct articulation to non-training settings. The third experiment demonstrated a procedure for producing such generalization by making each child a discriminative stimulus for correct articulaton by the other child, thus maintaining high levels of correct articulation for each child when in the presence of the other.     

Asymmetry of masking between noise and tone

A pure tone was used to mask narrow and wide bands of noise centered on the frequency of the tone. In a given experimental session, the sound-pressure level (SPL) of the tone was held constant and loudness balances were obtained between a masked and unmasked noise band of equal width. These results are compared to earlier measures of the partial masking of tone by noise. The comparison shows that noise masks a tone more effectively than the tone masks the noise. Although the effect of the tone on a critical band of noise is greater than its effect on either an octave-band noise or wide-band noise, it is considerably smaller than the effect of the noise on the tone. Decreasing the noise bandwidth still further to a subcritical width reduces the asymmetry of masking somewhat, but a difference at high intensities of about 20 dB between the masking effects of an equally intense noise and tone remains. Whether the masker is a tone or noise, masking ceases when the effective energy of the masked and masking stimuli is the same.