Effects of response variability on the sensitivity of rule-governed behavior

Two experiments examined the relation between response variability and sensitivity to changes in reinforcement contingencies. In Experiment 1, two groups of college students were provided complete instructions regarding a button-pressing task; the instructions stated “press the button 40 times for each point” (exchangeable for money). Two additional groups received incomplete instructions that omitted the pattern of responding required for reinforcement under the same schedule. Sensitivity was tested in one completely instructed and one incompletely instructed group after responding had met a stability criterion, and for the remaining two groups after a short exposure to the original schedule. The three groups of subjects whose responding was completely instructed or who had met the stability criterion showed little variability at the moment of change in the reinforcement schedule. The responding of these three groups also was insensitive to the contingency change. Incompletely instructed short-exposure responding was more variable at the moment of schedule change and was sensitive to the new contingency in four of six cases. In Experiment 2, completely and incompletely instructed responding first met a stability criterion. This was followed by a test that showed no sensitivity to a contingency change. A strategic instruction was then presented that stated variable responding would work best. Five of 6 subjects showed increased variability after this instruction, and all 6 showed sensitivity to contingency change. The findings are discussed from a selectionist perspective that describes response acquisition as a process of variation, selection, and maintenance. From this perspective, sensitivity to contingency changes is described as a function of variables that produce response variability.     

Instructional and probability manipulations of bias in multiletter matching

Ratcliff (1985) performed fits of his diffusion model to the results of multiletter-matching experiments conducted by Ratcliff and Hacker (1981) and Proctor, Rao, and Hurst (1984), in which bias to respond "same" or "different" was manipulated by instructions and probabilities, respectively. The fits showed that both bias manipulations affected settings of a goodness-of-match criterion, whereas instructions also affected sensitivity. Evaluations of the experimental procedures and of Ratcliff's model-fitting procedures were performed in the present study. Three experiments showed that instructions and probabilities had similar effects, regardless of whether the different pairs were blocked or randomized according to the number of mismatching positions. The most salient feature of the results--that "same" reaction times were traded off more than were "different" reaction times, with no corresponding asymmetry in the error rates--was evident in all situations. The evaluation of Ratcliff's model-fitting procedures indicated that the apparent influence of instructions on sensitivity likely is an artifact of unequal variance for the sets of same and different pairs. Moreover, the effects of bias can be explained in terms of settings of response criteria, rather than of the goodness-of-match criterion, as in Ratcliff's fits.     

The after-effects of ventriloquism

Subjects were tested for both ear-hand and eye-hand co-ordination before and after monitoring a synchronous series of noise bursts and of light flashes coming from the same spatial position, but with the virtual position of the flashes displaced 15° laterally by prisms. Attention was forced on both stimuli by the instruction to detect occasional reductions in intensity. No subject reported noticing the spatial discrepancy. Nevertheless ear--hand co-ordination was shifted in the direction of the prismatic displacement, and eye-hand co-ordination in the opposite direction. Both shifts were observed with instructions suggesting that the sound and the light came from one single source, with instructions suggesting two separate sources, and also with no information regarding the spatial relationship of sound and light. It is concluded that the resolution of auditory-visual spatial conflict involves recalibrations of both visual and auditory data and that these alterations last long enough to be detected as after-effects.     

Visual sensitivity and mindfulness meditation

Practitioners of the mindfulness form of Buddhist meditation were tested for visual sensitivity before and immediately after a 3-mo. retreat during which they practiced mindfulness meditation for 16 hr. each day. A control group composed of the staff at the retreat center was similarly tested. Visual sensitivity was defined in two ways: by a detection threshold based on the duration of simple light flashes and a discrimination threshold based on the interval between successive simple light flashes. All light flashes were presented tachistoscopically and were of fixed luminance. After the retreat, practitioners could detect shorter single-light flashes and required a shorter interval to differentiate between successive flashes correctly. The control group did not change on either measure. Phenomenological reports indicate that mindfulness practice enables practitioners to become aware of some of the usually preattentive processes involved in visual detection. The results support the statements found in Buddhist texts on meditation concerning the changes in perception encountered during the practice of mindfulness.     

Self-reinforcement: Impact of instructions,criterion setting,and tangible rewards

This investigation was designed to ascertain the effects of instructions, criterion setting, and the presence of tangible rewards on the self-reinforcement process. Fifty-two third- and fourth-grade subjects were assigned to one of four treatment groups: (a) stringent instructions/criterion setting/tangible reward, (b) stringent instructions/criterion setting/no tangible reward, (c) nonstringent instructions/criterion setting/tangible reward, and (d) nonstringent instructions/no tangible reward. In the stringent-instruction conditions, subjects received social reinforcement for selecting stringent performance criteria, whereas in the non-stringent-instruction conditions, social reinforcement was withheld. Subjects in the tangible-reward groups were allowed to select a prize following the successful completion of their self-selected work performance. Subjects in the no-tangible-reward groups received no prizes for their work. All subjects performed an arithmetic task in which the number of correct problems completed, number of problems attempted, and time at task served as dependent variables across five reinforcement and two extinction trials. The results suggest that the condition of stringent instructions, criterion setting, and tangible reward was more effective in producing behavior change than the other three conditions. Perceived task difficulty and previous achievement on arithmetic task performance were shown to affect criteria selected and mathematical performance. The results are discussed in light of the contributory role of instructions, criterion setting, and tangible rewards on the self-reinforcement procedure.This study is based on a doctoral dissertation submitted to the Faculty of Arts and Sciences at the University of Pittsburgh by Helen L. Evans. Dr. Russell T. Jones was the dissertation committee chairperson. It was partially funded by an American Psychological Association Minority Fellowship awarded to the first author. Special thanks are extended to the committee members, Drs. Lloyd Bond, Robert Glaser, Johnny Matson, and Samuel M. Turner, for their assistance. The authors would like to thank Thomas DeVoge, Paul Karoly, and Samuel M. Turner for reading and commenting on an early draft of this study. Portions of this paper were presented at the 1982 APA convention.     

Differences in visual sensitivity among mindfulness meditators and non-meditators

Tachistoscopic presentation of light flashes was used to test for differences in visual sensitivity among 3 groups of practitioners of Buddhist mindfulness meditation and non-meditator-controls. Meditation practitioners were able to detect light flashes of shorter duration than the non-meditators. There were no differences among the meditator groups. There were no differences among the groups in ability to discriminate between closely spaced successive light flashes. The lower detection threshold for single light flashes for the meditators may reflect an enduring increase in sensitivity, perhaps the long-term effects of the practice of mindfulness meditation on certain perceptual habit patterns. The lack of significant differences in the discrimination of successive light flashes probably reflects the resistance of other perceptual habit patterns to modification. The results support the statements found in Buddhist texts on meditation concerning the changes in perception encountered during the practice of mindfulness.     

Examining recognition criterion rigidity during testing using a biased-feedback technique: Evidence for adaptive criterion learning

Recognition models often assume that subjects use specific evidence values (decision criteria) to adaptively parse continuous memory evidence into response categories (e.g., "old," "new"). Although explicit pretest instructions influence criterion placement, these criteria appear extremely resistant to change once testing begins. We tested criterion sensitivity to local feedback using a novel biased-feedback technique designed to tacitly encourage certain errors by indicating they are the correct choices. Experiment 1 demonstrated that fully correct feedback had little effect on criterion placement, whereas biased feedback during Experiments 2 and 3 yielded prominent, durable, and adaptive criterion shifts, with observers reporting that they were unaware of the manipulation in Experiment 3. These data suggest that recognition criteria can be easily modified during testing through a form of feedback learning that operates independently of stimulus characteristics and observers' awareness of the nature of the manipulation. This mechanism may be fundamentally different from criterion shifts following explicit instructions and warnings, or shifts linked to manipulations of stimulus characteristics combined with feedback highlighting those manipulations.     

Anatomy of a flash. 1. Two-peak masking and a temporal filling-in

A modified paradigm of Crawford masking was used to link masking to brightness fluctuation, as distinct from flash brightness. Thresholds were measured for a 10 ms incremental pulse (the 'probe') presented before, during, or after a 500 ms pulse (the 'flash'). Both pulses were spatially coextensive with the background field, thus the criterion for probe detection was purely temporal. The flash occurred either in the tested eye, the opposite eye, or in both eyes. In all conditions, masking was strongly bimodal: thresholds peaked near flash onset and flash offset. The flash was perceived as a unitary event. Bimodal masking is attributed to cortical on-and off-effects, as (i) dichoptic masking was strong and (ii) the same incremental probe was masked by either incremental or decremental flashes. Strikingly, monocular probe thresholds were about equally elevated by binocular as by monocular flashes, although the binocular flashes were brighter. Therefore, some monocular features can be preserved in the larger net binocular response. A general conclusion is that masking depends on the same transient neural responses that bring about a brightness fluctuation, whereas the appearance of the flash as a single event, a unitary change of brightness, depends on a different mechanism, perhaps a sustained response that performs a temporal filling-in.     

Transient effects of acquisition history on generalization in a matching-to-sample task

This study examined the role of learning history on the acquisition of a matching-to-sample task. Twelve preschool children learned four stimulus classes through instructions, shaping, or imitation. After reaching criterion, the subjects were exposed to changed discrimination contingencies to determine how each learning history affected the acquisition of responses appropriate to the new contingencies. All subjects reached criterion on the new relations, although the subjects with a shaping history adapted slightly more quickly than those subjects with a history of instructions or imitation. Given sufficient exposure to changed contingencies, rule-driven insensitivity to contingencies was overcome by experience with consequences. This result may be specific to younger subjects, but it suggests that instructions can be used in education without creating insensitivity to contingencies.     

Recall criterion does not affect recall level or hypermnesia: A puzzle for generate/recognize theories

Subjects studied a mixed list of 70 words that varied in imagery value and then received three successive tests. Also varied were instructions given to subjects prior to list presentation (imagery or semantic rehearsal) and the type of recall test (standard free recall, an uninhibited-recall procedure in which subjects were encouraged to free associate and to guess while recalling the list, and a forced-recall condition in which they were also told to write a large number of responses to fill the allotted spaces). Recall improved across the three tests in all conditions, but the improvement was greater for high-than for low-imagery words. In addition, hypermnesia (the improved recall across tests) was shown to occur following semantic rehearsal instructions as well as imagery instructions and to occur with low-imagery words, contrary to the imagery hypothesis of the effect. Most importantly, the large variation in recall criterion produced by manipulating instructions at test (as measured by intrusions) did not affect the overall level of correct recall or the magnitude of improvements across tests. Apparently, the assumption of generate-recognize theories that people generate much more information in free recall than they produce (due to a stringent criterion for recognition of the generated material) is false.     

Effects of Changes in Instructions and Pictorial Variations on Story-telling Performance of Paranoid Schizophrenics

The purpose of this study was to investigate the effects of variations in instructions and pictorial stimuli on the story-telling performance of paranoid schizophrenic patients to TAT-like cards dealing with the dimensions of sex and hostility.

Twelve TAT-like pictures, six depicting sexual scenes and six representing hostile content were administered to 68 paranoid schizophrenics. One group of 34 Ss was instructed to tell stories in the first-person, while a different group of 34 Ss told stories in the third-person. Two criterion measures were examined; initial reaction time and total number of words.

Initial reaction time was significantly slower under first-person instructions, but only for the hostile pictures.

Initial reaction time was shortest for the moderately sexual pictures and verbal output was greatest for the least sexual pictures.

For the hostile pictures, neither the main effect of instructions nor the degree of hostility significantly affected any of the criterion measures.     

Be Careful What You Ask For: Effects of Response Instructions on the Construct Validity and Reliability of Situational Judgment Tests

The aim of this study was to examine how six different types of situational judgment test (SJT) instructions, used frequently in practice, influence the psychometric characteristics of SJTs. The six SJT versions used the exact same items and differed only in their instructions; these versions were administered in two phases. Phase I was a between–subjects design (n= 486) that had participants complete one version of the SJTs. Phase II was a within–subjects design (n= 231) held several weeks later that had participants complete all six versions of the SJTs. Further, 146 of these individuals completed both phases, allowing for an assessment of test–retest reliability. A variety of objective and subjective criteria were collected, including self and peer ratings. Results indicated that instructions had a large effect on SJT responses, reliability, and validity. In general, instructions asking what one ‘would do’ showed more favorable characteristics than those that asked what one ‘should do’. Correlations between these two types were relatively low despite the fact that the same items were used, and criterion–related validities differed substantially in favor of the ‘would do’ instructions. Overall, this study finds that researchers and practitioners must give careful consideration to the types of SJT instructions used; failing to do so could influence criterion–related validity and cloud inferences of construct validity.     

The influence of decision criteria upon remembering and knowing in recognition memory.

One may recognise an item as 'old' on basis of a recollective experience or by a feeling of familiarity without specific recollection. The former is called a 'remember' judgement; the latter a 'know' judgement. It has been claimed that remember and know responses reflect qualitatively distinct components of recognition memory, and not just derive from gradual differences in perceived trace strength or subjective certainty (i.e. remember judgments include memories of which one is more confident). Nonetheless, the present study examined the possibility that the distinction does relate to decision criteria placed upon a single familiarity axis (see Donaldson, 1996; Hirshman & Master, 1997). To this purpose, two groups of subjects were compared: one, which was instructed to be very conservative in their old-new judgements, while the other group was stimulated to be very lenient instead. Remember hit rates increased with more lenient criteria, whereas know hit rates did not, but false alarm rates did. While remember sensitivity was equal in the two groups, know sensitivity was lower with liberal criteria. Also it correlated with overall response bias. This lends support to the possibility that subjects not only apply an old-new decision criterion, but also set a remember-know criterion, which is affected in a similar way by liberal versus conservative instructions.     

Absolute sensitivity to white noise under auxiliary visual stimulation1

Absolute sensitivity to white noise was measured with the O in the dark, in constant illumination, and in the dark but with sound-synchronized flashes of light at three different intensities. A confidence rating procedure was used, and the results were analyzed in terms of the theory of signal detectability. There appeared to be no consistent effect of auxiliary visual stimulation on absolute auditory sensitivity for the four Os examined.     

Instructions, multiple schedules, and extinction: Distinguishing rule-governed from schedule-controlled behavior

Schedule sensitivity has usually been examined either through a multiple schedule or through changes in schedules after steady-state responding has been established. This study compared the effects of these two procedures when various instructions were given. Fifty-five college students responded in two 32-min sessions under a multiple fixed-ratio 18/differential-reinforcement-of-low-rate 6-s schedule, followed by one session of extinction. Some subjects received no instructions regarding the appropriate rates of responding, whereas others received instructions to respond slowly, rapidly, or both. Relative to the schedule in operation, the instructions were minimal, partially inaccurate, or accurate. When there was little schedule sensitivity in the multiple schedule, there was little in extinction. When apparently schedule-sensitive responding occurred in the multiple schedule, however, sensitivity in extinction occurred only if differential responding in the multiple schedule could not be due to rules supplied by the experimenter. This evidence shows that rule-governed behavior that occurs in the form of schedule-sensitive behavior may not in fact become schedule-sensitive even though it makes contact with the scheduled reinforcers.     

The effects of instructions and calculation procedures on observers' accuracy, agreement, and calculation correctness

Although the quality of observational data is generally evaluated by observer agreement, measures of both observer agreement and accuracy were available in the present study. Videotapes with a criterion protocol were coded by 16 observers. All observers calculated agreement scores both on their own and their partner's data and on a contrived data set misrepresented as data collected by other observers. Compared with agreement scores calculated by the experimenter, observers erroneously inflated their own agreement scores and deflated the agreement scores on the contrived data. Half of the observers (n = 8) had been given instructions emphasizing the importance of accuracy during observation while the other half had been given instructions emphasizing interobserver agreement. Accuracy exceeded agreement for the former group, whereas agreement exceeded accuracy for the latter group. The implications are that agreement should be calculated by the experimenter and that the accuracy-agreement relationship can be altered by differential observer instructions.     

Establishing generalized verb-noun instruction-following skills in retarded children

A transfer of stimulus control procedure was used to establish generalized verb-noun instruction-following skills in two severely retarded boys. Each of 12 verbs was trained, in a multiple baseline order, to criterion with each of 12 nouns in the form of verb-noun verbal instructions. Throughout training, reinforced probes were conducted on both trained and untrained verb-noun combinations. As training progressed, both subjects began to respond correctly to untrained verb-noun instructions. Eventually, a verb needed to be trained in combination with only one noun before generalization occurred to the as-yet-untrained 11 verb-noun instructions involving that verb.     

Instructional versus schedule control of humans' choices in situations of diminishing returns

Four adult humans chose repeatedly between a fixed-time schedule (of points later exchangeable for money) and a progressive-time schedule that began at 0 s and increased by a fixed number of seconds with each point delivered by that schedule. Each point delivered by the fixed-time schedule reset the requirements of the progressive-time schedule to its minimum value. Subjects were provided with instructions that specified a particular sequence of choices. Under the initial conditions, the instructions accurately specified the optimal choice sequence. Thus, control by instructions and optimal control by the programmed contingencies both supported the same performance. To distinguish the effects of instructions from schedule sensitivity, the correspondence between the instructed and optimal choice patterns was gradually altered across conditions by varying the step size of the progressive-time schedule while maintaining the same instructions. Step size was manipulated, typically in 1-s units, first in an ascending and then in a descending sequence of conditions. Instructions quickly established control in all 4 subjects but, by narrowing the range of choice patterns, they reduced subsequent sensitivity to schedule changes. Instructional control was maintained across the ascending sequence of progressive-time values for each subject, but eventually diminished, giving way to more schedule-appropriate patterns. The transition from instruction-appropriate to schedule-appropriate behavior was characterized by an increase in the variability of choice patterns and local increases in point density. On the descending sequence of progressive-time values, behavior appeared to be schedule sensitive, sometimes even optimally sensitive, but it did not always change systematically with the contingencies, suggesting the involvement of other factors.     

Nonverbal representation of time and number in adults

A wealth of human and animal research supports common neural processing of numerical and temporal information. Here we test whether adult humans spontaneously encode number and time in a paradigm similar to those previously used to test the mode-control model in animals. Subjects were trained to classify visual stimuli that varied in both number and duration as few/short or many/long. Subsequently subjects were tested with novel stimuli that varied time and held number constant (eight flashes in 0.8-3.2s) or varied number and held time constant (4-16 flashes in 1.6s). Adult humans classified novel stimuli as many/long as monotonic functions of both number and duration, consistent with simultaneous, nonverbal, analog encoding. Numerical sensitivity, however, was finer than temporal sensitivity, suggesting differential salience of time and number. These results support the notion that adults simultaneously represent the number and duration of stimuli but suggest a possible asymmetry in their representations.