Enhancement of conditioned reinforcement by uncertainty

Pigeons were trained in three conditions. In the baseline condition, the birds responded on a fixed-interval schedule with the response key white. When the interval was completed, the key turned either red or green for a delay interval that was terminated by a grain presentation dependent on no key pecks during the final 2 sec. In the uncertainty condition, no grain was presented at the end of the delay periods when the key was red. In the certainty condition, the white light appeared only on occasions when pecking would turn the key green and produce food. Otherwise, the key was illuminated red throughout the total time period. The highest response rate in white occurred in the uncertainty condition, the next highest in the certainty condition, and the lowest in baseline. The results suggest that uncertainty facilitated responding, although uncertainty is not a necessary condition for conditioned reinforcement.     

Gasoline conservation: a procedure for measuring and reducing the driving of college students

The study sought to motivate college students to reduce the number of miles they drove each day and thus save gasoline. Students in two psychology classes were divided by class into two groups. The experimental group was offered various combinations of prizes such as cash, a tour of a mental-health facility, car servicing, and a university parking sticker for reducing driving. The value of the prize received was scaled in terms of per cent reduction in driving. The contrast group received no inducements. The condition in which the experimental group's mileage reduction was reinforced was counterbalanced by two baseline conditions. Several special recording procedures were used to reduce and detect the possibility of subjects altering their odometers, the source of the driving data. Experimental subjects reduced their average daily mileage by 20% relative to the initial baseline; the contrast group did not change. During the one-month reinforcement condition, the 12 experimental subjects saved some 170 gallons (worth $102) of gasoline.     

Uncertainty reduction, conditioned reinforcement, and observing

In a concurrent-chains procedure, pigeons chose between equivalent mixed and multiple fixed-interval schedules of reinforcement. In the first experiment, preference for the multiple schedule was higher when the probability of the shorter fixed interval was less than .50 than for complementary points, an outcome consistent with the delay-reduction hypothesis of conditioned reinforcement and observing, but inconsistent with the uncertainty-reduction hypothesis which requires symmetrical preferences with a maximum when the two intervals are equiprobable. A second experiment assessed preference for equivalent mixed and multiple schedules when each choice outcome resulted in two reinforcements, one on the longer and one on the shorter fixed interval. The order of the two fixed intervals was determined probabilistically. Pigeons again preferred multiple to mixed schedules, although multiple-schedule preference did not vary systematically with the likelihood of the shorter fixed interval occurring first. The results from these choice procedures are consistent with those from the observing-response literature in suggesting that the strength of a stimulus cannot be well described as a function of the degree of uncertainty reduction the stimulus provides about reinforcement.     

Avoidance based on shock intensity reduction with no change in shock probability

Rats were trained on a free-operant avoidance procedure in which shock intensity was controlled by interresponse time. Shocks were random at a density of about 10 shocks per minute. Shock probability was response independent. As long as interresponse times remained less than the limit in effect, any shocks received were at the lower of two intensities (0.75 mA). Whenever interresponse times exceeded the limit, any shocks received were at the higher intensity (1.6 mA). The initial limit of 15 seconds was decreased in 3-second steps to either 6 or 3 seconds. All animals lever pressed to avoid higher intensity shock. As the interresponse time limit was reduced, the response rate during the lower intensity shock and the proportion of brief interresponse times increased. Substantial warmup effects were evident, particularly at the shorter interresponse-time limits. Shock intensity reduction without change in shock probability was effective in the acquisition and maintenance of avoidance responding, as well as in differentiation of interresponse times. This research suggests limitations on the generality of a safety signal interpretation of avoidance conditioning.     

Uncertainty about the rest of the sentence

A word-by-word human sentence processing complexity metric is presented. This metric formalizes the intuition that comprehenders have more trouble on words contributing larger amounts of information about the syntactic structure of the sentence as a whole. The formalization is in terms of the conditional entropy of grammatical continuations, given the words that have been heard so far. To calculate the predictions of this metric, Wilson and Carroll's (1954) original entropy reduction idea is extended to infinite languages. This is demonstrated with a mildly context-sensitive language that includes relative clauses formed on a variety of grammatical relations across the Accessibility Hierarchy of Keenan and Comrie (1977). Predictions are derived that correlate significantly with repetition accuracy results obtained in a sentence-memory experiment (Keenan & Hawkins, 1987).     

Does threatening imagery sensitize distress during contaminant exposure?

Prominent models of fear focus on the role of cognition in the development and maintenance of maladaptive responses. Little research, however, has evaluated the impact of cognition on distress reduction. The current study uses an experimental design to examine the effect of different types of imagery (moving harm, static harm, and safety) on reduction of distress associated with a contaminating stimulus in a normal university sample. Results indicate that use of moving harm imagery sensitizes distress during a 30-min exposure, whereas static harm and safety imagery reduce distress. These findings demonstrate that cognitive factors can moderate affective response during exposure. Clinical implications for the treatment of anxiety disorders are discussed.     

Emergence,Drop-Back And Reductionism in Living Systems Theory

Millers Living Systems Theory (LST) is known to be very comprehensive. It comprises eight nested hierarchical levels. It also includes twenty critical subsystems. While Millers approach has been analyzed and applied in great detail, some problematic features remain, requiring further explication. One of these is the relationship between reduction and emergence in LST. There are at least four relevant possibilities. One is that LST exhibits neither clear reductionism nor emergence, but is essentially neutral in this regard. Another is that the apparent comprehensiveness of LST is illusory, as the approach remains vulnerable to reduction that could ultimately reduce it to a shadow of its present self. The charge of reductionism has been made by critics leading Miller to defend this theory vehemently as nonreductionist in nature. A third possibility is that LST is not reductionist, but is in fact an emergent theory. Miller makes this claim quite strongly. A fourth possibility, and in some ways the most analytically problematic, is that LST exhibits evidence of both reductionism and emergence simultaneously. Some critics might see this fourth situation as evidence of a troubling paradox or anomaly that must be resolved before further progress can be made in the explication and application of LST. The purpose of the paper is to remove this apparent anomaly. The paper removes this anomaly by differentiating between new-variable emergence and transformational emergence. No concrete evidence is found to contradict Milers claim of emergence in LST, and thus no true anomaly exists.     

Unvaxxed and unafraid: Unvaccinated Americans perceive less disease risk than do vaccinated Americans

Is disease risk perception accurately calibrated among the unvaccinated? People shift their attitudes to rationalize their choices, so those who choose to be unvaccinated may be motivated to feel less at risk. In three studies (total N = 1446), we asked Americans how worried they were about catching/spreading influenza and COVID-19 and whether they were vaccinated against those diseases. Unvaccinated participants felt less at risk of catching/spreading the diseases they were unvaccinated against than vaccinated participants. For instance, unvaccinated participants felt ∼24% less at risk of catching/spreading COVID-19 and had ∼28% stronger intention to engage in activities that carried a high risk of COVID-19 transmission (Study 3). Overall, those who choose to be the most vulnerable to disease feel and act the least vulnerable.     

Factors Influencing Condom Use Among African American Women: Implications for Risk Reduction Interventions

Examined factors associated with condom use in a community-based sample of 423 sexually active African American women. Measures were selected to reflect the components in prevailing models of health behavior. Condom users were higher on AIDS health priority, prevention attitudes, stage of change, behavioral intentions, reported more frequent and comfortable sexual communication with partners, perceived greater partner and peer approval for condom use, and reported that peers also used condoms. Women in exclusive relationships evidenced earlier stage of change, lower intentions to use condoms, fewer peers who engaged in preventive behaviors, perceived themselves to have lower risk, and had lower rates of condom use, higher education, and family income. Women in fluid relationships were at particularly high risk, with lower rates of condom use relative to women not in a relationship and greater sexual risk for HIV. Implications for HIV-risk reduction interventions with African American women are discussed.     

Separating The Effects Of Trial-specific And Average Sample-stimulus Duration In Delayed Matching To Sample In Pigeons

Pigeons were studied in two experiments employing delayed matching-to-sample (DMTS) tasks in which the reduction in delay to reinforcement signaled by the onset of the sample stimulus was manipulated by varying sample-stimulus duration. In Experiment 1, the duration of the sample stimulus was either 5 s or 10 s for one sample stimulus and 10 s or 20 s for the other. Subjects matched more frequently when the sample duration was 10 s following the sample associated with the shorter average duration. This finding is analogous to the memory distribution effect found by Honig (1987) in a successive DMTS task that varied retention interval. In Experiment 2, sample duration was either 5 s or 15 s. In Phases 1 and 3 each sample duration was correlated with a particular sample color, and in Phase 2 sample duration and color were uncorrelated. When sample duration was 5 s, subjects matched more frequently when sample duration and color were correlated than when they were uncorrelated. Overall, subjects matched more frequently when sample duration and color were correlated. The data from both experiments support Wixted's (1989) model, which states that one determinant of choice in a DMTS task is the delay-reduction value of the sample stimulus.