Effects of methamphetamine on probability discounting in rats using concurrent chains.

How stimulant drugs affect risky choice and the role of reinforcement magnitude has been an important question for research on impulsivity. This study investigated rats' responding on a rapid acquisition, concurrent chains, probability discounting task under methamphetamine administration. In each block of four sessions, probability of reinforcement delivery was unequal (0.5/1.0, 1.0/0.5) or equal, (1.0/1.0, 0.5/0.5) while amount of reinforcement was constant and unequal. This allowed for an estimate of probability discounting and the magnitude effect (where larger reinforcers are discounted at a greater rate) in each block. Baseline, acute and chronic methamphetamine administration, and re-establish baseline phases were completed. Rats showed sensitivity to probability and magnitude in baseline, as well as a magnitude effect whereby preference for the larger reinforcement was greater with 100% than 50% reinforcement probability. Acute methamphetamine dose-dependently reduced the probability effect. There were no effects of chronic administration and only probability discounting was maintained in the re-establish baseline phase. This was the first procedure to find a magnitude effect with rats in a probability discounting procedure and demonstrates that acute methamphetamine reduces both the probability and magnitude effects which increases propensity for risky choice.

The psychological scaffolding of arithmetic.

Where does arithmetic come from, and why are addition and multiplication its fundamental operations? Although we know that arithmetic is true, no explanation that meets standards of scientific rigor is available from philosophy, mathematical logic, or the cognitive sciences. We propose a new approach based on the assumption that arithmetic has a biological origin: Many examples of adaptive behavior such as spatial navigation suggest that organisms can perform arithmetic-like operations on represented magnitudes. If so, these operations-nonsymbolic precursors of addition and multiplication-might be optimal due to evolution and thus identifiable according to an appropriate criterion. We frame this as a metamathematical question, and using an order-theoretic criterion, prove that four qualitative conditions-monotonicity, convexity, continuity, and isomorphism-are sufficient to identify addition and multiplication over the real numbers uniquely from the uncountably infinite class of possible operations. Our results show that numbers and algebraic structure emerge from purely qualitative conditions, and as a construction of arithmetic, provide a rigorous explanation for why addition and multiplication are its fundamental operations. We argue that these conditions are preverbal psychological intuitions or principles of perceptual organization that are biologically based and shape how humans and nonhumans alike perceive the world. This is a Kantian view and suggests that arithmetic need not be regarded as an immutable truth of the universe but rather as a natural consequence of our perception. Algebraic structure may be inherent in the representations of the world formed by our perceptual system. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Perceptual addition of continuous magnitudes in an 'artificial algebra'.

Although there is substantial evidence for an innate 'number sense' that scaffolds learning about mathematics, whether the underlying representations are based on discrete or continuous perceptual magnitudes has been controversial. Yet the nature of the computations supported by these representations has been neglected in this debate. While basic computation of discrete non-symbolic quantities has been reliably demonstrated in adults, infants, and non-humans, far less consideration has been given to the capacity for computation of continuous perceptual magnitudes. Here we used a novel experimental task to ask if humans can learn to add non-symbolic, continuous magnitudes in accord with the properties of an algebraic group, by feedback and without explicit instruction. Three pairs of experiments tested perceptual addition under the group properties of commutativity (Experiments 1a-b), identity and inverses (Experiments 2a-b) and associativity (Experiments 3a-b), with both line length and brightness modalities. Transfer designs were used in which participants responded on trials with feedback based on sums of magnitudes and later were tested with novel stimulus configurations. In all experiments, correlations of average responses with magnitude sums were high on trials with feedback. Responding on transfer trials was accurate and provided strong support for addition under all of the group axioms with line length, and for all except associativity with brightness. Our results confirm that adult human subjects can implicitly add continuous quantities in a manner consistent with symbolic addition over the integers, and that an 'artificial algebra' task can be used to study implicit computation.

Exploration of children's value patterns in relation to environmental education programmes.

During childhood we begin to develop values, including valuing the natural environment (biospheric values). Although biospheric values are believed to provide the foundation for pro-environmental behavior throughout the course of one's life, little research has investigated these values in children. The present study aimed to investigate the relationships between children's endorsement of biospheric values, their pro-environmental behaviors, and their perception of their friends' and peers' endorsement of biospheric values. Moreover, we investigated whether these values and behaviors, as well as the hypothesized relationships, were affected by educational programmes that were already implemented at schools. The results showed that children generally strongly endorse biospheric values, and that biospheric values were positively related to some personal and group pro-environmental behaviors. The study also found that, as in previous research with adults, the participants believed that their friends and peers endorsed biospheric values significantly less than they themselves did. Environmental educational programs were partially effective in reducing the participants' underestimation of their friends' biospheric values and increased the likelihood of some group pro-environmental behaviors. Our findings highlight the need for further research to investigate the effects of group pro-environmental behaviors and the perception of group values.

Cigarette smoking and e-cigarette use among university students in New Zealand before and after nicotine-containing e-cigarettes became widely available: results from repeat cross-sectional surveys.

AIM: To estimate prevalence and patterns of smoking and vaping, and associations between smoking and vaping, among university students in New Zealand when access to nicotine-containing e-cigarettes was restricted (ie, time point 1 or T1) and 12-months after restrictions were relaxed (ie, time point 2 or T2). METHOD: Cross-sectional surveys of university students across all eight universities: T1, March 2018 (n=1,932), and T2, March 2019 (n=2,004). Chi-squared tests compared responses between T1 and T2 and logistic regression examined associations between smoking and vaping with student characteristics. RESULTS: The patterns of smoking (T1 vs T2): current (10.6% vs 12.1%, p=0.716), daily (5.0% vs 4.6%, p=0.121), and cigarettes/day, time to first cigarette, and avoidance of smoking in smoke-free spaces were not significantly different. In contrast, vaping: current (6.8% vs 13.5%, p<0.001), daily (2.7% vs 5.4%, p<0.001), and possibly vaping in smoke-free spaces, were significantly higher at T2. At both periods, males had higher odds of smoking, vaping and dual use; students aged 25-34 and long-term residents had higher odds of vaping. Asian and Other students had lower odds of smoking at T1, and Other students had higher odds of vaping at T2. CONCLUSION: Vaping was significantly more prevalent at T2 than T1, without their being a corresponding decrease in smoking. Age, sex, student type and ethnicity predicted smoking and vaping.

Cigarette smoking and e-cigarette use among university students in Queensland, Australia and New Zealand: results of two cross-sectional surveys.

OBJECTIVES: Examine the patterns of cigarette smoking and e-cigarette use (vaping), the perceived harm of e-cigarettes compared with tobacco cigarettes, and associations between smoking and vaping with student characteristics. DESIGN: Cross-sectional studies. SETTING: The University of Queensland (UQ), Australia and eight New Zealand (NZ) universities. PARTICIPANTS: Students at UQ: 4957 (70.8% aged <25 years, 63.0% women) and NZ: 1854 (82.5% aged <25 years, 60.1% women). METHODS: Χ2 tests compared smoking by age and gender, and vaping by age, gender and smoking status. Two-sided p<0.05 was considered significant and 95% CIs reported where appropriate. Multinomial logistic regression examined associations between smoking and vaping (exclusive smoking, exclusive vaping, dual use and non-use) with age, gender and student type (domestic vs international). RESULTS: Smoking (UQ vs NZ, 95% CI): ever 45.2% (43.8% to 46.6%) vs 50.0% (47.7% to 52.3%), current 8.9% (8.1% to 9.7%) vs 10.4% (9.1% to 11.9%) and daily 5.2% (4.6% to 5.8%) vs 5.6% (4.6% to 6.7%), and not smoking in indoor 98.3% vs 87.7% or outdoor smoke-free spaces 83.8% vs 65.3%.Vaping (UQ vs NZ, 95% CI): ever 20.9% (19.8% to 22.1%) vs 37.6% (35.4% to 39.9%), current 1.8% (1.5% to 2.2%) vs 6.5% (5.4% to 7.7%) and daily 0.7% (0.5% to 1.0%) vs 2.5% (1.9% to 3.4%), and not vaping in indoor 91.4% vs 79.6% or outdoor smoke-free spaces 84.4% vs 71.3%. Of respondents, 71.7% (70.3% to 73.2%) vs 75.3% (72.9% to 77.6%) perceived e-cigarettes as less harmful than tobacco cigarettes.Men were more likely than women to smoke and vape, and to believe that e-cigarettes are less harmful. Regression models containing all predictors for smoking and vaping were significant and the effect of gender was significant for dual use, exclusive smoking and exclusive vaping (all p<0.01). Men had higher odds for smoking, vaping or dual use. CONCLUSIONS: Results suggest significant differences in patterns of smoking and vaping of university students in Australia and NZ, and a strong influence of gender on smoking and vaping.

Range and distribution effects on number line placement.

People's placement of numbers on number lines sometimes shows linear and sometimes compressive scaling. We investigated whether people's placement of numbers was affected by their range and distribution, as indicated by Parducci's (Psychological Review, 72, 407-418, 1965) range-frequency theory. Experiment 1 found large compressive effects when the endpoints were 1 and 1016. Experiment 2 showed compression when 14 logarithmically distributed numbers were placed on a line marked 1-1,000 and close to linear scaling when the numbers were linearly distributed. Thus, we found both range and frequency effects on compression. Where compression arose, it was not as pronounced as that predicted by logarithmic scaling, but analyses of the results from Experiments 1 and 2 indicate this was not explained by participants switching between linear and logarithmic scaling.

Associations of history of mental illness with smoking and vaping among university students aged 18-24 years in New Zealand: Results of a 2018 national cross-sectional survey.

OBJECTIVE: Data on associations of history of mental illness (HMI) with smoking and vaping in New Zealand (NZ) are lacking. This study examines these associations in university students aged 18-24 years. METHODS: Data came from a 2018 national cross-sectional study of university students and included information on demographic characteristics, smoking, vaping and participant health in the previous 12-months. χ2 tests compared patterns of smoking and vaping, and logistic regression assessed associations of HMI with smoking and vaping, controlling for age, gender and ethnicity. An HMI was defined as a diagnosis/treatment for depression, anxiety/nervous disorder, or other mental health condition in the previous 12-months. RESULTS: The sample comprised 1293 students: 61.3% aged 18-20; 62.8% female; 7.8% Maori, 92.2% non-Maori, and 18.5% reported an HMI. Smoking: 49.7% (95% CI 47.0-52.5) reported ever, 10.5% (8.9-12.3) current and 5.0% (3.9-6.4) daily smoking. Vaping: 38.7% (36.0-41.4) reported ever, 6.3% (5.1-7.8) current and 1.9% (1.3-2.8) daily vaping. Participants with HMI were significantly more likely to smoke: ever (64.9% vs 46.3%, p < .001), current (15.1% vs 9.5%, p = .011) and daily (7.5% vs 4.5%, p = .050), and vape: ever (49.4% vs 36.3%, p < .001) and current (9.2% vs 5.7%, p = .044) than participants without HMI. The model containing all predictors of HMI was significant, χ2 (5, N = 1293) = 24.09, p < .001. Gender (OR 0.54, (0.4-0.75)), current smoking (OR 1.82, (1.19-2.78)) and current vaping (OR 1.73, (1.02-2.93)) made unique significant contributions to the model. CONCLUSIONS: The prevalence of smoking and vaping were significantly higher in students with HMI, and there were strong associations between HMI and smoking and vaping.

Arthropod Intelligence? The Case for Portia.

Macphail's "null hypothesis," that there are no differences in intelligence, qualitative, or quantitative, between non-human vertebrates has been controversial. This controversy can be useful if it encourages interest in acquiring a detailed understanding of how non-human animals express flexible problem-solving capacity ("intelligence"), but limiting the discussion to vertebrates is too arbitrary. As an example, we focus here on Portia, a spider with an especially intricate predatory strategy and a preference for other spiders as prey. We review research on pre-planned detours, expectancy violation, and a capacity to solve confinement problems where, in each of these three contexts, there is experimental evidence of innate cognitive capacities and reliance on internal representation. These cognitive capacities are related to, but not identical to, intelligence. When discussing intelligence, as when discussing cognition, it is more useful to envisage a continuum instead of something that is simply present or not; in other words, a continuum pertaining to flexible problem-solving capacity for "intelligence" and a continuum pertaining to reliance on internal representation for "cognition." When envisaging a continuum pertaining to intelligence, Daniel Dennett's notion of four Creatures (Darwinian, Skinnerian, Popperian, and Gregorian) is of interest, with the distinction between Skinnerian and Popperian Creatures being especially relevant when considering Portia. When we consider these distinctions, a case can be made for Portia being a Popperian Creature. Like Skinnerian Creatures, Popperian Creatures express flexible problem solving capacity, but the manner in which this capacity is expressed by Popperian Creatures is more distinctively cognitive.

Attitudes towards the New Zealand Government's Smokefree 2025 goal associated with smoking and vaping in university students aged 18 to 24 years: results of a 2018 national cross-sectional survey.

OBJECTIVE: In March 2011, New Zealand (NZ) launched an aspirational goal to reduce smoking prevalence to 5% or less by 2025 (Smokefree 2025 goal). Little is known about university students' awareness of, support for and perceptions about this goal. We sought to narrow the knowledge gap. SETTING: University students in NZ. METHODS: We analysed data from a 2018 cross-sectional survey of university students across NZ. Logistic regression analysis examined the associations between responses about the Smokefree goal with smoking and vaping, while controlling for age, sex and ethnicity. Confidence intervals (95% CI) were reported where appropriate. PARTICIPANTS: The sample comprised 1476 students: 919 (62.3%) aged 18 to 20 and 557 (37.7%) aged 21 to 24 years; 569 (38.6%) male and 907 (61.4%) female; 117 (7.9%) Maori and 1359 (92.1%) non-Maori. Of these, 10.5% currently smoked (ie, smoked at least monthly) and 6.1% currently vaped (ie, used an e-cigarette or vaped at least once a month). RESULTS: Overall awareness of the Smokefree goal was 47.5% (95% CI: 44.9 to 50.1); support 96.9% (95% CI: 95.8 to 97.8); belief that it can be achieved 88.8% (95% CI: 86.8 to 90.7) and belief that e-cigarettes/vaping can help achieve it 88.1% (95% CI: 86.0 to 89.9).Dual users of tobacco cigarettes and e-cigarettes had greater odds of being aware of the Smokefree goal (OR=3.07, 95% CI: 1.19 to 7.92), current smokers had lower odds of supporting it (OR=0.13, 95% CI: 0.06 to 0.27) and of believing that it can be achieved (OR=0.15, 95% CI: 0.09 to 0.24) and current vapers had greater odds of believing that e-cigarettes/vaping can help to achieve it (OR=8.57, 95% CI: 1.18 to 62.52) compared with non-users. CONCLUSIONS: The results suggest strong overall support for the Smokefree goal and belief that it can be achieved and that e-cigarettes/vaping can help achieve it. Smoking and vaping were associated with high awareness of the Smokefree goal, but lower support and optimism that it can be achieved.

Differences and ratios in a nonsymbolic 'Artificial algebra': Effects of extended training.

Grace et al. (2018) showed that humans could estimate ratios and differences of stimulus magnitudes by feedback and without explicit instruction in a nonsymbolic 'artificial algebra' task, but that responding depended on both operations even though only one was trained. Here we asked whether control by the trained operation would increase over several sessions, that is, if perceptual learning would occur. Observers (n = 16) completed four sessions in which feedback was based on either ratios or differences for stimulus pairs that varied in brightness (Experiment 1) or line length (Experiment 2). Results showed that control by the trained and untrained operations increased and decreased, respectively, over the sessions, indicating perceptual learning. For about two thirds of individual sessions, regressions indicated significant control by both differences and ratios, suggesting that the perceptual system automatically computes two operations. The similarity of results across experiments with both intensive (brightness) and extensive (line length) stimulus dimensions suggests that differences and ratios are computed centrally, perhaps as part of a general system for processing magnitudes (cf. Walsh, 2003).

Electronic cigarette use among university students aged 18-24 years in New Zealand: results of a 2018 national cross-sectional survey.

OBJECTIVES: To examine electronic cigarette use, reasons for use and perceptions of harm among university students. DESIGN: Cross-sectional study. SETTING: University students across New Zealand. METHODS: We analysed data from a 2018 cross-sectional survey of university students, weighted to account for undersampling and oversampling by gender and university size. χ2 tests were used to compare e-cigarette use, reasons for use and perceptions of harm by age, gender, ethnicity and cigarette smoking. PARTICIPANTS: The sample comprised 1476 students: 62.3% aged 18-20 years, 37.7% aged 21-24 years; 38.6% male, 61.4% female; 7.9% Maori and 92.1% non-Maori. RESULTS: 40.5% of respondents (95% CI 37.9 to 43.1) reported ever, 6.1% (4.9-7.4) current and 1.7% (1.1-2.5) daily use. Regardless of frequency, 11.5% of vapers had vaped daily for ≥1 month, 70.2% of whom used nicotine-containing devices; 80.8% reported not vaping in indoor and 73.8% in outdoor smoke-free spaces. Among ever vapers, curiosity (67.4%), enjoyment (14.4%) and quitting (2.4%) were common reasons for vaping. 76.1% (73.4-78.7) of respondents believed e-cigarettes were less harmful than cigarettes.More males than females reported vaping (ever, current, daily and daily for ≥1 month), nicotine use and belief that e-cigarettes were less harmful than cigarettes. More participants aged 18-20 years reported not vaping in outdoor smoke-free spaces, vaping out of curiosity and belief that e-cigarettes were less harmful than cigarettes, while more participants aged 21-24 years vaped daily for ≥1 month and for enjoyment. More Maori than non-Maori ever vaped. More cigarette smokers than non-smokers vaped (ever, current, daily and daily for ≥1 month), used nicotine and vaped to quit, while more non-smokers did not vape in smoke-free spaces and vaped out of curiosity. CONCLUSIONS: Our results suggest high prevalence of e-cigarette ever and current use, particularly among males and smokers. Many vaped out of curiosity and perceived e-cigarettes as less harmful than cigarettes.

Matching theory and induction explain operant performance.

Matching theory is a general framework for understanding allocation of behavior among activities. It applies to choice in concurrent schedules and was extended to single schedules by assuming that other unrecorded behavior competes with operant behavior. Baum and Davison (2014) found that the competing activities apparently are induced by the "reinforcers" (phylogenetically important events, e.g., food) according to power functions. Combined with power-function induction, matching theory provides new equations with greater explanatory power. Four pigeons were exposed to conditions in which 7 different schedules of food delivery were presented within each experimental session. We replicated earlier results with variable-interval schedules: (a) a negatively accelerated increase of peck rate as food rate increased in the low range of food rates; (b) an upturn in pecking at higher rates; and (c) a downturn in pecking at extremely high food rates. When the contingency between pecking and food was removed, the food continued to induce pecking, even after 20 sessions with no contingency. A ratio schedule inserted in place of 1 variable-interval schedule maintained peck rates comparable to peck rates maintained by short interval schedules. We explained the results by fitting equations that combined matching theory, competition, and induction.

An International Exploration of the Effect of Media Portrayals of Postconcussion Management on Concussion Identification in the General Public.

BACKGROUND: Concussion portrayal in media broadcasts of sporting events may contribute to lack of public understanding regarding concussion. METHODS: In total, 828 participants from Australia, New Zealand, and the United Kingdom completed a questionnaire assessing concussion knowledge. Participants were randomly assigned to either receive sports return-to-play (RTP) guideline information (RTP group) or not (no-RTP group). Participants viewed 12 short clips from televised rugby games and indicated whether they believed the player in each clip had sustained a concussion. Participants were then informed whether the player was removed, returned, or stayed in the game and again asked whether they thought a concussion had occurred. RESULTS: Probability of reporting a likely concussion over all videos was 65.6%. When told a player's possible concussion was managed by removal from the game, participants were more likely to change their response from "no" (no concussion) to "yes" (concussion) than from "yes" to "no." When told the player stayed or returned to the game, participants were more likely to change their response from "yes" (concussion) to "no" (no concussion) than from "no" to "yes." There was no significant main effect for RTP guideline manipulation or interaction effect with RTP information. CONCLUSION: Additional player's injury management information influenced participants' judgments of concussion occurrence. Results show that information provided via sports media broadcasts influenced viewers' perceptions of concussion and appropriate concussion management.

On the origins of computationally complex behavior.

There is considerable evidence for computationally complex behavior, that is, behavior that appears to require the equivalent of mathematical calculation by the organism. Spatial navigation by path integration is perhaps the best example. The most influential account of such behavior has been Gallistel's (1990) computational-representational theory, which assumes that organisms represent key environmental variables such as direction and distance traveled as real numbers stored in engrams and are able to perform arithmetic computations on those representations. But how are these computations accomplished? A novel perspective is gained from the historical development of algebra. We propose that computationally complex behavior suggests that the perceptual system represents an algebraic field, which is a mathematical concept that expresses the structure underlying arithmetic. Our field representation hypothesis predicts that the perceptual system computes 2 operations on represented magnitudes, not 1. We review recent research in which human observers were trained to estimate differences and ratios of stimulus pairs in a nonsymbolic task without explicit instruction (Grace, Morton, Ward, Wilson, & Kemp, 2018). Results show that the perceptual system automatically computes two operations when comparing stimulus magnitudes. A field representation offers a resolution to longstanding controversies in psychophysics about which of 2 algebraic operations is fundamental (e.g., the Fechner-Stevens debate), overlooking the possibility that both might be. In terms of neural processes that might support computationally complex behavior, our hypothesis suggests that we should look for evidence of 2 operations and for symmetries corresponding to the additive and multiplicative groups. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Cigarette smoking among university students aged 18-24 years in New Zealand: results of the first (baseline) of two national surveys.

OBJECTIVES: Although the smoking prevalence continues to decline in New Zealand (NZ) overall, little is known about smoking in university students. A 2013 survey of students aged 17-25 years found that 14% were current smokers, and 3% daily smokers. However, the sample did not include students from all NZ universities. This study examines the prevalence and patterns of cigarette smoking among students aged 18-24 years. SETTING: University students across NZ. METHODS: Data came from a March to May 2018 survey of students from all NZ universities, and were weighted to account for undersampling and oversampling, based on gender and university size. χ2 tests were used to compare smoking by age, gender and ethnicity. PARTICIPANTS: 1476 participants were included: 919 (62.3%) aged 18-20 years and 557 (37.7%) aged 21-24 years; 569 (38.6%) male and 907 (61.4%) female; and 117 (7.9%) Maori and 1359 (92.1%) non-Maori. RESULTS: 49.8% (95% CI 47.2 to 52.4) of respondents reported ever smoking, 11.1% (95% CI 9.5 to 12.9) currently smoked (smoked at least once a month) and 5.9% (95% CI 4.8 to 7.3) smoked at least daily (daily smokers). Of current smokers, 63.6% smoked 1-5 cigarettes/day, 45.8% smoked daily, 73.4% smoked first cigarette >60 min after waking, 86.0% never/almost never smoked in indoor and 64.6% in outdoor smokefree spaces, 69.9% planned to quit and 32.4% had tried to quit. Ever, current and daily smoking were significantly higher in 21-24 compared with 18-20 years olds, and in males compared with females. Older participants were more likely to report smoking more cigarettes/day. Maori were more likely to report ever smoking than non-Maori. CONCLUSIONS: Current smoking among NZ university students aged 18-24 years appears to be declining but daily smoking could be increasing. However, many students appeared less addicted to nicotine, and willing to quit. We recommend increasing the availability of smokefree services for students who wish to quit.

Effects of schedule type and terminal-link duration on choice in concurrent chains.

Four pigeons responded in a three-component concurrent chains procedure in which the terminal-link schedules were either both fixed-interval (FI FI), both variable-interval (VI VI), both mixed-interval (MI MI) or variable-interval fixed-interval (VI FI). Across components within sessions, overall terminal-link duration was varied while schedule types were varied across conditions. For the conditions with homogeneous schedules, the strongest preference was obtained with FI FI, intermediate with MI MI, and weakest with VI VI. Preference increased with overall terminal-link duration for all schedules, but the increase was more rapid for VI FI. The hyperbolic value-added model (HVA) and cumulative decision model (CDM) were fitted to the choice data and accounted for 83.9% and 76.1% of the variance, respectively. However, deviations from both models' predictions were systematic. A modification of the CDM, which assumed that reinforcers delivered after variable delays were more effective, improved the fit of the model and substantially reduced the systematic deviations in residuals. Comparable modifications of HVA produced only limited improvement. Results show that preference in concurrent chains with homogeneous terminal links depends on the degree of variability in reinforcer delays, and that the CDM can provide an excellent account of results across different terminal-link schedules.

Therapeutic Engagement and Treatment Progress: Developing and Testing an In-Treatment Measure of Client Engagement Among Sex Offenders in a Group Program.

The engagement process of sexual offenders in group-based cognitive-behavioral treatment is an important area of study. Disclosure management style (DMS), a model developed from grounded-theory research of men undertaking a prototypical program, provides a framework to assess engagement in treatment. Our goal was to develop a quantitative measure of DMS, to test its reliability and validity, and to evaluate its utility as a measure of treatment progress by examining relationships between DMS and established measures of treatment change. We studied a sample of men (N = 93) who undertook an intensive prison-based treatment program in New Zealand. Variables included DMS measures, psychometric measures of dynamic risk and treatment change, static risk, clinician rating of treatment progress, and recidivism outcomes. We found that (a) DMS shows an acceptable level of agreement between independent raters, (b) DMS-based ratings of engagement changed over the course of treatment and were correlated with measures of change based on offender self-reports, and (c) offenders showed heterogeneity in terms of their trajectories of change as assessed by DMS ratings.

Rat choice in rapidly changing concurrent schedules.

In two experiments, experimentally naïve rats were trained in concurrent variable-interval schedules in which the reinforcer ratios changed daily according to a pseudorandom binary sequence. In Experiment 1, relative response rates showed clear sensitivity to current-session reinforcer ratios, but not to previous sessions' reinforcer ratios. Within sessions, sensitivity to the current session's reinforcement rates increased steadily, and by session end, response ratios approached matching to the current-session reinforcer ratios. Across sessions, sensitivity to the current session's reinforcer ratio decreased with continued exposure to the pseudorandom binary sequence, contrary to expectations based on previous studies demonstrating learning sets. Using a second group of naïve rats, Experiment 2 replicated the main results from Experiment 1 and showed that although there were increases over sessions in both changeover rate and response rate during the changeover delay, neither could explain the accompanying reductions in sensitivity. We consider the role of reinforcement history, showing that our results can be simulated using two separate representations, one local and one nonlocal, but a more complex approach will be needed to bring together these results and other history effects such as learning sets and spontaneous recovery.