A meta-analysis of agricultural conservation intentions, behaviors, and practices: Insights from 35 years of quantitative literature in the United States.

Conservation practices (CPs) are integral to maintaining the long-term viability of agro-ecological systems. Because farming systems and farmers' values and attitudes are heterogeneous, factors that consistently predict conservation behaviors remain elusive. Moreover, heterogeneity is present among studies regarding the type of CPs examined, and whether behavioral intentions or actual behaviors were measured. This study considers the characteristics of each CP, and whether a given study measured behavioral intention or actual behavior, to better understand farmers' adoption of CPs. We reviewed and analyzed 35 years (1982-2017) of quantitative conservation adoption literature in the United States. We categorized CPs based on their primary purpose, the type of benefit they provide, and whether they are operational or structural. We also examined the following five CPs: conservation tillage, buffers or borders, soil testing, grassed waterways, and cover crops. In our behavioral intention and actual behavior analysis, we found that attitudinal factors predicted both conservation intention and action (actual behavior), whereas current or previous use of practices only influenced actions, not stated conservation intentions. In our analysis focusing on CP characteristics, we found that having specific knowledge about and positive attitudes toward the CP, adoption of other CPs, seeking and using information, larger farm size, and vulnerable land predicted actual adoption across nearly all CP categorizations. Nuances emerge when comparing predictors of CPs that share a particular characteristic. For example, we found farm characteristics to be comparatively more important in predicting adoption of soil management CPs than nutrient and livestock management CPs, and farmers' stewardship identity to be more important for permanent practices than operational practices.

Prairie strips improve biodiversity and the delivery of multiple ecosystem services from corn-soybean croplands.

Loss of biodiversity and degradation of ecosystem services from agricultural lands remain important challenges in the United States despite decades of spending on natural resource management. To date, conservation investment has emphasized engineering practices or vegetative strategies centered on monocultural plantings of nonnative plants, largely excluding native species from cropland. In a catchment-scale experiment, we quantified the multiple effects of integrating strips of native prairie species amid corn and soybean crops, with prairie strips arranged to arrest run-off on slopes. Replacing 10% of cropland with prairie strips increased biodiversity and ecosystem services with minimal impacts on crop production. Compared with catchments containing only crops, integrating prairie strips into cropland led to greater catchment-level insect taxa richness (2.6-fold), pollinator abundance (3.5-fold), native bird species richness (2.1-fold), and abundance of bird species of greatest conservation need (2.1-fold). Use of prairie strips also reduced total water runoff from catchments by 37%, resulting in retention of 20 times more soil and 4.3 times more phosphorus. Corn and soybean yields for catchments with prairie strips decreased only by the amount of the area taken out of crop production. Social survey results indicated demand among both farming and nonfarming populations for the environmental outcomes produced by prairie strips. If federal and state policies were aligned to promote prairie strips, the practice would be applicable to 3.9 million ha of cropland in Iowa alone.

Spatially Representing Vulnerability to Extreme Rain Events Using Midwestern Farmers' Objective and Perceived Attributes of Adaptive Capacity.

Potential climate-change-related impacts to agriculture in the upper Midwest pose serious economic and ecological risks to the U.S. and the global economy. On a local level, farmers are at the forefront of responding to the impacts of climate change. Hence, it is important to understand how farmers and their farm operations may be more or less vulnerable to changes in the climate. A vulnerability index is a tool commonly used by researchers and practitioners to represent the geographical distribution of vulnerability in response to global change. Most vulnerability assessments measure objective adaptive capacity using secondary data collected by governmental agencies. However, other scholarship on human behavior has noted that sociocultural and cognitive factors, such as risk perceptions and perceived capacity, are consequential for modulating people's actual vulnerability. Thus, traditional assessments can potentially overlook people's subjective perceptions of changes in climate and extreme weather events and the extent to which people feel prepared to take necessary steps to cope with and respond to the negative effects of climate change. This article addresses this knowledge gap by: (1) incorporating perceived adaptive capacity into a vulnerability assessment; (2) using spatial smoothing to aggregate individual-level vulnerabilities to the county level; and (3) evaluating the relationships among different dimensions of adaptive capacity to examine whether perceived capacity should be integrated into vulnerability assessments. The result suggests that vulnerability assessments that rely only on objective measures might miss important sociocognitive dimensions of capacity. Vulnerability indices and maps presented in this article can inform engagement strategies for improving environmental sustainability in the region.

Upper midwest climate variations: farmer responses to excess water risks.

Persistent above average precipitation and runoff and associated increased sediment transfers from cultivated ecosystems to rivers and oceans are due to changes in climate and human action. The US Upper Midwest has experienced a 37% increase in precipitation (1958-2012), leading to increased crop damage from excess water and off-farm loss of soil and nutrients. Farmer adaptive management responses to changing weather patterns have potential to reduce crop losses and address degrading soil and water resources. This research used farmer survey ( = 4778) and climate data (1971-2011) to model influences of geophysical context, past weather, on-farm flood and saturated soils experiences, and risk and vulnerability perceptions on management practices. Seasonal precipitation varied across six Upper Midwest subregions and was significantly associated with variations in management. Increased warm-season precipitation (2007-2011) relative to the past 40 yr was positively associated with no-till, drainage, and increased planting on highly erodible land (HEL). Experience with saturated soils was significantly associated with increased use of drainage and less use of no-till, cover crops, and planting on HEL. Farmers in counties with a higher percentage of soils considered marginal for row crops were more likely to use no-till, cover crops, and plant on HEL. Respondents who sell corn through multiple markets were more likely to have planted cover crops and planted on HEL in 2011.This suggests that regional climate conditions may not well represent individual farmers' actual and perceived experiences with changing climate conditions. Accurate climate information downscaled to localized conditions has potential to influence specific adaptation strategies.

Farmers and Climate Change: A Cross-National Comparison of Beliefs and Risk Perceptions in High-Income Countries.

Climate change has serious implications for the agricultural industry-both in terms of the need to adapt to a changing climate and to modify practices to mitigate for the impacts of climate change. In high-income countries where farming tends to be very intensive and large scale, it is important to understand farmers' beliefs and concerns about climate change in order to develop appropriate policies and communication strategies. Looking across six study sites-Scotland, Midwestern United States, California, Australia, and two locations in New Zealand-this paper finds that over half of farmers in each location believe that climate change is occurring. However, there is a wide range of beliefs regarding the anthropogenic nature of climate change; only in Australia do a majority of farmers believe that climate change is anthropogenic. In all locations, a majority of farmers believe that climate change is not a threat to local agriculture. The different policy contexts and existing impacts from climate change are discussed as possible reasons for the variation in beliefs. This study compared varying surveys from the different locations and concludes that survey research on farmers and climate change in diverse locations should strive to include common questions to facilitate comparisons.

Understanding Farmer Perspectives on Climate Change Adaptation and Mitigation: The Roles of Trust in Sources of Climate Information, Climate Change Beliefs, and Perceived Risk.

Agriculture is vulnerable to climate change and a source of greenhouse gases (GHGs). Farmers face pressures to adjust agricultural systems to make them more resilient in the face of increasingly variable weather (adaptation) and reduce GHG production (mitigation). This research examines relationships between Iowa farmers' trust in environmental or agricultural interest groups as sources of climate information, climate change beliefs, perceived climate risks to agriculture, and support for adaptation and mitigation responses. Results indicate that beliefs varied with trust, and beliefs in turn had a significant direct effect on perceived risks from climate change. Support for adaptation varied with perceived risks, while attitudes toward GHG reduction (mitigation) were associated predominantly with variation in beliefs. Most farmers were supportive of adaptation responses, but few endorsed GHG reduction, suggesting that outreach should focus on interventions that have adaptive and mitigative properties (e.g., reduced tillage, improved fertilizer management).

Outreach, Screening, and Randomization of APOE ε4 Carriers into an Alzheimer's Prevention Trial: A global Perspective from the API Generation Program.

BACKGROUND: Alzheimer's disease (AD) prevention trials require a large outreach and screening funnel to identify cognitively unimpaired adults who meet the study's inclusion criteria, such as certain clinical or demographic criteria, genetic risk factors, and/or biomarker evidence of the disease. OBJECTIVES: Describe tactics and strategies to identify and enroll cognitively unimpaired adults with one (heterozygotes [HT]) or two (homozygotes [HM]) copies of the APOE ε4 allele, a genetic risk factor for dementia due to AD, into the Alzheimer's Prevention Initiative (API) Generation Program, the largest and only prevention trials for late onset AD using this enrichment technique. DESIGN AND SETTING: The Generation Program was comprised of two global, randomized, double-blind, placebo-controlled, parallel group adaptive design with variable treatment duration clinical trials. Generation Study 1 randomized participants into one of two cohorts: Cohort 1 which evaluated CAD106 vs. placebo or Cohort 2 which evaluated umibecestat vs placebo. Generation Study 2 randomized participants into two doses of umibecestat vs. placebo. The Generation Program was terminated early in 2019, while enrollment was still occurring. PARTICIPANTS: Both Generation Study 1 and Generation Study 2 enrolled cognitively unimpaired APOE ε4 HMs aged 60-75; Generation Study 2 also enrolled APOE ε4 HTs ages 60-75 with elevated brain amyloid. METHODS AND MEASUREMENTS: Describe results of the centralized and localized outreach, recruitment, screening strategies and tactics as well as characteristics of sites successful at enrolling genetically eligible participants, with a particular focus on APOE ε4 HMs given the 2-3% prevalence of this genotype. RESULTS: At the time the trial program was terminated, 35,333 individuals had consented to the optional prescreening ICF1a/ICFA and provided a sample of DNA for APOE genotyping, 1,138 APOE ε4 HMs consented to screening for Generation Study 1 (ICF1b), and 1,626 APOE ε4 carriers were randomized into either Generation Study 1 or Generation Study 2. Genetic testing registries, partnerships with genetic testing/counseling companies, and the optional prescreening ICF1a/ICFA were the most successful strategies for identifying genetically eligible participants for screening. CONCLUSIONS: It is feasible to recruit, screen and randomize cognitively unimpaired APOE ε4 carriers, particularly APOE ε4 HMs for a global AD prevention trial. The Generation Program was on track to complete enrollment by end of 2019. Factors that were key to this success included: working with sites to develop customizable outreach, recruitment, and screening programs specific to their site needs, providing forums for sites to exchange best practices, and developing partnerships between the sponsor team and trial sites.

Advancing the scholarship and practice of stakeholder engagement in working landscapes: a co-produced research agenda.

Participatory approaches to science and decision making, including stakeholder engagement, are increasingly common for managing complex socio-ecological challenges in working landscapes. However, critical questions about stakeholder engagement in this space remain. These include normative, political, and ethical questions concerning who participates, who benefits and loses, what good can be accomplished, and for what, whom, and by who. First, opportunities for addressing justice, equity, diversity, and inclusion interests through engagement, while implied in key conceptual frameworks, remain underexplored in scholarly work and collaborative practice alike. A second line of inquiry relates to research-practice gaps. While both the practice of doing engagement work and scholarly research on the efficacy of engagement is on the rise, there is little concerted interplay among 'on-the-ground' practitioners and scholarly researchers. This means scientific research often misses or ignores insight grounded in practical and experiential knowledge, while practitioners are disconnected from potentially useful scientific research on stakeholder engagement. A third set of questions concerns gaps in empirical understanding of the efficacy of engagement processes and includes inquiry into how different engagement contexts and process features affect a range of behavioral, cognitive, and decision-making outcomes. Because of these gaps, a cohesive and actionable research agenda for stakeholder engagement research and practice in working landscapes remains elusive. In this review article, we present a co-produced research agenda for stakeholder engagement in working landscapes. The co-production process involved professionally facilitated and iterative dialogue among a diverse and international group of over 160 scholars and practitioners through a yearlong virtual workshop series. The resulting research agenda is organized under six cross-cutting themes: (1) Justice, Equity, Diversity, and Inclusion; (2) Ethics; (3) Research and Practice; (4) Context; (5) Process; and (6) Outcomes and Measurement. This research agenda identifies critical research needs and opportunities relevant for researchers, practitioners, and policymakers alike. We argue that addressing these research opportunities is necessary to advance knowledge and practice of stakeholder engagement and to support more just and effective engagement processes in working landscapes. Supplementary Information: The online version contains supplementary material available at 10.1007/s42532-022-00132-8.

A prospective, single arm study of intraosseous basivertebral nerve ablation for the treatment of chronic low back pain: 12-month results.

Background: The basivertebral nerve (BVN) has been a recently discovered target as a potential source for vertebrogenic chronic low back pain (CLBP). Prior randomized controlled trials have demonstrated safety and efficacy of BVN ablation for vertebrogenic CLBP, but minimal data exists regarding BVN ablation's clinical effectiveness with broader application outside of strict trial inclusion criteria. Methods: Prospective, single arm, open label effectiveness trial of 48 patients from community spine and pain practices treated with BVN ablation. Inclusion criteria required more than 6 months of CLBP and type 1 or 2 Modic changes on MRI to be enrolled. Patients were followed post procedure for 12 months using ODI, VAS, EQ-5D-5L and SF-36 patient reported outcome metrics.Results: 47 patients successfully received BVN ablation and 45 patients completed 12 months of follow up. Mean reduction in ODI at 12 months was 32.31 +/- 14.07 (p<0.001) with 88.89% (40/45) patients reporting a ≥15 point ODI decrease at 12 months. Mean VAS pain score decrease was 4.31+/-2.51 at 12 months (p<0.001) and more than 69% reported a 50% reduction in VAS pain scale. Similarly, SF-36 and EQ-5D-5L scores improved 26.27+/-17.19 and 0.22+/-0.15 (each p<0.001). Conclusions: This data supports the clinical effectiveness of BVN ablation in the community practice setting, with similar 12 month improvements in patient reported outcomes as seen in previously published randomized control trials.

Laparoscopic management of insulinomas.

BACKGROUND: Conventional surgical management of insulinomas involves an open technique. The laparoscopic approach has advantages in terms of improved postoperative pain and recovery time. This retrospective study evaluated the laparoscopic management of pancreatic insulinomas. METHODS: Between December 2000 and March 2007, 23 patients were referred for consideration of laparoscopic insulinoma resection. Two patients were not deemed appropriate for the laparoscopic approach and were managed with open surgery. All surgery was performed by one experienced pancreatic surgeon. Laparoscopic intraoperative ultrasonography was not available for the first six procedures, but was used thereafter. RESULTS: Twenty-one patients (five men and 16 women, median age 46 (range 22-70) years) had a successful resection. All had single tumours, five in the head, nine in the body and seven in the tail of the pancreas. One conversion to open operation was performed in a patient with an insulinoma in the head of the pancreas who had dense adhesions resulting from pancreatitis. Three patients developed a postoperative pancreatic fistula. There has been no recurrence of symptoms in any patient. CONCLUSION: Laparoscopic management of insulinomas is feasible and safe. Laparoscopic intraoperative ultrasonography is a promising adjunct to the procedure, even after accurate preoperative localization.

Barriers and Motivators for Tractor ROPS Retrofitting in Iowa.

Iowa State University Extension and Outreach conducted an assessment of Iowa farm operators' perceptions of the barriers and motivators when considering retrofitting tractors with rollover protective structures (ROPS). A statewide sample of approximately 2,000 farm operators was surveyed in the 2017 Iowa Farm and Rural Life Poll. A series of questions was asked to evaluate the importance of potential barriers to decisions to not retrofit a tractor and potential motivators that could influence the decision to retrofit or purchase a tractor with ROPS. The survey received a 48% response rate (999 responses). Among the 76% of Iowa farm operators who reported at least one pre-1985 tractor, only 18.6% reported that all of those tractors had ROPS. The remaining 81.4% had at least one tractor that did not have ROPS. Iowa farm operators' perceptions of the barriers and motivators when considering retrofitting tractors with ROPS are shared. The results of Iowa farm operators' perceptions will be used as Iowa State University Extension and Outreach prepares to align efforts with the National Tractor Safety Coalition and participate in the National ROPS Rebate Program, with the goal of reducing tractor fatalities.

Relationship of hair dye use, benign breast disease, and breast cancer.

An epidemiologic case-control study of 118 breast cancer patients and 233 controls was conducted to test the hypothesis that hair dyes are related to breast cancer. Matched controls were selected by "random digit dialing," and all epidemiologic data were collected by telephone interviews. No overall association was detected. On a prospective basis, the interaction between hair dye exposure and six variables known to be risk factors for breast cancer then were examined: previous benign breast disease (BBD), "ever" versus "never" pregnant, age at first pregnancy, menopause induced by operation, age at menarche, and education. A statistically significant increased risk of breast cancer was found for women with a history of BBD and exposure to hair dyes as compared to women with BBD but no hair dye exposure: The relative risk (RR) was 4.5, and the 95% confidence intervals (C) were 1.20 and 15.78. A total of 24 women (19 patients and 5 controls) reported a history of BBD and hair dye use. Further analysis revealed a significant association between hair dye use and breast cancer among women 40-49 years of age (RR = 3.33; 95% CI: 1.1 and 10.85) and a highly significant (P = 0.0008) dose-response relationship among women who used hair dyes for changing their natural color as opposed to covering gray hair. The numbers of patients and controls included in this study were small and several hypotheses were tested. Additional epidemiologic studies are needed before firm conclusions can be reached concerning the nature of these associations.

Modulation by calcineurin of 5-HT3 receptor function in NG108-15 neuroblastoma x glioma cells.

1. We have investigated the mechanism of regulation of 5-HT3 receptor channel sensitivity in voltage-clamped (-80 mV) NG108-15 neuroblastoma cells. 2. The 5-HT-induced inward current activated rapidly. The fast onset was followed by a biphasic decay which was characterized by two time constants, tau 1 (1.1 +/- 0.21s) and tau 2 (8.9 +/- 1.6s), respectively. Brief applications of 5-HT, applied at 2 min intervals, induced a decrease in the amplitude of the 5-HT3 receptor-mediated peak inward currents. 3. Buffering of intracellular calcium with the calcium chelator BAPTA (10 mM) instead of EGTA (10 mM) attenuated the 5-HT-induced loss of responsiveness of 5-HT3 receptors. Omission of calcium from the extracellular medium yielded a similar attenuation of loss of responsiveness. 4. Inclusion of the protein kinase inhibitor, staurosporine (1 microM) or of okadaic acid (1 microM), an inhibitor of protein phosphatases 1 and 2A, in the intracellular buffer solution did not affect 5-HT3 receptor sensitivity. 5. Injection of cyclosporin A-cyclophilin A complex (20 nM), which potently inhibits calcineurin, did not affect the time constants of the biphasic decay of the 5-HT response tau 1 (1.4 +/- 0.28s) and tau 2 (11.3 +/- 1.7s). The complex, however, prevented the loss of 5-HT3, receptor responsiveness upon repeated application of 5-HT. A similar, but weaker effect was observed after intracellular application of the autoinhibitory peptide domain of calcineurin (1 microM). 6. The recovery of desensitized 5-HT3 receptors upon a second application of 5-HT (1 microM) showed a half-life time (tau 1/2) of 2.6 +/- 0.12 min in control cells which was reduced to 1.6 +/- 0.09 min in cells treated with cyclosporin A-cyclophilin A (20 nM) complex. 7. We conclude that calcineurin does not affect the fast decay of the 5-HT3 receptor response but may be involved in a slower process which regulates channel activity.

Transient concordant distributions of nicotinic receptors and acetylcholinesterase activity in infant rat visual cortex.

For a short period during the second week after birth, layer IV of rat visual cortex displays intense acetylcholinesterase (AChE) activity which demarcates area 17. We now report that this transient AChE pattern is paralleled by a marked increase in [3H]nicotine binding sites in layer IV of area 17. Muscarinic receptors show a different pattern. Neonatal bilateral enucleation results in a reduction of AChE reaction product and [3H]nicotine labelling in area 17, while leaving the pattern of muscarinic labelling virtually unaffected. The close association of [3H]nicotine labelling and AChE activity suggests that presynaptic nicotinic cholinergic receptors may modulate transmitter release while functional geniculocortical synapses are being formed.

Molecular characterisation of cloned bradykinin B1 receptors from rat and human.

This report describes the characterisation of cloned rat and human bradykinin B1 receptors in African green monkey kidney fibroblast (Cos-7) cells. A ligand binding assay with [3H]des-Arg10-kallidin was used to compare their pharmacology with respect to known bradykinin B1 and B2 receptor ligands. In addition, the pharmacology of T-kinin and its' derivative des-Arg11-T-kinin was investigated. The cloned rat receptor had a similar pharmacology to that of the recently described mouse receptor and differs from that described for the human receptor. The rat receptor had a higher affinity for des-Arg11-T-kinin than the human receptor. These differences in pharmacological properties may relate to the presence of T-kinin, bradykinin and their des-Arg derivatives as the major physiological peptides in rat and the predominance of kallidin and its derivatives in human. We confirm that the rat bradykinin B1 receptor gene is organised in a two exon structure and differs from the human gene which has a three exon structure and we further examine the inducible expression of this gene in a wide range of tissues using Northern blotting.

Expression of tetrodotoxin-resistant sodium channels in capsaicin-sensitive dorsal root ganglion neurons of adult rats.

We have used conventional whole-cell electrophysiological recording techniques to measure the level of expression of tetrodotoxin-sensitive (TTX-S) and tetrodotoxin-resistant (TTX-R) sodium currents in the capsaicin-sensitive and capsaicin-insensitive subpopulations of dorsal root ganglion neurons. We find that there are significantly higher levels of TTX-R expressed in the capsaicin-sensitive group but no difference in the levels of TTX-S. Since capsaicin is a selective stimulant of polymodal nociceptors, these data raise the possibility that TTX-R sodium channels may be an important determinant of nociceptor phenotype.

Dietary patterns of Australian adults and their association with socioeconomic status: results from the 1995 National Nutrition Survey.

OBJECTIVE: To describe dietary patterns among men and women in the Australian population, and to explore how these varied according to socioeconomic status (SES). DESIGN: A cross-sectional self-report population survey, the 1995 Australian National Nutrition Survey (NNS), was used. SETTING: Private dwelling sample, covering urban and rural areas across Australia. SUBJECTS: Data provided by 6680 adults aged 18-64 who participated in the NNS were used in the analyses. METHODS: Factor analyses were used to analyse data from a Food Frequency Questionnaire (FFQ) completed by participants. Associations between SES and dietary pattens were assessed using ANOVA. RESULTS: Separate factor analyses of the FFQ data for men and women revealed 15 factors, accounting for approximately 50% of the variance in both men's and women's dietary patterns. Several gender and SES differences in food patterns were observed. Lower SES males more frequently consumed 'tropical fruits', 'protein foods', and 'offal and canned fish', while high SES males more often ate 'breakfast cereals' and 'wholemeal bread'. Lower SES females more often ate 'traditional vegetables', 'meat dishes' and 'pasta, rice and other mixed foods', while high SES females more frequently ate 'ethnic vegetables' and 'breakfast cereal/muesli'. CONCLUSIONS: These findings contribute to a better understanding of the dietary patterns that underscore gender-specific SES differences in nutrient intakes. Analyses of the type employed in this study will facilitate the development of interventions aimed at modifying overall eating patterns, rather than specific components of the diet.

Changes in functional response units with briefly delayed reinforcement.

In two experiments, key-peck responding of pigeons was compared under variable-interval schedules that arranged immediate reinforcement and ones that arranged unsignaled delays of reinforcement. Responses during the nominal unsignaled delay periods had no effect on the reinforcer presentations. In Experiment 1, the unsignaled delays were studied using variable-interval schedules as baselines. Relative to the immediate reinforcement condition, 0.5-s unsignaled delays decreased the duration of the reinforced interresponse times and increased the overall frequency of short (<0.5-s) interresponse times. Longer, 5.0-s unsignaled delays increased the duration of the reinforced interresponse times and decreased the overall frequency of the short interresponse times. In Experiment 2, similar effects to those of Experiment 1 were obtained when the 0.5-s unsignaled delays were imposed upon a baseline schedule that explicitly arranged reinforcement of short interresponse times and therefore already generated a large number of short interresponse times. The results support earlier suggestions that the unsignaled 0.5-s delays change the functional response unit from a single key peck to a multiple key-peck unit. These findings are discussed in terms of the mechanisms by which contingencies control response structure in the absence of specific structural requirements.

A role for negative reinforcement of response omission in punishment?

This experiment attempted to disentangle response-rate reductions controlled by the direct suppressive effects of a punisher from those due to negative reinforcement of response omission. Key-peck responding of pigeons was maintained by a conjoint variable-interval 3-min schedule of food presentation variable-interval 30-s schedule of response-dependent electric shock presentation. Omission of responses for 5, 10, or 30 s resulted in the possibility of canceling a scheduled shock. Response rates were a function of required pause duration, with lower rates occurring when longer periods of response omission were required for shock cancellation. These results show that, with several parameters of punishment held constant, response rates were controlled by the negative reinforcement contingency. Such a finding argues for renewed consideration of the role of negative reinforcement in punishment contingencies.

Molecular contingencies in schedules of intermittent punishment.

In two experiments, key pecking of pigeons was maintained by a variable-interval 180-s schedule of food presentation. Conjointly, a second schedule delivered response-dependent electric shock. In the first experiment, shocks were presented according to either a variable-interval or a nondifferential interval-percentile schedule. The variable-interval shock schedule differentially delivered shocks following long interresponse times. Although the nondifferential shock schedules delivered shocks less differentially with respect to interresponse times, the two shock schedules equally reduced the relative frequency of long interresponse times. The second experiment differentially shocked long or short interresponse times in different conditions, with resulting decreases in the relative frequency of the targeted interresponse times. These experiments highlight the importance of selecting the appropriate level of analysis for the interaction of behavior and environment. Orderly relations present at one level of analysis (e.g., interresponse times) may not be revealed at other levels of analysis (e.g., overall response rate).