Comparing demand functions when different price manipulations are used: Does unit price help?

Six hens pecked a key (Experiment 1) or pushed a door (Experiment 2) to obtain food reinforcement. In both experiments and as an analogue of price changes, the response requirements were varied in two ways: by increasing the number of responses required and by increasing the required force of each response. The two price manipulations (response number and response force) had different effects on behavior and produced different-shaped demand functions when the rates of consumption were plotted logarithmically against the price analogues. Irrespective of response topography, when the number of required responses was varied, the data paths appeared linear, with slopes close to -1.0. When the required force of each keypeck and doorpush was varied, the data paths were clearly curved, with increasingly steep downward slopes as the force increased. Using the concept of unit price did not fully remove the different effects of the two price manipulations. Those differences are best attributed to the differing times needed in order to complete each response unit under those price manipulations

Precision teaching and fluency: the effects of charting and goal-setting on skaters’ performance

This research involved three successive studies where precision teaching methods were used to increase roller skaters performance rates of basic skating skills. The first study compared precision teaching methods both with and without the use of charting in a group design, and compared both within-subject and betweensubject differences for 12 skaters. Results showed that charting did not increase performance rates over that seen when charting was not used. The second study was a group design which compared two different types of goals, or performance aims, on skaters‟ performance. No difference was found between the two groups of 5 skaters when one group used a fixed, difficult goal and a second used a flexible, easier goal. In the final study, a single-subject design was used and 8 skaters completed a control condition where no goals were set before a goal was introduced for 4 skaters. It was found that an immediate increase in performance rates occurred following the introduction of the goal. Overall these three studies showed that skaters improved their performance rates over sessions, even in the absence of charting and/or goals, demonstrating that precision teaching can be applied to the sport of roller skating

Extinction-induced variability in human behavior

Participants earned points by pressing a computer space bar (Experiment 1) or forming rectangles on the screen with the mouse (Experiment 2) under differential-reinforcement-of-low-rate schedules, followed by extinction. Variability in interresponse time (the contingent dimension) increased during extinction, as for Morgan and Lee (1996); variability in diagonal length (the noncontingent dimension, Experiment 2) did not. In Experiment 3, points were contingent on rectangle size. Rectangle size and interresponse-time (the noncontingent dimension) variability increased in extinction. There was greater variability in the contingent dimension during extinction for participants with the more varied history of reinforcement in Experiment 2 but not in Experiment 3. Overall, variability in the contingent dimension increased in extinction, but the degree of increase was affected by reinforcement history

The matching law

This article introduces the quantitative analysis of choice behavior by describing a number of equations developed over the years to describe the relation between the allocation of behavior under concurrent schedules of reinforcement and the consequences received for alternative responses. Direct proportionality between rate of responding and rate of reinforcement was observed in early studies, suggesting that behavioral output matched environmental input in a mathematical sense. This relation is termed "strict matching," and the equation that describes it is referred to as "the matching law." Later data showed systematic departures from strict matching, and a generalized version of the matching equation is now used to describe such data. This equation, referred to as "the generalized matching equation," also describes data that follow strict matching. It has become convention to refer to either of these equations as "the matching law." Empirical support for the matching law is briefly summarized, as is the applied and practical significance of matching analyses

The effectiveness of an acceptance and commitment therapy self-help intervention for chronic pain

Objective: To evaluate the effectiveness of an Acceptance Commitment Therapy based self-help book for people with chronic pain. Method: This was a randomized 2 group study design. Over a 6-week period, 6 participants read the self-help book and completed exercises from it with weekly telephone support whereas 8 others formed a wait-list control group. Subsequently, 5 of the wait-list participants completed the intervention. Participants completed preintervention and postintervention questionnaires for acceptance, values illness, quality of life, satisfaction with life, depression, anxiety, and pain. Initial outcome data were collected for 8 control participants and 6 intervention participants. Including the wait-list controls, a total of 11 participants completed preintervention and postintervention measures. Whilst completing the self-help intervention, each week participants' rated the content of the book according to reading level and usefulness, and their comprehension of the content was also assessed. Results: Compared with controls, participants who completed the book showed improved quality of life and decreased anxiety. When data from all the treatment participants were pooled, those who completed the intervention showed statistically significant improvements (with large effect sizes) for acceptance, quality of life, satisfaction with life, and values illness. Medium effect sizes were found for improvements in pain ratings. Conclusions: These findings support the hypothesis that using the self-help book, with minimal therapist contact adds value to the lives of people who experience chronic pain

Reinforcer magnitude and demand under fixed-ratio schedules with domestic hens

This study compared three methods of normalizing demand functions to allow comparison of demand for different commodities and examined how varying reinforcer magnitudes affected these analyses. Hens responded under fixed-ratio schedules in 40-min sessions with response requirement doubling each session and with 2-s, 8-s, and 12-s access to wheat. Over the smaller fixed ratios overall response rates generally increased and were higher the shorter the magazine duration. The logarithms of the number of reinforcers obtained (consumption) and the fixed ratio (price) were well fitted by curvilinear demand functions (Hursh et al., 1988. Journal of the Experimental Analysis of Behavior 50, 419–440) that were inelastic (b negative) over small fixed-ratios. The fixed ratio with maximal response rate (Pmax) increased, and the rate of change of elasticity (a) and initial consumption (L) decreased with increased magazine duration. Normalizing consumption using measures of preference for various magazine durations (3-s vs. 3-s, 2-s vs. 8-s, and 2-s vs. 12-s), obtained using concurrent schedules, gave useful results as it removed the differences in L. Normalizing consumption and price (Hursh and Winger, 1995. Journal of the Experimental Analysis of Behavior 64, 373–384) unified the data functions as intended by that analysis. The exponential function (Hursh and Silberberg, 2008. Psychological Review, 115, 186–198) gave an essential value that increased (i.e., α decreased significantly) as magazine duration decreased. This was not as predicted, since α should be constant over variations in magazine duration, but is similar to previous findings using a similar procedure with different food qualities (hens) and food quantities (rats)

Isolation by Distance Explains Genetic Structure of Buggy Creek Virus, a Bird-Associated Arbovirus

Many of the arthropod-borne viruses (arboviruses) show extensive genetic variability and are widely distributed over large geographic areas. Understanding how virus genetic structure varies in space may yield insight into how these pathogens are adapted to and dispersed by different hosts or vectors, the relative importance of mutation, drift, or selection in generating genetic variability, and where and when epidemics or epizootics are most likely to occur. However, because most arboviruses tend to be sampled opportunistically and often cannot be isolated in large numbers at a given locale, surprisingly little is known about their spatial genetic structure on the local scale at which host/vector/virus interactions typically occur. Here, we examine fine-scale spatial structure of two sympatric lineages of Buggy Creek virus (BCRV, Togaviridae), an alphavirus transmitted by the ectoparasitic swallow bug (Oeciacus vicarius) to colonially nesting cliff swallows (Petrochelidon pyrrhonota) and invasive house sparrows (Passer domesticus) in North America. Data from 377 BCRV isolates at cliff swallow colony sites in western Nebraska showed that both virus lineages were geographically structured. Most haplotypes were detected at a single colony or were shared among nearby colonies, and pair-wise genetic distance increased significantly with geographic distance between colony sites. Genetic structure of both lineages is consistent with isolation by distance. Sites with the most genetically distinct BCRV isolates were occupied by large numbers of house sparrows, suggesting that concentrations of invasive sparrows may represent foci for evolutionary change in BCRV. Our results show that bird-associated arboviruses can show genetic substructure over short geographic distances

Isolation by Distance Explains Genetic Structure of Buggy Creek Virus, a Bird-Associated Arbovirus

Many of the arthropod-borne viruses (arboviruses) show extensive genetic variability and are widely distributed over large geographic areas. Understanding how virus genetic structure varies in space may yield insight into how these pathogens are adapted to and dispersed by different hosts or vectors, the relative importance of mutation, drift, or selection in generating genetic variability, and where and when epidemics or epizootics are most likely to occur. However, because most arboviruses tend to be sampled opportunistically and often cannot be isolated in large numbers at a given locale, surprisingly little is known about their spatial genetic structure on the local scale at which host/vector/virus interactions typically occur. Here, we examine fine-scale spatial structure of two sympatric lineages of Buggy Creek virus (BCRV, Togaviridae), an alphavirus transmitted by the ectoparasitic swallow bug (Oeciacus vicarius) to colonially nesting cliff swallows (Petrochelidon pyrrhonota) and invasive house sparrows (Passer domesticus) in North America. Data from 377 BCRV isolates at cliff swallow colony sites in western Nebraska showed that both virus lineages were geographically structured. Most haplotypes were detected at a single colony or were shared among nearby colonies, and pair-wise genetic distance increased significantly with geographic distance between colony sites. Genetic structure of both lineages is consistent with isolation by distance. Sites with the most genetically distinct BCRV isolates were occupied by large numbers of house sparrows, suggesting that concentrations of invasive sparrows may represent foci for evolutionary change in BCRV. Our results show that bird-associated arboviruses can show genetic substructure over short geographic distances

An analysis of U-Value as a measure of variability

The variability in behavior has frequently been assessed using a measure known as the U-value. Of concern in this article were the limits and constraints on U-value as a measure of variability. The relation between the U-value and aspects of variability was examined using three sets of simulated data. Our analysis demonstrates that the U-value as a measure of variability on its own fails to capture repetitive patterns in the sequence of responding. The U-value was shown to reflect the evenness of the distributions of responses across the categories/options used; however, when the number of categories actually used by the participant differed from the total number available, the relation between U-values and the number of categories allocated with responses was shown to be nonlinear. It was also shown that the same value of U can represent different levels of evenness in response distributions over categories, depending on the number of categories/options actually used. These constraints and limitations are discussed in relation to how researchers might report on behavioral variability

Ecological divergence of two sympatric lineages of Buggy Creek virus, an arbovirus associated with birds

Most arthropod-borne viruses (arboviruses) show distinct serological subtypes or evolutionary lineages, with the evolution of different strains often assumed to reflect differences in ecological selection pressures. Buggy Creek virus (BCRV) is an unusual RNA virus (Togaviridae, Alphavirus) that is associated primarily with a cimicid swallow bug (Oeciacus vicarius) as its vector and the Cliff Swallow (Petrochelidon pyrrhonota) and the introduced House Sparrow (Passer domesticus) as its amplifying hosts. There are two sympatric lineages of BCRV (lineages A and B) that differ from each other by .6% at the nucleotide level. Analysis of 385 BCRV isolates all collected from bug vectors at a study site in southwestern Nebraska, USA, showed that the lineages differed in their peak times of seasonal occurrence within a summer. Lineage A was more likely to be found at recently established colonies, at those in culverts (rather than on highway bridges), and at those with invasive House Sparrows, and in bugs on the outsides of nests. Genetic diversity of lineage A increased with bird colony size and at sites with House Sparrows, while that of lineage B decreased with colony size and was unaffected by House Sparrows. Lineage A was more cytopathic on mammalian cells than was lineage B. These two lineages have apparently diverged in their transmission dynamics, with lineage A possibly more dependent on birds and lineage B perhaps more a bug virus. The long-standing association between Cliff Swallows and BCRV may have selected for immunological resistance to the virus by swallows and thus promoted the evolution of the more bug-adapted lineage B. In contrast, the recent arrival of the introduced House Sparrow and its high competence as a BCRV amplifying host may be favoring the more bird-dependent lineage A