Shifting students toward testing: impact of instruction and context on self-regulated learning.

Much of the learning that college students engage in today occurs in unsupervised settings, making effective self-regulated learning techniques of particular importance. We examined the impact of task difficulty and supervision on whether participants would follow written instructions to use repeated testing over restudying. In Study 1, we found that when supervised, instructions to test resulted in changes in the self-regulated learning behaviors such that participants tested more often than they studied, relative to participants who were unsupervised during learning. This was true regardless of the task difficulty. In Study 2, we showed that failure to shift study strategies in unsupervised learning was likely due to participants avoidance of testing rather than failure to read the instructions at all. Participants who tested more frequently remembered more words later regardless of supervision or whether or not they received instructions to test, replicating the well-established testing effect (e.g., Dunlosky et al. in Psychol Sci Public Interest 14:4-58, 2013. http://doi.org/10.1177/1529100612453266 ). In sum, there was a benefit to testing, but instructing participants to test only increased their choice to test when they were supervised. We conclude that supervision has an impact on whether participants follow instructions to test.

Resistance to extinction versus extinction as discrimination.

The hypothesis that response strength might be measured by persistence of responding in the face of extinction was discredited in the 1960s because experiments showed that responding persists longer following intermittent reinforcers than following continuous reinforcers. Instead, researchers proposed that the longer persistence following intermittent reinforcers arises because intermittent reinforcement more closely resembles extinction-a discrimination theory. Attention to resistance to extinction revived because one observation seemed to support the persistence hypothesis: Following training on a multiple schedule with unequal components, responding usually persisted longer in the formerly richer component than in the formerly lean component. This observation represents an anomaly, however, because results with single schedules and concurrent schedules contradict it. We suggest that the difference in results arises because the multiple-schedule procedure, while including extensive training on stimulus discrimination, includes no training on discrimination between food available and food unavailable, whereas comparable single- and concurrent-schedule procedures include such training with repeated extinction. In Experiment 1, we replicated the original result, and in Experiment 2 showed that when the multiple-schedule procedure includes training on food/no-food discrimination, extinction following multiple schedules contradicts behavioral momentum theory and agrees with the discrimination theory and research with single and concurrent schedules.

Failure to find a distance effect in pigeon choice: Manipulating amount and delay of reinforcement.

The choice behavior of primates, including humans, displays a distance effect: Latency to choose between alternatives appears to increase with smaller differences in value. There is, so far, no demonstration of this effect in birds. Tests of distance effects in birds have been conducted in binary choice situations with a dominant alternative, where one alternative is superior to the other in all aspects that meaningfully contribute to value (e.g., provides access to the same reinforcer, but with a shorter delay). The present study considers the possibility that including dominant alternatives in choice tests precludes distance effects. Four pigeons were presented with binary choices between alternatives that varied in amount and delay. Some choices had a dominant alternative (smaller-sooner or larger-later vs. smaller-later) and some did not (smaller-sooner vs. larger-later). Across phases, only the delay to the smaller-sooner reinforcer varied. Distance effects were expected to be expressed as longer latencies as choice between smaller-sooner and larger-later reinforcers approached indifference. Despite the sensitivity of choice to differences in amount and delay, no distance effect was observed. Alternative explanations for the failure to find a distance effect in pigeon choice, including the Sequential Choice Model (SCM), are discussed.

Impact of food allergy on food insecurity and health literacy in a tertiary care pediatric allergy population.

BACKGROUND: Food insecurity (FI), limited availability of or access to nutritional foods, is linked to poor child/caregiver health. We examined FI in food-allergic and non-food-allergic children to determine whether dietary limitations associated with food allergy increases risk of FI. METHODS: Food-allergic and non-food-allergic children (1-17 years) were recruited from Arkansas Children's Hospital allergy/asthma clinics. The USDA Food Security Survey, the Newest Vital Sign Health Literacy (HL) questionnaire, and the Food Allergy Impact Scale QOL survey were administered. Logistic regression and analysis of covariance models were utilized for data analysis. RESULTS: Subjects (n = 650) included 325 food-allergic and 325 non-food-allergic children. Overall rate of FI was 21.5% (food allergic 22.2% and non-food allergic 20.9%) with no significant difference in the prevalence of FI between groups (OR = 1.30; 95% CI 0.86-1.96; P = 0.21). FI was increased in households of children with both milk and egg allergy when compared to those without food allergy and those with single food allergy (OR = 2.5; 95% CI 1.4-4.6; P = 0.003). Mean HL rates were higher in the food-secure vs food-insecure groups (mean diff = 0.31; 95% CI 0.03-0.59; P = 0.03). Among food-allergic children, QOL was better in the food-secure vs food-insecure group (mean diff = 0.61; 95% CI 0.002-1.23; P = 0.049). CONCLUSION: Food allergy to milk and egg was associated with increased risk of household FI. Food-insecure participants had lower HL than their food-secure counterparts. Further work is needed to define risks associated with FI among food-allergic children to improve screening and management strategies.

Concurrent variable-interval variable-ratio schedules in a dynamic choice environment.

Most studies of operant choice have focused on presenting subjects with a fixed pair of schedules across many experimental sessions. Using these methods, studies of concurrent variable- interval variable-ratio schedules helped to evaluate theories of choice. More recently, a growing literature has focused on dynamic choice behavior. Those dynamic choice studies have analyzed behavior on a number of different time scales using concurrent variable-interval schedules. Following the dynamic choice approach, the present experiment examined performance on concurrent variable-interval variable-ratio schedules in a rapidly changing environment. Our objectives were to compare performance on concurrent variable-interval variable-ratio schedules with extant data on concurrent variable-interval variable-interval schedules using a dynamic choice procedure and to extend earlier work on concurrent variable-interval variable-ratio schedules. We analyzed performances at different time scales, finding strong similarities between concurrent variable-interval variable-interval and concurrent variable-interval variable- ratio performance within dynamic choice procedures. Time-based measures revealed almost identical performance in the two procedures compared with response-based measures, supporting the view that choice is best understood as time allocation. Performance at the smaller time scale of visits accorded with the tendency seen in earlier research toward developing a pattern of strong preference for and long visits to the richer alternative paired with brief "samples" at the leaner alternative ("fix and sample").

Failure to find a distance effect in pigeon choice.

Primates take longer to choose between alternatives with smaller differences in value. This effect-a particular instance of the distance effect in symbolic comparisons-has not been replicated in birds. Instead, birds appear to respond independently to each alternative, such that the latency to choose depends primarily on the alternative of highest value. Three experiments tested for the distance effect in pigeons under conditions not previously considered. Experiment 1 presented pigeons with forced- and binary free-choice trials, where each alternative was one of three possible delays to reinforcement (4, 8, and 16 s). Pigeons were exposed to the choice stimuli for different amounts of time and with different sample response requirements prior to the choice response. Experiment 2 added a fourth (0-s delay) alternative. Experiment 3 substituted the 16-s delay with a second 4-s delay. In all experiments, pigeons systematically chose the shortest delay to reinforcement. Latency to choose the 4-s delay did not vary when choosing against the 8-s or 16-s delay, regardless of whether choice stimuli were exposed for the duration of nine pecks (Experiment 1), or whether a 0-s delay alternative was sometimes present (Experiment 2). Latency to choose the preferred of two identical alternatives (4-s vs. 4-s) was shorter than the latency to choose between different alternatives (4-s vs. 8-s; Experiment 3); this is the opposite of a distance effect. These results show no evidence of a distance effect in pigeon choice, consistent with the hypothesis that pigeons respond independently to each choice alternative.

The spacing effect in older and younger adults: does context matter?

Age-related memory change has been a topic of much investigation in recent years, including spacing benefits and reliance on contextual cues. We manipulated the spacing schedule and the context of learning and observed the effects on long-term recall ability in healthy older and younger adults. After learning Swahili-English word pairs, half practiced immediately (massed) and half practiced 24 h later (spaced) either in the same room or a different room (context) from the initial session. A final recall test 10 days after the practice session occurred in the same room as the first session. Participants in the spaced condition remembered more than those in the massed condition 10 days later. Younger adults remembered more word pairs than older adult participants. Context change eliminated the spacing benefit for both age groups.

Effect of a single free food presentation on extinction responding in a multiple schedule.

The present study was designed to assess the effect of a single, response-independent food presentation on responding during extinction. Using a two-component multiple schedule, we examined differences in pigeons' extinction responding resulting from a single response-independent food presentation occurring at the beginning of the experimental session (30-s prior to the beginning of the first component). One component presented reinforcement according to a variable interval 45-s schedule and the second presented reinforcement according to a variable interval 180-s schedule. After establishing stable baseline responding we extinguished responding. We systematically manipulated the presence or absence of a single 3-s free food presentation using the food hopper that occurred 30-s prior to the presentation of the first component. We found the single free food presentation increased persistence of responding in extinction. This finding is inconsistent with behavioral momentum theory inasmuch as it assigns a response disruptive role to food presentations occurring outside of the context of the target operant.

Fifty-six-year-old man with anaphylaxis: A novel delayed food hypersensitivity reaction.

Anaphylaxis and urticaria are commonly seen in both primary care and allergy clinics. Foods, drugs, and insects are frequent culprits for immediate reactions; however, the trigger for recurring and/or chronic episodes is often unclear. We present a 56-year-old male with recurrent symptoms of urticaria, angioedema, and anaphylaxis found to be triggered by sensitization to galactose-alpha 1, 3-galactose (alpha-gal), a novel food allergen.

Within-session spacing improves delayed recall in children.

Multiple retrievals of a memory over a spaced manner improve long-term memory performance in infants, children, younger and older adults; however, few studies have examined spacing effects with young school-age children. To expand the understanding of the spacing benefit in children, the current study presented weakly associated English word-pairs to children aged 7-11 and cued their recall two times immediately (massed), after a delay of 5 or 10 items (spaced) or not at all (control). After this encoding session with or without two retrievals, participants were tested two times for memory of all word-pairs: immediately and 30 minutes after the encoding session. Multiple retrievals significantly improved memory on the tests. However, words repeated in a spaced design were remembered at higher rates than those that were massed, while gap size between repetitions (5 or 10) did not differentially impact performance. The data show that a within-session spacing strategy can benefit children's ability to remember word-pairs after 30 minutes. Thus, asking students to recall what they have learned within a lesson is a technique that can be used in a classroom to improve long-term recall.

Long-term memory, sleep, and the spacing effect.

Many studies have shown that memory is enhanced when study sessions are spaced apart rather than massed. This spacing effect has been shown to have a lasting benefit to long-term memory when the study phase session follows the encoding session by 24 hours. Using a spacing paradigm we examined the impact of sleep and spacing gaps on long-term declarative memory for Swahili-English word pairs by including four spacing delay gaps (massed, 12 hours same-day, 12 hours overnight, and 24 hours). Results showed that a 12-hour spacing gap that includes sleep promotes long-term memory retention similar to the 24-hour gap. The findings support the importance of sleep to the long-term benefit of the spacing effect.

Effects of changeover delay on response allocation during probe tests.

The present study assessed whether a pattern of responding that develops when choosing between two alternatives generalizes to novel choice tests when alternatives are presented in new combinations. Pigeons were trained on a two-component multiple schedule. In both components, a concurrent variable-interval (VI) 40-s VI 80-s schedule was used. The COD was 1 s in one component and 10 s in the other. The long COD produced consistently longer dwell times than the short COD did. Following training, subjects were presented with four types of probe-test components in which one alternative was drawn from the component with the short COD and one alternative was drawn from the component with the long COD. When the schedule values of the two alternatives were identical (VI 40 vs. VI 40 and VI 80 vs. VI 80), subjects preferred the alternative trained with the long COD (Ms = .78 and .61, respectively). Additionally, subjects preferred the VI 40-s alternative trained with the long COD to the VI 80-s alternative that was trained with the short COD (M = .85). Systematic preference was not observed when subjects were given a choice between the VI 40-s alternative that was trained with the short COD and the VI 80-s alternative that was trained with the long COD. These results demonstrate that a stimulus associated with a longer COD, and thus longer dwell times in baseline training, may be more preferred during probe tests than expected on the basis of the rate of primary reinforcement associated with that stimulus.

Conditioned reinforcement in chain schedules when time to reinforcement is held constant.

Two alternative approaches describe determinants of responding to a stimulus temporally distant from primary reinforcement. One emphasizes the temporal relation of each stimulus to the primary reinforcer, with relative proximity of the stimulus determining response rate. A contrasting view emphasizes immediate consequences of responding to the stimulus, the key factor being the conditioned reinforcement value of those immediate consequences. To contrast these approaches, 4 pigeons were exposed to a two-component multiple schedule with three-link chain schedules in each component. Only middle-link stimuli differed between chains. Baseline reinforcement probabilities were 0.50 for both chains; during discrimination phases it was 1.0 for one chain and 0.0 for the other. During discrimination phases pigeons responded more to the reinforcement-correlated middle link than to the extinction-correlated middle link, demonstrating that responding was affected by the probability change. Terminal link responding was also higher in the reinforced chain, even though the terminal link stimulus was identical in both chains. Of greatest interest is initial link responding, which was temporally most distant from reinforcement. Initial link responding, necessarily equal in the two chains, was significantly higher during the 1.0/0.0 discrimination phases, even though overall reinforcement probability remained constant. For 3 of 4 birds, in fact, initial-link response rates were higher than terminal-link response rates, an outcome that can be ascribed only to the potent conditioned reinforcement properties of the middle-link stimulus during the discrimination phases. Results are incompatible with any account of chain behavior based solely on relative time to reinforcement.

Severe asthma: an expanding and mounting clinical challenge.

Although all patients with asthma have variable airflow obstruction, airway inflammation, and bronchial hyperresponsiveness, some have disease that is severe in many aspects: persistent airflow obstruction, ongoing symptoms, increased frequency of exacerbations, and, most importantly, a diminished response to medications. A number of definitions have emerged to characterize the clinical features of severe asthma, but a central feature of this phenotype is the need for high doses of medications, especially corticosteroids, in attempts to achieve disease control. The prevalence of severe asthma is also undergoing reevaluation from the usual estimate of 10% to larger numbers on the basis of medication needs and the lack of disease control achieved. At present, the underlying mechanisms of severe asthma are not established but likely reflect a heterogeneous pattern, rather than a single unifying process. Guideline-directed treatment for severe asthma has limits with usual approaches centered on high doses of inhaled corticosteroids, long-acting ß-agonists, and trials with omalizumab, the monoclonal antibody to IgE. With the development of approaches to recognize asthma phenotypes with distinct pathogenesis and hence unique therapeutic targets, it is hoped that a personalized strategy in treatment directed toward disease-specific features will improve outcomes for this high-risk, severely affected population of patients.

Diminished but not forgotten: effects of aging on magnitude of spacing effect benefits.

OBJECTIVES: Age-related changes in memory performance are common in paired associate episodic memory tasks, although the deficit can be ameliorated with distributed practice. Benefits of learning episode spacing in older adults have been shown in single-session studies with spaced presentations of items followed by a test. This study examined the magnitude of the spacing effect benefit in older adults relative to younger adults when given a multiday spacing effect paradigm. METHOD: We examined the impact of spacing gap (~15min vs. 24hr) in younger (N = 51, Mage = 19 years, SD = 0.6) and older (N = 54, Mage = 65 years, SD = 8.8) adults with a 10-day retention interval. RESULTS: Spacing of learning episodes benefited both younger and older adults. There was an age-related difference in the magnitude of this benefit that has not been observed in earlier studies. DISCUSSION: These results suggest that spacing benefited the long-term memory of older adults, however the effect was diminished and qualitatively different from that of younger adults.

Addressing antimicrobial resistance to treat children with atopic dermatitis in a tertiary pediatric allergy clinic.

BACKGROUND: Secondary skin infection with Staphylococcus aureus is a significant problem in atopic dermatitis (AD) patients. OBJECTIVE: This study evaluated antimicrobial resistance patterns of S aureus isolates from skin lesions in AD patients and empiric antimicrobial prescribing patterns. METHODS: Resistance patterns from positive skin cultures obtained from AD patients in the Allergy/Immunology clinic from May 1, 2006, to December 31, 2008, were compared with all outpatient wound cultures over the same period. RESULTS: Fifty-nine cultures were obtained from 38 AD patients. S aureus was the most common pathogen cultured from AD patients (53/59 cultures). S aureus resistance to clindamycin and methicillin differed significantly between the study group and the outpatient reference population (37.7% vs 9.4% and 45.3% vs 76.4%). Clindamycin was the most commonly prescribed antimicrobial (59%). Overall, 31.4% of organisms showed resistance to the antimicrobial prescribed. CONCLUSIONS: Susceptibility profiles of S aureus isolates from AD patients vary significantly from that of the general population.

Signals, resistance to change, and conditioned reinforcement in a multiple schedule.

The effect of signals on resistance to change was evaluated using pigeons responding on a three-component multiple schedule. Each component contained a variable-interval initial link followed by a fixed-time terminal link. One component was an unsignaled-delay schedule, and two were equivalent signaled-delay schedules. After baseline training, resistance to change was assessed through (a) extinction and (b) adding free food to the intercomponent interval. During these tests, the signal stimulus from one of the signaled-delay components (SIG-T) was replaced with the initial-link stimulus from that component, converting it to an unsignaled-delay schedule. That signal stimulus was added to the delay period of the unsignaled-delay component (UNS), converting it to a signaled-delay schedule. The remaining signaled component remained unchanged (SIG-C). Resistance-to-change tests showed removing the signal had a minimal effect on resistance to change in the SIG-T component compared to the unchanged SIG-C component except for one block during free-food testing. Adding the signal to the UNS component significantly increased response rates suggesting that component had low response strength. Interestingly, the direction of the effect was in the opposite direction from what is typically observed. Results are consistent with the conclusion that the signal functioned as a conditioned reinforcer and inconsistent with a generalization-decrement explanation.