Contributions of stimulus equivalence paradigm for studying attitudes

Considerando a abordagem analítico-comportamental, atitudes podem ser consideradas respostasavaliativas emitidas de acordo com uma história prévia de aprendizagem. O paradigma deequivalência de estímulos, utilizando procedimentos que simulam o comportamento simbólico nolaboratório, tem possibilitado entender a formação de atitudes como uma rede de relações arbitráriasentre classes de estímulos e atributos avaliativos. Esta visão tem auxiliado na compreensão de comofenômenos sociais, tais como estereótipos e preconceitos, podem ser estabelecidos e modificados. Oobjetivo deste trabalho é apresentar algumas contribuições, a partir de evidências empíricasdemonstradas por pesquisas que utilizaram este paradigma nas últimas décadas, particularmente apartir da década de 90, que fortalecem a equivalência de estímulos como um modelocomportamental importante para o estudo das atitudes.According to the behavior-analytic approach, attitudes can be viewed as responses emitted based ona previous learning history. Stimulus equivalence paradigm, using procedures that simulatesymbolic behavior in the laboratory, has made possible to understand attitude formation as arbitraryrelational networks between stimulus classes and evaluative attributes. This view has enabledunderstanding how social phenomena, such as prejudices and stereotypes, can be established andchanged. The aim of this research is to present contributions, from empirical evidence demonstratedby stimulus equivalence research carried out in the last decades, especially from the 1 990’s, thatstrengthen this paradigm as an important behavioral model for studying attitudes

Naming New Stimuli After Selection by Exclusion

O responder por exclusão em tarefas de escolha de acordo com o modelo é um dos padrões mais robustos do comportamento humano. Contudo, uma única resposta por exclusão não assegura a aprendizagem da relação arbitrária entre dois estímulos. O presente estudo teve por objetivo investigar a quantidade de exposição necessária até que oito pré-escolares nomeassem duas figuras novas emparelhadas, por exclusão, a palavras novas. Após o estabelecimento de uma linha de base de emparelhamentos entre figuras e palavras ditadas, duas palavras novas eram introduzidas em sondas de exclusão. Em cada sonda, uma palavra nova era ditada e uma figura nova era apresentada entre outras figuras definidas experimentalmente. Sondas em tarefas de emparelhamento e de nomeação das figuras mostraram aprendizagem das relações condicionais e emergência da nomeação depois de três a 10 tentativas de exclusão. A nomeação correta tendeu a ocorrer de forma mais regular quando a fase de ensino estabeleceu controle de estímulos por seleção.El responder por exclusión en tareas de igualación a la muestra es uno de los patrones más robustos del comportamiento humano. No obstante, una única respuesta por exclusión no garantiza el aprendizaje de la relación arbitraria entre dos estímulos. El presente estudio investigó la cantidad de exposiciones necesarias para que ocho estudiantes preescolares nominaran dos figuras nuevas emparejadas, por exclusión, con palabras nuevas. Después del establecimiento de una línea de base de emparejamientos entre figuras y palabras dictadas, dos palabras nuevas eran introducidas en pruebas de exclusión. En cada prueba, una palabra nueva era dictada y una figura nueva presentada entre otras definidas. Pruebas de aprendizaje en tareas de igualación al modelo y de nominación de las figuras mostraron que la nominación emergió después de tres a 10 ensayos de exclusión. Se observó que la nominación correcta ocurrió de forma más fidedigna cuando el control era por selección.Responding by exclusion in matching-to-sample tasks is a robust behavioral pattern in humans. A single selection, however, does not ensure learning of the arbitrary relationship between the sample and the selected comparison stimulus. The present study aimed to investigate the amount of exposure required until eight preschoolers were able to name two undefined pictures, matched by exclusion, to two undefined words. After establishing a matching-to-sample baseline between pictures and dictated words, two new words were introduced in exclusion probes. On each probe, a new word was dictated and the matrix of comparison stimuli included a new picture and two experimentally defined pictures. Naming emerged after three to10 exclusion trials. Correct naming tended to occur more reliably when the teaching phase established stimulus control by selection

Naming New Stimuli After Selection by Exclusion

Responding by exclusion in matching-to-sample tasks is a robust behavioral pattern in humans. A single selection, however, does not ensure learning of the arbitrary relationship between the sample and the selected comparison stimulus. The present study aimed to investigate the amount of exposure required until eight preschoolers were able to name two undefined pictures, matched by exclusion, to two undefined words. After establishing a matching-to-sample baseline between pictures and dictated words, two new words were introduced in exclusion probes. On each probe, a new word was dictated and the matrix of comparison stimuli included a new picture and two experimentally defined pictures. Naming emerged after three to10 exclusion trials. Correct naming tended to occur more reliably when the teaching phase established stimulus control by selection

Behavioral contrast in fixed-interval components: effects of extinction-component duration.

Seven albino rats were exposed to a multiple schedule of reinforcement in which the two components (fixed interval and extinction) alternated such that a presentation of the extinction component followed each fixed-interval reinforcement. In baseline sessions, the duration of the extinction component was constant and always one-third of the fixed-interval value. Probe sessions contained a probe segment in which the duration of the extinction component was increased; the response rate in fixed-interval components during the probe segment was compared with the response rate in the segments preceding and following the probe. The effect of increasing the duration of the extinction component was studied under three values of fixed interval: 30 s, 120 s, and 18 s, in three successive conditions. Response rate within fixed intervals was a direct function of duration of the extinction component. Pausing at the beginning of the fixed interval decreased as extinction duration increased. These effects were larger and more consistent for the shorter fixed-interval values (18 s and 30 s). These results indicate a functional relation between relative component duration and responding. For the component providing more frequent reinforcement, this could be stated as an inverse relationship between relative component duration and response rate. This relation is similar to findings regarding the ratio of trial and intertrial duration in Pavlovian conditioning procedures, and suggests that behavioral contrast may be related to Pavlovian contingencies underlying the multiple schedule

Geoeconomic variations in epidemiology, ventilation management, and outcomes in invasively ventilated intensive care unit patients without acute respiratory distress syndrome: a pooled analysis of four observational studies

Background: Geoeconomic variations in epidemiology, the practice of ventilation, and outcome in invasively ventilated intensive care unit (ICU) patients without acute respiratory distress syndrome (ARDS) remain unexplored. In this analysis we aim to address these gaps using individual patient data of four large observational studies. Methods: In this pooled analysis we harmonised individual patient data from the ERICC, LUNG SAFE, PRoVENT, and PRoVENT-iMiC prospective observational studies, which were conducted from June, 2011, to December, 2018, in 534 ICUs in 54 countries. We used the 2016 World Bank classification to define two geoeconomic regions: middle-income countries (MICs) and high-income countries (HICs). ARDS was defined according to the Berlin criteria. Descriptive statistics were used to compare patients in MICs versus HICs. The primary outcome was the use of low tidal volume ventilation (LTVV) for the first 3 days of mechanical ventilation. Secondary outcomes were key ventilation parameters (tidal volume size, positive end-expiratory pressure, fraction of inspired oxygen, peak pressure, plateau pressure, driving pressure, and respiratory rate), patient characteristics, the risk for and actual development of acute respiratory distress syndrome after the first day of ventilation, duration of ventilation, ICU length of stay, and ICU mortality. Findings: Of the 7608 patients included in the original studies, this analysis included 3852 patients without ARDS, of whom 2345 were from MICs and 1507 were from HICs. Patients in MICs were younger, shorter and with a slightly lower body-mass index, more often had diabetes and active cancer, but less often chronic obstructive pulmonary disease and heart failure than patients from HICs. Sequential organ failure assessment scores were similar in MICs and HICs. Use of LTVV in MICs and HICs was comparable (42·4% vs 44·2%; absolute difference -1·69 [-9·58 to 6·11] p=0·67; data available in 3174 [82%] of 3852 patients). The median applied positive end expiratory pressure was lower in MICs than in HICs (5 [IQR 5-8] vs 6 [5-8] cm H2O; p=0·0011). ICU mortality was higher in MICs than in HICs (30·5% vs 19·9%; p=0·0004; adjusted effect 16·41% [95% CI 9·52-23·52]; p<0·0001) and was inversely associated with gross domestic product (adjusted odds ratio for a US$10 000 increase per capita 0·80 [95% CI 0·75-0·86]; p<0·0001). Interpretation: Despite similar disease severity and ventilation management, ICU mortality in patients without ARDS is higher in MICs than in HICs, with a strong association with country-level economic status