Effects of variability requirements on difficult sequence learning.

The present study investigated the effects of variability requirements on learning difficult target sequences in humans. Twenty university students emitted five-response sequences. For the experimental groups, 30 nontarget sequences were reinforced according to the Lag-10 variation criterion or the Lag-3 repetition criterion across conditions. For the control groups, the probability of reinforcers for nontarget sequences was yoked to that obtained by the experimental groups. In addition, for both groups, two difficult target sequences were continuously reinforced. U values were higher with the Lag-10 variation criterion than with the Lag-3 repetition criterion for the experimental groups and were unsystematic for the control groups. Higher U values ​​were accompanied by a random pattern in the emission of nontarget sequences for all groups. Higher levels of variability, regardless of whether they were directly produced by reinforcement or were contingency induced, facilitated learning of difficult target sequences.

Reciprocity With Unequal Payoffs: Cooperative and Uncooperative Interactions Affect Disadvantageous Inequity Aversion.

Cooperation among unrelated individuals can evolve through reciprocity. Reciprocal cooperation is the process in which lasting social interactions provide the opportunity to learn about others' behavior, and to further predict the outcome of future encounters. Lasting social interactions may also decrease aversion to unequal distribution of gains - when individuals accept inequity payoffs knowing about the possibility of future encounters. Thus, reciprocal cooperation and aversion to inequity can be complementary phenomena. The present study investigated the effects of cooperative and uncooperative interactions on participants' aversion to disadvantageous inequity. Participants played an experimental task in the presence of a confederate who acted as a second participant. In reality, the participant interacted with a computer programed to make cooperative and uncooperative choices. After interacting with a cooperative or uncooperative computer, participants chose between blue cards to produce larger gains to the computer and smaller for him/her or green cards to produce equal and smaller gains for both. Results confirmed our first hypothesis that uncooperative interactions would produce aversion to disadvantageous inequity. Lastly, half of the participants were informed that points received during the experiment could be later exchanged for money, and half were not. Results indicated that information about monetary outcomes did not affect aversion to inequity, contradicting our second hypothesis. We discuss these results in the light of theories of reciprocal cooperation, inequity aversion, and conformity.

Recaída de Variabilidade Operante com a Combinação dos Procedimentos de Renovação, Restabelecimento e Ressurgência / Relapse of Operant Variability with the Combination of the Renewal, Reinstatement, and Resurgence Procedures

Resumo O reaparecimento de variabilidade comportamental previamente extinta (i.e., recaída) foi investigado por meio dos modelos experimentais de renovação, restabelecimento e ressurgência. Na Fase de Treino (contexto A), ao serem expostos ao esquema múltiplo Lag 10 Acoplado, ratos apresentaram níveis similares de variabilidade nos dois componentes. Na Fase de Eliminação (contexto B), o esquema múltiplo Repetição Repetição promoveu a extinção da variabilidade. Na Fase de Teste (contexto A), com a suspensão da contingência de repetição e a liberação de reforços independentes, a variabilidade reapareceu no componente "Lag 10", anteriormente correlacionado com reforçamento da variação, mas não no componente "Acoplado". Esse resultado sugere que a variabilidade observada no teste de recaída corresponde à variabilidade operante, e não à variabilidade induzida pela extinção.

Abstract The reappearance of previously extinguished behavioral variability (i.e. relapse) was investigated with three experimental models: renewal, reinstatement and resurgence. In the Training Phase (context A), when exposed to the multiple Lag 10 Yoke schedule, rats showed similar levels of variability in both components. In the Elimination Phase (context B), the multiple Repetition schedule promoted the extinction of variability. In the Test Phase (context A), with the suspension of the repetition contingency and the delivery of response-independent reinforcers, variability reappeared in the "Lag 10" component, the one previously correlated with the reinforcement of variation, but not in the "Yoke" component. This result suggests that the variability observed in the relapse test corresponded to operant variability, and not to extinction-induced variability.

Resurgence is greater following a return to the training context than remaining in the extinction context.

The present study examined whether resurgence of a previously reinforced target response upon removing alternative reinforcement would be greater when (1) returning to the original training context (ABA context changes) versus (2) remaining in the analogue treatment context in which the alternative response was differentially reinforced (ABB context changes). Experiment 1 arranged reinforcement of button pressing with points exchangeable for money in university students. Experiment 2 arranged reinforcement of lever pressing with food for rats. Experiment 3 arranged reinforcement of responses to a touchscreen with small bites of food with children diagnosed with ASD. Overall, resurgence of target responding tended to be greater when returning to the original training context (A) than when remaining in the analogue treatment context (B). These findings suggest context changes with differential reinforcement treatments could exacerbate the recurrence of problem behavior resulting from reductions in treatment integrity through failure to reinforce appropriate behavior.

Response-reinforcer dependency and resistance to change.

The effects of the response-reinforcer dependency on resistance to change were studied in three experiments with rats. In Experiment 1, lever pressing produced reinforcers at similar rates after variable interreinforcer intervals in each component of a two-component multiple schedule. Across conditions, in the fixed component, all reinforcers were response-dependent; in the alternative component, the percentage of response-dependent reinforcers was 100, 50 (i.e., 50% response-dependent and 50% response-independent) or 10% (i.e., 10% response-dependent and 90% response-independent). Resistance to extinction was greater in the alternative than in the fixed component when the dependency in the former was 10%, but was similar between components when this dependency was 100 or 50%. In Experiment 2, a three-component multiple schedule was used. The dependency was 100% in one component and 10% in the other two. The 10% components differed on how reinforcers were programmed. In one component, as in Experiment 1, a reinforcer had to be collected before the scheduling of other response-dependent or independent reinforcers. In the other component, response-dependent and -independent reinforcers were programmed by superimposing a variable-time schedule on an independent variable-interval schedule. Regardless of the procedure used to program the dependency, resistance to extinction was greater in the 10% components than in the 100% component. These results were replicated in Experiment 3 in which, instead of extinction, VT schedules replaced the baseline schedules in each multiple-schedule component during the test. We argue that the relative change in dependency from Baseline to Test, which is greater when baseline dependencies are high rather than low, could account for the differential resistance to change in the present experiments. The inconsistencies in results across the present and previous experiments suggest that the effects of dependency on resistance to change are not well understood. Additional systematic analyses are important to further understand the effects of the response-reinforcer relation on resistance to change and to the development of a more comprehensive theory of behavioral persistence.

Effects of reinforcement value on instruction following under schedules of negative reinforcement.

The effects of reinforcement value and social control on instruction following under a negative-reinforcement (escape) schedule were studied. Initially, responding produced timeouts from pressing a force cell under a low and a high force requirement on a fixed-ratio 1 schedule of reinforcement. Next, participants were reexposed to the low and high force requirements, but were instructed that the experimenter expected them to decrease the number of timeouts relative to the previous exposures to the procedure. Even though following the instruction led to a decrease in number of timeouts and to an increase in effort (i.e., was non-efficient), instruction following occurred consistently for each participant and was modulated by reinforcement value. That is, the decrease in the number of timeouts (i.e., instruction following) was lower under the high force requirement than under the low force requirement. These results replicate and extend previous findings that instructions interact with social and nonsocial contingencies in controlling human behavior.

Reaparecimento de sequências com diferentes números de respostas em contextos de extinção e de variação / Reappearance of Sequences with Different Number of Responses in Extinction and Variation Contexts

RESUMO O reaparecimento de uma resposta previamente extinta quando os reforços para uma resposta alternativa são descontinuados é denominado ressurgência. Foram investigados os efeitos de três variáveis sobre o reaparecimento de sequências de respostas: probabilidade da sequência (alta e baixa), contexto de teste (extinção e variação operante) e número de respostas por sequência (três e cinco). Sequências muito prováveis reapareceram mais frequentemente que sequências pouco prováveis, o reaparecimento da sequência alvo foi mais frequente no contexto de extinção do que de variação e o reaparecimento da sequência alvo variou inversamente ao número de respostas por sequência. O reaparecimento da sequência alvo, entretanto, não foi conceitualizado como ressurgência, uma vez que sua frequência foi menor que a das sequências controle.

ABSTRACT The reappearance of a response previously extinguished when an alternative response no longer produces reinforcers is called resurgence. The effects of three variables on the reappearance of response sequences - sequence probability (high and low), context of test (extinction and operant variation) and number of responses per sequence (three and five responses) - were investigated. Sequences with high probability reappeared more often than sequences with low probability, the reappearance of the target sequence was more frequent under extinction than under variation, and the reappearance of the target sequence varied inversely with the number of responses by sequence. The reappearance of the target sequence was not conceptualized as resurgence because its frequency was lower than that of the control sequences.

Choice between contingencies of variation: effects of the requirement of variation upon preference.

The present study investigated whether choices between contingencies of variation are affected by the degree of variability required. For such, five pigeons were exposed to a concurrent chain schedule. In the initial links, responses in one key initiated the terminal link with the most stringent variation requirement while responses in the other key initiated the terminal link with the least stringent variation requirement. In both terminal links, four-responses sequences were reinforced according to a variation criterion, which favored less frequent and less recent sequences. The probability of reinforcement in the terminal link with the least stringent criterion was manipulated in order to generate similar percentage and rate of reinforcers in both terminal links. Choices for the terminal link with the least stringent criterion were more frequent than choices for the terminal link with the most stringent criterion. It is possible that situations that demand lower levels of behavior variability are chosen due to the lower response cost correlated to those situations.

Varied but not necessarily random: human performance under variability contingencies is affected by instructions.

The goal of the present study was to evaluate the role of verbal stimuli in the production of response variability in humans. College students were distributed into three groups and asked to type three-digit sequences. Participants in the systematic group were instructed to produce sequences according to a rule of their choice; those in the random group were instructed to produce sequences according to chance; and those in the control group were not instructed about how to produce sequences. The experiment employed an ABA design. During the A phases, low-frequent sequences were reinforced (variability contingency), whereas during the B phase, reinforcement was withdrawn (extinction). The results indicated the following: (1) The instructions were efficient at producing systematic and random-like patterns for the systematic and random groups, respectively; in the absence of instructions, a mix of both patterns was observed. (2) Behavior was sensitive to extinction independently of the instructions provided. (3) Systematic patterns favored a more equiprobable distribution of sequences across trials. (4) Reaction times were longer for responding in a systematic than in a random-like fashion. The present findings suggest that individual differences in meeting variability contingencies may be due, at least partially, to instructional control.

Extinção e estímulos independentes da resposta: efeitos de relações de não-contingência sobre o comportamento / Extinction and response-independent stimuli: effects of non-contingent relations on behavior

A extinção e a apresentação de estímulos independentes da resposta são dois procedimentos tradicionais de suspensão da contingência entre resposta e consequência. O objetivo dessa revisão é discutir algumas similaridades e divergências nos efeitos comportamentais desses procedimentos. Dentre as similaridades encontram-se a redução na taxa de respostas, o estabelecimento de controle de estímulos, a renovação e o aumento na variabilidade comportamental. Dentre as divergências observam-se o maior grau de redução na taxa de respostas, a ocorrência de respostas emocionais e efeitos de contraste sob a extinção; comportamento supersticioso e o reestabelecimento sob o procedimento de estímulos independentes. Os diversos efeitos comportamentais foram analisados à luz das similaridades (não-contingência) e diferenças (estímulo reforçador ausente vs. presente) na programação dessas condições...

Extinction and presentation of response-independent stimuli are two traditional procedures to suspend a response-consequence contingency. The goal of this review is to discuss some similarities and divergences in the behavioral effects of those procedures. Among the similarities, we found responserate deceleration, stimulus control development, renewal, and increase in behavioral variability. Among the divergences, we observed the higher degree of responserate deceleration, the occurrence of emotional responses and behavioral contrast effects under extinction; superstitious behavior and reinstatement under response-independent stimuli conditions. Such behavioral effects were discussed in light of the similarities (non-contingency) and differences (presence versus absence of reinforcing stimuli) in programming those conditions...

Extinção e estímulos independentes da resposta: efeitos de relações de não-contingência sobre o comportamento / Extinction and response-independent stimuli: effects of non-contingent relations on behavior

A extinção e a apresentação de estímulos independentes da resposta são dois procedimentos tradicionais de suspensão da contingência entre resposta e consequência. O objetivo dessa revisão é discutir algumas similaridades e divergências nos efeitos comportamentais desses procedimentos. Dentre as similaridades encontram-se a redução na taxa de respostas, o estabelecimento de controle de estímulos, a renovação e o aumento na variabilidade comportamental. Dentre as divergências observam-se o maior grau de redução na taxa de respostas, a ocorrência de respostas emocionais e efeitos de contraste sob a extinção; comportamento supersticioso e o reestabelecimento sob o procedimento de estímulos independentes. Os diversos efeitos comportamentais foram analisados à luz das similaridades (não-contingência) e diferenças (estímulo reforçador ausente vs. presente) na programação dessas condições.(AU)

Extinction and presentation of response-independent stimuli are two traditional procedures to suspend a response-consequence contingency. The goal of this review is to discuss some similarities and divergences in the behavioral effects of those procedures. Among the similarities, we found responserate deceleration, stimulus control development, renewal, and increase in behavioral variability. Among the divergences, we observed the higher degree of responserate deceleration, the occurrence of emotional responses and behavioral contrast effects under extinction; superstitious behavior and reinstatement under response-independent stimuli conditions. Such behavioral effects were discussed in light of the similarities (non-contingency) and differences (presence versus absence of reinforcing stimuli) in programming those conditions.(AU)

History effects on induced and operant variability.

Two experiments evaluated history effects on induced and operant variability. College students typed three-digit sequences on a computer keyboard. Sequence variability was induced (by no reinforcement or variation-independent reinforcement) or reinforced (by variation- or repetition-dependent reinforcement). Conditions with induced and operant variability were presented according to a reverse between-groups design. In Experiment 1, we examined transitions from the variation or repetition contingencies to no reinforcement, and vice versa. In Experiment 2, the variation or repetition contingencies were followed or preceded by variation-independent reinforcement. The results showed that (1) a history of no reinforcement impaired operant variability learning; (2) induced variability levels were higher and lower after a history of reinforcement for variation and repetition, respectively; (3) repetition was more easily disrupted by no reinforcement and independent reinforcement than was variation; and (4) response variability and stability were a function of past and current reinforcement conditions. These results indicate that reinforcement history influences both induced and operant variability levels.

Discriminative proprieties of Vary and Repeat contingencies.

Pigeons were trained on an arbitrary matching-to-sample task in which Vary and Repeat contingencies served as sample stimuli. During the sample component, two keys were lit red and a four-peck sequence was reinforced if its frequency was less than a certain threshold (Vary sample) or if it comprised one of two target sequences (Repeat sample). During the comparison component, two keys were lit white and green, and correct choices depended on the previous sample contingency. Pigeons learned to emit high and low variability levels during the sample, and correct matching choices were obtained. In two discrimination testing phases, the requirement of variation (Vary sample) or of repetition (Repeat sample) was parametrically manipulated such that behavioral variability became undifferentiated between samples (low sample disparity) and then differentiated (high sample disparity) again. Accurate choices fell to chance under low sample disparity conditions, but improved under high disparity conditions. The results provide evidence that high and low variability levels can be produced in the absence of antecedent cues and that pigeons can accurately report whether they had experienced a Vary or a Repeat contingency, thus indicating that those contingencies may serve discriminative functions.

Verbal mediating responses: effects on generalization of say-do correspondence and noncorrespondence.

We analyzed the effects of verbal mediating responses on the acquisition and generalization of say-do correspondence and noncorrespondence. Participants were assigned to groups in which either reinforcers (feedback and tokens) were arranged for say-do correspondence and noncorrespondence, or no reinforcers were programmed. Participants in these groups were further subdivided into groups in which they were required to repeat what was said previously, were required to repeat random numbers, or no verbalizations were required. When correspondence was reinforced, repetition of what was said produced greater acquisition and generalization of correspondence. When noncorrespondence was reinforced, repetition of numbers facilitated acquisition and generalization of noncorrespondence. Verbal mediating responses interacted with contingencies of reinforcement in determining acquisition and generalization of correspondence and noncorrespondence.

Falácia da conjunção: definição e variáveis de controle / Conjunction fallacy: definition and control variables

A falácia da conjunção ocorre quando a conjunção de dois eventos é julgada como mais provável de ocorrer do que seus eventos constituintes. Esse fenômeno tem sido investigado principalmente por psicólogos cognitivistas, mas, recentemente, tem atraído o interesse de alguns analistas do comportamento. O presente trabalho consiste em um resumo da literatura sobre falácia, no qual são enfatizadas as estratégias metodológicas utilizadas e os resultados empíricos obtidos. Dentre as variáveis controladoras analisadas, são destacadas a representatividade, o uso inadequado de regras probabilísticas, as experiências passadas com os eventos constituintes e compostos, o treino estatístico e os aspectos verbais e contextuais.

The conjunction fallacy occurs when the conjunction of two events is judged as more probable to occur than its constituent events. This phenomenon has been investigated mainly by cognitive psychologists but, recently, it has called the attention of some behavior analysts. The present study summarizes the literature on fallacy, emphasizing the methodological strategies used and the empirical results attained. Among the control variables analyzed, some special attention is given to the representativeness, the inadequate use of probabilistic rules, the previous experiences with constituent and compound events, the statistical training, and verbal and contextual aspects.

Falácia da conjunção: definição e variáveis de controle / Conjunction fallacy: definition and control variables

A falácia da conjunção ocorre quando a conjunção de dois eventos é julgada como mais provável de ocorrer do que seus eventos constituintes. Esse fenômeno tem sido investigado principalmente por psicólogos cognitivistas, mas, recentemente, tem atraído o interesse de alguns analistas do comportamento. O presente trabalho consiste em um resumo da literatura sobre falácia, no qual são enfatizadas as estratégias metodológicas utilizadas e os resultados empíricos obtidos. Dentre as variáveis controladoras analisadas, são destacadas a representatividade, o uso inadequado de regras probabilísticas, as experiências passadas com os eventos constituintes e compostos, o treino estatístico e os aspectos verbais e contextuais(AU)

The conjunction fallacy occurs when the conjunction of two events is judged as more probable to occur than its constituent events. This phenomenon has been investigated mainly by cognitive psychologists but, recently, it has called the attention of some behavior analysts. The present study summarizes the literature on fallacy, emphasizing the methodological strategies used and the empirical results attained. Among the control variables analyzed, some special attention is given to the representativeness, the inadequate use of probabilistic rules, the previous experiences with constituent and compound events, the statistical training, and verbal and contextual aspects(AU)

Reversão dos efeitos da história de incontrolabilidade sob contingências de variação comportamental / Reversing the effects of a history of uncontrollability under behavior variation contingencies / Reversión de los efectos de la historia de incontrolabilidad bajo contingencias de variación

A exposição a eventos incontroláveis produz dificuldade na aprendizagem de novos comportamentos. O presente estudo investigou o papel da instrução e da exposição à controlabilidade na reversão dos efeitos da história de incontrolabilidade. No treino, estudantes universitários foram expostos à controlabilidade (grupo CC) ou à incontrolabilidade (grupos IC, ICi, II, IIi). Na "terapia", os grupos CC, IC e ICi foram expostos à controlabilidade, enquanto os grupos II e IIi continuaram expostos à incontrolabilidade. Os grupos ICi e IIi receberam uma instrução de incontrolabilidade/controlabilidade. No teste, todos os grupos foram expostos a controlabilidade. Os participantes expostos apenas à incontrolabilidade (grupos II e IIi) apresentaram maior persistência do responder do que aqueles expostos à "terapia" (grupos IC e ICi), os quais não diferiram dos participantes expostos apenas à controlabilidade (Grupo CC), a despeito da instrução. O procedimento de "terapia", portanto, foi mais efetivo do que a instrução para reverter os efeitos da história de incontrolabilidade.(AU)

Pre-exposure to uncontrollable events interferes with subsequent learning of new behaviors. The present study investigated the role of instructions and of the exposure to controllability in reversing the effects of a history of uncontrollability. During training, college students were exposed to controllability (CC Group) or to uncontrollability (IC, ICi, II and Iii groups). During "therapy", the CC, IC and ICi groups were exposed to controllability while the II and IIi groups remained exposed to uncontrollability. An instruction on uncontrollability/controllability was given to the ICi and IIi groups. During testing, all groups were exposed to controllability. The participants exposed only to uncontrollability (II and IIi groups) showed greater response persistence than those exposed to "therapy" (IC and ICi groups) that did not differ from those exposed only to controllability (CC Group). The "therapy" procedure, then, was more effective than instructions in reversing the effects of a history of uncontrollability.(AU)

La exposición a eventos incontrolables produce dificultad en el aprendizaje de nuevos comportamientos. El presente estudio investigó el rol de la instrucción y de la exposición a la controlabilidad en la reversión de los efectos de la historia de incontrolabilidad. En el entrenamiento, estudiantes universitarios fueron expuestos a la controlabilidad (grupo CC) o a la incontrolabilidad (grupos IC, ICi, II, IIi). En la "terapia", los grupos CC, IC y ICi fueron expuestos a la controlabilidad, mientras que los grupos II y IIi siguieron expuestos a la incontrolabilidad. Los grupos ICi y IIi recibieron una instrucción de incontrolabilidad/controlabilidad. En el test, todos los grupos fueron expuestos a la controlabilidad. Los participantes expuestos sólo a la incontrolabilidad (grupos II y IIi) presentaron mayor persistencia del responder, comparados a aquellos expuestos a la "terapia" (grupos IC y ICi), los cuales no se distinguieron de los participantes expuestos sólo a la controlabilidad (Grupo CC), pese a la instrucción. El procedimiento de "terapia", por lo tanto, fue más efectivo que la instrucción para revertir los efectos de la historia de incontrolabilidad.(AU)

Reversão dos efeitos da história de incontrolabilidade sob contingências de variação comportamental / Reversing the effects of a history of uncontrollability under behavior variation contingencies / Reversión de los efectos de la historia de incontrolabilidad bajo contingencias de variación

A exposição a eventos incontroláveis produz dificuldade na aprendizagem de novos comportamentos. O presente estudo investigou o papel da instrução e da exposição à controlabilidade na reversão dos efeitos da história de incontrolabilidade. No treino, estudantes universitários foram expostos à controlabilidade (grupo CC) ou à incontrolabilidade (grupos IC, ICi, II, IIi). Na "terapia", os grupos CC, IC e ICi foram expostos à controlabilidade, enquanto os grupos II e IIi continuaram expostos à incontrolabilidade. Os grupos ICi e IIi receberam uma instrução de incontrolabilidade/controlabilidade. No teste, todos os grupos foram expostos a controlabilidade. Os participantes expostos apenas à incontrolabilidade (grupos II e IIi) apresentaram maior persistência do responder do que aqueles expostos à "terapia" (grupos IC e ICi), os quais não diferiram dos participantes expostos apenas à controlabilidade (Grupo CC), a despeito da instrução. O procedimento de "terapia", portanto, foi mais efetivo do que a instrução para reverter os efeitos da história de incontrolabilidade.

Pre-exposure to uncontrollable events interferes with subsequent learning of new behaviors. The present study investigated the role of instructions and of the exposure to controllability in reversing the effects of a history of uncontrollability. During training, college students were exposed to controllability (CC Group) or to uncontrollability (IC, ICi, II and Iii groups). During "therapy", the CC, IC and ICi groups were exposed to controllability while the II and IIi groups remained exposed to uncontrollability. An instruction on uncontrollability/controllability was given to the ICi and IIi groups. During testing, all groups were exposed to controllability. The participants exposed only to uncontrollability (II and IIi groups) showed greater response persistence than those exposed to "therapy" (IC and ICi groups) that did not differ from those exposed only to controllability (CC Group). The "therapy" procedure, then, was more effective than instructions in reversing the effects of a history of uncontrollability.

La exposición a eventos incontrolables produce dificultad en el aprendizaje de nuevos comportamientos. El presente estudio investigó el rol de la instrucción y de la exposición a la controlabilidad en la reversión de los efectos de la historia de incontrolabilidad. En el entrenamiento, estudiantes universitarios fueron expuestos a la controlabilidad (grupo CC) o a la incontrolabilidad (grupos IC, ICi, II, IIi). En la "terapia", los grupos CC, IC y ICi fueron expuestos a la controlabilidad, mientras que los grupos II y IIi siguieron expuestos a la incontrolabilidad. Los grupos ICi y IIi recibieron una instrucción de incontrolabilidad/controlabilidad. En el test, todos los grupos fueron expuestos a la controlabilidad. Los participantes expuestos sólo a la incontrolabilidad (grupos II y IIi) presentaron mayor persistencia del responder, comparados a aquellos expuestos a la "terapia" (grupos IC y ICi), los cuales no se distinguieron de los participantes expuestos sólo a la controlabilidad (Grupo CC), pese a la instrucción. El procedimiento de "terapia", por lo tanto, fue más efectivo que la instrucción para revertir los efectos de la historia de incontrolabilidad.