João só limpa a casa para a mãe, quando a mesma lhe oferece uma recompensa. Com relação ao reforçador natural, indique a alternativa que não contempla o trecho. Reforçar comportamentos adequados no sujeito com gratificações faz parte das normas desse reforçador. João devemos comprar nossos filhos com presentes e sim conscientiza-los da importância de contribuir na limpeza da casa. O reforço aumentara a probabilidade do comportamento voltar a ocorrer futuramente. As consequências reforçadoras naturais não são tão obvias como ganhar um brinquedo, mas são consequências poderosas do comportamento.

The authors of the paper "fudging the numbers: distributing chocolate influences student evaluations of an undergraduate course"† carried out a study to see if events unrelated to an undergraduate course could affect student evaluations. students enrolled in statistics courses taught by the same instructor participated in the study. all students attended the same lectures and one of six discussion sections that met once a week. at the end of the course, the researchers chose three of the discussion sections to be the "chocolate group." students in these three sections were offered chocolate prior to having them fill out course evaluations. students in the other three sections were not offered chocolate. the researchers concluded that "overall, students offered chocolate gave more positive evaluations than students not offered chocolate." indicate whether the study is an observational study or an experiment. give a brief explanation for your choice.