It's important for classrooms to provide a welcoming and even fun environment where students feel comfortable. Especially in the case of younger students, in kindergartens and primary schools, teachers tend to decorate classrooms with various visual stimuli - for example, posters with colorful words and numbers, drawings of the students, posters with animals, maps. However, too many visual stimuli in a classroom can distract students and negatively affect their learning.
This is the conclusion of a study conducted in 2014 by a group of researchers from Carnegie Mellon University in the United States and published in the journal Psychological Science, which tested the influence of visual stimuli in the classroom on the ability of pupils aged around 5 to concentrate.
The researchers transformed a laboratory room into a classroom and varied how the walls were decorated (with posters, students' work, maps, etc.) or whether they were practically empty, with no irrelevant materials. After five familiarization lessons with the teacher (i.e. a lab assistant) and the classroom, the students attended six short lessons on six subjects: tectonic plates, stone tools, volcanoes, the solar system, insects and flight. The students attended three lessons in the decorated room and three lessons in the undecorated room. After each lesson, the students took a test with six questions which they had to answer by selecting the correct visual answer. In addition to their performance in the final tests, the researchers also measured the students' behavior during each lesson. To do this, they recorded the lessons and asked four independent observers to code the direction of the students' gaze during the lesson - how much time they spent looking at the teacher or lesson materials and how much time they spent looking in another direction.
The results indicated that students spent significantly less time looking at the teacher or class materials when the classroom had decorations, i.e. they spent more time distracted in the presence of decorations than in their absence (38.58% vs. 28.42% of class time). Specifically, in the plainer classroom, students spent 3.21% of their lesson time looking around. In the decorated classroom, they spent 20.56% of their time distracted. When they were in the undecorated classroom, students were more distracted by looking at their classmates or by themselves than when they were in the decorated classroom. Total distraction was lower in the undecorated classroom. These attentional differences were reflected in the results in the final tests: performance in the tests on topics learned in the undecorated classroom was 10% higher than performance in the tests on topics worked on in the decorated classroom. Comparing performance on final tests with performance on pre-tests, the researchers estimated that the students learned about 33% in the undecorated room and only 18% in the decorated room. Análises adicionais indicaram que a pior aprendizagem na sala decorada estava ligada ao tempo que os alunos passaram distraídos. Em 2022, a mesma equipa de investigadores publicou um estudo no qual testaram se a quantidade e a variabilidade de cor dos enfeites em salas de aula reais influenciavam o tempo que os alunos passavam distraídos. Os resultados indicaram que em salas de aula com mais decorações e variabilidade de cor os alunos passavam mais tempo distraídos (Godwin et al., 2022a).
One possible explanation for these effects is the cognitive load theory, as described in a study published in 2020 by Paas & van Merriënboer. According to this theory, in addition to other factors, the environment in which learning takes place influences the amount of working memory available to process the information to be learned. Thus, the irrelevant visual stimuli in the decorated classroom will have consumed part of the limited resources of the working memory, decreasing the ability to process the stimuli to be learned.
In short, the visual environment in which students learn influences their attention, which is reflected in their learning - by directing their attention to visual stimuli, students pay less attention to the lesson. In a 2022 study, researchers used a similar procedure in elementary school classrooms and measured students' habituation to visual stimuli over a 15-week period. The results were similar to those obtained in the laboratory: students continued to show greater distraction in the decorated classroom even after they had become accustomed to the decoration (Godwin et al., 2022b). These results indicate that prolonged exposure to the visual stimuli of a classroom does not seem to reduce the negative effects of these stimuli on attention. However, more research is needed to determine whether these effects occur in age groups other than the very young group (around 5 years old) that was studied. In practical terms, it is important to understand that this study does not mean that classrooms should be sterile environments without any decoration. However, it is important for teachers to know that too much visual stimulation can have negative effects on learning and to use this knowledge to optimize the decoration of their classrooms. An alternative could be, for example, to use decorations that are relevant to the topics being studied.