# The Influence of Classroom Illumination Environment on the Efficiency of Foreign Language Learning
## 1 Introduction  
Sentiment factor in language learning is attracting more and more attention with the emergence and development of humanistic psychology. In language teaching, \"sentiment\" refers to the learners' emotions, feeling, mood, and attitude, among other factors in learning process [1]. Foreign language learning is closely related to sentiment, as sentimental factors can not only reflect the learners' physiological and psychological status but also influence their learning efficiency [2]. Human acquisition of external information is derived 80% or more from vision [3], thus foreign language learners' sentimental factors may, to a certain degree, be stimulated or induced by classroom learning conditions.  
In classrooms, illumination is a very important design factor [4]. Illumination affects not only visual response but also nonvisual reactions, such as performance, mood, and attention [5; 6; 7; 8]. Improvements in the quality of illumination environments increase productivity in students and teachers [9]. Different illumination environments in a classroom will trigger different sentiments, which may influence learners' ability to concentrate and attendance [10]. Indoor illumination will cause the following reactions generally: it will affect information processing, result in physiological change, and affect psychological reactions of sentiment or mood [11]. In this paper, the influence of indoor illumination on foreign language learning efficiency was researched in the following three aspects: foreign language skills testing, the objective evaluation of physiological reaction, and the subjective evaluation of psychological reaction (Figure 1). The three aspects were correlated, and formed a reaction process that influenced the sentimental status of foreign language learning and, finally, influenced the efficiency of foreign language learning.  
This paper set up four illumination environments by different illuminance and color temperatures, tested foreign language learners' language skills, and made subjective and objective assessments of their physiological and psychological reactions through foreign language vocabulary association skills testing in mind-map, stress value determination by salivary amylase activity, and questionnaires on sentimental status related to \"concentration\" and \"association\". In addition, this paper analyzed the influence of illumination environment on foreign language learning efficiency, in order to recommend what kind of illuminating condition might best improve foreign language learners' optimistic sentiment, create their perfect learning status, and increase their learning efficiency.  
Lighting arrangements can be used to enhance the clarity, relaxation, and pleasantness of a room [12]. In recent years, it has been considered to be an effective method to define the \"pleasing zone\" of lighting environments in terms of the combination of illuminances and color temperatures. The Kruithof curve indicates that combinations at high (low) illuminances and high (low) color temperatures could be pleasing zones [13]. Figure 2 shows the pleasing zone defined by [PERSON]. Feeling comfortable is the primary condition for the ideal classroom lighting environment. This paper assumes that [PERSON]'s pleasing zone is a comfortable classroom lighting environment, and the experiment was conducted based on different combination of illuminances and color temperatures within [PERSON]'s pleasing zone in order to determine a sound classroom lighting environment for foreign language learning.