A survey was conducted on eight graduate students of A-university (four males and four females in their twenties to fifties) in November 2020. These participants were selected because they are people of various ages.

A questionnaire was conducted in a classroom of the graduate school. The participants took a class about psychological stress model, evaluation of stressful situations (harm/loss, threat, and challenge), and mental and physical stress responses before the participation in the questionnaire. After the class, they were asked to answer the following questions (Table 1) about stress in the form of free description.

Free description acquired from the questionnaire was transcribed and each answer to the above questions was analyzed respectively. The software “KH Coder ( Higuchi, 2016, 2017)” was used for text mining. After morphological analysis was conducted as preprocessing for text data, co-occurrence network and self- organizing maps were performed. The results of the questionnaire were discussed based on the co-occurrence network images and the self-organizing maps made by the above methods.

Figure 1 and Figure 2 show a co-occurrence network image and a self-organizing map created using free-description about “eustress”. In addition, Japanese-English translation for these figures was shown in Table 2. Focusing on the co-occur- rence network image, the stress situations include “match”, “announcement”, and “examination”, and the psychological states at that time include “tension” and “confidence”. In particular, the word “tension” is associated with the word “good”, suggesting that the respondents themselves positively perceive the tension they felt. In the self-organizing map, “announcement” and “tension”, “confidence” and “preparation”, and “result” form the same cluster. The former seems to be a performance in a tense state, and the latter is a group of words related to the process of gaining self-confidence.

Even in a stressful situation, tension as a stress reaction occurs in situations such as sports games, presentation of research results, academic examinations, etc., where one challenges a goal set by oneself. It is thought that moderate tension in the challenging scene brought about positive effects such as improvement

of concentration and led to the performance. In addition, by making sufficient preparations in advance, you can confidently face situations that involve tension such as exams and games. Alternatively, the experience of overcoming difficulties can lead to confidence gain and can be reflected as a good stress experience. From the above, the following two points can be mentioned as the characteristics of the situation where stress brings about good results. The first point is that by challenging one’s own goals, a sense of tension is created in a good way, leading to improved performance. The second point is that the experience of getting into production with sufficient preparation or overcoming difficult situations leads to self-confidence and positively views the stress situation.

Figure 3 and Figure 4 show a co-occurrence network image and a self-organizing map created using free-description about “distress”. In addition, Japanese-English translation for these figures was shown in Table 3. Focusing on the co-occur- rence network image, “work” was mentioned as the word indicating stress status, and “depression”, “anxiety”, “tension”, “calmness”, and “concentration” were mentioned as the words indicating psychological states. In particular, “calm” and “concentrate” were used negatively in the form of “restless” and “unable to concentrate” in the answers. Among the above words, “anxiety” forms a network with many words, and anxiety about whether or not the stress situation faced can be overcome may lead to a negative psychological state. Also, “tension” is associated with the word “mistake”, suggesting that tension causes poor performance in situations where stress has adverse consequences. In the self-orga- nizing map, “anxiety” and “concentration”, “reality”, and “escape” formed the same cluster. From this, it is possible that the anxiety caused by the stress situation reduces concentration and also causes escape behavior.

Among stressful situations, situations that cause anxiety, that is, situations that are perceived as a threat to the parties concerned, are likely to experience a negative psychological state. The tension felt in such a situation can be interpreted as causing

a decrease in performance in that it induces mistakes. Furthermore, anxiety causes behaviors that contrast with the above-mentioned challenge scenes, such as escape behaviors, and can be said to be emotions that characterize bad stress.

Figure 5 and Figure 6 show a co-occurrence network image and a self-organizing map created using free description regarding stress that is felt as a threat. In addition, Japanese-English translation for these figures was shown in Table 4.

Focusing on the co-occurrence network image and the self-organizing map, “escape” was mentioned as a word to indicate behavior in situations where “threat” was felt, and “moody” was mentioned as a word to indicate psychological state. As mentioned above, escape behavior is also seen in situations where stress has adverse consequences and is considered to be anxiety-induced behavior. The rating for stress situations is said to be “challenge” if you are confident that you can overcome the obstacles and difficulties you are facing, and “threat” if you feel down ( Lazarus, 1999). In a situation where you feel a “threat”, you may not be confident in overcoming obstacles and difficulties, so you may easily fall into escape behavior with anxiety. “Grumpy” is a psychological state that is measured as a type of stress response along with anger. Even in stressful situations, situations rated as “threat” are characterized by negative emotions ( Lazarus & Folkman, 1984), which is consistent with the findings of previous studies.

Figure 7 and Figure 8 show the co-occurrence network image and the self-orga-

nizing map created using the free description regarding the stress felt as a challenge. In addition, Japanese-English translation for these figures was shown in Table 5. Focusing on the co-occurrence network image and the self-organizing map, it is characteristic that the words “solution” and “cause” are linked to “stress” and form the same cluster.

In situations that feel “challenge,” you become more motivated to solve the problems you are facing and focus on the problems that are causing stress. In this way, it is presumed that the selection of positive problem-focused coping is a characteristic of stress situations that are felt as “challenge”.

Figure 9 and Figure 10 show the co-occurrence network image and the self-

organization map created using the free description regarding the transformation of the evaluation for stress. In addition, Japanese-English translation for these figures was shown in Table 6. Focusing on the co-occurrence network image and the self-organizing map, the words “stress” and “problem”, “solution”, “cause”, and “feeling” are linked to each other to form the same cluster. Focusing on problem solving and trying to eliminate the cause are common to thinking and actions in situations that feel “challenge.” Furthermore, if a situation that was felt as a “threat” becomes a “challenge,” it is suggested that there is a change in feelings. In the free description to Question 5 (Change of evaluation of stress), there are many descriptions about positive psychological transformation, such as reducing stress as the problem is solved, feeling “I can do it”, and positively grasping the situation I am facing. In addition, some respondents cited the support of those around them, such as consulting with others and having them listen to them, as a trigger for the above-mentioned transformation. These behaviors can also be interpreted as being related to the “tend-and-befriend response ( Taylor et al., 2000)”, which increases the desire to connect with people under stressful conditions. The experience of gaining support and experiencing connections through relationships with those around us increases confidence in overcoming the obstacles and dangers people face and makes stress situations a “challenge” ( Lazarus, 1999). It is suggested that it may be a contributing factor.