Keywords

1 Theoretical Background

Leukemia includes cancers of the hematopoietic and lymphatic systems. The only curative treatment for leukemia is stem cell transplantation. However, there is still a high demand for new and fitting donors. A healthy and tissue-compatible donor is required for stem cell donation. Despite around 80% of patients being able to find a close match, the demand for new donors is still very high (Hochhaus et al., 2004; ZKRD, 2018, 2021).

In order to explain why some people decide themselves to become donors or not, the Theory of Planned Behavior (TPB) can be used (Ajzen, 2005). TPB assumes that the proximal cause of behavior is one’s intention to adopt the action in question. Intention can be defined as an indicator of how hard a person is willing to try in order to perform a given behavior (Frey et al., 2001). Therefore, intention includes motivational factors. Intention is influenced by three determinants (Fig. 13.1), which are attitudes towards the behavior, subjective norms and perceived behavioral control (Eagly & Chaiken, 1993). The attitudes are defined as affective evaluations which show how likely or unlikely an individual is to perform the behavior in question. Subjective norms represent a person’s belief that significant others (people whose opinion is valued as important) think that they should adopt a certain behavior. It represents the social pressures on individuals regarding the performance of a given behavior. Finally, perceived behavioral control can be defined as the individual’s perception of how easy or difficult the performance of behavior is (Ajzen, 1991; Ajzen & Fishbein, 2002). According to the TPB, it can be assumed that the more positive the attitudes, subjective norm and perceived behavioral control, the stronger the intention should be and thus the more likely the conduct of the behavior (Ajzen, 2005). These three determinants of intention can be traced to specific sets of beliefs, referred to as behavioral beliefs, normative beliefs and control beliefs (Fig. 13.1): “These beliefs provide us with insight into the underlying cognitive foundation of the behavior, i.e., they tell us why people hold certain attitudes, subjective norms, and perceptions of behavioral control and, therefore, why they intend to perform the behavior in question” (Ajzen, 2005, p. 137).

Fig. 13.1
A model has 3 elements, control, normative, and behavioral beliefs. They have 2 sub elements each including perceived facilitations, norms, and belief strength in order. They result in perceived behavioral control, subjective norm, and attitudes, further resulting in intention and behavior.

TPB-model. (Based on Ajzen, 2005)

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According to the TPB, changing behavior requires changing or modifying these underlying beliefs using the fact that beliefs are the fundamental determinants of any behavior.

Ajzen (2011) has admitted the potential for other constructs to be added to the TPB to enhance its prediction of intention or behavior. As an example, studies on blood donation have identified that three variables are particularly influential in intention prediction, namely knowledge (Holdershaw et al., 2007), moral obligation (Schwartz & Howard, 1981) and self-identity (Conner & Armitage, 1998). These findings have been partially confirmed by a further empirical investigation in the context of this study: In order to identify influential predictors of intention to register as a stem cell donor, a regression analysis was performed. It became clear that above all, knowledge and moral obligation are factors that determine intention (for more detailed information, see Holzer & Elster, 2021).

Furthermore, in this study two further variables, namely empathy and moral reasoning, are investigated, as they are positively related to pro-social behavior (see e.g. studies of Bierhoff, 2010; Emler & Rushton, 1974; Krebs & Rosenwald, 1977; Demir & Kumkale, 2013). These five variables are presented in more detail below.

Moral obligation can be described as an individual’s perception of the moral correctness or incorrectness of performing a behavior and represented as “feelings of personal responsibility or duty to perform a behavior” (Ajzen, 1991, p. 199; Schwartz & Howard, 1981). Self-identity is a construct that reflects the different identities of a person. In the context of stem cell donation in this study, this construct reflects the extent to which a person considers themselves as a helper (self-identity as a helper) (Stryker, 1968, 1997). Moral reasoning involves cognitive processes in which action decisions are made based on moral considerations (Richardson, 2018). Such decisions are not under the influence of individual moral standards (what individuals prefer to do), but are governed by what is expected of them in the face of moral standards. Empathy has been extensively studied in social psychology. The perception of someone else’s need or suffering tends to create emotional distress in the viewer. The experience of this arousal is called empathy, and it is believed that it comes from a learned or acquired or genetic competence to look at events from the perspective of those to whom one feels similarly (Schwartz, 1977).

The present study not only expands the norm component by additionally considering moral obligation and the variable self-identity, but also examines knowledge regarding stem cell donation and leukemia. For example, Feeley (2007) found from the analysis of about 27 studies that students have an insufficient level of knowledge regarding tissue and organ donation. However, research shows that knowledge is positively related to other key factors, such as attitudes and intention (Bilgel et al., 2006; Horton & Horton, 1991; Morgan & Miller, 2002; Rubens et al., 1998). Kaiser and Frick (2002) and Kaiser and Fuhrer (2003) distinguish three forms of knowledge, namely system knowledge, action-related knowledge and effectiveness knowledge. Even if the differentiation of the three dimensions of knowledge could not always be confirmed empirically (cf. Kaiser & Frick, 2002), the differentiation on the theoretical level nevertheless appears to be meaningful. System knowledge is comparable to the constructs of conceptual and situational knowledge (Zeyer, 2012). Action-related knowledge comprises knowledge about possible options for action and provides an assessment of whether corresponding actions can be carried out and with which “costs” they are associated (Frick et al., 2004). The third form of knowledge is effectiveness knowledge, which indicates how effective an action option can be, and whether it is ultimately profitable to bear the costs associated with performing the action (Kaiser & Fuhrer, 2003). Therefore, effectiveness knowledge describes the potential of a certain action or the relative potential of different actions (Kaiser & Frick, 2002). It has been empirically shown that system knowledge predicts action-related knowledge and effectiveness knowledge, whereby action-related knowledge predicts effectiveness knowledge and the last two types of knowledge finally predict behavior (Frick et al., 2004).

Since the presented constructs (moral obligation, moral reasoning, knowledge, self-identity, empathy) turned out to be useful extensions of the TPB, especially in the context of blood and organ donation, according to the results of the literature research, they are also examined in this study alongside the classic constructs of the TPB. Within this study, such an extended TPB is named as the TPB+ model.

2 Research Design and Methodology

According to TPB, anything that changes beliefs in the appropriate direction will increase the likelihood of behavioral change. However, also focusing on predictive factors of intention regarding stem cell donation can affect behavioral change positively (Ajzen, 2006). For this purpose, the overall objective of this study is to investigate changes of factors of the extended version of TPB (including the model-external variables moral obligation, self-identity as helper, knowledge, empathy, moral reasoning) among a sample of students.

A questionnaire was distributed before and after the teaching unit “Wake up” to the student sample (age ø: 17.14; n = 48♀/n = 46 ♂). The sample was split by the median of “intention”, which was 4.0 on the 7-point Likert scale. All students with “intention” equal or lower than 4.0 were defined as non-intenders (persons with low level of intention) and all students with higher values than 4.0 in their intention were defined as intenders (persons with high level of intention to act as a donor). All of them participated as students in the teaching unit “Wake up”. T-tests were performed to assess post-intervention changes in the measured constructs. This is a so-called “paired t-test”, since the changes were tested among intenders and non-intenders.

The same questionnaire was used in the pre- and post-test. Measurement of TPB (Table 13.1) follows closely the guidelines recommended by Ajzen (2005). Thereby, the TPB constructs were formulated by the authors, but the correspondence principle (degree of specificity of the items) according to Ajzen (2005) was observed in the formulation of the items, as well as the 7-point Likert scales. When looking at the beliefs, Ajzen (2005) distinguishes between the expectation component, i.e., the expectation or probability that a certain belief can become true, and the evaluation component, i.e., the evaluation of this belief. Both components have to be multiplied together and product terms have to be formed and interpreted in the course of the data analysis (Ajzen, 2005). Therefore, product terms are also obtained in this study. Thus, in Table 13.1 belief-based-constructs of TPB are product terms (expectation component × evaluation component). Regarding behavioral beliefs, the present study distinguishes between belief-based positive attitudes (positive behavioral beliefs) and belief-based negative attitudes (negative behavioral beliefs) based on the empirical investigation.

Table 13.1 Factors and examples of TPB, and model external variables and the reliability of scales
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Table 13.1 provides an overview of the TPB variables, model external variables, Cronbach’s alpha values of scales, and examples of items. The construct knowledge includes two forms of knowledge, namely system knowledge and action-related knowledge. Due to time limitations, effectiveness knowledge was not assessed in the questionnaire. System knowledge comprises knowledge about normal blood formation on the one hand, and knowledge about its malfunction, which is discussed in this study in the context of leukemia, on the other hand. Action-related knowledge includes relevant knowledge that is important for the action or registration as a stem cell donor or for stem cell donation. It should be emphasized that system knowledge and action-related knowledge are not considered separately, but under one construct, since the constructs were not empirically confirmed as separate constructs in this study. In Table 13.1, the knowledge that was collected using open and closed questions is considered separately in order to clearly present the calculated quality criteria. However, closed and open knowledge questions measure both types of knowledge, namely system knowledge and action-related knowledge. With regard to the open and closed knowledge questions, it should be mentioned that while the closed knowledge questions were coded with 0 (if wrong answer) and 1 (if right answer), the open knowledge questions were analyzed using scaling structuring based on the qualitative content analysis (Mayring, 2015). Different points were assigned depending on the different characteristics of an answer. To ensure objectivity, 25% of the data was coded by another coder and a Cohen’s Kappa was calculated (Table 13.1).

3 Teaching Unit “Wake Up: Sensitization for Stem Cell Donation”

During the 5-h-long intervention “Wake up”, the students gathered information and participated in discussions relevant to leukemia and stem cell donation. Table 13.2 summarizes the schedule and topics of the teaching intervention “Wake up”, as well as all promoted constructs of TPB+.

Table 13.2 Teaching unit “wake up”
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The teaching unit “Wake up” comprises three teaching phases, namely the introductory phase (confrontation with the problem), the elaboration phase and the evaluation phase (Table 13.2). The “problem” – personified by the figure of the adolescent, Jonas, who is diagnosed with leukemia – is presented immediately after the short introduction “Stem cells are special cells”. The students are then asked to write down possible questions that a 17-year-old boy might ask himself. In the following elaboration phase, Jonas’s questions are answered. The elaboration phase is divided into four stations, in which the clinical picture of leukemia is treated (station 1) and the aspects of stem cell donation are elaborated (station 2–4). In the evaluation phase, the central results of the teaching unit are discussed, as well as different points of view regarding stem cell donation. In the course of the intervention, not only are many misconceptions and beliefs regarding stem cell donation and leukemia discussed, but also normative and moral aspects are reflected (Table 13.2). In addition, it should be noted that the intention to become a stem cell donor is not directly promoted by the “Wake-up” teaching unit, but, above all, is indirectly influenced by reflective discussions in the final evaluation phase. The goal of the teaching is to raise awareness about the problems experienced by people with leukemia. It is important to emphasize that there is no intention to exert any influence on the participants in either direction.

4 Findings

In order to analyze the changes in all assessed TPB+ factors after the intervention, especially among intender and non–intenders, t-tests were performed. While positive attitude-related beliefs and normative beliefs remain stable on the level of “whole sample” in the post-test (Table 13.3), negative attitude-related beliefs decrease and control beliefs increase significantly in the post-test. In the following, the results regarding belief-based negative attitude and belief-based perceived behavioral control are reported by taking a closer look at beliefs among intenders and non-intenders. Negative belief-based attitudes include beliefs such as fear of pain and damage to health when stem cells are donated. In addition, there is a belief regarding the state of health, which reflects the perception of whether this is considered suitable for carrying out a stem cell donation. The last one expressed the level of trust in the medical system in the field of stem cell donation (Table 13.4). It can be concluded that all negative attitude-related beliefs significantly decrease in the post-test, especially with higher effect sizes among non-intenders (Table 13.4).

Table 13.3 Results of the t-test: changes in TPB-factors in whole sample (n = 94)
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Table 13.4 Results of the t-tests: changes in negative attitude-related beliefs in subgroups
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After the intervention, it was observed that among the control beliefs, three out of the six assessed beliefs underwent changes (see Table 13.1). The belief “perception of effort” describes if students perceive effort regarding stem cell donation. “Awareness of opportunity” shows if participants see an opportunity in their daily life to register as a stem cell donor and donate their cells. The last belief “time consuming” expresses if students perceive the process of registration and the donation process as time consuming. There are increases, for example, among non-intenders in some control beliefs: “no perception of effort”, “awareness of opportunity”, as well as in “not time consuming” (Table 13.5).

Table 13.5 Results of the t-tests: changes in control beliefs in subgroups
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The results of the t-test (n = 93) demonstrate that the intention after the intervention increases significantly (M = 3.68pre /4.47post; Table 13.3). More specifically, the intention in the non-intenders group (M = 2.68pre /3.87post; p = .000, d = .904) increases significantly in the post-test, while it remains stable in the intenders group (M = 5.28pre/5.42post; p = .388). There are also changes in the number of non-intenders and intenders after the intervention (Fig. 13.2): 26 non-intenders show higher values after the intervention (>4.0) in their intention than in the pre-test; therefore they become intenders. Only 5 intenders move after intervention to non-intenders, which means that their value of intention decreases (1.00 to ≤4.0).

Fig. 13.2
A bar graph of the distribution of non-intenders and intenders pretest with a total of 57 and 36, respectively. Non-intenders to non-intenders and intenders to intenders top with 31, followed by non-intenders to intenders with 26, and intenders to non-intenders with 5, in order.

Numbers of intenders and non-intenders after Wake-up-intervention

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Focusing on post-changes, it can be summarized that in the non-intenders subgroup, the moral obligation (while among intenders there were increases in moral reasoning instead of in moral obligation) and self-identity helper increase significantly in the post-test (Table 13.6). There is also a significant increase in knowledge in both groups (Table 13.7). The effect sizes range from r = 0.545 to 0.609, which are interpreted as strong effects according to Cohen (1988) (Table 13.7). There is no significant change in empathy, but it shows high values already in the pre-test (Table 13.6).

Table 13.6 Results of the t-tests: changes in model-external factors among subgroups
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Table 13.7 Wilcoxon-test: changes in knowledge (K) among subgroups
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5 Discussion and Conclusion

While positive attitudes do not change significantly after the intervention in the whole sample – as they are already very high – negative attitudes show significant decreases. The negative attitudes show significant decreases among intenders and non-intenders, although these increases occur slightly more among non-intenders (Table 13.4). It can be concluded that “fear of pain” decreases significantly in the post-test. Furthermore, the students think that the donation process is “less harmful to health” and they perceive “health status” as more appropriate for stem cell donation after the intervention. They also show a higher degree of “trust in the medical system”. These results clearly show that the intervention has a positive effect, especially on negative attitudes, but to varying degrees depending on the subgroup. Above all, negative behavioral beliefs, such as fears, are reduced during the elaboration phase of the intervention (Table 13.2) by specific tasks and the acquisition of knowledge.

It can be summed up that there is a significant change in some control beliefs in the post-test: The students (intenders/non-intenders) perceive “less effort in performance of behavior”, they are “more aware of opportunities for registration as a stem cell donor”, and they are more aware that the registration and donation processes do “not consume a lot of time”. It can be summarized that the significant increases within the subgroups after the intervention (Table 13.5) can be attributed to the effectiveness of the intervention. The control beliefs were also specifically addressed in the elaboration phase (Table 13.2), primarily through text work, as well as video material. Behavioral beliefs and control beliefs were also discussed and doubts clarified in the plenary session during the evaluation phase.

Students, especially non-intenders, show a significantly higher intention with regard to the registration as a stem cell donor after the intervention. When looking at the two subgroups, it becomes clear that the intenders’ intention is already high in the pre-test and remains stable in the post-test. 26 students, which were characterized as non-intenders before intervention, change their status to intenders, because of a significant increase in their intention regarding stem cell donation, which reflects a positive effect of the teaching unit.

Taking a closer look at model-external factors, such as moral obligation, self-identity, moral reasoning, empathy, as well as knowledge, which especially in the context of blood donation and in the context of prosocial behavior proved to be influential factors of intention, it can be summarized that some of them show lower values before the teaching unit. However, this changes after the intervention. After the intervention, the constructs self-identity helper and knowledge increase significantly in both groups (Tables 13.6 and 13.7). While a significant increase in moral obligation is observed among non-intenders, a significant increase in the moral reasoning construct is observed only in the intenders group. These findings demonstrate impressively that the intervention addresses both groups (albeit in slightly different ways) regarding internal and external model factors. Furthermore, these results show that it is important to take into account and promote influential factors of intention regarding stem cell donation. While knowledge (regarding stem cell donation und leukemia) and empathy were promoted throughout all phases of the teaching intervention, through text material and specific tasks (Table 13.2), moral reasoning, moral obligation, and self-identity were targeted mainly in the elaboration phase and in the evaluation phase (Table 13.2).

While moral obligation, moral reasoning, knowledge regarding leukemia and stem cell donation and self-identity change after the intervention, empathy remains stable. This finding could possibly be explained by the fact that empathy already had a very high level in the pre-test (mean value <5.0 measured on the 7-point Likert scale) and therefore did not increase after the intervention. In order to promote empathy, activities focusing on perspective taking are used. In further studies, other activities and methods, like “role playing” can be tested and reflected regarding their effectiveness in promoting empathy.

Significant changes in TPB+ factors can be attributed to the positive effectiveness of the “Wake up” intervention, as already indicated. However, the significant increases in the measured constructs could also be attributed to sources other than the intervention. It is therefore advisable for further studies to survey a control group (without intervention) in addition to the intervention group.

Negative beliefs, as well as misconceptions regarding the topic, could be reduced by the “Wake up” teaching unit and most constructs of TPB could be fostered and promoted. Thus, the TPB+ model proves to be a successful decision-making model in the context of health education and should be tested in other contexts, such as organ donation.

What about the actual behavior regarding the registration as a stem cell donor? This question can be answered only in terms of measured intention, as behavior or actual registration as a stem cell donor was not captured in this study. Since many model-internal as well as model-external factors of the TPB+ increase after the intervention, as well as the intention, it can be concluded with regard to behavior that this becomes more likely or that the gap between intention and behavior is reduced. In other words, the higher the intention, the more probable the actual performance of behavior (Ajzen, 2005). However, further studies are needed, which also measure behavior in order to verify this theoretical assumption.

Regarding TPB-based intervention, it can be concluded that it can act as a possible instructional design tool to assist teachers in structuring and planning their teaching units. Biology teachers should be the key players in the promotion of cancer education (Barros et al., 2016), but their intention to teach such a complex interdisciplinary health topic is low and based on the emotional nature of topic (Carey, 1992). Furthermore, Heuckmann et al. (2020) pointed out that teachers’ fear of the emotional reactions of students strongly contributed to the perceived burden of teaching the subject of cancer. Therefore, TPB-based interventions in the classroom are necessary in order to make a complex subject easier to talk about. In this way, the teaching unit “Wake up” provides teachers with support on how to deal with the topic of cancer in the classroom, using the example of leukemia and stem cell donation.