With an ever increasing demand on blood supplies worldwide, there is an immense need to ensure a safe and sufficient supply of blood products. However, recruiting and retaining blood donors remain key challenges for blood agencies. In an attempt to address these problems, researchers have identified a range of socio-demographic, organizational, physiological, and psychological factors that influence people's willingness to donate blood. While past research has largely focused on donor recruitment, in particular, demographic variables associated with blood donation behavior, the issue of donor retention has become increasingly important. A growing number of studies have also highlighted the role of psychological factors in explaining, predicting, and promoting blood donation behavior. In line with recent trends in blood donation research, the present paper reviews the contributions of, and current directions in, psychological research on blood donation attitudes and behavior, with special emphasis on donor return and repeat blood donation behavior. Although there is overlap between factors that predict the initiation and the maintenance of blood donation behavior, it is suggested that changes in motivation and the development of self-identity as a blood donor are crucial for understanding the processes whereby first-time donors become repeat donors. THE PSYCHOLOGY OF BLOOD DONATION: CURRENT RESEARCH AND FUTURE Following Titmuss 1 , whole blood donation has historically been marketed as "perhaps the purest example" 2 (p. 46) of altruistic or prosocial behavior 3 . The debate as to whether whole blood donation should be characterized as a wholly altruistic act or merely a prosocial act is beyond the scope of this paper, however it is noteworthy that whole blood donation (and apheresis donation in Australia) is a behavior that people undertake voluntarily with few obvious or immediate rewards. As Healy 4 noted in his recent analysis of blood and organ donation, blood is "an odd kind of gift" (p. 84). The method of giving and the personal nature of what is given make it different to other altruistic or prosocial acts such as donating money to charity (cf., 5 ). In an age of increasing stringent exclusion criteria stemming from fears about blood safety (e.g., vCJD), it is a rare type of gift in that it is one that may routinely be refused. As Healy 4 notes the 'call for all' evident historically in much blood donor marketing (cf. ARCBS Winter 2007 campaign) contrasts sharply with the selectivity that blood collection agencies around the world now have to exercise. 6 As a result of such selectivity, blood collection agencies around the world struggle with how to recruit and retain 'life's best gift givers', those eligible to donate blood. In recent decades, a number of excellent reviews have been undertaken to consider both structural (e.g. organizational level factors 4, 7, 8 ) and individual 7,9-11 level factors that may impact on the decision to donate blood. Reflecting the general body of literature in the area, these reviews have typically considered influences across the donation lifespan, whilst noting that there are likely to be differences in the type and strength of the key motivators of new, early career and well-established donors. 7, 10, 12 An emphasis of recent research has been on the role of structural factors in facilitating blood donation. 4, 7, 8, [13] [14] [15] [16] In contrast to this emphasis, the current review primarily focuses on the role of psychological factors in 4 explaining, predicting, and promoting blood donation behavior. Although we agree with Healy 3 that structural features should be configured to maximize the opportunity for donation, we contend that ultimately the resolution to (repeatedly) donate blood remains an inherently personal decision. 17 For the individual who is considering donating blood, it is the perception and relative weighting of many factors that will ultimately determine his or her behavior. 18, 19 In addition to a specific focus on the role of psychological factors in blood donation, Figure 1 ) is a well known behavioral decision making model designed to account for behaviors that are not under an individual's complete volitional control. The TPB is based on the premise that intention is the most proximal determinant of behavior. Intention, in turn, is proposed to be influenced by attitude (positive or negative evaluations of performing the behavior), subjective norm (perceptions of social pressure for performance of the behavior) and perceived behavioral control (perceptions of control over performing the behavior). In addition to the indirect influence on behavior via intention, perceived behavioral control is proposed to have a direct effect on behavior for behaviors that cannot be performed at will. It should be noted that some TPB researchers distinguish clearly between the control constructs of perceived behavioral control and self-efficacy (the perception of the ease or difficulty of performing a behavior 28 ), whereas some do not (for an overview, see 29 ). For the purposes of the current review, these constructs will be termed 6 either control factors or perceived behavioral control (unless a specific reference is made to self-efficacy). When considering our current knowledge of the psychology of repeat blood donation, this review first considers the contribution of studies adopting a basic TPB framework in predicting blood donation intentions and behavior. Next, consistent with our focus on the psychology of repeat blood donation, we draw on the recent TPB literature and donor behavior literature to consider the evidence for the inclusion of a number of additional constructs in the TPB in attempting to account for the factors that influence blood donors' intentions and behavior over their lifespan as donors. Further, using an augmented TPB framework, we document specifically how the influences on blood donors' intention and behavior might evolve over the career path of the donor. Finally, we draw on the TPB and the 8 broader donor behavior literature to understand and reflect on the critical role that perceptions of control have on blood donors' early career intentions and behavior. As one of the most commonly utilized models of attitude-behavior relations, the TPB and its components have been used successfully by many researchers to predict blood donation intentions and behavior. 9 Studies adopting a TPB framework typically use combined samples comprising both blood donors and non-donors. 37 More recently, studies have narrowed their focus to the prediction of blood donation decisions according to stage in the donation career (e.g., 'never' and 'ever' donors; see 38 ); a focus that is crucial as a first step in understanding how first-time blood donors become regular blood donors. 22 As noted by Callero and Piliavin 22 (see also 39 ), the specific type of factors and relative weighting of the factors that influence the decision to donate blood may well be expected to vary according to the number of times an individual has donated blood in the past. As Ferguson and colleagues 9 recently noted, however, there is little consensus in the TPB or broader blood donor behavior literature as to how donors at different stages of their blood donation career should be distinguished and defined. For the purposes of this discussion, we have adopted the terminology of 'mixed sample' to refer to those studies combining donors and non-donors or where donation history of the sample was not reported; 'non-donor' to refer to those who had never donated or where studies identified their sample as non-donors; 'first-time donors' to refer to those identified by the authors to have only donated blood a single time and 'donor' to refer to participants who had donated blood in the past. For this latter group, where more fine-grained delineation of donor samples is provided by the authors, then this is noted. A review of studies using the theory of planned behavior to predict the blood donation intentions and behavior of mixed samples found that the TPB model accounted for between 9 31% and 72% of the variance in blood donation intentions 37, [40] [41] [42] [43] and between 54% and 56% in blood donation behavior. 37, 41 In three studies illustrative of standard TPB research in the area 37, 40, 41 , the influence of attitudes towards blood donation, subjective norms, and perceived behavioral control on current donor and non donor students' blood donation intentions were assessed. In these studies and in line with the TPB, attitude, subjective norm, and perceived behavioral control all significantly predicted intention to donate blood. Other studies assessing the TPB variables in mixed samples and samples differentiated by donation history have shown a less consistent pattern of findings in predicting blood donation intentions. Specifically, attitude and control factors consistently emerge as predictors of blood donation intentions, in samples that are mixed 38, 41, 42 and differentiated by donor history, 26, 38, 43, 44 with the control component consistently demonstrating the largest beta weight of the predictors. The influence of subjective norm on intentions, however, is less consistent (see Table 1 ). For instance, several studies have found subjective norm to contribute significantly to the prediction of blood donation intentions amongst both donors and non-donors 5,43-46 and in mixed samples, 47 yet in other studies, subjective norm had no significant effect. 26, 38, 41, 42 Although much of the TPB blood donation research assesses influences on blood donation intentions, comparatively few TPB studies provide an assessment of blood donation behavior. Of those studies assessing behavior, intention is the only consistent predictor of behavior. 7 Despite its consistent influence, however, the relative strength of intention is impacted on by the number of times a behavior, in this case blood donation, has been performed in the past.  The influence of control on behavior also appears to be a function of blood donation experience. For instance, in two studies utilising mixed samples, 37,41 only intention to donate blood (but not control) predicted reported blood donation behavior. In contrast, in the single study that has considered predictors of behavior at different points in the career of the blood donor, Godin et al. 26 found that perceptions of control over donating were important in the prediction of behavior for donors, but not for those who had only donated a single time (firsttime donors). Across all of these studies, three consistent findings are noteworthy. First, in line with the predictions of the TPB model, intention is the only consistent predictor of behavior. Second, control factors consistently demonstrate the largest beta weight and emerge as significant predictors of intention to donate blood regardless of blood donation experience. The important and consistent influence of control on intention, regardless of donation career stage, suggests that a focus on perceptions of control for both non-donors and donors may be particularly effective in increasing intention to donate blood, a point we return to later in this review (see also   9 ). Third, subjective norm emerged as the weakest predictor of intention for non donors and donors alike. Whilst this finding is consistent with the application of the TPB in a variety of contexts, 18 it is contrary to the emphasis in the wider blood donation literature on the importance of others' expectations and external normative pressure for the initiation of blood donation. 22, 45 Whilst this inconsistency may be due to differences in measurement of the constructs or sampling strategies, it seems more likely that a difference in the conceptualization of social influences on blood donation across studies is the relevant factor. In considering the sufficiency of the TPB, questions have been raised as to whether the basic TPB model accounts adequately for moral beliefs or for affective outcomes (either 11 positive or negative) associated with the performance of some behaviors. 30, 49 In the specific context of blood donation, accounting for moral values and affective outcomes may be particularly important as the decision to donate blood is likely to involve a consideration of moral beliefs and the potentially negative outcomes associated with blood donation (e.g., anxiety or fear) for some people. 28, 38, 49 In attempting to account for factors that influence blood donors' intentions and behavior over their lifespan as donors, additional constructs have been suggested to augment the standard TPB model. Thus, first we turn our attention to two constructs which have been highlighted as particularly relevant to blood donation behavior, namely, moral norm and anticipated regret, followed by a discussion of two factors important to the development of a blood donation career, namely past behavior or habit and self-or role-identity. Moral norm. A number of recent studies 4, 17, 50 have noted the rhetoric of morality that surrounds blood donation. Early career donors report feelings of moral satisfaction at donating whereby donors and non donors alike equate the act of donating blood with moral superiority. 17, 50 In line with the associations between morality and blood donation documented in the broader literature, research undertaken from an extended TPB perspective has found support for the inclusion of a moral component in relation to blood donation. 26, 38, 41, 44 Within the TPB, the concept of moral norm (or personal norm) refers to feelings of personal responsibility or duty to perform a behaviour. reported an increase in attitudes of duty towards giving blood across a 7 year period. As the level of intrinsic motivation increases (e.g., feelings of duty or moral obligation), the influence of external social pressure is expected to decrease. 22 In short, having intrinsic motivations, operationalised in this context as a personal or moral norm, appears of key
Masser et al. REF provide a review and overview of existing research in this area.
The Psychology of Blood Donation : Current Research and Future Directions
Transfusion medicine reviews
Transfusion medicine reviews
Psychology Medicine