The GIM (Seyd and Whiteley 1992; Whiteley and Seyd 1996, 2002) states that activism is a result of both the incentives that participation in YPO activities offer to individuals, as well as the effect of other socio-psychological factors. Regarding incentives, previous research has suggested that they might play an important role (Brutter and Harrison 2009). The GIM includes those incentives considered by rational choice models, namely collective benefits derived from political participation, personal costs of participating and selective incentives (that is, benefits that the individual enjoys independently of achieving the collective goals). Here, Seyd and Whiteley (1992) distinguish between outcome incentives (selective material incentives associated with benefits individuals obtain from participating, such as offices or career opportunities), process incentives (benefits obtained from participation itself, such as meeting like-minded people or just having fun) and ideological incentives, this being a particular kind of process incentive, where individuals feel rewarded by the mere pursuit of their personal ideas. In the case of YPOs, and following the logic of the collective action derived from rational choice assumptions, selective incentives would be crucial in explaining members’ activism.

In addition to this rational choice baseline, the GIM model also includes a number of socio-psychological factors influencing individual activism. First, there is the sentiment of personal efficacy, that is, believing that one’s participation can make a difference in the organisation. This is a long-recognised factor explaining participation in collective action (Pateman 1970; Moe 1980). Second, we also add a feeling of group efficacy (Whiteley and Seyd 2002; Smith et al. 2021), that is, believing that collective action through the YPO will produce positive outcomes. Finally, in some studies non-rational motivations have been added to these factors, such as expressing sentiments of attachment or adhering to a social norm (Seyd and Whiteley 1992; Gallagher et al. 2002; Alarcón 2021), although in other works both these factors remain within the SPM model (Whiteley and Seyd, 1996 2002). In this study, they have been included within the SPM model, under a pragmatic approach.

This is probably the best known and utilised among the different theoretical approaches to political participation (Verba and Nie 1972; Milbrath and Goel 1977; Verba et al. 1978, 1995). Starting from the observation that political behaviour is not evenly distributed across social groups, the model has emphasised the importance of resources associated with an individual’s social position to explain their political participation.

Social status, educational level, income and time are the four basic resources considered in the CVM. Jointly or separately, they are positively correlated with electoral participation (Rosenstone and Hansen 1993; Blais et al. 2004) as well as with other forms of political engagement (Verba et al. 1995; Nie et al. 1996; Pedersen et al. 2004; Whiteley et al. 2011). They act through psychological mechanisms, fostering individuals’ material and cognitive interests (civic skills) in the functioning of the political community, as well as a normative commitment (particularly in the case of education).

In line with this literature, we expect educational level and social status to influence positively activism within YPOs (Verba et al.1993). Regarding income, we think it is not as important as the other two factors when considering YPO members. Since many of them are at the beginning of their professional careers or have not started them yet, and their income still significantly depends on the support of parents or relatives, income is probably greatly determined by social status.

With respect to the fourth resource, time, we expect that its impact on YPO members’ activism relates to a certain life cycle effect. Though some forms of political participation increase with age (Quintelier 2007), for activities implying a high participative intensity it is likely that the adult-life obligations (professional or family-related) may constitute a limitation. So, as free time may imply a higher level of activism among YPO members, we must also consider the impact of life cycle dynamics.

Verba et al. (1978) also distinguish between individual and group resources. The absence of individual resources can be compensated for by the development of group resources that originate in their membership or contact with social and associative networks such as political parties, unions, associations or informal groups. These networks may also trigger psychological, cognitive and normative mechanisms inducing party activism.. For instance, having relatives in political parties increases formal and informal knowledge about the structure of political parties and can stimulate party activism (Recchi 1998; Cross and Young 2008a). In YPOs these external supporting networks are formed by friends and relatives, as well as fellow participants in other associations.

Finally, as we have mentioned above, in the CVM these structural factors influence individual behaviour through psychological mechanisms promoting political participation, particularly the development of civic interests and skills. The CVM includes variables such as the sense of political efficacy or psychological commitment to politics (Verba et al. 1995). Regarding YPO members’ activism, we expect that these mediating variables have also a relevant explanatory role in this model.

The social-psychological approach model is grounded on Fishbein and Ajzen’s work on the theory of reasoned action (Ajzen and Fishbein 1980) and the theory of planned behaviour (Ajzen 1991), which helps explain behaviour by focusing on attitudes towards specific types of behaviour.

The SPM describes the relationship between beliefs and attitudes by assuming that attitudes have a direct influence on behaviour (in this case, party activism). Therefore, the individual assessments about a certain object predisposes people to carry out certain actions with regard to this object. Two main factors affect political behaviour according to the SPM (Whiteley and Seyd 1996, 2002): expected benefits and social norms. Expected benefits are understood as the benefits reported by the course of actions. Individuals are considered as utilitarian people who calculate the benefit of each type of participation. Thus, YPO members will participate if they consider that the different activities YPOs promote will bring some benefit (either individual or social).

In turn, social norms are determined by the context of the individual, largely influenced by culture and societal beliefs. We consider two kinds of norms: internal and external. The former refer to internalised values, so that a person will participate in a YPO if they believe that the political action is normatively justified. Regarding external norms, societal beliefs are determined by attitudes of other people whose opinions have influence on the individual’s values. Therefore, if relatives, friends or other people an individual has a close relationship with value positively political participation, individuals will be more motivated to be active in YPOs. The underlying idea is that people will participate in politics because they want to be accepted or integrated.

The SPM was completed with the introduction of two additional elements - personal political efficacy and an affective factor related to normative support for the organisation. The affective factor calibrates the emotional union of the subject with the YPO, and it should have an important influence on party membership. Therefore, higher levels of activism may depend on the extent to which an individual identifies with the YPO.

We test these models using data from a survey on members of the youth sections of Spanish political parties. Fieldwork was carried out between April and November 2016, using an online questionnaire in a self-administered format. The link to the questionnaire was sent by email with the assistance and collaboration of the staff of the youth sections. The total used sample size was 2144 people, belonging to the youth sections of Spanish political parties represented in Parliament. The online supplementary information provides additional details on the survey and the sample ¹ .

The activism of YPO members was measured through their participation in different types of activities in the organisation in the last twelve months: payment of fees ² ; donating money to the political organisation; participation in activities of the youth section (events, collecting signatures, parties, demonstrations, etc.); voluntary party work (unpaid); and recruiting members. In addition, the questionnaire asked if they had held any executive position in the structure of the youth organisation. This repertoire of activities follows previous works about activities of party members (Seyd and Whiteley 1992; Whiteley and Seyd, 1996, 2002; Cross and Young 2008a, 2008b; Van Haute and Gauja 2015; Scarrow 2015). The different modalities can be divided into two groups, depending on the energy and resources individuals must invest in them. Membership fees and donating money are passive modalities of activism, as they do not require interaction with other members nor any significant time investment. The other four modalities imply a substantive energy investment on the part of the YPO member. For instance, voluntary work implies renouncing leisure time, and in some cases, attendance to events involves an economic cost (Webb et al. 2020). Internal party office is deemed to be a ‘high-intensive’ activism form (Whiteley and Seyd 2002:62). An executive committee is necessary in order to ensure the youth section survives and functions effectively. Members occupying or having held a party office position in the youth section have more responsibilities in the youth section and are also expected, at least in theory, to spend a great deal of time on and be active in the youth section. In sum, passive modalities of activism are related to the definition of party membership while the other four activities are related to party activism ³ . Both kinds of activism - economic activism and active party activities - have been considered as dependent variables used to test alternative models of political participation.

Table 1 shows different rates of participation in the seven samples of YPO in the six party activities examined. The variability in the responses ranges between 18 in participation in activities and 58 points of difference in party fees, with some differences being significant. The number of those who reported involvement in at least one of the three active modalities (participation in activities, voluntary work and recruitment of young people) represented over the half of the members of each youth sections. On the other hand, both passive modalities of activism show more pronounced differences between members of YPO. This is due, on the one hand, to the different individual profiles of members that we can find within youth sections, and on the other hand, that young people under 18 years of age are exempt from paying membership fees. An additional reason could be that political parties, in view of retaining members, were not very strict in controlling membership fees. In the case of the PSOE, Méndez (2000: 228) points out that at the end of the 90s, only 67% of the affiliates were up to date with the payment of the fees and only between 30 and 35% of the affiliates declared carrying out other types of internal activities. The data show that members of both Catalan non-state-wide parties - JERC and JNC - provide a high level of economic support to their parent political party or the corresponding youth section, either by paying fees or through donating money. In contrast, lower levels of economic support are to be found among members of NNGG.

In the analysis, we will model these two types of activism separately. Economic activism is operationalised through a dichotomic variable, where 1 means paying fees and/or donating money to the YPO (range 0-1, mean = 0,75; Standard deviation = 0,431); and active modalities of activism an additive intensity scale (range 0-4; mean = 2,93; Standard deviation = 1,155).

To test the different theoretical models, we have three blocks of independent variables, one for each model, plus a number of control variables related to the sociodemographic characteristics. We briefly introduce here the variables associated with each model, while the details about their operationalisations and the main descriptive statistics can be found in the online supplementary material to this article.

The analyses testing the GIM include variables measuring both individual and group political efficacy. Here, we must point out the generalised high perceptions among YPO members in these two variables. The GIM also includes variables measuring the respondents’ perceptions about the collective benefits and the costs associated with participation in YPOs. Regarding collective benefits, instead of benefits linked to the policies each party promotes, we focus on collective benefits for the entire community produced by political parties, such as a better working of democratic institutions (Pattie et al. 2004). The variable measuring the outcome incentives is a scale measuring the extent to which individuals are predisposed to following a political vocation (Alarcón and Trujillo 2020). Finally, the GIM also includes two measures for process and ideological incentives.

In turn, the CVM includes variables measuring respondents’ resources. We consider educational level and social status, together with free time. The latter is necessary for participating in active modalities of political activism (though not in the case of paying fees or donating money). This theoretical model also includes two variables measuring civic interests and skills. The first one is the self-perception of political efficacy (also included in the GIM). The second variable measuring civic interests refers to the respondents’ perception of political participation as a civic duty. Finally, the CVM also considers the importance of individuals’ networks as a factor influencing political participation (Verba et al. 1995). Here, we consider different indicators of respondents’ involvement networks that could favour their participation in the YPO: membership in other associations, having party members in the family and being recruited by a friend, a relative or a classmate.

The variables included in the SPM refer to the expected benefits individuals associate with different courses of action, as well as to external social norms (the normative perceptions of participation in political parties). It also includes the indicator of individual political efficacy and a measure of expressive attachment or identification to the YPO.

Finally, we include in our models a number of control variables related to sociodemographic features in the respondents. The literature on political participation has demonstrated their influence in party activism (Rainsford 2017; Alarcón 2021). For instance, studies suggest different patterns of political participation between young and old people and indicate that certain forms of political participation increases with age, especially when young people are fully incorporated into adult life (Quintelier 2007). Although in the case of party activism, the opposite phenomenon may be observed, due to adult life obligations. Entering into adult life implies certain obligations that may constitute limitations to party activism. Apart from age, in the models we also control for other life cycle variables that reflect those adult life obligations, such as living together with one’s partner, or having children. Finally, we also consider the possible differential effect of gender.

This section presents the results of the statistical analysis. The tables in this section show the results of the tests of the models for each theoretical framework: GIM (1), CVM (2) and, SPM (3) and, a full model with all the variables (4). Table 2 presents the logistic regression models for the first dependent variable (economic activism). In turn, for the active modalities of activism, we have resorted to OLS regression (Table 3). All these models also include a block of dummy variables for each YPOs (NNGG as reference category), aimed at controlling the fixed effects inherent to each political organisation.

In Table 2 we observe that the explanatory power of each model on economic activism is quite similar (i.e. the Nagelkerke’s R2 statistic ranges from 36,5% to 37,2%). The amount of explained variance in the full model (4) is still low (Nagelkerke’s R2 = 0.41) given the considerable number of variables entered. In terms of parsimony, the socio-psychological model, only comprising four variables, has the best fit.

In passive modalities of activism, several variables in the GIM present statistically significant coefficients. Members of YPOs with a higher sense of political group efficacy are more likely to support the youth section or political party through the payment of membership fees and the donation of money. Also, economic activism is more likely the higher the perception of participation costs and with lower levels of process incentives - that is when respondents do not find political participation as something fun or an environment to socialise in. In contrast, economic activism is more likely to be found among more extremist members. Finally, individual political efficacy does not have any significant impact on economic activism.

The second model evaluates the civic voluntarism model for economic activism. First, the expectation that those with a higher educational level have passive activism is not verified. It should be noted that the educational level variable includes the last completed educational qualification, so the higher levels correspond to a higher biological age. This result is not in line with the literature on political participation and party membership, where it is pointed out that the oldest people present higher levels of activism. In contrast, free time has a significant effect on economic activism. The negative, significant coefficient in this variable corroborates the theoretical expectation that those who economically support their party do not need free time. On the contrary, members of the YPO with allegedly less free time (because they are in the labour market) seem to show higher probability of staying up-to-date on membership fees and donate money. Moreover, we find significant effects of associationism on party activism, both economic and active activities (Tables 2 and 3). The data validate the expectation about the implications that participation in civil society organisations boost party activism. Both analyses indicate that those young people who participate in a greater number of associations before joining the YPO are also more active in youth sections. Such importance emerges in the analysis of the CVM model and the full model (4) in Table 2. Regarding the way individuals are recruited, it does not have a significant effect on economic party activities. There is no significant difference between those who join the organisation at their own initiative and those recruited through other types of networks (friends, relatives or classmates).

In the model evaluating the SPM in Table 2, members who felt that they were very strong supporters were more likely to pay membership fees and donate money. The emotional attachment to the youth section seems to be a strong predictor of economic activism. Expected benefits have also a positive and significant impact on economic activism. If members of youth sections in political parties perceive the fact that a particular method of participation is effective or influential for their party goals, they are more likely pay party fees. Finally, and in contrast to expectation, social norms do not have an impact on economic activism.

Concerning the control variables included in the models in Table 2, age of membership and being under 18 years old have significant, negative coefficients in all models. People who became a YPO member younger were more likely to pay fees than members who be engaged in a more advanced age. A possible explanation for this patter is that those who arrived younger and are still on the YPO have had to renew their membership or support for the youth section every year. However, when the individual is a minor (under Spanish legal age to membership - 18 years old), their involvement is not full due to that fact that they may not be able to afford the necessary economic resources.

As we expected, gender has an effect on economic activism, but is only significant in the SPM and the full models. Among men, it is more likely to find members who support economically the YPOs, and - as we can see in Table 3 - participate more in party life than women do. Finally, in contrast to previous expectations, members of YPOs who are in couple are more likely to be economically active; the impact of this variable is positive in the CVM the SPM models.

As in economic activism, when accounting for participation in other party activities (Table 3), the SPM is the most parsimonious model and its explanatory power is substantially higher the civic voluntarism and the general incentive models. Also, the explanatory gain of the full model (4) in terms of the R2 statistic is low. Thus, the expected benefits of partisan activities and the affective factor of partisanship have an impact on conducting activities within the youth section. Members with high levels of party identification with the YPO or the parent party are more likely show higher levels of participation in party activities. Also, greater expected benefits of active participation makes participation more likely.

As in economic activism, in the general incentives model group political efficacy and a more intense prcption of collective benefits have a positive impact on participation in party activities. Selective outcome incentives have also a significant effect on party activities, suggesting that party members are motivated by vocational engagement: members that think of politics as a part of their calling are clearly far more active - in the line of expectation for ‘professional-minded’ members (Bruter and Harrison 2009; Weber 2020). Moreover, the positve, significant coefficient in ideological incentives shows that current extremist members are more motivated to participate in party activities. Finally, process incentives do not make a contribution to the explanation of activities, which is contrary to the sociability function of youth sections (Cross and Young 2008b; Bruter and Harrison 2009; Dechezelles 2009).

The model testing the CVM in Table 3, we personal efficacy has a positive impact on time devoted to party activities (Alarcón 2021). Besides, having free time is not related to a more in-depth engagement with the YPOs. Thus, party members who have full time jobs as well as studying simultaneously are more likely to be active members in the youth section. Also, a higher level of education increases involvement of young party members in party activities; while having relatives who are party members does not correspond to a higher level of party activism - quite the opposite, in fact: those who joined the YPOs and without relatives being party members are more active (Eldersveld 1966). These results suggest that those joining the party because of family ties - family party membership - may be mostly motivated by the impulse of satisfying their relatives rather than because of genuine interest in party activism. At the same time, neither being recruited through personal networks nor a higher sense of civic duty show a significant relationship with active participation in youth sections. As we have pointed out in reference to family membership, in some sense these variables direct the affiliation of young members but not their involvement in party activities.

The feelings of personal political efficacy show influence in two of the three models in Table 3 - CVM and SPM. A high sense of individual political efficacy is linked to the intensity of party activism in both models. In contrast, individual political efficacy does not have a significant effect on participation in activities under the general incentives model and the full model (4).

As we expected, gender is related to participation in party activities; young female members display lower levels of activism. These results are in line with our expectations and previous research on young party members carried out in other contexts (Bargel 2008; Cross and Young 2008b; Espinosa and Madrid 2010) and Spain (Alarcón 2021). Party membership and party activism remain a traditionally male domain. In partisan activities, none of the two variables that help us to identify the life cycle present significant coefficients in the GIM, the SPM and the full models: members of the YPOs with family responsibilities are just as likely to engage in party activities as members without it. In contrast, in the CVM model, young people who live with their partner show lower intensity of participation in party activities. Living as a couple implies planning together, and less time for party activities and active engagement with youth sections. Finally, as in the case of economic activism, those who have joined the youth section younger are more likely to engage in party service. In contrast, underage party members present weak ties with YPOs. This means the pursuit of a multi-speed approach to party membership (Scarrow 2015) by parties and youth sections for some members - minors - in order to connect with new people and renew membership figures in order to survive.