This thesis argues that people choose specific occupational roles to satisfy individual dispositions and needs, characteristics that have arisen in childhood as a means of establishing an ecological niche of diversity within families. I first examine the notion that birth order promotes differentiation amongst siblings, and that these differences represent a distal basis for individual differences in personality variables, motives and occupational role preferences. Building on that knowledge, I then argue that organizations typically are comprised of people grouped into clusters based on their roles; the make up of each cluster is somewhat similar in terms of biographical, personality and motive variables, and each cluster is differentiated from the other clusters. The occupational role clusters of interest are 'administrative/support', 'technical/professional', and 'supervisory/managerial'. Finally, I suggest that the nature of these relatively internally homogeneous role clusters and the differences between these clusters may have consequences for an organization's capacity to be innovative.
The research comprises three studies. The first examined the possibility of individual differences between siblings based on birth order. The second examined individual differences as they apply to occupational role clusters within organizations. In both of these studies, my primary interest with respect to individual differences was in 'motives', a domain of human behaviour that has been largely succeeded in the research literature by personality variables, particularly the so-called 'big-5', which I have also considered. The research therefore considered both motive and personality variables, though with more theoretical emphasis on the former. The third study, which was exploratory, examined whether more innovative organizations can be differentiated from less innovative organizations on the basis of occupational role clusters and the nature of the individual differences within and between them.
In Study 1, I investigated sibling differences using a novel methodology designed to overcome criticisms of prior birth order research. The sample consisted of 379 adult participants, (151 first-borns, 136 middle-borns, and 92 last- borns) all of whom came from families of only three siblings. Respondents completed a survey seeking information about themselves and their two siblings (thus producing a total sample of 1137) with respect to motive, personality and occupational role preference variables. The data on the 1137 adults were then analysed. Results provided partial support for the hypotheses that birth order underpins motives, personality variables and occupational role preference, and strong support for the proposal that motives underpin occupational role preference.
In Study 2,1 examined employees in four different organizations, three public sector and one private sector, to ascertain if different occupational roles display any relationship to the individual differences between the people occupying those different roles. The survey was sent to all staff in the four organizations, and were targeted at the three different role clusters of 'administrative/support', 'technical/professional' and 'supervisory/managerial'. The survey included questions on biographical details, birth order, motives, personality and occupational role preference. A total of 266 responses (116 administrative/support, 114 technical/professional, 36 supervisory/managerial) was received. Discriminant analysis provides strong support for the notion that occupancy of the supervisory/managerial role can be predicted successfully via individual differences. There was negligible support for the prediction of the other two roles based on individual differences, though there were effects for birth order.
Study 3 explored the relationship between patterns of individual difference within occupational roles, on the one hand, and an organization's capacity to be innovative, on the other. Participating organizations were a subset of those involved in Study 2. The level of innovation within each participating organization was determined by structured face-to-face interviews with nine peer-selected staff members (three from each of the role clusters of interest) from each of the four organizations. Individual difference data, partitioned from the data captured in Study 2, were analysed to assess their relationship to the organizational-level data. Though based on a very small sample of organizations, the data provided strong support for the notion that the aggregation of individual differences into clusters and the resultant nature of those clusters demonstrate a clear relationship to organizational innovation. Again the variables related to birth order revealed their significant presence.
Collectively, the three studies demonstrate a plausible link between evolutionary psychology on the one hand and contemporary management on the other.