In most species with parental care, offspring disperse from the natal territory either at sexual maturity or when they are competent to survive independently. In humans and numerous avian species, dispersal from the natal family may not coincide with these developmental markers. This presents an adaptive puzzle, since delaying dispersal typically delays reproduction. Various ecological explanations for delayed dispersal in birds have been proposed and tested. Emlen (1995) suggested parallels between humans and birds with regard to the circumstances that influence family formation and dispersal timing. Work by other authors has applied Emlens model to humans using proxy measures of Natal Territory Quality (NTQ). Using the Panel Study of Income Dynamics, a longitudinal survey of U.S. families, I extract direct measures of NTQ to more rigorously test Emlens prediction that higher NTQ leads to later dispersal. I use two age-based cohorts (born in 1957 and 1967). Focusing on three dispersal events (residential dispersal, first marriage, and first reproduction), I test whether economic variables describing family of origin (NTQ) and local conditions influence dispersal age. Multiple linear regression analysis is employed to elucidate the relationships between dispersal and NTQ.
The independent variables appear to have different influences on the three dispersal events, suggesting differential salience of the independent variables for each dispersal type. Results also point to discrepancies across the two cohorts. For the older cohort, family income, fathers employment status, and local unemployment rate appear to influence the timing of residential dispersal. Age at first reproduction and age at first marriage are both influenced by parents education and household density; marriage timing is also affected by fathers employment status also affecting marriage timing. For the younger cohort, fathers employment status and household density affect residential dispersal timing, fathers employment status, mothers education, and family income affect reproductive timing, and fathers occupational prestige affects marriage timing. Females experience all dispersal events earlier than males. All results above reflect significant regression coefficients. However, according to criteria of acceptance for the models tested, the hypothesis was supported only for reproductive dispersal timing in the 1957 cohort.
| Identifer | oai:union.ndltd.org:PITT/oai:PITTETD:etd-08182004-095010 |
| Date | 23 September 2004 |
| Creators | Blum, Elizabeth R. |
| Contributors | Dr. Steven J.C. Gaulin, Dr. Kathleen M. DeWalt, Dr. Janine E. Janosky, Dr. Michael I. Siegel |
| Publisher | University of Pittsburgh |
| Source Sets | University of Pittsburgh |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.library.pitt.edu/ETD/available/etd-08182004-095010/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University of Pittsburgh or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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