Accommodation~assimilation relations were theorized by Kelso and Engstrom (2006) as independent and dependent complementary pairs. This study defined relationships between organisms that experienced complementary interactions of accommodation~assimilation in diverse ecologies designed with universal design for learning environments (UDLE) compared to a control group (non-UDLE). A quantitative, post-test-only quasi-experimental research design defined and evaluated relationships between individuals and environments within accommodation~assimilation to examine the fidelity of Kelso and Engstrom's complementary pair theory. Quantitative data on public postsecondary learners' perceptions (N = 129) of educational environments were compared and contrasted using a researcher-developed Likert rating item, the Student Affordance Survey (SAS), adapted with permission from the Center for Applied Special Technology (CAST, 2011b). No scales indicated a significant correlation between disability status or UDLE participation using a Kendall partial rank correlation. Results of the Mann-Whitney "U" analysis indicated significant differences between male and female perceptions of engagement (z = -2.44, p = 0.015) and other perceptions (z = -2.07, p = 0.038). Females tended to agree instructors participated in selection of classroom materials (M = 2.94) to a greater extent than males (M = 2.24) and felt respected by instructors (M = 4.68) to a greater extent than males (M = 4.44). Data-driven outcomes from both null hypotheses confirmed a lack of positive associations between learners and ecologies rich with accommodation or assimilation that predicted independence or mutual dependence, which confirmed Kelso and Engstrom's theory for accommodation~assimilation. The usefulness of intervention implementation on dynamic organizational systems was also explored. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]