PAPERS
This section includes working papers by members of the Sustasis Collaborative. Click on the image of each book or paper to open.
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We also have a selection of papers already published in journals, available here.
Michael W. Mehaffy and Nikos A. Salingaros​​​​​​​​​​​​​​​​​​​​​​​​​​​​​
LIVABLE PLACES AND GREEN MACHINERY
Rob Knapp
Emeritus Professor, Physics and Sustainable Design
The Evergreen State College, Olympia, Washington, USA
A serious obstruction in the search for sustainable ways of life is the chasm that separates engineering and experience, or more precisely the engineering approach to low-impact buildings and the experience of thoroughgoing livability. Though much is known on both sides, about cost-effective, low-impact heating and cooling, for example, and about truly satisfying dwellings and workplaces, the professions of architecture, development and construction have generated few examples in which they come together. This paper tackles that challenge. Discussion of the nature of the problem leads to some possible patterns of the Alexander style which unite aspects of engineering and lived experience, and to three proposed approaches to finding more.
Jenny Quillien​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​
POUNDBURY: A DIFFERENT SET OF QUESTIONS
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​What follows is a confession and an informal chronicling of some clumsy sleuthing on my part as I tried to come to grips with the making of livable cities. A heuristic insight was eventually obtained.​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​
THE COMPLEXITY-SYMMETRY (C-S) MODEL:
A framework for Evaluating and Generating Architectural Attractiveness
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A growing body of evidence indicates that many contemporary buildings are
widely perceived as unattractive or unsatisfying by their users, with documented
implications for psychological well-being, stress, and long-term attachment to place.
Despite these findings, architectural theory and practice have largely lacked a coherent
explanatory framework capable of accounting for robust, cross-cultural patterns in human
responses to the built environment. This paper addresses that gap by synthesizing recent
findings from environmental psychology, neuroscience, and complexity science with
established research on symmetry, perception, and aesthetic preference. Building on prior
theoretical work on structured complexity and multi-scale order, including contributions
by Nikos Salingaros, we propose the Complexity–Symmetry Model as a unified
framework for evaluating architectural attractiveness. The model posits that human
perceptual and cognitive systems preferentially respond to environments that exhibit
intermediate levels of complexity organized through compound symmetries—including
nested, broken, and hierarchical symmetries across multiple scales—rather than to either
monotonous uniformity or unstructured complexity. We advance the hypothesis that the
frequently observed preference for many traditional and pre-modern buildings is not
primarily attributable to nostalgia, age, or cultural familiarity, but instead to the presence
of these measurable geometric characteristics. To test this hypothesis, the paper reports
an empirical study in which participants rate the attractiveness of a curated set of
buildings, while those same buildings are independently evaluated using symmetry–
complexity metrics derived from the proposed model. The results demonstrate a
statistically significant correspondence between user evaluations and model predictions,
supporting the model’s explanatory and predictive validity. The paper concludes by
arguing that the systematic absence of these geometric properties in much contemporary
architecture represents not merely a stylistic divergence, but a missed opportunity for the
profession to align more closely with human perceptual and cognitive needs. Re-
engaging with complexity and symmetry as generative design principles offers a
promising pathway for enhancing architectural quality, livability, and professional
relevance in addressing the challenges of the built environment.
SUMMARY OF THE COMPLEXITY-SYMMETRY MODEL AND ITS FORMULAS FOR COMPUTATION
Michael W. Mehaffy (With consultation by Nikos A. Salingaros)​​​​​​​​​​​​​​​​​​​​​​​​​​​​​
This short two-page summary is an "explainer" of the "complexity-symmetry model for architectural attractiveness. It explains the key elements and their formula elements, each of which goes into the algorithm for calculating the final result. The same methodology is used to generate results, using the methodology that is explained in the appendix to the full paper (shown above).
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FROM LOCK-IN TO IMPLEMENTATION:
Identifying Effective Pathways to Sustainable Urbanism
Michael W. Mehaffy​​​​​​​​​​​​​​​​​​​​​​​​​​​​​
Despite widespread agreement on the goals of sustainable urbanism, implementation remains
slow, fragmented, and politically fragile. Building on prior analysis of structural lock-in in
contemporary urban development, this paper shifts the focus from diagnosis to transition by
examining how sustainability-oriented change can occur within entrenched urban planning
systems. These systems—comprising regulatory frameworks, financial and valuation practices,
institutional procedures, governance arrangements, and cultural expectations—exhibit strong
path dependence that inhibits reform even where sustainability objectives are formally endorsed.
The paper conceptualizes urban development as governed by an implicit “operating system for
growth” and proposes a typology of implementation pathways capable of weakening lock-in
without requiring wholesale system replacement. These include code-adjacent regulatory
innovation, incremental economic realignment, procedural and institutional reform, and cultural
and perceptual reframing. Central to the framework is the role of public legitimacy and perceived
quality, articulated through the QUIMBY (“Quality In My Back Yard”) framework as a
stabilizing condition for durable transition. Together, these elements support an agile, user-
friendly approach to advancing sustainable urbanism through iterative, context-sensitive
implementation.