01
Event
What happened: the incident, action or immediate circumstances.
What happened, as distinct from what it meant?
IAD Knowledge · CDT Model
Development Onion
Ten layers of construction.
A map for exploring what is being constructed, which layer is visible and where a further distinction may become usable.
The layered map
Which layer is active? Which can be seen?
The visual moves from the immediately observable encounter towards the construction organising it. The layers are analytical distinctions, not separate compartments in the mind or levels of human worth.
Conceptual depth, not a numerical developmental score. Select a layer to read its explanation.
Reading the Onion
Ten ways to locate the construction.
02
Reaction
The immediate emotional, cognitive or behavioural response.
What did you notice yourself feeling, thinking or doing?
03
Interpretation
The meaning given to the event.
What did you take the event to mean?
04
Cognitive Intention
The directions of cognition shaping that interpretation.
What direction of attention may be organising this meaning?
05
Pattern
A recurring combination of directions and responses in context.
Where else does this construction appear, and where does it not?
06
Self-Construction
The version of self that makes the pattern intelligible.
Who do you need to be for this response to feel necessary?
07
Social Construction
Roles, norms, expectations and collective meanings sustaining the construction.
Which expectations are being treated as given?
08
Systemic Construction
Incentives, institutions, histories, resources and power shaping the encounter.
What does this setting reward, penalise or make difficult?
09
Meaning Construction
How deeper meanings of worth, success, failure, loss or belonging are being made.
How is this meaning being constructed, and what does it organise?
10
Construction of Construction
Awareness of the whole process as constructed, consequential and open to revision.
What changes when this entire account is seen as a construction?
Questions are illustrative invitations, not a diagnostic checklist. Any interpretation should be checked with the person and the context.
Practice and developmental availability
Explore the next usable layer.
Depth is not the goal.
The useful question is where a further distinction becomes available. A clear account of the event, practical support or an apology may matter more than exploring meaning or identity.
A person may discuss a layer fluently without being aware of its operation during a live encounter. Naming a layer does not demonstrate developmental change.
Keep consent and context explicit.
Do not use the model to insist on an interpretation, expose someone or take inquiry beyond what they can use. The practitioner’s assumptions are part of the construction being examined.
Social and systemic explanations should not erase personal responsibility; personal responsibility should not erase environmental constraints.
A contextual map
The layer being discussed is not the person’s AQ.
The ten Onion layers and the AQ4–AQ10 map describe different things. There is no one-to-one layer-to-AQ conversion, and Layer 10 does not establish AQ10.
Constructed illustration
One disagreement, several possible layers.
Event, reaction and interpretation
A colleague questions a proposal. The speaker interrupts and interprets the question as disrespect. These distinguish the event, response and assigned meaning.
Direction, pattern and self
Inquiry might explore where authority is located, whether defending proposals is recurrent and whether being competent has become equated with being unquestioned. These are hypotheses, not conclusions from the interruption alone.
Social and systemic conditions
The group may expect leaders to appear certain, and the organisation may penalise admitted mistakes. Those conditions need examination rather than assuming an entirely individual problem.
Meaning and construction
If useful and available, the person may examine what competence means and recognise the account itself as a construction. That does not make the event unreal or remove its consequences.
A usable next move might simply be distinguishing a question about the proposal from a judgement about the person. The example is fictional and need not be explored through every layer.
Related CDT Knowledge
The Onion helps locate the inquiry.
Real-Time Modelling →
RTM is a method of collaboratively examining construction. The Onion can help locate what is being examined, without becoming a model imposed on the person.
IACR →
IACR describes intention, awareness, choice and response. The Onion elaborates possible layers of what becomes visible within that architecture.
Awareness Quotient →
AQ concerns contextual awareness and availability. The Onion concerns layers of construction; they should not be treated as equivalent scales.
Cognitive Intentions →
CIs concern directions of cognition. Layer 4 explores their possible use; Layer 5 considers recurring combinations without turning them into diagnoses.
Zone of Dynamic Development →
ZDD concerns the next usable construction. It helps frame how far and when to extend an inquiry, rather than assuming that deeper is always better.
Developmental Environment →
The social and systemic layers hold relationships, institutions and power within the account. Construction is not simply an isolated internal property.
Theory & evidence status
The current map extends the earlier model.
Current formulation
A ten-layer conceptual model.
The Vade Mecum develops an account from Event to Construction of Construction. This page follows that current practical formulation and supplies illustrative inquiry questions. [1]
The earlier thesis Onion concerns the accumulation and revisiting of CI awareness. The ten-layer model is a later conceptual extension, not the same object with a new label. [2]
Empirical boundary
Direct validation remains open.
Initial research on parts of CDT does not independently validate these ten layers, their order or interventions guided by them. The Onion is not presented here as a clinical diagnostic, scored assessment or proven developmental mechanism.
Further work would need to examine observer agreement, usefulness beyond alternative explanations, outcomes over time and potential harms of misapplied interpretation.
Sources & citation
Referencing Development Onion.
- Stevens, D. (2026). Constructed Development Theory: A Vade Mecum — The Portable Field Guide to Awareness, Choice, and Deliberate Construction.
Authorial manuscript. The Constructed Development Onion and its relationship to AQ and IACR.
- Stevens, D. (2020). Does Constructed Development Exist as a Conceptual Measure of Self-Awareness in the Moment?
PhD thesis, Coventry University. Earlier developmental model and academic foundation.