Developmental Theory & Hypotheses (devpsych-theory-and-hypotheses)
Developmental Psychology rewards a theory of change and age-graded, directional hypotheses.
Because the journal asks for a credible developmental claim and applies JARS reporting, the cardinal
rule is: state the developmental mechanism and the predicted form of change before the data, and
label exploratory analyses as exploratory.
When to trigger
- Writing the theoretical framing and hypotheses
- Preparing a preregistration / pre-analysis plan for a developmental study
- Reconciling what you predicted about change with what the trajectories show
- A reviewer flagged the work as "atheoretical," "not developmental," "post hoc," or "HARKed"
Build the developmental argument
- State the mechanism of change. What developmental process (maturation, learning, transactional
parent–child dynamics, scaffolding, cumulative risk) predicts the effect, and why it changes with age.
- Specify the form of the developmental hypothesis. Be explicit about which of these you predict:
an age main effect, an age × condition interaction, a growth-curve shape (slope sign,
acceleration), a within-person change, or a moderated trajectory.
- Derive directional predictions. Give a sign and, where possible, a magnitude/effect-size
expectation — not "age will be related to X."
- Mark hypothesis status. Separate confirmatory (preregistered, predicted) from exploratory
(generated after seeing data) analyses, clearly, per JARS.
- State what would disconfirm the developmental account — e.g., a flat trajectory, a reversed age
slope, or invariance failure that means the construct is not the same across ages.
Age-graded hypothesis forms (name yours)
| Hypothesis form |
What it claims |
Typical test |
| Age main effect |
level differs by age |
age as predictor (cross-sectional or wave) |
| Age × condition |
manipulation effect differs by age |
interaction term |
| Growth shape |
within-person slope/curvature |
latent growth / multilevel |
| Sensitive period |
effect concentrated in an age window |
nonlinear / spline age terms |
| Transactional |
child→parent and parent→child over time |
cross-lagged / RI-CLPM |
Worked micro-example — theory to hypothesis status (illustrative)
A longitudinal effortful-control package, written so the developmental claim and status are legible.
Mechanism: Sensitive, contingent parenting scaffolds the maturation of
effortful control; the scaffolding payoff grows across early childhood.
H1 (confirmatory, preregistered): Effortful control shows positive
within-person growth from age 4 to 8 (latent slope > 0).
H2 (confirmatory): Maternal scaffolding at wave 1 predicts a steeper slope
(scaffolding × time interaction, directional).
H3 (exploratory): Bidirectional child→parent effects across waves
(RI-CLPM) — labeled exploratory; preregister for a future sample.
Disconfirming: a flat/negative latent slope, or measurement non-invariance
across ages (the construct is not the same thing being "grown").
Avoiding HARKing in developmental work
- Do not present an unexpected age interaction or a trajectory shape you discovered post hoc as if it had
been predicted. If you found it after seeing the data, say so and frame it for confirmation.
- Constraints on generality matter here: name the ages, populations, and cohort/era to which the
developmental claim is meant to apply, rather than implying it holds at every age and place.
Theory-stage reviewer pushback and the venue fix
| Reviewer pushback |
Developmental Psychology fix |
| "Atheoretical / mechanism unclear" |
state the developmental mechanism and why it changes with age in one or two sentences |
| "This is not developmental" |
recast the hypothesis as change (slope/interaction/within-person), not a single-age correlation |
| "Looks HARKed" |
show the preregistration; relabel post hoc trajectory shapes exploratory |
| "Claim outruns the design" |
scale H1 to what the ages/waves can support; add a constraints-on-generality clause |
Anti-patterns
- Hypotheses about a relationship "in children/older adults" with no change component
- Non-directional "age will be associated with X" predictions
- Blurring confirmatory and exploratory analyses (JARS expects the split)
- Ignoring that an effect could be cohort, not age, and theorizing as if it were maturation
- No statement of what trajectory or interaction would disconfirm the account
Output format
【Mechanism of change】the developmental process, briefly
【Developmental hypothesis form】age effect / age×condition / growth shape / within-person / moderated
【Hypotheses】directional, testable (H1, H2, …)
【Status】confirmatory (preregistered) vs exploratory
【Disconfirming evidence】trajectory/interaction/invariance result that counts against it
【Next】devpsych-literature-positioning
Supplementary resources
1---2name: devpsych-theory-and-hypotheses3description: Use when stating the developmental theory and age-graded hypotheses for a Developmental Psychology (APA) manuscript. The journal rewards hypotheses that are explicitly about change (age effects, within-person trajectories, mechanisms) and a clean confirmatory/exploratory split under JARS. Structures the argument; it does not run analyses.4---56# Developmental Theory & Hypotheses (devpsych-theory-and-hypotheses)78Developmental Psychology rewards a **theory of change** and **age-graded, directional hypotheses**.9Because the journal asks for a credible developmental claim and applies **JARS** reporting, the cardinal10rule is: **state the developmental mechanism and the predicted form of change before the data**, and11label exploratory analyses as exploratory.1213## When to trigger1415- Writing the theoretical framing and hypotheses16- Preparing a preregistration / pre-analysis plan for a developmental study17- Reconciling what you predicted about change with what the trajectories show18- A reviewer flagged the work as "atheoretical," "not developmental," "post hoc," or "HARKed"1920## Build the developmental argument21221. **State the mechanism of change.** What developmental process (maturation, learning, transactional23 parent–child dynamics, scaffolding, cumulative risk) predicts the effect, and *why it changes with age*.242. **Specify the form of the developmental hypothesis.** Be explicit about which of these you predict:25 an **age main effect**, an **age × condition interaction**, a **growth-curve shape** (slope sign,26 acceleration), a **within-person change**, or a **moderated trajectory**.273. **Derive directional predictions.** Give a sign and, where possible, a magnitude/effect-size28 expectation — not "age will be related to X."294. **Mark hypothesis status.** Separate **confirmatory** (preregistered, predicted) from **exploratory**30 (generated after seeing data) analyses, clearly, per JARS.315. **State what would disconfirm the developmental account** — e.g., a flat trajectory, a reversed age32 slope, or invariance failure that means the construct is not the same across ages.3334## Age-graded hypothesis forms (name yours)3536| Hypothesis form | What it claims | Typical test |37|-----------------|----------------|--------------|38| Age main effect | level differs by age | age as predictor (cross-sectional or wave) |39| Age × condition | manipulation effect differs by age | interaction term |40| Growth shape | within-person slope/curvature | latent growth / multilevel |41| Sensitive period | effect concentrated in an age window | nonlinear / spline age terms |42| Transactional | child→parent and parent→child over time | cross-lagged / RI-CLPM |4344## Worked micro-example — theory to hypothesis status (illustrative)4546A longitudinal effortful-control package, written so the developmental claim and status are legible.4748```49Mechanism: Sensitive, contingent parenting scaffolds the maturation of50 effortful control; the scaffolding payoff grows across early childhood.51H1 (confirmatory, preregistered): Effortful control shows positive52 within-person growth from age 4 to 8 (latent slope > 0).53H2 (confirmatory): Maternal scaffolding at wave 1 predicts a steeper slope54 (scaffolding × time interaction, directional).55H3 (exploratory): Bidirectional child→parent effects across waves56 (RI-CLPM) — labeled exploratory; preregister for a future sample.57Disconfirming: a flat/negative latent slope, or measurement non-invariance58 across ages (the construct is not the same thing being "grown").59```6061## Avoiding HARKing in developmental work6263- Do not present an unexpected age interaction or a trajectory shape you discovered post hoc as if it had64 been predicted. If you found it after seeing the data, **say so** and frame it for confirmation.65- Constraints on generality matter here: name the **ages, populations, and cohort/era** to which the66 developmental claim is meant to apply, rather than implying it holds at every age and place.6768## Theory-stage reviewer pushback and the venue fix6970| Reviewer pushback | Developmental Psychology fix |71|-------------------|------------------------------|72| "Atheoretical / mechanism unclear" | state the developmental mechanism and *why it changes with age* in one or two sentences |73| "This is not developmental" | recast the hypothesis as change (slope/interaction/within-person), not a single-age correlation |74| "Looks HARKed" | show the preregistration; relabel post hoc trajectory shapes exploratory |75| "Claim outruns the design" | scale H1 to what the ages/waves can support; add a constraints-on-generality clause |7677## Anti-patterns7879- Hypotheses about a relationship "in children/older adults" with no change component80- Non-directional "age will be associated with X" predictions81- Blurring confirmatory and exploratory analyses (JARS expects the split)82- Ignoring that an effect could be cohort, not age, and theorizing as if it were maturation83- No statement of what trajectory or interaction would disconfirm the account8485## Output format8687```88【Mechanism of change】the developmental process, briefly89【Developmental hypothesis form】age effect / age×condition / growth shape / within-person / moderated90【Hypotheses】directional, testable (H1, H2, …)91【Status】confirmatory (preregistered) vs exploratory92【Disconfirming evidence】trajectory/interaction/invariance result that counts against it93【Next】devpsych-literature-positioning94```9596## Supplementary resources9798- [`../../resources/external_tools.md`](../../resources/external_tools.md) — preregistration templates and developmental-theory references99- [`../../resources/official-source-map.md`](../../resources/official-source-map.md) — JARS reporting standards and scope
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