# experiments

Does the field actually do work, or is riverbed an elaborate prompt?

The whole architecture rests on one claim of Kieran's — **the route changes the
parser**. If two fields that have been through different things traverse the same
new experience identically, then the persistence, the weighting, and the erosion
are decoration, and the only thing doing work is the induction text in the system
prompt. That is worth knowing before mounting this on anything.

Run in order; each depends on artifacts from the last.

| script | question | cost |
|---|---|---|
| `two_riverbeds.py` | do differently-eroded fields diverge? | ~8 turns |
| `weights_alone.py` | …with vocabulary held constant? | ~2 turns |
| `signal_vs_noise.py` | is that above the sampling-noise floor? | ~8 turns |
| `promotion_effect.py` | pre-registered: does promotion steer attachment? | ~24 turns |

## Log

**two_riverbeds** — identical genesis seed, then three physical/material
experiences vs three observation/coupling experiences, then the same multivalent
plaza-crowd experience run dry on both. 80% divergence in what each attached to.
Looked strong. It wasn't: 3 of the 5 witness attachments were to nodes that exist
*only* in the witness field. A graph with different nodes gives different answers.
That is trivially true and shows nothing about weighting.

**weights_alone** — the isolation. One field cloned twice, 28 identical nodes and
31 identical edges, differing only in which shapes carry weight. 67% divergence.
Better evidence — vocabulary can no longer explain it.

**signal_vs_noise** — the control that mattered, and it **killed the claim**. The
generator runs at temperature 1.15, so two runs of the *same* field disagree too.
Measured: within-field divergence **63%**, between-field **66%**. A +3% effect.
Both prior numbers were sampling noise. On the pre-registered set-comparison
metric, weighting does not change traversal.

Post-hoc, a targeted pattern survived that the set metric drowned: each field
reached for its *own* promoted shapes 3/8 runs and for the *other* field's
promoted shapes 0/8. Jaccard over whole attachment sets is dominated by the noisy
tail of incidental attachments, so a narrow real effect can hide inside it.
Post-hoc findings are hypothesis-generating and nothing more — hence:

**promotion_effect** — written before seeing its data. Within-subject 2×2, each
shape appearing in both a promoted and an unpromoted condition, primary outcome
fixed in advance (per-run binary hit), decision rule fixed in advance (Fisher
exact one-sided, p < 0.05), N=12 per field chosen from a power check: 4/12 vs
0/12 clears, 3/8-scale effects need this much n to be visible. No other
comparison from that run gets reported as evidence.

**RESULT — effect supported, decisively.**

    attached to target when PROMOTED:   16/23  (70%)
    attached to target when UNPROMOTED:  0/23  ( 0%)
    Fisher exact one-sided: p = 2.5e-07

Not carried by one lucky condition — both fields clear independently
(A: 9/11 vs 0/11, p=0.0001; B: 7/12 vs 0/12, p=0.0023). One parse failure
excluded, hence 23 rather than 24.

So weighting *does* steer what a traversal reaches for. The earlier null was a
measurement failure, not an absence: set-Jaccard over whole attachment sets
buries a sharp effect under the noisy tail of incidental attachments. Same
mechanism, same kind of data, right instrument.

Note also what did NOT move. `alluvial` is high-weight in both clones and appears
in 21/23 runs regardless of condition, while the promoted shapes steer locally.
A strong orientation persisting across perturbation while weaker ones redirect
attention is exactly the behaviour the weighting is meant to produce — and it
was not asked for anywhere in the prompt.

**What this licenses, and what it does not.** It shows the field's *current*
weights change traversal: the mechanism is live, not decorative. It does NOT
show that weights arrived at by *erosion* carry the same force — `two_riverbeds`
remains confounded by vocabulary — nor that this survives a stronger navigator,
a second test passage, or more than one field lineage. Those are the next runs.

**erosion_steers** — the thesis test, pre-registered. Setting a weight by hand is
turning a knob; the claim riverbed actually makes is that the knob turns itself.
Flat seed (genesis levelled to 1.0 so erosion has room — previously `alluvial`
entered at 5.0 and swamped everything), five material experiences vs five
relational ones, targets chosen by a mechanical differential rule fixed in
advance and restricted to nodes present in BOTH fields.

**RESULT — supported.**

    attached to shapes ITS OWN erosion raised:     18/20  (90%)
    attached to shapes the OTHER's erosion raised:  7/20  (35%)
    Fisher exact one-sided: p = 0.00039

Read the decomposition before believing it is uniform, because it is not:

    set A (nonlinguistic-transformation, recurrence)  9/10 vs 1/10   p=0.0006
    set B (cognition, manifestation)                  9/10 vs 6/10   p=0.15

Set A carries the result. Set B moves in the predicted direction but does not
clear on its own — `cognition` is simply a highly attachable idea for a passage
about a crowd, so it gets reached for whether or not erosion raised it. The
honest statement is that erosion-derived weight steers traversal, **and target
base-rate is a real confound the design did not control**. A cleaner version
would match targets on unconditional attachment rate, or use several test
passages so no single one favours a term.

Worth noting how *little* weight movement produced this: the separations were
+0.75, +0.30, -0.60, -0.60 on a flat seed. Erosion barely moved these nodes and
the traversal followed anyway.

**erosion_multipassage** — pre-registered replication closing the base-rate hole.
Four passages (rhythm, law, ecology, tide) chosen so none is *about* any target
shape, reusing the fields and target sets erosion_steers already selected so
nothing is re-chosen after seeing outcomes.

**RESULT — replicated.**

    attached to shapes ITS OWN erosion raised:     18/24  (75%)
    attached to shapes the OTHER's erosion raised:  5/24  (21%)
    Fisher exact one-sided: p = 0.0002

All four passages point the same way (5/6-1/6, 5/6-1/6, 5/6-2/6, 3/6-1/6), so no
single passage carries it. And this time **both target sets clear on their own**:

    set A (nonlinguistic-transformation, recurrence)  7/12 vs 0/12   p=0.0023
    set B (cognition, manifestation)                 11/12 vs 5/12   p=0.0136

Note what the control actually taught. It ruled out the explanation offered for
set B's earlier failure — that `cognition` suited the crowd passage specifically —
because set B leaks into the wrong field at the same rate (5/12) across four
unrelated passages. The bias is not topical; those two terms are simply more
attachable in general. Set A remains perfectly discriminating: 0/12 in the field
whose erosion did not raise it, across every passage.

So erosion-derived weight steers traversal, and the size of the steer depends on
how attachable the shape already was. High-base-rate shapes get reached for
anyway; low-base-rate shapes are reached for *only* when erosion raised them.
That is a more interesting finding than a flat effect, and it was not designed
for — it fell out of controlling the confound.

## Standing caveats

Everything here is one 24B model, one test experience, one field lineage. A
negative result at this scale means "not demonstrated here," not "impossible" —
a stronger navigator may show what this one cannot. And a positive result on one
multivalent experience would still need replication across experiences before it
characterizes the system rather than this prompt.