same-words-different-judgements / analysis /common /_voice_variation_replication.py
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Correct ICC variance components: square random-effect SDs
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"""Do the paper's audio-side findings survive a change of voice?
python analysis/06_voice_study/05_replication.py
python analysis/06_voice_study/05_replication.py --skip-models # fast
The voice study holds the words fixed and swaps the voice. The paper's claim is not
"audio ratings are high" but "audio judgments are behaviourally distinct from
text": raters commit to a winner at smaller gaps, lean on length less, favour
the second-presented item, and agree with the text winner at near chance. If
those signatures only exist for Kokoro af_heart they are properties of one TTS
voice, not of the audio modality. This script recomputes each of them per arm.
Five quantities, matching Section 4 of the paper:
threshold Mean per-prompt rating gap on non-tie trials (paper Fig. 1):
audio 26.0 vs text 39.8 over 100 prompts. The paper's threshold
text and tables pool trials instead (audio 27.9, text 41.7);
08_cross_study/01_threshold_summary.py reports that version.
length Coefficient on z-scored response character length (paper Table 1;
audio b = 3.52, text b = 4.92).
recency Coefficient on presented-first (paper b = -2.61: first-presented
rated LOWER, i.e. the second item is favoured).
icc ICC(2,1) and ICC(2,k) from crossed random effects
(paper audio .333 / .821, text .295 / .788).
agreement Winner agreement with the ORIGINAL TEXT condition, per prompt.
Every arm-level number is also recomputed for the original af_heart audio and
the original text on the SAME 30 prompts. The published values cover 100
prompts, so comparing a 30-prompt arm against them would confound the voice
with the stimulus subset. The matched columns are the honest comparison; the
published ones are shown only for orientation.
"""
from __future__ import annotations
import argparse
import sys
import warnings
from pathlib import Path
import numpy as np
import pandas as pd
warnings.filterwarnings("ignore")
sys.path.insert(0, str(Path(__file__).resolve().parent)) # for lme4.py
ROOT = Path(__file__).resolve().parent.parent.parent
VOICE_DATA = ROOT / "data/voice_study"
CONTEXT_DATA = ROOT / "data/audio_context_study"
DERIVED = ROOT / "results/06_voice_study"
SD = ROOT / "data/main_study"
# Published values, 100 prompts. Orientation only -- see module docstring.
# ICCs are variance ratios from squared random-effect SDs, matching
# 02_main_study/02_reliability_icc_alpha.py calc_icc and the variances this
# module's own icc() gets from lmer_varcomp. (Earlier values -- audio
# 0.333/0.821, text 0.295/0.788 -- were SD ratios and are not comparable.)
PAPER = {
"audio": dict(threshold=27.9, length=3.52, recency=-2.61,
icc1=0.312, icck=0.806),
"text": dict(threshold=41.7, length=4.92, recency=-2.61,
icc1=0.241, icck=0.738),
}
# --------------------------------------------------------------- loading ----
def load_lengths() -> pd.Series:
"""AudioClip -> response character length."""
s = pd.read_csv(SD / "survey_long_format.csv")
return s.set_index("AudioClip")["TextLength"]
def load_arms(prompts: set[str] | None) -> pd.DataFrame:
"""New voice arms, plus original audio and text as reference arms."""
frames = []
abl = VOICE_DATA / "long_voice_normalized.csv"
if abl.exists():
frames.append(pd.read_csv(abl))
else:
print(f"!! {abl.relative_to(ROOT)} missing — run build_long_tables.py")
for name, f in (("ORIGINAL af_heart", "long_audio_table_normalized.csv"),
("ORIGINAL text", "long_text_table_normalized.csv")):
d = pd.read_csv(SD / f)
d = d[~d["IsAttentionCheck"].astype(bool)].copy()
d["Arm"] = name
frames.append(d)
df = pd.concat(frames, ignore_index=True)
df = df.dropna(subset=["Rating"])
if prompts is not None:
df = df[df["PromptID"].isin(prompts)]
return df
# --------------------------------------------------------------- metrics ----
def decision_threshold(g: pd.DataFrame) -> tuple[float, int]:
"""Mean per-prompt rating gap on trials where a winner was declared.
One trial contributes two rows (the two clips), so the gap is taken within
(participant, prompt) and only where overallPreference is not a Tie.
"""
d = g[g["overallPreference"].isin(["A", "B"])]
gaps = (d.groupby(["ParticipantID", "PromptID"])["Rating"]
.agg(lambda x: x.max() - x.min() if len(x) == 2 else np.nan)
.dropna())
if gaps.empty:
return np.nan, 0
per_prompt = gaps.groupby(level="PromptID").mean()
return per_prompt.mean(), len(per_prompt)
def winner(g: pd.DataFrame, col: str = "Rating") -> pd.Series:
"""PromptID -> winning clip, or 'tie' when the two clip means are equal."""
m = g.groupby(["PromptID", "AudioClip"])[col].mean().reset_index()
out = {}
for pid, sub in m.groupby("PromptID"):
if len(sub) < 2:
continue
sub = sub.sort_values(col, ascending=False)
top, second = sub.iloc[0], sub.iloc[1]
out[pid] = "tie" if top[col] == second[col] else top["AudioClip"]
return pd.Series(out, name="winner")
def fit_bias_model(g: pd.DataFrame, lengths: pd.Series):
"""Paper Table 1, one arm at a time.
Rating ~ presented_first + char_len_z + trial_z + (1|participant) + (1|clip)
Crossed random effects, so lme4. Not via pymer4: 0.9.2 cannot convert a
DataFrame under rpy2 3.6, so lme4.py drives R directly. That substitution
reproduces the paper's Table 1 exactly -- see validate_against_paper.py.
Returns (recency_b, recency_p, length_b, length_p) or NaNs.
"""
from _lme4 import lmer_fixed
d = g.copy()
d["char_len"] = d["AudioClip"].map(lengths)
d = d.dropna(subset=["char_len", "Rating", "TrialNumber"])
if d["ParticipantID"].nunique() < 3 or len(d) < 40:
return (np.nan,) * 4
for src, dst in (("char_len", "char_len_z"), ("TrialNumber", "trial_z")):
sd = d[src].std()
d[dst] = 0.0 if not sd else (d[src] - d[src].mean()) / sd
d["presented_first"] = d["PresentedFirst"].astype(int)
try:
fit = lmer_fixed(d, "Rating ~ presented_first + char_len_z + trial_z "
"+ (1|ParticipantID) + (1|AudioClip)")
pick = lambda t, c: (float(fit.loc[t, c]) if t in fit.index else np.nan)
return (pick("presented_first", "estimate"),
pick("presented_first", "p"),
pick("char_len_z", "estimate"),
pick("char_len_z", "p"))
except Exception as e: # noqa: BLE001
print(f" model failed: {type(e).__name__}: {e}")
return (np.nan,) * 4
def icc(g: pd.DataFrame):
"""ICC(2,1) and ICC(2,k) from a crossed random-effects decomposition.
Uses the paper's model on raw ratings, with order and trial position as
fixed effects:
Rating ~ presented_first + trial_z + (1|AudioClip) + (1|ParticipantID).
Variance attributable to the stimulus over stimulus + rater + residual.
k is the mean number of raters per clip, so ICC(2,k) answers "how reliable
is the mean of the raters we actually have".
"""
from _lme4 import lmer_varcomp
d = g.dropna(subset=["Rating", "TrialNumber", "AudioClip"]).copy()
if d["ParticipantID"].nunique() < 3 or d["AudioClip"].nunique() < 3:
return np.nan, np.nan, np.nan
d["pf"] = d["PresentedFirst"].astype(int)
sd = d["TrialNumber"].std()
d["trial_z"] = (d["TrialNumber"] - d["TrialNumber"].mean()) / (sd if sd else 1)
try:
rv = lmer_varcomp(
d, "Rating ~ pf + trial_z + (1|AudioClip) + (1|ParticipantID)")
v_stim = float(rv.get("AudioClip", np.nan))
v_rater = float(rv.get("ParticipantID", np.nan))
v_res = float(rv.get("Residual", np.nan))
k = d.groupby("AudioClip").size().mean()
icc1 = v_stim / (v_stim + v_rater + v_res)
icck = v_stim / (v_stim + (v_rater + v_res) / k)
return icc1, icck, k
except Exception as e: # noqa: BLE001
print(f" icc failed: {type(e).__name__}: {e}")
return np.nan, np.nan, np.nan
# ------------------------------------------------------------------ main ----
def main() -> None:
ap = argparse.ArgumentParser()
ap.add_argument("--skip-models", action="store_true",
help="threshold and agreement only; no lme4 fits")
ap.add_argument("--all-prompts", action="store_true",
help="do not restrict the reference arms to the 30")
args = ap.parse_args()
lengths = load_lengths()
sel = pd.read_csv(ROOT / "stimuli/voice_study/prompts.csv")["PromptID"]
prompts = None if args.all_prompts else set(sel)
if prompts:
print(f"restricted to the {len(prompts)} Ablation-A prompts "
f"(reference arms recomputed on the same set)")
df = load_arms(prompts)
text_win = winner(df[df["Arm"] == "ORIGINAL text"])
rows = []
for arm, g in df.groupby("Arm", sort=True):
n_part = g["ParticipantID"].nunique()
n_prompt = g["PromptID"].nunique()
per_clip = g.groupby("AudioClip").size()
thr, n_thr = decision_threshold(g)
w = winner(g)
both = w.index.intersection(text_win.index)
agree = (np.nan if len(both) == 0
else float((w[both] == text_win[both]).mean()))
rec_b = rec_p = len_b = len_p = i1 = ik = kbar = np.nan
if not args.skip_models:
print(f" fitting {arm} ...")
rec_b, rec_p, len_b, len_p = fit_bias_model(g, lengths)
i1, ik, kbar = icc(g)
rows.append(dict(arm=arm, n=len(g), participants=n_part,
prompts=n_prompt,
raters_per_clip=f"{per_clip.min()}-{per_clip.max()}",
threshold=thr, recency_b=rec_b, recency_p=rec_p,
length_b=len_b, length_p=len_p,
icc1=i1, icck=ik, k=kbar,
agree_with_text=agree, n_agree=len(both)))
res = pd.DataFrame(rows)
out = DERIVED / "voice_replication.csv"
res.to_csv(out, index=False)
pd.set_option("display.width", 200, "display.max_columns", 50)
print("\n" + "=" * 78)
print("REPLICATION OF THE PAPER'S AUDIO SIGNATURES, BY VOICE")
print("=" * 78)
show = res[["arm", "participants", "prompts", "raters_per_clip",
"threshold", "recency_b", "length_b", "icc1", "icck",
"agree_with_text"]]
print(show.to_string(index=False, float_format=lambda x: f"{x:7.3f}"))
print("\npublished (100 prompts, for orientation only):")
for k, v in PAPER.items():
print(f" {k:6} threshold {v['threshold']:.1f} length b {v['length']:.2f}"
f" recency b {v['recency']:.2f} ICC(2,1) {v['icc1']:.3f}"
f" ICC(2,k) {v['icck']:.3f}")
thin = res[res["participants"] < 10]
if not thin.empty:
print("\n!! UNDERPOWERED — fewer than 10 raters in: "
+ ", ".join(thin["arm"]))
print(" The design targets 10 ratings per item. Treat every number "
"above as a pipeline check, not a result.")
print(f"\nwrote {out.relative_to(ROOT)}")
if __name__ == "__main__":
sys.exit(main())