[KD21] #
Perceptual difficulty differences predict asymmetry in redundant modification with color and material adjectives. Proceedings of the Linguistic Society of America 6(1): 676-688, 2021.
Core Argument #
Material adjectives are harder to perceive than color adjectives (Exps 1, 3), and color adjectives are used redundantly more often than material adjectives (Exp 2). This anti-correlation between perceptual difficulty and redundant-use rate supports a noise-based RSA account ([WD21]) where the noise parameter reflects perceptual difficulty of property verification.
Experiments #
- Exp 1 (§2, N = 105: 120 recruited, 15 excluded): Perceptual difficulty norms. Participants verified whether an adjective applied to an object. Material adjectives produced higher error rates (β = 0.48) and slower RTs (β = 5.44).
- Exp 2 (§3, N ≈ 95: 100 recruited, 5 excluded): Redundant modifier production. Speakers described objects in contexts where one property was sufficient. Color was used redundantly more than material (β = 2.32).
- Exp 3 (§4, N = 376: 400 recruited, 24 excluded): Perceptual difficulty measured with Exp 2 displays. Material remained harder (error β = 0.96, RT β = 0.24).
Verified Data #
All regression coefficients verified against paper text (§2.3, §3.3, §4.3).
Noise-Model Connection #
The cs-RSA model ([DHG+20]) explains redundant modification via noisy perception: features with higher perceptual discrimination contribute more signal to the literal listener. This paper grounds the asymmetry perceptually — material is harder to verify than color (Exps 1, 3), and color is used redundantly more (Exp 2) — establishing the ordering (color easier than material), not specific channel parameters. The full S1 redundancy prediction requires the incremental model of [WD21] (re-exported below).
A regression result from one of the paper's mixed-effects models. Sign convention varies by experiment: in Exps 1/3, positive β means material > color (harder); in Exp 2, positive β means color > material (more redundant). See individual def docstrings for interpretation.
- beta : ℚ
Fixed-effect coefficient
- se : ℚ
Standard error
- tStat : Option ℚ
t-statistic (when reported)
- significant : Bool
All reported effects are p < .0001
Instances For
Equations
Equations
- One or more equations did not get rendered due to their size.
Instances For
Material → higher error rates (§2.3: β = 0.48, SE = 0.12, p < .0001). Log odds of incorrect response.
Equations
- KursatDegen2021.exp1_error = { beta := 0.48, se := 0.12, significant := true }
Instances For
Material → slower RTs (§2.3: β = 5.44, SE = 4.74, t = 11.49, p < .0001). RT difference in ms (material − color). NOTE: The paper's SE and t are inconsistent (5.44/4.74 ≈ 1.15 ≠ 11.49); likely SE = 0.474 (giving 5.44/0.474 ≈ 11.48). Values as printed.
Equations
- KursatDegen2021.exp1_rt = { beta := 5.44, se := 4.74, tStat := some 11.49, significant := true }
Instances For
Color used redundantly more than material (§3.3: β = 2.32, SE = 0.64, p < .0001). Log odds of including the redundant modifier.
Equations
- KursatDegen2021.exp2_redundancy = { beta := 2.32, se := 0.64, significant := true }
Instances For
The strong version of the perceptual difficulty hypothesis — within-property-type difficulty predicts item-level redundancy — is not supported (§3.3: insufficient speakers for material items).
Equations
Instances For
Material → higher error rates in context (§4.3: β = 0.96, SE = 0.09, p < .0001).
Equations
- KursatDegen2021.exp3_error = { beta := 0.96, se := 9e-2, significant := true }
Instances For
Material → slower RTs in context (§4.3: β = 0.24, SE = 0.018, t = −59.62, p < .0001). Log-transformed RT.
Equations
- KursatDegen2021.exp3_rt = { beta := 0.24, se := 18e-3, tStat := some (-59.62), significant := true }
Instances For
Material is harder to perceive than color: both error and RT effects are significant in Exp 1 (isolated properties) and Exp 3 (in context).
All difficulty effects have positive β: material produces more errors and slower RTs than color.
Color is used redundantly more than material: positive β in Exp 2.
The core finding: perceptual difficulty and redundant use are anti-correlated across property types. Material is harder to perceive (positive β in Exps 1, 3) AND less redundantly used (positive β in Exp 2 means color > material). All effects significant.
The full redundancy prediction requires the incremental CI-RSA model
([WD21]), which processes utterances word-by-word. The
incremental model's three predictions are verified as theorems in
WaldonDegen2021.lean — here we re-export the key result showing that
redundant color > redundant size in English, which is the color/size
analogue of the color/material asymmetry tested in Exp 2.
The CI-RSA incremental model predicts English speakers use redundant color more than redundant size (Waldon & Degen 2021, Prediction 1). This is the color/size version of the color/material asymmetry observed in Exp 2. Stated as the chain-rule trajectory comparison on the exact-ℚ speaker face.