Transformers underlie almost all state-of-the-art language models in computational linguistics, yet their cognitive adequacy as models of human sentence processing remains disputed. In this work, we use a surprisal-based linking mechanism to systematically evaluate eleven autoregressive transformers of varying sizes and architectures on a more comprehensive set of English agreement attraction configurations than prior work. Our experiments yield mixed results: While transformer predictions generally align with human reading time data for prepositional phrase configurations, performance degrades significantly on object-extracted relative clause configurations. In the latter case, predictions also diverge markedly across models, and no model successfully replicates the asymmetric interference patterns observed in humans. We conclude that current transformer models do not explain human morphosyntactic processing, and that evaluations of transformers as cognitive models must adopt rigorous, comprehensive experimental designs to avoid spurious generalizations from isolated syntactic configurations or individual models.
Figures & tables
Subject
Number
Grammatical?
Example
(a/b)
singular
grammatical
The slogan on the poster(s) unsurprisingly was designed …
(c/d)
singular
ungrammatical
*The slogan on the poster(s) unsurprisingly were designed …
(e/f)
plural
grammatical
The slogans on the poster(s) unsurprisingly was designed …
(g/h)
plural
ungrammatical
*The slogans on the poster(s) unsurprisingly were designed …
Table 1: The eight conditions of Experiment 1: agreement attraction in prepositional modifier constructions. Attraction is theoretically possible when the number of the distractor (here “poster(s)”) differs from subject number. In humans, attraction is observed only in (c/d).
Figure 1: Surprisal predictions across models and conditions for Experiment 1. Top left panel: Schematic human performance. Each sub-panel shows the effect of attraction in one of the four relevant configurations (Table 1 ): Singular subjects (sg) in sub-panels 1–2; plural (pl) in sub-panels 3–4. Geometric means, confidence intervals 95%.
Reference
GPT
Bloom
XGLM
Gemma-3
Subject
Gramm.
Human
Theor. poss.
120M
2 (127M)
2 (744M)
560M
1.7B
3B
564M
1.7B
2.9B
1B
4B
singular
gramm.
↗
↘
↘
singular
ungramm.
↘
↘
↘
↘
↘
↘
↘
↘
↘
↘
↘
↘
↘
plural
gramm.
↗
plural
ungramm.
↘
↘
↘
↘
↘
↘
↘
↘
↘
↘
Table 2: Experiment 1: Observed and predicted agreement attraction effects for prepositional modifiers. Gramm. : (un)grammatical condition. Arrows indicate significant effects: upward = inhibitory, downward = facilitatory. Theor. poss. : effects that are explainable in terms of agreement attraction.
RC subject number
Grammatical?
Example
(a/b)
singular
grammatical
The marine(s) who the officer wants to promote …
(c/d)
singular
ungrammatical
*The marine(s) who the officer want to promote …
(e/f)
plural
grammatical
The marine(s) who the officers want to promote …
(g/h)
plural
ungrammatical
*The marine(s) who the officers wants to promote …
Table 3: The eight conditions of Experiment 2: agreement attraction in object-extracted relative clause constructions. Attraction is theoretically possible when the number of the distractor (here “marine(s)”) differs from subject number. In humans, attraction is observed only in (c/d).
Figure 2: Surprisal predictions across models and conditions for Experiment 2. Top left panel: Schematic human performance. Sub-panels show attraction effects in one of the four relevant configurations (able 3 ): Singular RC-subjects (sg) in sub-panels 1–2; plural (pl) in sub-panels 3–4. Geometric means, confidence intervals 95%.
Reference
GPT
Bloom
XGLM
Gemma-3
RC subject
Gramm.
Human
Theor. poss.
120M
2 (127M)
2 (744M)
560M
1.7B
3B
564M
1.7B
2.9B
1B
4B
singular
gramm.
↗
↘
↘
↗
↗
singular
ungramm.
↘
↘
↘
↘
↘
↘
↘
↘
↘
↘
plural
gramm.
↗
↘
↘
↘
↘
↘
↘
↘
↘
↘
↘
plural
ungramm.
↘
↘
↘
↘
↘
↘
↘
↘
↗
Table 4: Experiment 2: Observed and predicted agreement attraction effects for relative clauses. Gramm. : (un)grammatical condition. Arrows indicate significant effects: upward = inhibitory, downward = facilitatory. Theor. poss. : effects that are explainable by agreement attraction. NB. All predicted effects in the plural/grammatical configuration are in the direction that cannot be explained.
Appendix figures & tables8 assets
Supplementary material from the paper’s appendix.
Appendix
Fixed effects
Estimate
Std. Error
t value
(Intercept)
5.51182
0.35612
15.478
pl
0.04180
0.07201
0.580
attr
-0.11356
0.07201
-1.577
pl × attr
0.08413
0.10184
0.826
Appendix
Table 5: Regression results for prepositional modifier construction, grammatical sentences. Observations: 1056. Random effects: by-item and by-model random intercepts (item: 24 levels; model: 11 levels); random slopes were omitted because models with a maximal random-effects structure did not reliably converge.
Fixed effects
Estimate
Std. Error
t value
(Intercept)
12.7320
0.4395
28.97
pl
-1.5696
0.1036
-15.14
attr
-2.3755
0.1036
-22.92
pl × attr
2.0008
0.1466
13.65
Appendix
Table 6: Regression results for prepositional modifier construction, ungrammatical sentences. Observations: 1056. Random effects: by-item and by-model random intercepts (item: 24 levels; model: 11 levels); random slopes were omitted because models with a maximal random-effects structure did not reliably converge.
Fixed effects
Estimate
Std. Error
t value
(Intercept)
11.8113
0.4490
26.306
pl
-0.8533
0.1128
-7.563
attr
0.1168
0.1128
1.035
pl × attr
-0.9307
0.1596
-5.833
Appendix
Table 7: Regression results for object-extracted relative clauses, grammatical sentences. Observations: 2112. Random effects: by-item and by-model random intercepts (item: 48 levels; model: 11 levels); random slopes were omitted because models with a maximal random-effects structure did not reliably converge.
Fixed effects
Estimate
Std. Error
t value
(Intercept)
15.4838
0.4439
34.880
pl
2.7572
0.1388
19.859
attr
-0.9144
0.1388
-6.586
pl × attr
0.3678
0.1963
1.873
Appendix
Table 8: Regression results for object-extracted relative clauses, ungrammatical sentences. Observations: 2112. Random effects: by-item and by-model random intercepts (item: 48 levels; model: 11 levels); random slopes were omitted because models with a maximal random-effects structure did not reliably converge.
Fixed effects
Estimate
Std. Error
t value
(Intercept)
5.5118
0.3783
14.570
ungram
7.2202
0.1076
67.082
attr
-0.1136
0.1076
-1.055
ungram × attr
-2.2620
0.1522
-14.860
Appendix
Table 9: Regression results for prepositional modifier construction, singular subject. Observations: 1056. Random effects: by-item and by-model random intercepts (item: 24 levels; model: 11 levels); random slopes were omitted because models with a maximal random-effects structure did not reliably converge.
Fixed effects
Estimate
Std. Error
t value
(Intercept)
5.55362
0.36811
15.087
ungram
5.60875
0.08834
63.491
attr
-0.02943
0.08834
-0.333
ungram × attr
-0.34526
0.12493
-2.764
Appendix
Table 10: Regression results for prepositional modifier construction, plural subject. Observations: 1056. Random effects: by-item and by-model random intercepts (item: 24 levels; model: 11 levels); random slopes were omitted because models with a maximal random-effects structure did not reliably converge.
Fixed effects
Estimate
Std. Error
t value
(Intercept)
11.8113
0.4759
24.818
ungram
3.6725
0.1384
26.531
attr
0.1168
0.1384
0.844
ungram × attr
-1.0312
0.1958
-5.268
Appendix
Table 11: Regression results for object-extracted relative clauses, singular subject. Observations: 2112. Random effects: by-item and by-model random intercepts (item: 48 levels; model: 11 levels); random slopes were omitted because models with a maximal random-effects structure did not reliably converge.
Fixed effects
Estimate
Std. Error
t value
(Intercept)
10.9580
0.3971
27.593
ungram
7.2830
0.1140
63.869
attr
-0.8139
0.1140
-7.137
ungram × attr
0.2673
0.1613
1.657
Appendix
Table 12: Regression results for object-extracted relative clauses, plural subject. Observations: 2112. Random effects: by-item and by-model random intercepts (item: 48 levels; model: 11 levels); random slopes were omitted because models with a maximal random-effects structure did not reliably converge.