IC-056Influence scores of pretraining documents correlate across reasoning queries of the same type, indicating Command R 7B and 35B rely on shared procedural knowledge rather than retrieving specific answers

Laura Ruis, Maximilian Mozes, Juhan Bae, Siddhartha Rao Kamalakara, Dwaraknath Gnaneshwar, Acyr Locatelli, Robert Kirk, Tim Rocktäschel, Edward Grefenstette, Max Bartolo

SourceProcedural Knowledge in Pretraining Drives Reasoning in Large Language Models

Using EK-FAC influence functions, the authors rank 5 million pretraining documents by their influence on model completions for 40 reasoning and 40 factual queries. For reasoning queries of the same mathematical type (e.g., calculating slope between different point pairs), the influence scores of all 5 million documents show a strongly significant positive Pearson correlation (p < 4e-8), while factual queries show no such correlation (p ~ 4e-3). Qualitative inspection confirms the top influential documents for slope queries contain code or math implementing the slope formula, appearing in the top 100 documents for 16/20 queries (7B) and all 20 queries (35B). Control queries that are superficially similar but require no reasoning show no such correlation.

Evidence
correlational
Key metric
Pearson's r p-values all below 4e-8 for same-type reasoning queries; p-values all around 4e-3 for factual queries; slope procedure documents in top 100 for 16/20 queries (7B, 38 times) and all 20 queries (35B, 51 times); 7 unique code documents and 13 math documents implementing slope found
Caveat
Influence is computed over a 2.5B token sample of pretraining data, not the full training set; only MLP parameters are considered (attention treated as fixed); the authors note an alternative explanation that the truly influential documents for reasoning may be too infrequent to appear in the sample
Model
Cohere Command R 7B, 35B
Methods
EK-FAC Influence Functions [primary], Pearson correlation [eval]
Related findings
IC-057, IC-058, IC-059
Extraction
automatic-extraction