Diagnosis biases

This article examines the cognitive biases that affect tree diagnosis in amenity arboriculture. Starting from the observation that the human brain is not a tool for reading reality but for assessing it, the author explores how paradigms, cognitive dissonance and motivated reasoning influence diagnostic outcomes. Drawing on the history of medicine, including the cases of Semmelweis and Pasteur, the article demonstrates that resistance to new concepts in arboriculture follows the same cognitive patterns observed in other disciplines. The author presents an original experiment conducted in three training centres, showing that the title of a survey specification alone significantly alters the recommendations made by evaluators, revealing the power of anchoring and pressure biases. A taxonomy of twelve diagnostic biases specific to amenity arboriculture is proposed, along with practical strategies for reducing their influence through reflexivity and evidence-based practices. Published in ARB Magazine, Issue 199, Winter 2022, The Arboricultural Association. Mots-clés : diagnostic bias cognitive bias clinical arboriculture tree risk assessment anchoring bias reflective practice amenity arboriculture paradigm evidence-based practice diagnosis methodology