Seven reasons to (still) doubt the existence of number adaptation: A rebuttal to Burr et al. and Durgin

• Published in: Cognition 2025-01, Vol.254, p.105939, Article 105939
• Main Authors: Yousif, Sami R., Clarke, Sam, Brannon, Elizabeth M.
• Format: Article
• Language: English
• Subjects: Adaptation, Physiological - physiology; Humans; Mathematical Concepts; Visual Perception - physiology
• ISSN: 0010-0277; 1873-7838; 1873-7838
• DOI: 10.1016/j.cognition.2024.105939

Does the visual system adapt to number? For more than fifteen years, most have assumed that the answer is an unambiguous “yes”. Against this prevailing orthodoxy, we recently took a critical look at the phenomenon, questioning its existence on both empirical and theoretical grounds, and providing an alternative explanation for extant results (the old news hypothesis). We subsequently received two critical responses. Burr, Anobile, and Arrighi rejected our critiques wholesale, arguing that the evidence for number adaptation remains overwhelming. Durgin questioned our old news hypothesis — preferring instead a theory about density adaptation he has championed for decades — but also highlighted several ways in which our arguments do pose serious challenges for proponents of number adaptation. Here, we reply to both. We first clarify our position regarding number adaptation. Then, we respond to our critics' concerns, highlighting seven reasons why we remain skeptical about number adaptation. We conclude with some thoughts about where the debate may head from here.