Fidelity Versus Validity Using Anendophasia as an Example: Commentary on Nedergaard and Lupyan (2024) and Lind (2025)

Abstract

Nedergaard and Lupyan (2024) presented four studies aimed at validating anendophasia (i.e., experiencing no inner speech). ¹ However, Lind (2025) held that no one, including Nedergaard and Lupyan, has demonstrated that anendophasia exists. In both articles, the authors support their positions using the findings of descriptive experience sampling. Here, I show that descriptive experience sampling is a fidelity-aspiring method; I highlight the distinction between fidelity and validity (an important distinction for psychological science in general and for anendophasia in particular). Anendophasia is an experiential phenomenon, not a construct, and therefore requires incorporating fidelity-based investigations. Nedergaard and Lupyan treated anendophasia as a construct (providing validity-based investigations), but drew phenomenon-based conclusions. I distinguish between completely and mostly anendophasic individuals, noting that, in practice, that distinction might be impossible to make. I suggest that anendophasic (or at least mostly anendophasic) individuals do in fact exist (probably frequently) and are worthy of fidelity-based (as well as validational) investigations.