Many physics, chemistry, and computer science studies suffer from these as well. Science is hard, and there are a lot of constraints on research. Typically the first finding is made with limited funding, meaning limited ability to do the study right. Also, usually there is no perfect study, just a balancing of different strengths and weaknesses. That is why in psychology and neuroscience research, we talk about converging evidence. 'Converging' here means evidence employing multiple modalities, measures, and procedures. This might mean combining evidence from animal and human models, molecular and neuroimaging, etc. Its messy stuff, and every approach has tradeoffs.

*Seeing a plausible mechanism underlying a theory isn’t enough. So I’m writing this comment as a placeholder. Who here has checked the source studies?*

You are writing a comment as a placeholder for what exactly? So far in your comment, it just seems like an excuse to bash on Psychology research, which is too often a cheap thrill here on HN, and usually from someone who has read little serious psychological research save the most flashy in-the-news findings.

*Roughly speaking what is the total number of people in all studies pertaining to this claimed effect?*

This appears to be a logical question, and within the immediate context, understandable. However, the more informed context would understand that the so-called "Doorway Effect" is just a specific example of a more general and prevalent cognitive phenomenon: The role of spatio-temporal context in memory and cognition.

You ask for specific sample sizes from studies that use tasks that look at the effect passing through doors, and well there may be just an of a few hundred.

But, I being somewhat knowledgeable int he field (PhD in memory research) would instead ask: What is it about doorways that could cause such an effect. Ah yes, it involves a change in the spatiotemporal context. What is the evidence that context changes impose costs to memory function? Well: https://scholar.google.com/scholar?hl=en&as_sdt=0%2C5&q=cont...

So many, for so long.. Its a HUGE literature. Point is, its not about doors, and this is just one finding in a long list of similar findings that created CONVERGING evidence of a phenomenon.