Yes, the devil always seems to be in the details in psychology experiments. Were the experimenters giving subtle cues to the child, and was this simply a test at how deftly the child picked up these cues? What was the exact wording of the “deal” offered to the child and would a wording change alter the results? Was the experiment conducted at a time of food scarcity or abundance? What were the prevailing cultural norms of how a child “ought” to behave? Would the results change if average child age was 6 months older or younger when experiment was conducted? What was in the drinking water and the air and the paint at the testing site? (With strong claims in the literature that all these are correlated with measures such as average population IQ!)

In the face of all these potential confounders, more statistics and controls seem necessary than, say, in a physics collider experiment on electrons (each electron possessing exactly two characteristics, location and spin, and all such electrons behaving identically regardless of location or time). Yet, even in this setting of simplicity and reproducibility, physicists have still found it necessary to establish a stringent, five-sigma threshold for discovery — 3 sigma anomalies come and go. Such a stringent threshold is unthinkable in psychology due to practical considerations. Ergo, it’s hard for to see how psychology can become a reliable empirical science.