&gt; “If you make the altered task too different, people do not get the gain we observed during reconsolidation. The modification between sessions needs to be subtle”<p>I saw that quote but I have no idea what the researcher is basing it on. As described, the study can only show that blocking&#x2F;interleaving is superior to massed practice:<p>&gt; The volunteers were split into three groups, and each spent 45 minutes practising this. Six hours later, one of the groups was asked to repeat the same training exercise again, while another group performed a slightly different version that required different squeezing force to move the cursor. The third group only completed the first training session, so they could act as a control.<p>That is, as described, there is no &#x27;interleaved subtle-difference&#x27; vs &#x27;interleaved gross-difference&#x27; comparison, because they only compared &#x27;near-zero-practice&#x27; vs &#x27;massed-practice&#x27; vs &#x27;interleaved-practice&#x27;. They seem to be wildly extrapolating from there, in ignorance of a good deal of prior work.