This is an excellent article. Perhaps it could be shortened a little, or some material such as methods could go in a subsection. The authors' preferred theoretical explanation of boundary extension is somewhat speculative (I am not fully convinced), but interesting: that it is an error in source memory. It might be helpful to have a short paragraph on further questions about boundary extension.
This is a very nice summary of boundary extension.
This is a nice, detailed overview of boundary extension. It takes a bit more of a theoretical stand on the preferred interpretation for boundary extension than I would expect for an encyclopedia entry. Perhaps the authors could make it a little more neutral. It might also be nice to add a section on unresolved issues and discrepancies with existing accounts. The entry is also fairly long for a brief review of this sort.
A couple minor notes: line 3 is missing an "of" in error of commission. The pros and cons section mentions 3 distinctive patterns but the numbered list after the colon only has 2. The term "ocular occlusion" needs to be defined -- it's jargon.