In this paper we provide a reader friendly axiomatic characterization of the default bias extended choice rule, in the framework available in lecture 3 of Rubinstein (2016). As noted there “experimental evidence and introspection tell us that a default option is often viewed positively by a decision maker, a phenomenon known as the status quo bias”. A different axiomatic characterization of the extended choice rule is available in that lecture. Our proof makes use of the Szpilrajn's extension which for finite sets (as in our case) has a very simple proof.
