Figure 1. Three distinct protocols.

(A) Protocol 1: In our standard protocol (as used in Nonaka et al, 2017), there was a single encoding trial consisting of three runs (black path) out to either of two sandwells (one of which was rewarded) followed by returns to the same startbox (green paths). After a memory delay, a choice trial included a run out (red path) to choose amongst 6 sandwells (only one correct) and then a return once again to same startbox. (B) Protocol 2: The primary modification was the use of four different startboxes within a session, thereby changing from 3 rewards at encoding within a single trial (Protocol 1) to three encoding trials each with a single reward pellet. The green return paths are representative in displaying the confusion of the animals about the location to which to return. The choice trial was from the fourth location of the day. (C) Protocol 3: The primary further modification was the use of a fixed 'home-base' (blue) to which the animals had to carry the food that they had dug up (green paths). Encoding was now divided into only 2 trials, but included the opportunity to run out of the home-base back to the sandwell on each trial (i.e. 4 rewards during encoding). The recall choice trial (and any probe trial) was started from a novel location on that session, as in Protocol 2.