Table 2.

Phases of the disappearing object task

Phase	Object location and barrier placement (if present)	Criterion for reaching next phase
Shaping Phase (Stage 1)	Object placed on floor next to dog, dog encouraged verbally and by pointing to touch the object (successful trial recorded when object is touched)	5 successful consecutive trials
Shaping Phase (Stage 2)	Object moved slightly closer to boxes with each successful trial	Object reaches boxes
Shaping Phase (Stage 3)	Object placed midway between two (randomly selected) boxes	10 successful trials
Shaping Phase (Stage 4)	Object placed behind box	8 trials (2 per box)
Training phase	Object placed behind box and barrier put in place momentarily (0 s to habituate dog to presence of barrier) then removed before releasing dog	12 trials (3 per box)
Testing phase	Object placed behind box and barrier then put in place for either 0, 60 or 120 s (memory retention interval) before releasing dog	12 trials (1 per box per retention interval)