Fig. 15. Distances averaged over 200 trials where the agent has returned from a beacon 0.75 distance units away to the fictive nest position and is performing the search behaviour. Top line: average distance of agent from the nest; linear regression fitted is d=1.5820x10^–6t+0.0519. Middle line: average distance of agent from home vector (HV) zero point (see text); model fitted is d=1.0598x10^–6t+0.0496. Bottom line: average distance of HV zero point from nest; linear regression model (not plotted) is d=1.0484x10^–6t+0.0091. The middle line, which increases during the search behaviour, suggests the agent is `deliberately' searching further from the nest the longer it has been searching.