Kea (Nestor Notabilis) and the Ephemeral Reward Task: Success and Hurdles Explored

Abstract The Ephemeral Reward Task, employed in animal cognition research, appears deceptively straightforward but is, in reality, highly counterintuitive. Our study delved into the performance of kea (Nestor notabilis) on this task as well as investigating their motivation to acquire two pieces of reward as opposed to one in a basic quantity discrimination task. Both experiments were conducted using setups that featured visible and non-visible rewards. The results unveiled that a greater proportion of kea successfully solved the Ephemeral Reward Task when the rewards were directly visible, compared to when they were non-visible. Likewise, in the Quantity discrimination task, the kea exhibited a preference for selecting two pieces of reward over one, with higher success rates observed in the setup with visible rewards. These findings indicate that kea possess the potential to meet the success criteria in both tasks and demonstrate the ability to discriminate between quantities of rewards. Nonetheless, it is worth noting that not all subjects successfully solved the Quantity discrimination task, and even those that did accomplish it, did not do so spontaneously from the first session. Additionally, the study emphasizes the necessity to reevaluate the standardized 100-trial limit imposed by previous studies and advocates for employing testing to a criterion and adapting methodologies to account for individual motivations, ecological relevance, and prior experiences.