Ten years of research into avian models of episodic-like memory and its implications for developmental and comparative cognition

Episodic memory refers to the ability to remember specific personal events from the past. Ever since Tulving first made the distinction between episodic memory and other forms of declarative memory in 1972, most cognitive psychologists and neuroscientists have assumed that episodic recall is unique to humans. The seminal paper on episodic-like memory in Western scrub-jays (Aphelocoma californica) by Clayton and Dickinson [4] has inspired a number of studies and in a wide range of species over the past 10 years. Here we shall first review the avian studies of what-where-when memory, namely in the Western scrub-jays, magpies, black-capped chickadees and pigeons; we shall then present an alternative approach to studying episodic-like memory also tested in pigeons. In the second and third section we want to draw attention to topics where we believe the bird model could prove highly valuable, namely studying development of episodic-memory in pre-verbal children, and the evolution and ontogeny of brain areas subserving episodic(-like) memory.

Research highlights▶ Western scrub-jays are capable of episodic-like memory, in that they recall what happened, when and where, in an integrated representation, that can also be used flexibly to update these memories when new information becomes available after the initial information was encoded. ▶ Magpies and black-capped chickadees have been shown to possess what-where-when memories, and future work should test whether the birds’ memories for what happened where and when is stored as an integrated representation, and its capacity to be flexibly deployed. ▶ Studies using non-verbal tasks can address the question of whether children under the age of four are incapable of episodic recall or they simply cannot share their episodic memories in the absence of language. Furthermore, the relationship between episodic-like memory and episodic memory can be inferred by studying the relative timing at which such memories develop in young children. ▶ Birds are a highly promising biomedical model to study episodic-like memory and episodic recall with the respective underlying brain areas due to functional as well as some mechanistic similarities between the avian and mammalian hippocampus.