**1. Introduction**

24 Advances in Object Recognition Systems

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Episodic memory is characterized by Tulving (1983, 2002) as a discrete form of memory that involves mentally re-enacting previously experienced events. Traditionally, the investigation of episodic memory has been restricted to human subjects because the ability to mentally re-enact past experiences suggests that it requires self-consciousness and the ability to mentally travel forward and backward in time (Tulving, 1983, 2002). Because of the difficulty of demonstrating these abilities without the use of complex verbal language, many believed that episodic memory could not be studied in non-humans. However, through a series of elegant experiments, Clayton, Dickinson and their colleagues (e.g., Clayton & Dickinson, 1998) have developed a paradigm that allows researchers to model some aspects of episodic memory in non-humans. In particular, they focus on the abilities of food-caching birds to represent the "what/where/when" of an event into a single tripartite code. While this model has opened up the field of episodic memory to testing in non-humans, it is not easily applied to non-caching species. More recently, Eacott and Norman (2004) have developed a paradigm using object recognition that allows researchers to model episodic memory in a wider variety of non-human animals. Their paradigm involves altering the "what/where/*when*" code of Clayton and Dickinson to a tripartite code consisting of "what/where/*which.*"

In this chapter, we make the argument that this use of object recognition is a better paradigm for studying episodic memory in non-humans. We begin with a description of episodic memory and the paradigms used to study it in non-human animals. We then describe studies of object recognition in non-human animals and studies that use object recognition to test episodic-like memory in rodents and pigs. And finally, we discuss how this research complements the growing field of episodic-like memory in non-human animals.
