In this chapter, we delve into the intriguing world of memory development, from infancy to adulthood. We begin by emphasizing the fundamental role memory plays in learning. We explore two distinct memory systems: one we are conscious of and another that operates behind the scenes. We examine various memory types, their testing methods, and the brain regions responsible for them. Our focus then shifts to episodic memory, questioning its exclusivity to humans. We dissect the brain structures involved in memory formation and their developmental changes. Additionally, we explore the interconnectedness of memory, thinking processes, and decision-making. Our goal in this chapter is to provide a comprehensive understanding of memory development across different life stages, laying the groundwork for a deeper grasp of this intricate cognitive process.

Computational models of episodic memory provide tools to better understand the latent neurocognitive processes underlying retention of information about specific events from one’s life. This chapter discusses the representations, associations, and dynamics of influential models of episodic memory, with particular emphasis on models of recognition and free recall tasks. In-depth discussion and model-fitting results of four models – the retrieving effectively from memory (REM) model, the bind cue decide model of episodic memory (BCDMEM), the search of associative memory (SAM) model, and the temporal context model (TCM) – are provided to facilitate understanding of these models, as well as similarities and differences between them. Alternative modeling frameworks, including neural network models, are discussed. Throughout, the importance of context in models of episodic memory is emphasized, particularly for free recall tasks.

The idea that memory behavior relies on a gradually changing internal state has a long history in mathematical psychology. This chapter traces this line of thought from statistical learning theory in the 1950s, through distributed memory models in the latter part of the twentieth century and early part of the twenty-first century through to modern models based on a scale-invariant temporal history. We discuss the neural phenomena consistent with this form of representation and sketch the kinds of cognitive models that can be constructed and connections with formal models of various memory tasks.

This chapter discusses the kind, episodic memory, which has recently garnered a great deal of attention from philosophers. In light of current empirical work, it has become increasingly challenging to accept an influential and intuitively plausible philosophical account of memory, namely the “causal theory of memory.” It is unlikely that each episodic memory can be associated with a trace or “engram” that can be shown to be linked by an uninterrupted causal chain to an episode in the thinker’s past. Some philosophers and psychologists have responded by effectively abandoning the category of episodic memory and assimilating memory to imagination or hypothetical thinking. But I argue that there is still room for a distinct cognitive kind, episodic memory, a cognitive capacity whose function it is to generate representational states that are connected to past episodes in the experience of the thinker, which bear traces of these episodes that are individuated not at the neural level but at the “computational level.”

Metacognition, or awareness of one’s cognition, involves several different but overlapping cognitive abilities, such as working memory, explicit memory, monitoring, and control. These processes are guided by multiple internal or external signals, including memory signals in the case of metamemory. Primate species including apes and rhesus monkeys have demonstrated that they can respond to both internal and external signals, and like humans, these signals can be additive and fallible. In the past few decades, there have been about five dozen studies published on nonhuman animal metacognition and while robust results have been obtained, rigorous experimental paradigms have been employed, and general progress has been made, there is a still a lot we do not know. For example, there are only a few species whose metacognitive abilities have been relatively well characterized, and even in those species significant open questions remain. After an introduction, what is known and what is not known will be explored. Similarities and differences among different primate species will be highlighted. As the chapter is comparative in nature, disparities in behavioral findings across apes and monkeys, New World and Old World monkeys, as well as primates and non-primate species will be explored. The extent to which methods can or cannot be standardized across species will be discussed, with special consideration of species’ ecological niches and experimental methods typically employed. Limitations in nonhuman metacognition research will also be considered, including the fact that most metacognition studies focus on just one species. Finally, possibilities for promising future directions in research will be offered.

Mental time travel involves remembering personal past events (i.e., episodic memory) and thinking about future ones (i.e., future thinking). Despite empirical evidence showing that animals might be capable of mental time travel, some still remain skeptical about this issue. The aim in this chapter will be to reflect on the concept of episodic memory and future thinking as well as on the experimental approaches used in comparative psychology to study these abilities. A critical analysis of both the conceptualization of mental time travel and the experimental paradigms will be provided. I will finish by questioning the extent to which the sense of past has been addressed in this type of research and by suggesting lines of future research.

This chapter presents the hypothesis that working memory and language evolved in tandem. It reviews the evolutionary origins of each of the components of Baddeley’s working memory model and their role in the evolution of language. The chapter reviews the gradualist position that language did evolve slowly from aurally directed early primate calls and notes that the primary purpose of language has always been communication. The chapter also presents the novel idea that the pragmatics of speech (the purposes of speech) also evolved in tandem with the evolution of working memory. The chapter also reviews the saltationist idea that something happened to language more recent than 100,000 years ago, and that is the release of the fifth pragmatic of speech, the subjunctive mood, which expresses wishes and ideas contrary to fact. The subjunctive mood required fully modern working memory capacity, sufficient phonological storage capacity, and an enhanced visuospatial sketchpad, which are also critically involved in episodic memory recall and simulation. The phenotypic result of this genotype meant that thought experiments could be conducted in a recursive manner. We propose that the fruits of Homo sapiens’s cultural explosion, cave art, creative figurines, and highly ritualized burials, were the direct result of the wishes and imaginings that arise from subjunctive thinking and subjunctive language.

To conceptualize the communicative role of working memory (WM), the Ease-of-Language Understanding (ELU) model was proposed (e.g., Rönnberg, 2003; Rönnberg et al., 2008, 2013, 2019, 2020). The model states that ease of language understanding is determined by the speed and accuracy with which the signal is matched to existing multimodal language representations. When matching is fast and complete, language understanding is effortless; this process may be facilitated by predictions based on the contents of WM. However, when the contents of the language signal mismatches with existing representations, WM is triggered to access knowledge in semantic long-term memory (SLTM) and personal experience from episodic long-term memory (ELTM) – promoting inference-making and postdictions in WM. The interplay between WM and LTM is fundamental to language understanding; its efficiency becomes apparent in adverse conditions and its breakdown may explain cognitive decline and dementia. Empirical support, limitations, and future studies will be discussed.

Memory for our own personal experiences comprises episodic memory. Episodic memory in people is characterized by multiple events and the sequential order of such events. Here, I summarize research that suggests that rats remember multiple events and the sequential order of events. These studies focus on remembering items-in-context and the replay of episodic memories. Next, I explore connections between episodic memory and hippocampal replay. Finally, I explore open questions for future research. The approaches described here may be used to explore the evolution of cognition.

The hippocampus of mammals, birds, reptiles, and amphibians is a fundamental brain structure for certain forms of relational memory. We review here the experimental evidence indicating that the hippocampal pallium of teleost fish, like the hippocampus of land vertebrates, is involved in relational map-like spatial memory, endowing fish behavior with the capability for allocentric navigation and allowing the flexible expression of spatial memory. In addition, recent evidence suggests that the teleost fish hippocampal pallium plays an important role in the processing of the temporal dimensions of relational memory. The functional similarities in the hippocampal pallium of taxa that diverged millions of years ago suggest the possibility that some features of the hippocampal networks allowing the processing of the spatial as well the temporal dimensions of relational associative memories appeared early in vertebrate evolution and were conserved through phylogenesis.

In this chapter, I focus on the origins of memory, posing the question of what were the very initial forces that led to the evolution of learning. Although the common answer is that the function of memory is to allow future behavior to benefit from past experiences, I argue that future benefit is too small to overcome the large energetic costs associated with the neural mechanisms that support memory formation. Instead, I advance the hypothesis that memory evolved to solve an immediate problem, the identification of novel biologically significant objects. Although such identification is often attributed to innate recognition, reliance on genetic encoding would require enormous genomic space and would be unreliable when phylogenetically novel but important objects were encountered. Some often-unappreciated features of Pavlovian conditioning make it an ideal mechanism for immediate perceptual identification of biologically important objects. Although episodic memory is most clearly identified with this recognition process, immediate perceptual identification may be a general function of several memory systems.