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Cited by 27Memory Processes and InfluencesMemory and Neural MechanismsCognitive Functions and Memory

Is episodic-like memory like episodic memory?

Open access
Davies, James R., Clayton, Nicola S.·2024·Philosophical Transactions of the Royal Society B: Biological Sciences
DOI 10.1098/rstb.2023.0397PMC PMC11449162
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Abstract

Episodic memory involves the conscious recollection of personally experienced events and when absent, results in profound losses to the typical human conscious experience. Over the last 2.5 decades, the debate surrounding whether episodic memory is unique to humans has seen a lot of controversy and accordingly has received significant research attention. Various behavioural paradigms have been developed to test episodic- like memory; a term designed to reflect the behavioural characteristics of episodic memory in the absence of evidence for consciously experienced recall. In this review, we first outline the most influential paradigms that have been developed to assess episodic-like memory across a variety of non-human taxa (including mammals, birds and cephalopods), namely the what–where–when memory, incidental encoding and unexpected question, and source memory paradigms. Then, we examine whether various key features of human episodic memory are conceptually represented in episodic-like memory across phylogenetically and neurologically diverse taxa, identifying similarities, differences and gaps in the literature. We conclude that the evidence is mixed, and as episodic memory encompasses a variety of cognitive structures and processes, research on episodic-like memory in non-humans should follow this multifaceted approach and assess evidence across various behavioural paradigms that each target different aspects of human episodic memory. This article is part of the theme issue ‘Elements of episodic memory: lessons from 40 years of research’.

AI snapshot

Written from the paper’s full text.

TL;DR

This review asks whether episodic-like memory in non-human animals is like human episodic memory, concluding that the evidence is mixed. It argues that episodic-like memory shares some features with episodic memory but differs in others, especially across phylogenetically and neurologically diverse taxa.

Key findings

  • The review concludes there is sufficient evidence that, like episodic memories, episodic-like memories are formed over a single occurring episode and, in mammals at least, depend on the hippocampus and show natural age-related decay in performance.
  • With less certainty, it finds some evidence that both processes are reconstructive, involve automatic encoding of associated event details, and correlate with future planning.
  • There is relatively strong evidence that in non-mammalian taxa—namely cuttlefish and birds—episodic-like memory can exist without a hippocampus, or without high-order pallial inputs into the hippocampus, respectively.
  • There is little evidence that episodic-like memory is flexible across contexts in the same way as human episodic memory; most non-human studies are restricted to food-acquiring behaviour or require repeated training.

Methods

  • Narrative review of behavioural paradigms used to test episodic-like memory in non-human taxa, including mammals, birds and cephalopods: what–where–when memory, incidental encoding and unexpected question, and source memory.
  • The paper examines key features of human episodic memory against episodic-like memory evidence: hippocampal dependence, age-related decay, reconstruction, single-episode automatic encoding, future planning, contextual flexibility, and subjective experience.
  • No new empirical data are reported; the analysis synthesizes previously published studies and identifies similarities, differences and gaps in the literature.

Limitations

  • The paper states that the evidence is mixed and that research on episodic-like memory should follow a multifaceted approach across paradigms targeting different aspects of human episodic memory.
  • It states that there are no widely accepted non-linguistic markers of consciousness, making it potentially impossible to establish whether non-human animals have true, conscious episodic memory; future-planning evidence is also described as highly controversial.
  • It notes gaps including little evidence for the structure and flexibility criteria in what–where–when studies, scarce source memory research in non-humans, and no published experimental studies assessing wild subjects on memories for personal, unique events that cannot be explained through non-episodic-like mechanisms.
  • Evident from the text: this is a narrative review without systematic search criteria or quantitative synthesis, so its conclusions depend on the cited literature rather than new meta-analytic estimates.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1098/rstb.2023.0397

Cites

208 of 208 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

0 of 251 cited sources checked · 0 supported · 0 flagged

  • Interpretationreasoning

    The evidence on whether episodic-like memory is like episodic memory is mixed.

    “We conclude that the evidence is mixed, and as episodic memory encompasses a variety of cognitive structures and processes, research on episodic-like memory in non-humans should follow this multifaceted approach and assess evidence across various behavioural paradigms that each target different aspects of human episodic memory.”
    Quote in the paperSubstantial claim
  • Premisecitation

    The same brain activation patterns are generated when people imagine the future as when they remember the past.

    “Indeed, functional magnetic resonance imaging studies on healthy subjects reveal that the same brain activation patterns are generated when people imagine the future as when they remember the past [21–24]”
    Quote in the paperSubstantial claim0 of 4 sources checked
    • cites [21] Buckner RL, Carroll DC. 2007 Self-projection and the brain. Trends Cogn. Sci. 11, 49– 57. (10.1016/j.tics.2006.11.004) 17188554 source

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    • cites [22] Schacter DL, Addis DR, Buckner RL. 2007 Remembering the past to imagine the future: the prospective brain. Nat. Rev. Neurosci. 8, 657– 661. (10.1038/nrn2213) 17700624 source

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    • cites [23] Schacter DL, Addis DR, Buckner RL. 2008 Episodic simulation of future events: concepts, data, and applications. Ann. NY Acad. Sci. 1124, 39– 60. (10.1196/annals.1440.001) 18400923 source

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    • cites [24] Schacter DL, Addis DR, Hassabis D, Martin VC, Spreng RN, Szpunar KK. 2012 The future of memory: remembering, imagining, and the brain. Neuron 76, 677– 694. (10.1016/j.neuron.2012.11.001) 23177955 PMC3815616 source

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  • Premisecitation

    Clayton & Dickinson demonstrated that scrub-jays can encode and use what-where-when memories.

    “Coining the term episodic-like memory, Clayton & Dickinson [52] demonstrated that scrub-jays (a member of the corvid family) can encode and use what–where–when memories.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [52] Clayton NS, Dickinson A. 1998 Episodic-like memory during cache recovery by scrub jays. Nature 395, 272– 274. (10.1038/26216) 9751053 source

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  • Interpretationreasoning

    When information is encoded incidentally and subsequently tested in an unexpected memory assessment, the transformation of this information into a preselected future action is impossible.

    “By contrast, when information is encoded incidentally and subsequently tested in an unexpected memory assessment, the transformation of this information into a preselected future action is impossible [79,82,85,90]”
    Quote in the paperSubstantial claim0 of 4 sources checked
    • cites [79] Zentall TR, Clement TS, Bhatt RS, Allen J. 2001 Episodic-like memory in pigeons. Psychon. Bull. Rev. 8, 685– 690. (10.3758/bf03196204) 11848586 source

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    • cites [82] Zhou W, Hohmann AG, Crystal JD. 2012 Rats answer an unexpected question after incidental encoding. Curr. Biol. 22, 1149– 1153. (10.1016/j.cub.2012.04.040) 22633809 PMC3376895 source

      Not checked in the free run.

    • cites [85] Crystal JD. 2021 Evaluating evidence from animal models of episodic memory. J. Exp. Psychol. Anim. Learn. Cogn. 47, 337– 356. (10.1037/xan0000294) 34618532 source

      Not checked in the free run.

    • cites [90] Crystal JD. 2016 Comparative cognition: action imitation using episodic memory. Curr. Biol. 26, R1226– R1228. (10.1016/j.cub.2016.10.010) 27923129 source

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  • Premisereasoning

    Episodic memory is not a completely independent system and is influenced by wider cognitive processes and cortical areas.

    “While episodic memory does have its own distinct features, i.e. memory for personal events that are mentally re-experienced, and appears to be centralized in the hippocampus, it is not a completely independent system and is influenced by a number of wider cognitive processes and cortical areas.”
    Quote in the paperNot a substantial claim
  • Classified as probably not a substantial claim. 21
  • May combine two claims. 47

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Episodic memory, relative to semantic memory, declines rapidly and dramatically with normal ageing.

    “Similarly, episodic memory, relative to semantic memory, declines rapidly and dramatically with normal ageing [10–15].”
    Quote in the paperNot a substantial claim0 of 6 sources checked
    • cites [10] Craik FI, Jennings JM. 1992 Human memory. In The handbook of aging and cognition (eds FI Craik, T Salthouse), pp. 51– 110. Hillsdale, MI: Lawrence Erlbaum Associates.

      Not checked in the free run.

    • cites [11] Charlton RA, Barrick T, Markus H, Morris R. 2010 The relationship between episodic long-term memory and white matter integrity in normal aging. Neuropsychologia 48, 114– 122. (10.1016/j.neuropsychologia.2009.08.018) 19699215 source

      Not checked in the free run.

    • cites [12] Schacter DL, Koutstaal W, Norman KA. 1997 False memories and aging. Trends Cogn. Sci. 1, 229– 236. (10.1016/S1364-6613(97)01068-1) 21223912 source

      Not checked in the free run.

    • cites [13] Schacter DL, Kaszniak AW, Kihlstrom JF, Valdiserri M. 1991 The relation between source memory and aging. Psychol. Aging 6, 559– 568. (10.1037/0882-7974.6.4.559) 1777144 source

      Not checked in the free run.

    • cites [14] St Jacques PL, Levine B. 2007 Ageing and autobiographical memory for emotional and neutral events. Memory 15, 129– 144. (10.1080/09658210601119762) 17534107 PMC1995658 source

      Not checked in the free run.

    • cites [15] Martinelli P, Sperduti M, Piolino P. 2013 Neural substrates of the self-memory system: new insights from a meta-analysis. Hum. Brain Mapp. 34, 1515– 1529. (10.1002/hbm.22008) 22359397 PMC6870171 source

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  • Probably not a substantial claim: may not pass S2 (checkable), S4 (based).

    Premisenone given

    Episodic memory encompasses a variety of cognitive structures and processes.

    “as episodic memory encompasses a variety of cognitive structures and processes”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    In patients with hippocampal damage, semantic memory largely remains intact but severe deficits in episodic memory are observed.

    “This separation is true of other amnesic patients, especially those resulting from hippocampal damage, whereby semantic memory largely remains intact but severe deficits in episodic memory are observed [6–9].”
    Quote in the paperNot a substantial claim0 of 4 sources checked
    • cites [6] Scoville WB, Milner B. 1957 Loss of recent memory after bilateral hippocampal lesions. J. Neurol. Neurosurg. Psychiatr. 20, 11– 21. (10.1136/jnnp.20.1.11) PMC497229 13406589 source

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    • cites [7] Tulving E, Schacter DL, McLachlan DR, Moscovitch M. 1988 Priming of semantic autobiographical knowledge: a case study of retrograde amnesia. Brain Cogn. 8, 3– 20. (10.1016/0278-2626(88)90035-8) 3166816 source

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    • cites [8] Vargha-Khadem F, Gadian DG, Watkins KE, Connelly A, Van Paesschen W, Mishkin M. 1997 Differential effects of early hippocampal pathology on episodic and semantic memory. Science 277, 376– 380. (10.1126/science.277.5324.376) 9219696 source

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    • cites [9] Aggleton JP, Brown MW. 1999 Episodic memory, amnesia, and the hippocampal-anterior thalamic axis. Behav. Brain Sci. 22, 425– 444. (10.1017/S0140525X99002034) 11301518 source

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    Interpretationcitation

    The hippocampus seems critical in both the retrieval of episodic memories and the generation of imagined future events.

    “Again, this shared deficit is true of other amnesic patients with comparable hippocampal damage [16–20], and thus the hippocampus seems critical in both the retrieval of episodic memories and the generation of imagined future events.”
    Quote in the paperSubstantial claim0 of 5 sources checked
    • cites [16] Corballis MC. 2014 Mental time travel how the mind escapes from the present. Cosmol. 18, 139– 145.

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    • cites [17] Hassabis D, Kumaran D, Vann SD, Maguire EA. 2007 Patients with hippocampal amnesia cannot imagine new experiences. Proc. Natl Acad. Sci. USA 104, 1726– 1731. (10.1073/pnas.0610561104) 17229836 PMC1773058 source

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    • cites [18] Rosenbaum RS, Köhler S, Schacter DL, Moscovitch M, Westmacott R, Black SE, Gao F, Tulving E. 2005 The case of KC: contributions of a memory-impaired person to memory theory. Neuropsychologia 43, 989– 1021. (10.1016/j.neuropsychologia.2004.10.007) 15769487 source

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    • cites [19] Tulving E. 1985 Memory and consciousness. Can. Psychol./Psychol. Can. 26, 1– 12. (10.1037/h0080017) source

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    • cites [20] Klein SB, Loftus J, Kihlstrom JF. 2002 Memory and temporal experience: the effects of episodic memory loss on an amnesic patient’s ability to remember the past and imagine the future. Soc. Cogn. 20, 353– 379. (10.1521/soco.20.5.353.21125) source

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  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Functionality in brain areas involved in visual perception and visual imagery is linked to experienced vividness and visual perspective during episodic memory recall.

    “functionality in brain areas involved in visual perception [36,37] and visual imagery [38–41] have been linked to the experienced vividness and visual perspective during episodic memory recall [42].”
    Quote in the paperNot a substantial claim0 of 7 sources checked
    • cites [36] Sheldon S, Farb N, Palombo DJ, Levine B. 2016 Intrinsic medial temporal lobe connectivity relates to individual differences in episodic autobiographical remembering. Cortex 74, 206– 216. (10.1016/j.cortex.2015.11.005) 26691735 source

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    • cites [37] Daselaar SM, Rice HJ, Greenberg DL, Cabeza R, LaBar KS, Rubin DC. 2008 The spatiotemporal dynamics of autobiographical memory: neural correlates of recall, emotional intensity, and reliving. Cereb. Cortex 18, 217– 229. (10.1093/cercor/bhm048) 17548799 source

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    • cites [38] Freton M, Lemogne C, Bergouignan L, Delaveau P, Lehéricy S, Fossati P. 2014 The eye of the self: precuneus volume and visual perspective during autobiographical memory retrieval. Brain Struct. Funct. 219, 959– 968. (10.1007/s00429-013-0546-2) 23553546 source

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    • cites [39] Hebscher M, Levine B, Gilboa A. 2018 The precuneus and hippocampus contribute to individual differences in the unfolding of spatial representations during episodic autobiographical memory. Neuropsychologia 110, 123– 133. (10.1016/j.neuropsychologia.2017.03.029) 28365362 source

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    • cites [40] Sreekumar V, Nielson DM, Smith TA, Dennis SJ, Sederberg PB. 2018 The experience of vivid autobiographical reminiscence is supported by subjective content representations in the precuneus. Sci. Rep. 8, 1– 19. (10.1038/s41598-018-32879-0) 30297824 PMC6175904 source

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    • cites [41] St Jacques PLS, Szpunar KK, Schacter DL. 2017 Shifting visual perspective during retrieval shapes autobiographical memories. Neuroimage 148, 103– 114. (10.1016/j.neuroimage.2016.12.028) 27989780 PMC5344759 source

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    • cites [42] Berg JJ, Gilmore AW, Shaffer RA, McDermott KB. 2021 The stability of visual perspective and vividness during mental time travel. Conscious. Cogn. 92, 103116. (10.1016/j.concog.2021.103116) 34038829 source

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    Premisecitation

    Emotion- and sensory-related brain regions are recruited during remembering and contribute to phenomenological features of episodic memory recall.

    “As such, emotion- and sensory-related brain regions are recruited during remembering and contribute to the phenomenological features of episodic memory recall [37].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [37] Daselaar SM, Rice HJ, Greenberg DL, Cabeza R, LaBar KS, Rubin DC. 2008 The spatiotemporal dynamics of autobiographical memory: neural correlates of recall, emotional intensity, and reliving. Cereb. Cortex 18, 217– 229. (10.1093/cercor/bhm048) 17548799 source

      Not checked in the free run.

  • May combine two claims.

    Interpretationcitation

    Studies using the what-where-when paradigm predominantly focus on the content criterion, and there is little evidence for the structure and flexibility criteria in the literature.

    “these predominantly focus on the content criterion, and as a result, there is little evidence for the structure (but see [68,75]) and flexibility (but see [74]) criteria in the literature.”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites [68] Crystal JD, Smith AE. 2014 Binding of episodic memories in the rat. Curr. Biol. 24, 2957– 2961. (10.1016/j.cub.2014.10.074) 25466681 PMC4269559 source

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    • cites [75] Martin-Ordas G, Haun D, Colmenares F, Call J. 2010 Keeping track of time: evidence for episodic-like memory in great apes. Anim. Cogn. 13, 331– 340. (10.1007/s10071-009-0282-4) 19784852 PMC2822233 source

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    • cites [74] Zhou W, Crystal JD. 2011 Validation of a rodent model of episodic memory. Anim. Cogn. 14, 325– 340. (10.1007/s10071-010-0367-0) 21165663 PMC3079053 source

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    Premisecitation

    Scrub-jays show correct search behaviour even when event memories share the same 'what' and 'where' information but differ with respect to 'when', demonstrating that these memories are formed in an integrated structure.

    “Furthermore, they show the correct search behaviour even when the event memories share the same ‘what’ and ‘where’ information, but differ with respect to ‘when’, demonstrating that these memories are formed in an integrated structure [59]”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [59] Clayton NS, Yu KS, Dickinson A. 2001 Scrub jays (Aphelocoma coerulescens) form integrated memories of the multiple features of caching episodes. J. Exp. Psychol. Anim. Behav. Process. 27, 17– 29. (10.1037//0097-7403.27.1.17) 11199511 source

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    Premisecitation

    Rats are able to discriminate between self- or experimenter-generated information, a form of source memory known as reality monitoring.

    “Furthermore, rats were shown to be able to discriminate between self- or experimenter-generated information [99]; a form of source memory known as reality monitoring [100].”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [99] Crystal JD, Alford WT, Zhou W, Hohmann AG. 2013 Source memory in the rat. Curr. Biol. 23, 387– 391. (10.1016/j.cub.2013.01.023) 23394830 PMC3595394 source

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    • cites [100] Johnson MK, Hashtroudi S, Lindsay DS. 1993 Source monitoring. Psychol. Bull. 114, 3– 28. (10.1037/0033-2909.114.1.3) 8346328 source

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  • Classified as probably not a substantial claim.

    Premisecitation

    Episodic memory in humans is dependent on a functioning hippocampus.

    “As discussed, episodic memory in humans is dependent on a functioning hippocampus [46].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [46] Tulving E, Markowitsch HJ. 1998 Episodic and declarative memory: role of the hippocampus. Hippocampus 8, 198– 204. (10.1002/(sici)1098-1063(1998)8:33.0.co;2-g) 9662134 source

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    Premisecitation
    § Is episodic-like memory like episodic memory?

    Humans appear to use conscious episodic memory in episodic-like memory tasks in some instances, but in others they fail the tasks altogether.

    “However, although humans appear to use conscious episodic memory in episodic-like memory tasks in some instances [106], in others they fail the tasks altogether [107,108].”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites [106] Holland SM, Smulders TV. 2011 Do humans use episodic memory to solve a what-where-when memory task? Anim. Cogn. 14, 95– 102. (10.1007/s10071-010-0346-5) 20661614 source

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    • cites [107] Martin-Ordas G, Atance CM. 2019 Adults’ performance in an episodic-like memory task: the role of experience. Front. Psychol. 9, 2688. (10.3389/fpsyg.2018.02688) 30719017 PMC6348334 source

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    • cites [108] Martin-Ordas G, Atance CM, Caza J. 2017 Did the popsicle melt? preschoolers’ performance in an episodic-like memory task. Memory 25, 1260– 1271. (10.1080/09658211.2017.1285940) 28276982 source

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    Interpretationcitation
    § Is episodic-like memory like episodic memory?

    Human performance across different episodic-like memory paradigms is not necessarily related, suggesting that distinct psychological processes may be employed for each.

    “Furthermore, human performance across different paradigms is not necessarily related [109], suggesting that distinct psychological processes may be employed for each [107,109,110].”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites [109] Cheke LG, Clayton NS. 2013 Do different tests of episodic memory produce consistent results in human adults? Learn. Mem. 20, 491– 498. (10.1101/lm.030502.113) 23955172 source

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    • cites [107] Martin-Ordas G, Atance CM. 2019 Adults’ performance in an episodic-like memory task: the role of experience. Front. Psychol. 9, 2688. (10.3389/fpsyg.2018.02688) 30719017 PMC6348334 source

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    • cites [110] Easton A, Webster LA, Eacott MJ. 2012 The episodic nature of episodic-like memories. Learn. Mem. 19, 146– 150. (10.1101/lm.025676.112) 22411421 source

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    Premisecitation

    Rodents with hippocampal lesions fail in both what-where-when tasks and incidental encoding tasks.

    “These observations are supported by research using established episodic-like memory paradigms, showing that rodents with hippocampal lesions fail in both what–where–when tasks [70,72] as well as incidental encoding tasks [82].”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites [70] Ergorul C, Eichenbaum H. 2004 The hippocampus and memory for “what,” “where,” and “when.” Learn. Mem. 11, 397– 405. (10.1101/lm.73304) 15254219 PMC498318 source

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    • cites [72] DeVito LM, Eichenbaum H. 2010 Distinct contributions of the hippocampus and medial prefrontal cortex to the “what–where–when” components of episodic-like memory in mice. Behav. Brain Res. 215, 318– 325. (10.1016/j.bbr.2009.09.014) 19766146 PMC2891645 source

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    • cites [82] Zhou W, Hohmann AG, Crystal JD. 2012 Rats answer an unexpected question after incidental encoding. Curr. Biol. 22, 1149– 1153. (10.1016/j.cub.2012.04.040) 22633809 PMC3376895 source

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  • Classified as probably not a substantial claim. May combine two claims.

    Interpretationcitation

    The effect of age was not apparent in the standard what-where-when task, leading authors to conclude that non-episodic solutions are possible in what-where-when tasks.

    “Interestingly, this effect was not apparent in the standard what–where–when task, leading the authors to conclude that non-episodic solutions are possible in what–where–when tasks, as suggested by others [79,85].”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [79] Zentall TR, Clement TS, Bhatt RS, Allen J. 2001 Episodic-like memory in pigeons. Psychon. Bull. Rev. 8, 685– 690. (10.3758/bf03196204) 11848586 source

      Not checked in the free run.

    • cites [85] Crystal JD. 2021 Evaluating evidence from animal models of episodic memory. J. Exp. Psychol. Anim. Learn. Cogn. 47, 337– 356. (10.1037/xan0000294) 34618532 source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    In humans, episodic memory declines with normal ageing and deteriorates earliest and most dramatically compared to other forms of memory.

    “In humans, episodic memory is well known to decline with normal ageing [10,11] and deteriorates the earliest and most dramaticlly compared to other forms of memory [12–15].”
    Quote in the paperNot a substantial claim0 of 6 sources checked
    • cites [10] Craik FI, Jennings JM. 1992 Human memory. In The handbook of aging and cognition (eds FI Craik, T Salthouse), pp. 51– 110. Hillsdale, MI: Lawrence Erlbaum Associates.

      Not checked in the free run.

    • cites [11] Charlton RA, Barrick T, Markus H, Morris R. 2010 The relationship between episodic long-term memory and white matter integrity in normal aging. Neuropsychologia 48, 114– 122. (10.1016/j.neuropsychologia.2009.08.018) 19699215 source

      Not checked in the free run.

    • cites [12] Schacter DL, Koutstaal W, Norman KA. 1997 False memories and aging. Trends Cogn. Sci. 1, 229– 236. (10.1016/S1364-6613(97)01068-1) 21223912 source

      Not checked in the free run.

    • cites [13] Schacter DL, Kaszniak AW, Kihlstrom JF, Valdiserri M. 1991 The relation between source memory and aging. Psychol. Aging 6, 559– 568. (10.1037/0882-7974.6.4.559) 1777144 source

      Not checked in the free run.

    • cites [14] St Jacques PL, Levine B. 2007 Ageing and autobiographical memory for emotional and neutral events. Memory 15, 129– 144. (10.1080/09658210601119762) 17534107 PMC1995658 source

      Not checked in the free run.

    • cites [15] Martinelli P, Sperduti M, Piolino P. 2013 Neural substrates of the self-memory system: new insights from a meta-analysis. Hum. Brain Mapp. 34, 1515– 1529. (10.1002/hbm.22008) 22359397 PMC6870171 source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Older dogs and apes show lower performances in an incidental encoding and what-where-when test, respectively, compared with younger conspecifics.

    “Furthermore, older dogs and apes who were otherwise healthy showed lower performances in an incidental encoding and what–where–when test, respectively, compared with younger conspecifics [75,146].”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [75] Martin-Ordas G, Haun D, Colmenares F, Call J. 2010 Keeping track of time: evidence for episodic-like memory in great apes. Anim. Cogn. 13, 331– 340. (10.1007/s10071-009-0282-4) 19784852 PMC2822233 source

      Not checked in the free run.

    • cites [146] Sanches FJ, de Melo JC, Ferreira SP, Trinca LA, Arambula OG, Padovani FHP, Schelp AO, Amorim RM. 2022 Aging-related episodic-like memory decline in dogs. Behav. Brain Res. 422, 113762. (10.1016/j.bbr.2022.113762) 35077771 source

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  • May combine two claims.

    Premisecitation

    Scrub-jays integrate novel semantic information with an original episodic-like memory of a caching event, and acquired this information after the event.

    “Scrub-jays were observed to integrate novel semantic information with an original episodic-like memory of a caching event, and importantly, acquired this information after said event [60].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [60] Clayton NS, Yu KS, Dickinson A. 2003 Interacting cache memories: evidence for flexible memory use by western scrub-jays (Aphelocoma californica). J. Exp. Psychol. Anim. Behav. Process. 29, 14– 22. (10.1037/0097-7403.29.1.14) 12561130 source

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  • May combine two claims.

    Interpretationcitation

    Scrub-jays could differentiate between two similar events, suggesting that the 'when' information was bound to each memory during reconstruction.

    “Having demonstrated that jays could differentiate between two similar events [59], this suggests that the ‘when’ information was bound to each memory during reconstruction which, facilitated by source monitoring processes, allowed them to alter their decision-making in accordance with each specific caching event.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [59] Clayton NS, Yu KS, Dickinson A. 2001 Scrub jays (Aphelocoma coerulescens) form integrated memories of the multiple features of caching episodes. J. Exp. Psychol. Anim. Behav. Process. 27, 17– 29. (10.1037//0097-7403.27.1.17) 11199511 source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Episodic memories are rapidly acquired over a single learning episode, without the need for subsequent rehearsal.

    “Episodic memories are rapidly acquired over a single learning episode, without the need for subsequent rehearsal [31].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [31] Gallo DA, Wheeler ME. 2013 Episodic memory. In The oxford handbook of cognitive psychology, pp. 189– 205. New York, USA: Oxford University Press.

      Not checked in the free run.

  • May combine two claims.

    Interpretationcitation

    This suggests that at the time of cache retrieval, the episodic-like memory was recombined and integrated with novel semantic information, providing further evidence of reconstruction in episodic-like memory.

    “This suggests that at the time of cache retrieval, the episodic-like memory was recombined and integrated with (novel) semantic information, providing further evidence of reconstruction in episodic-like memory.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisereasoning

    Experiments using other paradigms typically involve repeated trials to train subjects to attend to certain information, resulting in explicit encoding of these details.

    “Experiments using other paradigms, however, typically involve repeated trials to train the subjects to attend to certain information such as perishability rates of food types, resulting in the explicit encoding of these details.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    Both scrub-jays and Eurasian jays appear to plan for future needs that differ from their current motivational states.

    “both scrub-jays and Eurasian jays appear to plan for future needs that differ from their current motivational states [160,161]”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [160] Cheke LG, Clayton NS. 2012 Eurasian jays (Garrulus glandarius) overcome their current desires to anticipate two distinct future needs and plan for them appropriately. Biol. Lett. 8, 171– 175. (10.1098/rsbl.2011.0909) 22048890 PMC3297405 source

      Not checked in the free run.

    • cites [161] Correia SP, Dickinson A, Clayton NS. 2007 Western scrub-jays anticipate future needs independently of their current motivational state. Curr. Biol. 17, 856– 861. (10.1016/j.cub.2007.03.063) 17462894 source

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  • May combine two claims.

    Premisecitation

    Rats and Rhesus macaques appear to fail at the future planning task, while squirrel monkeys were successful.

    “While rats [162] and Rhesus macaques [163] appear to fail at this task, other monkeys (squirrel monkeys) were successful [162].”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [162] Naqshbandi M, Roberts WA. 2006 Anticipation of future events in squirrel monkeys (Saimiri sciureus) and rats (Rattus norvegicus): tests of the Bischof-Kohler hypothesis. J. Comp. Psychol. 120, 345– 357. (10.1037/0735-7036.120.4.34) 17115855 source

      Not checked in the free run.

    • cites [163] Paxton R, Hampton RR. 2009 Tests of planning and the Bischof-Köhler hypothesis in Rhesus monkeys (Macaca mulatta). Behav. Processes 80, 238– 246. (10.1016/j.beproc.2008.12.016) 20161113 PMC2739929 source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Both the caching and previous future planning paradigms have been criticized for not showing evidence of true foresight as seen in humans, or have failed to replicate.

    “both this and the previous paradigm have been criticized for not showing evidence of true foresight as seen in humans [164,165], or have failed to replicate [166].”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [164] Redshaw J. 2014 Does metarepresentation make human mental time travel unique? Wiley Interdiscip. Rev. Cogn. Sci. 5, 519– 531. (10.1002/wcs.1308) 26308742 source

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    • cites [165] Suddendorf T, Corballis MC. 2008 New evidence for animal foresight? Anim. Behav. 75, e1– e3. (10.1016/j.anbehav.2008.01.006) source

      Not checked in the free run.

    • cites [166] Amodio P, Brea J, Farrar BG, Ostojić L, Clayton NS. 2021 Testing two competing hypotheses for Eurasian jays’ caching for the future. Sci. Rep. 11, 835. (10.1038/s41598-020-80515-7) 33436969 PMC7804264 source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Rats have been argued to show behavioural and neurological evidence for what appears to be future planning, or at least precursors to planning.

    “rats have been argued to show behavioural and neurological evidence for what appears to be future planning [172], or at least, the precursors to planning [89,173,174].”
    Quote in the paperNot a substantial claim0 of 4 sources checked
    • cites [172] Pfeiffer BE, Foster DJ. 2013 Hippocampal place-cell sequences depict future paths to remembered goals. Nature New Biol. 497, 74– 79. (10.1038/nature12112) PMC3990408 23594744 source

      Not checked in the free run.

    • cites [89] Crystal JD. 2013 Remembering the past and planning for the future in rats. Behav. Processes 93, 39– 49. (10.1016/j.beproc.2012.11.014) 23219951 PMC3582767 source

      Not checked in the free run.

    • cites [173] Wilson AG, Pizzo MJ, Crystal JD. 2013 Event-based prospective memory in the rat. Curr. Biol. 23, 1089– 1093. (10.1016/j.cub.2013.04.067) 23727093 PMC3690169 source

      Not checked in the free run.

    • cites [174] Wilson AG, Crystal JD. 2012 Prospective memory in the rat. Anim. Cogn. 15, 349– 358. (10.1007/s10071-011-0459-5) 21922257 PMC3292651 source

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  • May combine two claims.

    Premisecitation

    Cuttlefish have been demonstrated to show flexible and future-dependent foraging decisions in response to dynamic prey conditions, although not adhering to any generally approved future planning paradigm.

    “although not adhering to any generally approved future planning paradigm, cuttlefish have also been demonstrated to show flexible and future-dependent foraging decisions in response to dynamic prey conditions [171].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [171] Billard P, Schnell AK, Clayton NS, Jozet-Alves C. 2020 Cuttlefish show flexible and future-dependent foraging cognition. Biol. Lett. 16, 20190743. (10.1098/rsbl.2019.0743) 32019464 PMC7058941 source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    These ape studies were conducted without adequate controls to rule out simple associative explanations, unlike the New Caledonian crow study.

    “these studies were importantly conducted without adequate controls to rule out simple associative explanations [169], as were implemented in the New Caledonian crow study ([50]; but see [170]).”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites [169] Suddendorf T, Corballis MC, Collier-Baker E. 2009 How great is great ape foresight? Anim. Cogn. 12, 751– 754. (10.1007/s10071-009-0253-9) 19565281 source

      Not checked in the free run.

    • cites [50] Boeckle M, Schiestl M, Frohnwieser A, Gruber R, Miller R, Suddendorf T, Gray RD, Taylor AH, Clayton NS. 2020 New Caledonian crows plan for specific future tool use. Proc. R. Soc. B 287, 20201490. (10.1098/rspb.2020.1490) PMC7735258 33143583 source

      Not checked in the free run.

    • cites [170] Osvath M, Martin-Ordas G. 2014 The future of future-oriented cognition in non-humans: theory and the empirical case of the great apes. Phil. Trans. R. Soc. B 369, 20130486. (10.1098/rstb.2013.0486) 25267827 PMC4186238 source

      Not checked in the free run.

  • May combine two claims.

    Interpretationcitation

    This pre-play directly predicts future navigation behaviour, suggesting its role in future planning.

    “This pre-play directly predicts future navigation behaviour, suggesting its role in future planning.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [172] Pfeiffer BE, Foster DJ. 2013 Hippocampal place-cell sequences depict future paths to remembered goals. Nature New Biol. 497, 74– 79. (10.1038/nature12112) PMC3990408 23594744 source

      Not checked in the free run.

  • May combine two claims.

    Interpretationcitation

    Overall, the strongest evidence that currently exists for future planning in non-human animals comes from corvids, which were also the original animal models for episodic-like memory.

    “the strongest evidence that exists currently [50,164] comes from corvids who were also the original animal models for episodic-like memory [52]”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites [50] Boeckle M, Schiestl M, Frohnwieser A, Gruber R, Miller R, Suddendorf T, Gray RD, Taylor AH, Clayton NS. 2020 New Caledonian crows plan for specific future tool use. Proc. R. Soc. B 287, 20201490. (10.1098/rspb.2020.1490) PMC7735258 33143583 source

      Not checked in the free run.

    • cites [164] Redshaw J. 2014 Does metarepresentation make human mental time travel unique? Wiley Interdiscip. Rev. Cogn. Sci. 5, 519– 531. (10.1002/wcs.1308) 26308742 source

      Not checked in the free run.

    • cites [52] Clayton NS, Dickinson A. 1998 Episodic-like memory during cache recovery by scrub jays. Nature 395, 272– 274. (10.1038/26216) 9751053 source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationcitation

    This replay raises the possibility that replay allows for future planning.

    “raising the possibility that replay allows for future planning.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [157] Wu CT, Haggerty D, Kemere C, Ji D. 2017 Hippocampal awake replay in fear memory retrieval. Nat. Neurosci. 20, 571– 580. (10.1038/nn.4507) 28218916 PMC5373994 source

      Not checked in the free run.

  • May combine two claims.

    Interpretationreasoning

    Although the recalled information is not necessarily associated with the species' natural behaviours, these memories do not occur spontaneously without training to attend to them.

    “although the recalled information is not necessarily associated with the species’ natural behaviours, they do not occur spontaneously without training to attend to them.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing), S4 (based). May combine two claims.

    Interpretationnone given

    Humans also receive what can be thought of as 'training', as we learn (often socially) to form various associations and to attend to certain informational variables.

    “as humans we too receive what can be thought of as ‘training’, as we learn (often socially) to form various associations and to attend to certain informational variables.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationcitation

    The recall of incidental social information in dolphins concerned human experimenters and was encoded visually, which does not represent cetaceans' natural social information and primary method of communication (auditory).

    “The recall of incidental social information is particularly interesting, as this concerned human experimenters and was encoded visually, which does not represent cetaceans’ natural social information and primary method of communication (auditory).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [83] Davies JR, Garcia-Pelegrin E, Baciadonna L, Pilenga C, Favaro L, Clayton NS. 2022 Episodic-like memory in common bottlenose dolphins. Curr. Biol. 32, 3436– 3442. (10.1016/j.cub.2022.06.032) 35882234 source

      Not checked in the free run.

  • May combine two claims.

    Interpretationcitation

    Some experiments required birds to remember details of caches they did not make themselves, but this is still within their naturally occurring behavioural repertoire.

    “While some of these experiments required the birds to remember details of caches that they did not make themselves [62,92], this is still under the remit of their naturally occurring behavioural repertoire.”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [62] Feeney MC, Roberts WA, Sherry DF. 2009 Memory for what, where, and when in the black-capped chickadee (Poecile atricapillus). Anim. Cogn. 12, 767– 777. (10.1007/s10071-009-0236-x) 19466468 source

      Not checked in the free run.

    • cites [92] Davies JR, Garcia-Pelegrin E, Clayton NS. 2024 Eurasian jays (Garrulus glandarius) show episodic-like memory through the incidental encoding of information. PLoS One 19, e0301298. (10.1371/journal.pone.0301298) 38748646 PMC11095760 source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Dolphins have been demonstrated to be able to spontaneously recall information that was not trained to be attended to, representing both spatial and social information.

    “dolphins have been demonstrated to be able to spontaneously recall information that was not trained to be attended to, representing both spatial and social information [83].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [83] Davies JR, Garcia-Pelegrin E, Baciadonna L, Pilenga C, Favaro L, Clayton NS. 2022 Episodic-like memory in common bottlenose dolphins. Curr. Biol. 32, 3436– 3442. (10.1016/j.cub.2022.06.032) 35882234 source

      Not checked in the free run.

  • May combine two claims.

    Interpretationcitation

    It could be argued that dolphins were able to generalize social information across species, demonstrating some level of episodic-like memory flexibility, although intensive training over their lifetime likely facilitated this flexibility.

    “Subsequently, it could be argued that they were able to generalize social information across species, demonstrating some level of episodic-like memory flexibility, although it is likely that the intensive training they received over their lifetime facilitated this flexibility [176].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [176] Davies JR, Garcia-Pelegrin E. 2023 Bottlenose dolphins are sensitive to human attentional features, including eye functionality. Sci. Rep. 13, 12565. (10.1038/s41598-023-39031-7) 37532744 PMC10397197 source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Interpretationreasoning

    Alternatively, this may reflect a large distinction between episodic memory and episodic-like memory.

    “Alternatively, however, this may reflect a large distinction between episodic memory and episodic-like memory.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Recent evidence demonstrates that humans have conscious access to incidentally encoded information within memories and can target this information in order to solve memory tasks.

    “recent evidence demonstrates that humans have conscious access to incidentally encoded information within memories and can target this information in order to solve memory tasks [154,177–179].”
    Quote in the paperSubstantial claim0 of 4 sources checked
    • cites [154] Matthews J, Schröder P, Kaunitz L, van Boxtel JJ, Tsuchiya N. 2018 Conscious access in the near absence of attention: critical extensions on the dual-task paradigm. Phil. Trans. R. Soc. B 373, 20170352. (10.1098/rstb.2017.0352) 30061465 PMC6074075 source

      Not checked in the free run.

    • cites [177] Matthews J, Wu J, Corneille V, Hohwy J, van Boxtel J, Tsuchiya N. 2019 Sustained conscious access to incidental memories in RSVP. Atten. Percept. Psychophys. 81, 188– 204. (10.3758/s13414-018-1600-1) 30291551 source

      Not checked in the free run.

    • cites [178] Qianchen L, Gallagher RM, Tsuchiya N. 2022 How much can we differentiate at a brief glance: revealing the truer limit in conscious contents through the massive report paradigm (MRP). R. Soc. Open Sci. 9, 210394. (10.1098/rsos.210394) 35619998 PMC9128849 source

      Not checked in the free run.

    • cites [179] Kaunitz LN, Rowe EG, Tsuchiya N. 2016 Large capacity of conscious access for incidental memories in natural scenes. Psychol. Sci. 27, 1266– 1277. (10.1177/0956797616658869) 27507869 source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Interpretationcitation

    These observations raise the possibility that non-human animals may also have conscious access to incidental information within memories.

    “these observations nevertheless raise the possibility that non-human animals may also have conscious access to incidental information within memories.”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites [179] Kaunitz LN, Rowe EG, Tsuchiya N. 2016 Large capacity of conscious access for incidental memories in natural scenes. Psychol. Sci. 27, 1266– 1277. (10.1177/0956797616658869) 27507869 source

      Not checked in the free run.

    • cites [180] Soto D, Mäntylä T, Silvanto J. 2011 Working memory without consciousness. Curr. Biol. 21, R912– R913. (10.1016/j.cub.2011.09.049) 22115455 source

      Not checked in the free run.

    • cites [181] Hassin RR, Bargh JA, Engell AD, McCulloch KC. 2009 Implicit working memory. Conscious. Cogn. 18, 665– 678. (10.1016/j.concog.2009.04.003) 19442537 PMC2760263 source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    To access incidentally encoded information, an animal must recall a holistic representation of the episode, containing many details surrounding the event as well as the event narrative sequence, and subsequently replay, target and manipulate this information within the event representation.

    “To access incidentally encoded information, an animal must recall a holistic representation of the episode, containing many details surrounding the event as well as the event narrative sequence, and subsequently replay, target and manipulate this information within the event representation [85,92,94,114].”
    Quote in the paperSubstantial claim0 of 4 sources checked
    • cites [85] Crystal JD. 2021 Evaluating evidence from animal models of episodic memory. J. Exp. Psychol. Anim. Learn. Cogn. 47, 337– 356. (10.1037/xan0000294) 34618532 source

      Not checked in the free run.

    • cites [92] Davies JR, Garcia-Pelegrin E, Clayton NS. 2024 Eurasian jays (Garrulus glandarius) show episodic-like memory through the incidental encoding of information. PLoS One 19, e0301298. (10.1371/journal.pone.0301298) 38748646 PMC11095760 source

      Not checked in the free run.

    • cites [94] Sheridan CL et al. 2024 Replay of incidentally encoded episodic memories in the rat. Curr. Biol. 34, 641– 647. (10.1016/j.cub.2023.12.043) 38218186 source

      Not checked in the free run.

    • cites [114] Panoz-Brown D et al. 2018 Replay of episodic memories in the rat. Curr. Biol. 28, 1628– 1634. (10.1016/j.cub.2018.04.006) 29754898 PMC5964044 source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing), S4 (based).

    Interpretationreasoning

    It is highly likely that we have evolved to satisfy the cognitive demands of language, tool use, cooperation, and complex sociality, which currently constitute base components of our episodic memories.

    “it is highly likely that we have evolved to satisfy the cognitive demands of language, tool use, cooperation, and complex sociality that make up the foundations of our lives both in prehistory and today and currently still constitute the base components of our episodic memories”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing), S4 (based). May combine two claims.

    Interpretationreasoning

    This lack of evidence may simply represent a dearth of relevant research, as exploiting natural behaviours is a clever and efficient technique to explore animal cognition.

    “this may simply represent a dearth of relevant research, as exploiting natural behaviours is a clever and efficient technique to explore the cognition of animal subjects.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Interpretationcitation

    This source memory paradigm may provide more detail about the subjective experience of the animal during recall.

    “Therefore, this paradigm may provide more detail about the subjective experience of the animal during recall (i.e. ‘what did I just experience?’) [101].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [101] Billard P, Clayton NS, Jozet-Alves C. 2020 Cuttlefish retrieve whether they smelt or saw a previously encountered item. Sci. Rep. 10, 1– 7. (10.1038/s41598-020-62335-x) 32214190 PMC7096502 source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing), S4 (based). May combine two claims.

    Interpretationreasoning

    It could be argued that the environment we have built around us is essentially our natural habitat, as although civilization and modern ways of life were not present during most of our evolutionary history, much of our socio-ecological practices remained consistent throughout.

    “it could be argued that the environment we have built around us is essentially our natural habitat, as although civilization and the resulting modern ways of life were not present during the majority of our evolutionary history, much of the socio-ecological practices we engage in (i.e. our behavioural repertoire) remained consistent throughout (albeit within different physical and social”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Interpretationcitation

    This replay often occurs during sleep and, as activity takes place within the visual cortex as well as the hippocampus, it may directly relate to an experience of perceptual imagery during sleep states.

    “this reply often occurs during sleep and as activity takes place within the visual cortex as well as the hippocampus, it may directly relate to an experience of perceptual imagery during sleep states [186].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [186] Ji D, Wilson MA. 2007 Coordinated memory replay in the visual cortex and hippocampus during sleep. Nat. Neurosci. 10, 100– 107. (10.1038/nn1825) 17173043 source

      Not checked in the free run.

  • May combine two claims.

    Interpretationcitation

    Although hippocampal sharp-wave-ripples have been linked to visual episodic memory recall in humans, they do not necessarily represent the neural markers of subjective experience in non-human animals.

    “although hippocampal sharp-wave-ripples have been linked to visual episodic memory recall in humans [117], they do not necessarily represent the neural markers of subjective experience in non-human animals.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [117] Norman Y, Yeagle EM, Khuvis S, Harel M, Mehta AD, Malach R. 2019 Hippocampal sharp-wave ripples linked to visual episodic recollection in humans. Science 365, 657– 671. (10.1126/science.aax1030) 31416934 source

      Not checked in the free run.

  • May combine two claims.

    Interpretationreasoning

    This suggests that dreaming and mental time travel are both part of a continuum of spontaneous, offline (re)constructive thought, generated across sleep and waking states.

    “This suggests that rather than dreaming being a completely distinct phenomenon to mental time travel, they are both part of a continuum of spontaneous, offline (re)constructive thought, generated across sleep and waking states [199,202].”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [199] Nielsen TA, Stenstrom P. 2005 What are the memory sources of dreaming? Nature 437, 1286– 1289. (10.1038/nature04288) 16251954 source

      Not checked in the free run.

    • cites [202] Wamsley EJ. 2020 How the brain constructs dreams. Elife 9, e58874. (10.7554/eLife.58874) 32508304 PMC7279884 source

      Not checked in the free run.

  • May combine two claims.

    Interpretationcitation

    As consciousness is multidimensional with many different and complex parameters, some of these features, but not others, may be present in episodic-like memory recall, with the combination depending on the species.

    “as consciousness is multidimensional with many different and complex parameters [203], some of these features, but not others, may be present in episodic-like memory recall (the combination of which depending on the species in question [204]).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [203] Birch J, Schnell AK, Clayton NS. 2020 Dimensions of animal consciousness. Trends Cogn. Sci. 24, 789– 801. (10.1016/j.tics.2020.07.007) 32830051 PMC7116194 source

      Not checked in the free run.

    • cites [204] Templer VL, Hampton RR. 2013 Episodic memory in nonhuman animals. Curr. Biol. 23, R801– R806. (10.1016/j.cub.2013.07.016) 24028963 PMC3799964 source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    While the replay of complete episodic memories is rare during dreaming, dream imagery and content is made up of fragmentations and transformations of episodic stimuli.

    “while the replay of complete episodic memories is rare during dreaming [197], dream imagery and content is made up of fragmentations and transformations of episodic stimuli [196–198].”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [197] Fosse MJ, Fosse R, Hobson JA, Stickgold RJ. 2003 Dreaming and episodic memory: a functional dissociation? J. Cogn. Neurosci. 15, 1– 9. (10.1162/089892903321107774) 12590838 source

      Not checked in the free run.

    • cites [196] Cavallero C, Foulkes D, Hollifield M, Terry R. 1990 Memory sources of REM and NREM dreams. Sleep 13, 449– 455. (10.1093/sleep/13.5.449) 2287856

      Not checked in the free run.

    • cites [198] Wamsley EJ. 2022 Constructive episodic simulation in dreams. PLoS One 17, e0264574. (10.1371/journal.pone.0264574) 35316266 PMC8939783 source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    In humans, recent evidence shows that mental time travel and dreaming may be generated through similar networks in the brain, share parallels in their (re)constructive processes, and share deficits owing to injury and disease.

    “In humans, recent evidence shows that mental time travel and dreaming may be generated through similar networks in the brain [194,195], share parallels in their (re)constructive processes [196–199] as well as deficits owing to injury and disease [200,201].”
    Quote in the paperNot a substantial claim0 of 8 sources checked
    • cites [194] Fox KC, Nijeboer S, Solomonova E, Domhoff GW, Christoff K. 2013 Dreaming as mind wandering: evidence from functional neuroimaging and first-person content reports. Front. Hum. Neurosci. 7, 412. (10.3389/fnhum.2013.00412) 23908622 PMC3726865 source

      Not checked in the free run.

    • cites [195] Graveline YM, Wamsley EJ. 2015 Dreaming and waking cognition. Transl. Issues Psychol. Sci. 1, 97– 105. (10.1037/tps0000018) source

      Not checked in the free run.

    • cites [196] Cavallero C, Foulkes D, Hollifield M, Terry R. 1990 Memory sources of REM and NREM dreams. Sleep 13, 449– 455. (10.1093/sleep/13.5.449) 2287856

      Not checked in the free run.

    • cites [197] Fosse MJ, Fosse R, Hobson JA, Stickgold RJ. 2003 Dreaming and episodic memory: a functional dissociation? J. Cogn. Neurosci. 15, 1– 9. (10.1162/089892903321107774) 12590838 source

      Not checked in the free run.

    • cites [198] Wamsley EJ. 2022 Constructive episodic simulation in dreams. PLoS One 17, e0264574. (10.1371/journal.pone.0264574) 35316266 PMC8939783 source

      Not checked in the free run.

    • cites [199] Nielsen TA, Stenstrom P. 2005 What are the memory sources of dreaming? Nature 437, 1286– 1289. (10.1038/nature04288) 16251954 source

      Not checked in the free run.

    • cites [200] Spanò G, Pizzamiglio G, McCormick C, Clark IA, De Felice S, Miller TD, Edgin JO, Rosenthal CR, Maguire EA. 2020 Dreaming with hippocampal damage. Elife 9, e56211. (10.7554/eLife.56211) 32508305 PMC7279885 source

      Not checked in the free run.

    • cites [201] Dawes AJ, Keogh R, Andrillon T, Pearson J. 2020 A cognitive profile of multi-sensory imagery, memory and dreaming in aphantasia. Sci. Rep. 10, 10022. (10.1038/s41598-020-65705-7) 32572039 PMC7308278 source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Interpretationreasoning

    These anatomical differences may result in drastic consequences regarding the structure, development, mechanisms, and experience involved in episodic-like memory across these species.

    “with these anatomical differences potentially resulting in drastic consequences regarding the structure, development, mechanisms, and experience involved in episodic-like memory across these species.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S2 (checkable).

    Interpretationreasoning

    The combination of multiple, converging lines of evidence using different approaches will lead to much stronger inferences.

    “the combination of multiple, converging lines of evidence using different approaches will lead to much stronger inferences [111].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [111] Crystal JD. 2018 Animal models of episodic memory. Comp. Cogn. Behav. Rev. 13, 105– 122. (10.3819/CCBR.2018.130012) source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Human episodic memory encompasses a variety of cognitive structures and processes amalgamating into an episodic memory system, and each episodic-like memory paradigm targets a different aspect of this system.

    “human episodic memory encompasses a variety of cognitive structures and processes amalgamating into an episodic memory system, and importantly each episodic-like memory paradigm targets a different aspect of this system [85,109].”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [85] Crystal JD. 2021 Evaluating evidence from animal models of episodic memory. J. Exp. Psychol. Anim. Learn. Cogn. 47, 337– 356. (10.1037/xan0000294) 34618532 source

      Not checked in the free run.

    • cites [109] Cheke LG, Clayton NS. 2013 Do different tests of episodic memory produce consistent results in human adults? Learn. Mem. 20, 491– 498. (10.1101/lm.030502.113) 23955172 source

      Not checked in the free run.

  • May combine two claims.

    Interpretationreasoning

    There is relatively strong evidence to suggest that in non-mammalian taxa, namely cuttlefish and birds, episodic-like memory can exist in the absence of a hippocampus, or in the absence of high-order pallial inputs into the hippocampus, respectively.

    “there is relatively strong evidence to suggest that in non-mammalian taxa, namely cuttlefish and birds, episodic-like memory can exist in the absence of a hippocampus, or in the absence of high-order pallial inputs into the hippocampus, respectively”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S2 (checkable). May combine two claims.

    Interpretationreasoning

    This represents an important gap in the literature and addressing this gap would lead to more astute investigations of the evolution of episodic-like memory abilities across taxa.

    “This represents an important gap in the literature and addressing this gap would lead to more astute investigations of the evolution of episodic-like memory abilities across taxa.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S2 (checkable). May combine two claims.

    Interpretationcitation

    The interpretations that can be reasonably drawn from these observational data would be significantly strengthened through controlled experimental research, as it is often impossible to rule out the influence of various environmental cues in dictating behaviour.

    “the interpretations that can be reasonably drawn from these data would be significantly strengthened through controlled experimental research, as, for example, it is often impossible to rule out the influence of various environmental cues in dictating behaviour [208].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [208] van Schaik CP, Damerius L, Isler K. 2013 Wild orangutan males plan and communicate their travel direction one day in advance. PLoS One 8, e74896. (10.1371/journal.pone.0074896) 24040357 PMC3770631 source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S2 (checkable). May combine two claims.

    Interpretationreasoning

    Many natural behaviours observed in the wild may suggest an episodic-like memory ability and consequently represent valuable opportunities for use in experimental research.

    “many natural behaviours observed in the wild may suggest an episodic-like memory ability and consequently represent valuable opportunities for use in experimental research.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Sumatran orangutan long calls predict their future travel trajectories, perhaps involving remembered past travel routes and outcomes.

    “Sumatran orangutan long calls, in which flanged males emit loud calls to convey social information to females and other males, predict their future travel trajectories [208], perhaps involving remembered past travel routes and outcomes.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [208] van Schaik CP, Damerius L, Isler K. 2013 Wild orangutan males plan and communicate their travel direction one day in advance. PLoS One 8, e74896. (10.1371/journal.pone.0074896) 24040357 PMC3770631 source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Observational data on wild grey-cheeked mangabey foraging behaviour may suggest a form of memory that includes recalling the 'what' (fruit), 'where' (tree location) and 'when' (timing relative to fruiting) aspects of previous foraging experiences, while incorporating recent weather conditions with these memories to flexibly dictate decision-making.

    “observational data on wild grey-cheeked mangabey foraging behaviour may suggest a form of memory that includes recalling the ‘what’ (fruit), ‘where’ (tree location) and ‘when’ (timing relative to fruiting) aspects of previous foraging experiences [206], while incorporating recent weather conditions (semantic information) with these memories to flexibly dictate decision-making [207].”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [206] Janmaat KR, Byrne RW, Zuberbühler K. 2006 Evidence for a spatial memory of fruiting states of rainforest trees in wild mangabeys. Anim. Behav. 72, 797– 807. (10.1016/j.anbehav.2005.12.009) source

      Not checked in the free run.

    • cites [207] Janmaat KR, Byrne RW, Zuberbühler K. 2006 Primates take weather into account when searching for fruits. Curr. Biol. 16, 1232– 1237. (10.1016/j.cub.2006.04.031) 16782015 source

      Not checked in the free run.

59 of 59

  • The authors state this as an assumption.

    Animal models can be used to understand the human brain because there is some level of continuity in form and function.

    “Indeed, many studies use animal models to understand the human brain (e.g. [34,68,88,94,99,111]), assuming some level of continuity in form and function.”

  • The authors state this as an assumption.

    Animals with similar brain structures are susceptible to similar effects of physiological ageing in regards to episodic(-like) memory performance.

    “While the evidence suggests that we may be able to assume that animals with similar brain structures are susceptible to similar effects of physiological ageing in regards to episodic(-like) memory performance [78]”

  • The paper relies on this without support.

    In humans, amnesic patients who cannot remember their past also cannot think about their future.

    “In humans, amnesic patients who cannot remember their past also cannot think about their future.”

  • The paper relies on this without support.

    Rodent studies on episodic-like memory typically involve foraging for food within mazes, akin to tunnels, and so also centre around natural (food-related) contexts.

    “Similarly, rodent studies on episodic-like memory typically involve foraging for food within mazes, akin to tunnels, and so also centre around natural (food-related) contexts.”
4 of 4

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

Cites

Flagged first, then by citations

Research works printed but not linked: 4

  1. Tulving E. 1972 Episodic and semantic memory. In Organization of memory (eds E Tulving, W Donaldson), pp. 381–403. New York, NY: Academic Press.
  2. Corballis MC. 2014 Mental time travel how the mind escapes from the present. Cosmol. 18, 139–145.
  3. Bartlett FC. 1932 Remembering. Cambridge, UK: Cambridge University Press.
  4. Luce GG. 1976 Research on sleep and dreams. vol. 75. Maryland, USA: U.S. Department of Health, Education and Welfare, Public Health Service, Alcohol, Drug Abuse, and Mental Health Administration [and] National Institute of Mental Health.

Cited by

Sorted by citations

Related

Authors
Davies, J. R., & Clayton, N. S.
Affiliations
University of Cambridge (GB)
Corresponding author
Davies, James R.
ORCID
Venue
Philosophical Transactions of the Royal Society B: Biological Sciences
Publisher
The Royal Society
Published
2024-09-16
Volume
379
Issue
1913
Pages
20230397-20230397
ISSN
  • 0962-8436 (ISSN-L)
  • 1471-2970
DOI
10.1098/rstb.2023.0397
PMC
PMC11449162
OpenAlex
W4402550787
Cited by
27
References
208
Citations by year
2026: 11 · 2025: 13 · 2024: 3
FWCI
1.74
Type
journal article
Language
en
Open access
Licence
Locations
  • Philosophical Transactions of the Royal Society B Biological Sciences (publishedVersion, cc-by)
  • PubMed Central (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • Apollo (University of Cambridge) (submittedVersion, cc-by)
  • Apollo (cc-by)
Topics
  • Life Sciences › Neuroscience › Cognitive Neuroscience › Memory Processes and Influences
  • Life Sciences › Neuroscience › Cognitive Neuroscience › Memory and Neural Mechanisms
  • Social Sciences › Psychology › Experimental and Cognitive Psychology › Cognitive Functions and Memory
Keywords
episodic-like memory, episodic memory, animal cognition, incidental encoding, source memory, conscious recollection, non-human animals, cephalopods, birds, mammals, comparative cognition
MeSH terms
Animals, Humans, Mental Recall, Memory, Episodic

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-09.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-09.

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