kamrulkonok/evalllm2026-french-defense huggingface dataset:
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Aphantasia, SDAM, and Episodic Memory
13
tion is probably not a reliable method to distinguishing such total aphantasia—if it
exists—from near-total aphantasia, and perhaps even from variants of far-from-total
aphantasia. It may turn out to be the case that self-reported total aphantasia is never
really “total”.
Around the time of the (2015) paper by Zeman and colleagues, two other related
papers were published. Daniel Greenberg and Barbara Knowlton (2014) investigated
the role of visual imagery in autobiographical memory, and one of the experiments in
that study involved two non-imagers (or aphantasics). Both participants had “highly
abnormal ratings for reliving”, which according to the authors conﬁrms “previous
work showing that mental imagery is necessary (though not suﬃcient) for a strong
sense of reliving” (931), and which explains the aforementioned self-reported memory
deﬁciencies of aphantasics.
Daniela Palombo and colleagues (2015) also reported on a study about “re-
living” or “the subjective sense of re-experiencing” in episodic memory, and coined
the term “severely deﬁcient autobiographic memory” (SDAM) to describe three cases
of healthy adults reporting not to “re-live” or “subjectively re-experience” previously
experienced events. All three cases scored normal on most standard neuropsycholog-
ical tests except for complex ﬁgure recall: their test scores were “notable for impaired
recovery of visual information” (111). fMRI showed reduced activation of brain re-
gions involved in autobiographic memory, and structural neuroimaging revealed a
slight reduction in the volume of the right hippocampus, which is associated among
others with the recollection of non-verbal/visual information. (On the role of the
hippocampus, see section 6.)
SDAM is deﬁned as “a mnemonic syndrome that is conﬁned to an inability
to mentally travel backwards in time in the absence of detectable neuropathology
or signiﬁcant daily handicap” (Palombo et al. 2015: 111), or more informally as
“the inability to re-experience personal events” (106). All three documented cases of
SDAM are also aphantasics, and it seems plausible that their aphantasia is the cause
of their SDAM. If re-living experiences requires imagery, then a total aphantasic is
incapable of re-experiencing mental events, and then all cases of total aphantasia
would be cases of SDAM. However, someone with involuntary imagery, imagery in
at least some relevant modalities, or very weak imagery would not necessarily have
SDAM. The other way around, it is conceivable that someone has functioning im-
agery abilities, but cannot use that ability to re-live her own past. This would be a
(hypothetical?) case of SDAM without aphantasia.
Although there is now a growing body of evidence for the phenomena of aphan-
tasia and SDAM3, much about the two conditions and their relation remains unclear
3 In addition to papers mentioned above, Jacobs, Schwartzkopf, & Silvanto (2018) and
Fuentemilla, Palombo, & Levine (2018) present further evidence on aphantasia and
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and is in need of further research. Nevertheless, the available evidence makes the
idea that aphantasia doesn’t exist and that non-imagers are mistaken about their
own experiences increasingly implausible. It is to this skeptical idea that we turn
next.
3
While there has been heated debate about the status, role, and nature of men-
tal imagery since the 1970s, both sides in that debate share a conception of mental
imagery as well as the belief that the experience and phenomenology of imagery are
universal (e.g. Thomson 2007). For example, Daniel Dennett wrote that “nobody
denies that when we engage in mental imagery we seem to be making pictures in
our head” (2002: 189). Given the almost universal acceptance of the idea that we
all share the same kind of mental imagery, it should not come as a surprise that the
rejection of that very idea by people who claim not to experience imagery at all has
been met with considerable skepticism and even hostility. As Bill Faw observed:
Much of the current imaging literature either denies the existence of wakeful non-
mental imagers, views non-imagers motivationally as “repressors” or “neurotic”,
or acknowledges them but does not fully incorporate them into their models.
(2009: 45)
One of the most outspoken recent skeptics is Eric Schwitzgebel. The experience
of imagery is a recurring theme in a series of articles on the unreliability of introspec-
tion (2002; 2008; 2011; 2012a; 2012b). According to Schwitzgebel, “we are prone to
gross error, even in favorable circumstances of extended reﬂection, about our ongoing
emotional, visual, and cognitive phenomenology” (2008: 259). His argument is that
there should be vast diﬀerences in the abilities between imagers and non-imagers (i.e.
aphantasics), but there is no evidence of such diﬀerences and given that introspection
is evasive and indeterminate, the most plausible explanation for this lack of evidence
is that self-described non-imagers are mistaken about their own imaging abilities.
Spelled out, the argument consists of three premises and a conclusion:
1) Mental imagery is evasive and indeterminate. “My experiences ﬂee and scatter
as I reﬂect” (2008: 267), and it is unclear, for example, how much you can visu-
alize at once. Because of this, questions about the details of imagery are hard to
answer (contrary to questions about the details of perception), and consequently,
introspection of imagery is unreliable.
2) “If diﬀerences in imagery ability are as vast” as suggested by the self-reports
of aphantasics and hyperphantasics, then “we should presumably expect vast
SDAM, respectively.
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Aphantasia, SDAM, and Episodic Memory
15
corresponding diﬀerences on cognitive tasks involving imagery” (2011: 44).
3) However, there is no evidence for such diﬀerences: “self-described high- and
low-imagery people do not appear to perform any diﬀerently, in general, on psy-
chological tests that have widely been thought to be aided by visual imagery”
(2012a: 187).
4) Therefore, non-imagers are mistaken about their imagery experience, “diﬀer-
ences in imagery reports do not reliably reﬂect diﬀerences in imagery experience”
(2002: 45), and there are no substantial diﬀerences in imagery capability across
individuals: “people are largely the same except when they introspect” (2008:
264).
I’ll respond to the three premises (1 to 3) in the given order.
(ad 1) — In case of visual perception “we have the illusion that we are taking in
all of the details simultaneously, when in fact the experience is built up sequentially”
(Engelbert & Carruthers 2010: 251). If we cannot focus on the whole picture at once
in visual imagery, then visual imagery would be very similar to visual experience,
except that visual imagery would be lacking this illusion of simultaneity. This is
hardly an argument for the unreliability of introspection of mental imagery (relative
to the reliability of visual experience, at least).
Moreover, while the evasiveness and indeterminacy of mental imagery certainly
seem to imply that we can be—and perhaps often are—wrong about the details of
imagery, it does not imply that we are “prone to gross error”.
That we can be
wrong about anything does not imply that we can be wrong about everything4. If
we would be prone to gross error in introspective judgment of our own emotions, for
example, and thus would consistently misjudge how we feel, then our self-ascribed
emotional states and our actual emotional states as revealed by our behavior would
we completely unrelated. Aside from the fact that this obviously isn’t the case, it
is doubtful that this would even be possible. If there would be no relation between
the observed behavior of others and their self-ascribed emotional states, it would be
very diﬃcult—and, perhaps, even impossible—to learn words to describe emotional
states5. (A vocabulary to describe third person behavior may still be possible, but
that is not suﬃcient.) And lacking a vocabulary for emotional states, we would be
4 Many forms of skepticism are based on variants of this fallacious argument. The er-
ror in such arguments is a shift in the scope of the modal operator—that is, from the
premise that ∀p[♦false(p)] in which p is a sentence or statement, it is invalidly inferred
that ♦∀p[false(p)].
5 How could one ever learn a word “happy” if there is no discernible pattern or con-
tinuity in the word’s use? If meaning is use and/or meaning is learned in observing
word use, then a lack of such patterns would make the use of the word in question
apparently random, and therefore, meaningless.
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Aphantasia, SDAM, and Episodic Memory
17
high-imagers.
For example, one of the most common kinds of tests that are supposed to in-
volve imagery are mental rotation tests. Subjects get to see one ﬁgure and have to
compare that ﬁgure to one or more other ﬁgures to judge whether one or more of
those other ﬁgures are rotated versions of the original ﬁgure. However, if the ﬁrst
ﬁgure and test ﬁgures are shown simultaneously, the subject can just glance back
and forth between pictures to compare details of the ﬁgures without ever forming a
mental image, and even if the ﬁrst ﬁgure must be remembered to do the test, the
subject can remember a verbal description of the ﬁgure—provided that the ﬁgure is
simple enough, which usually is the case—and then compare the test ﬁgure(s) with
that description8. These suggestions do, of course, imply that non- or low-imagers
and high-imagers use diﬀerent brain regions in mental rotation tasks, and there is
evidence for such a diﬀerence indeed (Logie et al. 2011).
If some people lack a certain mental ability, and there are ways of compensating
that deﬁciency in many (perhaps even most) circumstances, then one would expect
that deﬁciency only to have rather subtle eﬀects. Considering that a lack of (speciﬁc
kinds of) imagery can probably be compensated in various ways in many circum-
stances, if there are signiﬁcant diﬀerences in imagery abilities across individuals, one
would expect there to be subtle—but not vast— corresponding diﬀerences on cogni-
tive tasks involving imagery, and some of those diﬀerences might only show up on an
fMRI scan or by means of another imaging technique.
(ad 3) — As mentioned two paragraphs back, Logie et al. (2011) found that low-
and high-imagers show diﬀerent brain activation patterns in mental rotation tasks.
The study that deﬁned SDAM by Palombo et al. (2015) found that their aphantasic
cases were in the severely impaired range for complex ﬁgure recall. Zeman (2017)
found a link between aphantasia and prosopagnosia (reduced facial recognition). And
directly contradicting Schwitzgebel’s claims, Rebecca Keogh and Joel Pearson (2018)
found that “congenital aphantasia is characterised by a lack of low-level sensory visual
imagery, and is not due to a lack of metacognition or an inability to introspect”.
There isn’t much evidence for (the eﬀects of) aphantasia yet, but Schwitzgebel’s
claim that there is no evidence is false. (But it must be noted that all of this evi-
dence was published after Schwitzgebel published his main papers on introspection.)
It is true, however, that most earlier studies do not reveal any substantial diﬀerences
between low- and high-imagers on cognitive tasks involving imagery. This apparent
negative evidence may be due to three methodological ﬂaws, the ﬁrst two of which
8 Considering that such non-imaginistic comparison procedures might be more reliable
than the use of imagery, it may even be the case that an aphantasic who is used to
relying thereon scores higher on a simple mental rotation task than someone who is
used to relying on imagery.
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18
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Vol. 28
were already pointed at above.
Most tests ignore the possibility of compensating for deﬁciencies. Mental ro-
tation tests, for example, nearly always allow for various answering strategies that
do not require mental imagery. Secondly, and related to the neglected possibility of
compensation, diﬀerences between low- and high-imagers are more likely to be subtle
than vast and may only be revealed by means of neuroimaging. Thirdly, virtually all
the research on the eﬀects of vividness of imagery until now compares low-imagers
to high-imagers, but it may be the case that low-imagers are more similar to high-
imagers than to non-imagers.
To illustrate the latter, imagine a test that requires the subject to read a single,
short word every once in a while. People who are very good at reading and people
who can just barely read are not likely to score very diﬀerently on this test (assuming
that reading skill is not correlated to whatever is tested), but people who cannot
read at all will deviate signiﬁcantly. Similarly, if a test requires only very basic im-
agery, low-imagers and high-imagers are not likely to score signiﬁcantly diﬀerently,
but non-imagers will (except if they can compensate for the lack of imagery).
Research into aphantasia and SDAM and their eﬀects is still in its infancy. More
research is needed, but future research also needs to take the above three method-
ological points into account.
Schwitzgebel’s skeptical conclusion (4) about aphantasia follows from premises
(1) to (3), but we have found that all three of these premises are false. Consequently,
his argument against aphantasia fails.
If there is no successful argument against
aphantasia we should take the condition seriously and consider its implications for
our conceptualizations of and research on memory. This is the topic of the remainder
of this paper.
4
One of the most inﬂuential distinctions of kinds of memory is that between se-
mantic and episodic memory by Endel Tulving (1972; 1983). Semantic memory is
memory of facts; episodic memory is—more or less—memory of experienced episodes.
In (1972), Tulving deﬁned episodic memory as memory of what/where/when,
adding the phenomenology of the “recollective experience” in (1983). The original
what/where/when conceptualization remains inﬂuential, however, and in laboratory
tests episodic memory is often operationalized as memory of visual stimuli. Conse-
quently, the concept of “episodic memory” has become somewhat muddled.
In Elements of Episodic Memory (1983), Tulving listed 28 “diagnostic features”
of episodic and semantic memory (see his table 3.1 on page 35). These features are
a rather varied bunch including items like usefulness, likelihood of realization in ar-
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Aphantasia, SDAM, and Episodic Memory
19
Table 1
selected “diagnostic features” of episodic and semantic memory
diagnostic feature
episodic memory
semantic memory
1
source
sensation
comprehension
2
units
events, episodes
facts, ideas, concepts
3
organization
temporal
conceptual
4
reference
self
universe
5
registration
experiential
symbolic
6
aﬀect
more important
less important
7
retrieval queries
time? place?
what?
8
recollective experience
remembered past
actualized knowledge
(source: Tulving 1983: 35)
tiﬁcial intelligence, and admissibility as legal testimony, in addition to a number of
apparently more likely candidates for deﬁning features of the semantic/episodic dis-
tinction. (It must be noted that Tulving admitted himself that “some features may
turn out to be irrelevant to the distinction” (35).) Table 1 lists the eight most rele-
vant “diagnostic features”. (Omitted features are either very similar, or consequences
more than essential characteristics.)
Tulving (1983) thinks of the retrieval of episodic memory as a kind or replay
or re-experiencing. Except (4) and (6), all of the features in the “episodic memory”
column in Table 1 are related to this conception of episodic memory. The source
of episodic memory is sense experience and its recollection is (more or less) a revis-
iting of that sense experience. This implies that episodic memory depends on the
sense modalities—it is a replay or reconstruction of sensation. That replay or recon-
struction always and by necessity involves at least one sense modality, but is often
multi-modal (i.e. involving more than one sense modality). In contrast, the content
of semantic memory—as characterized by the “diagnostic features” in the rightmost
column in the table— is symbolic and conceptual rather than sensory-experiential,
and consequently, the sense modalities play no (central) role in semantic memory. In
other words, while episodic memory is necessarily sense-modal and often multi-modal,
semantic memory is essentially amodal.
The remaining two features, (4) and (6), seem to refer to two diﬀerent, albeit
possibly related, aspects of episodic memory: self-referentiality (4) and the emotional
attachment to some kinds of memories (6). (The ﬁrst of these is what was called
the subjective identiﬁcation of the remembering subject with the subject that expe-
rienced the original episode in the introduction.) Mark Johnston (2010) suggested
that the self is something like “an arena with some person at the phenomenological
center” (237). Episodic memory is the memory of what happened in that arena and
to (the subject/self at) its center. Features (5) and (8) also refer to the focus of
episodic memory on that arena and its center. These features and their counterparts
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for semantic memory imply that episodic memory is self-centered and, therefore, per-
sonal, while semantic memory—lacking any similar kind of focus —is uncentered and
impersonal.
The role of feature (6), aﬀect, in episodic memory is often alluded to as the
“warmth and intimacy” that suﬀuses remembering (James 1890: 239). Supposedly,
we feel an emotional attachment to our episodic memories, while semantic memories
are more emotionally neutral.
The eight listed features can thus be grouped into three diﬀerent contrasting
pairs: (i) modal/amodal, (ii) personal/impersonal, and (iii) aﬀective/neutral.
Of
these three, the modal/amodal contrast appears to be most fundamental. It may
also be the most problematic.
In Mental Time Travel (2016), Kourken Michaelian shows that episodic mem-
ory is mental time travel into the past and that mental time travel in general is a
kind of imagination. Hence, episodic memory is imagination of the experienced past.
But episodic memory is modal memory and, therefore, a kind of modal imagination,
and modal imagination is mental imagery. By implication, people who lack mental
imagery—that is, aphantasics—lack modal memory, but there is nothing that indi-
cates that aphantasics lack personal and/or aﬀective memory (even if some of them
have deﬁciencies—such as SDAM—in one or both of these respects).
According to Lawrence Barsalou (1999; 2009) and other advocates of “situated
cognition” and similar theories there is no independent amodal memory, however.
Even the memory of words and concepts involves imagery-like simulations of relevant
situations in memory. If this is true, then aphantasics really do have mental im-
agery corresponding to their conscious thoughts, but somehow just aren’t aware of it.
Rebecca Keogh and Joel Pearson’s (2018) ﬁndings (see above), as well as the diﬀer-
ences in brain activation patterns between low- and high-imagers (Logie et al. 2011),
and the documented neural correlates of semantic and episodic memory, which are
often operationalized more or less as amodal and modal memory (e.g. Wiggs, Weis-
berg, & Martin 1998) all seem to contradict this suggestion, however9. Furthermore,
even if it is true that the vast majority of people always activate modal memory or
imagery-like simulations, this doesn’t imply that all people necessarily do so. Neither
Barsalou, nor anyone else has investigated whether aphantasics also activate some
kind of (unconscious) mental imagery when processing apparently amodal informa-
tion. Given the—admittedly still scarce— available evidence, it seems more likely
that aphantasics (as well as people with SDAM) lack modal memory indeed.
9 More speciﬁcally, it suggests that aphantasics don’t have unconscious imagery that
more or less systematically corresponds with their conscious mental content. It does.
however, not imply that aphantasics don’t have unconscious imagery at all. See also
below in this section and section 6.
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Aphantasia, SDAM, and Episodic Memory
21
But if aphantasics lack modal memory, then how do they remember shapes,
sounds, and other modal or sensory “information”? This question stands in need of
an answer because low-imagers do not score signiﬁcantly worse on mental rotation
tasks (there is no separate data for aphantasics, unfortunately), and aphantasics do
not appear to suﬀer from any cognitive impairments. The answer to this question
was already (partially) given above, however: aphantasics rely on the conceptual-
ization of modal/sensory information. In a mental rotation test, an aphantasic can
compensate for her lack of mental imagery by memorizing a verbal description of the
test ﬁgure. Behaviorally—that is, from a third-person point of view—the aphantasic
subject will appear to have functional modal memory when doing a mental rotation
test, while she is really relying on amodal memory. If this is right, then there is a
kind of memory that has some apparent characteristics of both amodal and modal
memory. I’ll call this pseudo-modal memory in the following.
Pseudo-modal memory is verbalized/conceptualized and “de-modalized”, ab-
stracted, or “semanticized” sensory experience.
It is memory of a visual experi-
ence of a purple triangle in the form of a description (i.e. “purple triangle”), rather
than in the form of imagery. From an outside or third-person point of view, it is
often indistinguishable whether someone relies on modal or pseudo-modal memory
(thus explaining the normal scores of non- and low-imagers on many tests), but the
phenomenology is very diﬀerent. In other words, pseudo-modal memory is behav-
iorally (or from the third-person point of view) modal, but phenomenologically (and
thus from the ﬁrst-person point of view), and presumably also neurophysiologically,
amodal.
While the notion of pseudo-modal memory explains some aspects of aphantasia,
it also suggests a new skeptical argument against congenital aphantasia. If aphan-
tasics lack modal memory and rely on conceptual, amodal, and/or pseudo-modal
memory, then it seems that an aphantasic infant would have no memory at all, and
because of that, would also lack the ability to learn concepts and language. Without
memories of the use of the word “table” in apparent reference to things that shared
certain features (i.e. tables), how could a child ever learn the word “table”? But if
an aphantasic child would be unable to learn words and language, then it would not
grow up to become a normally functioning adult, and consequently, aphantasia must
be acquired rather than congenital.
This skeptical argument fails, however, because the memories that concept for-
mation depends on (such as memories of tables) do not need to be conscious (and
aphantasia does not exclude the possibility of unconscious imagery and unconscious
modal memory). In fact, it is more likely that these memories are unconscious given
that consciousness itself gradually develops in the ﬁrst few years of a (normal) hu-
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22
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Table 2
amodal/modal and impersonal/personal memory
amodal
pseudo-modal
modal
impersonal
(a)
(b)
(c)
personal
(d)
(e)
(f)
man life, while categorization by infants starts within a few months after birth10.
Hence, the processes of category formation and (much later) of associating words
with things in the earliest stages of language learning are probably largely uncon-
scious (and automatic—we are “born to categorize”, as Quinn’s (2011) overview of
categorization by infants and children is appropriately titled).
Moreover, if aphantasic toddlers learn language by means of something like un-
conscious modal memory, then adult aphantasics might also have unconscious modal
memory, which would explain the self-reported occurrence of imagery in the dreams of
many aphantasics11, for example, but which would also raise further questions. Con-
sidering that unconscious modal memory appears not to be automatically and con-
sistently activated when an aphantasic remembers something (Palombo et al. 2015;
Keogh & Pearson 2018), What activates unconscious modal memory in aphantasics
and what cognitive role(s) does it play?12
5
If aphantasics lack modal memory but have personal memory and aﬀective mem-
ory (the other two aspects of episodic memory distinguished above), then these three
are not just diﬀerent aspects of the same kind of memory, but are two or three in-
dependent dimensions or kinds of memory instead. The three distinctions on the
amodal/modal dimension combined with the personal/impersonal memory contrast
results—at least hypothetically—in six diﬀerent kinds of memory, as shown in Ta-
ble 2.
In addition to the SDAM and aphantasia-related evidence, which supports the
column distinctions, there is other evidence for some of the row distinctions in this
table. Louis Renoult and colleagues (2012) argue for something they call “personal
semantics”, which is “highly personal (like episodic memory), yet, at the same time,
devoid of any subjective sense of recollection” (550). Personal semantics lacks the
modality of episodic memory—it is personal and amodal, and therefore, cell (d)
and/or (e) in the table. While Renoult et al. points at the diﬀerence between im-
10 On categorization by infants and young children, see Quinn (2011). On the develop-
ment of consciousness in children, see Zelazo, Gao, & Todd (2007).
11 As well as other kinds of involuntary imagery. See section 2.
12 Answering this question is obviously outside the scope of this paper, but it should be
added to the other open questions mentioned in section 2.
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Aphantasia, SDAM, and Episodic Memory
23
Table 3
... and neutral/aﬀective memory
amodal
pseudo-modal
modal
neutral
impersonal
(a)
(b)
(c)
personal
(d)
(e)
(f)
aﬀective
(g)
(h)
(i)
personal and personal amodal memory, Hung-Yu Chen and colleagues (2017) have
recently shown that impersonal and personal modal memory—that is, (c) and (f)—
activate diﬀerent brain networks.
Personal semantics as conceptualized by Renoult et al. includes self-knowledge,
which “has most often been operationalized as the summary of one’s personality
traits” and “because they focus on self image, these aspects of [personal semantics]
may be strongly inﬂuenced by emotional and social factors during encoding and re-
trieval” (555). While this suggests a link between personal and aﬀective memory,
Mark Wheeler (2000) summarizes empirical evidence that dissociates personal from
aﬀective memory. There are patients with prefrontal cortical damage (including the
subjects of the psychosurgical procedure of frontal leucotomy that was performed in
the ﬁrst half of the 20th century) that have more or less normally functioning personal
memory, but that lack an interest in those personal memories. What these patients
lack is a sense of their own self-continuity and an interest in themselves as persons.
And consequently, “although the patients knew all of the personal facts . . . that
they did before, the facts were experienced with a lack of ‘warmth and intimacy’ that
William James had attributed to the way humans typically think about their lives”
(Wheeler 2000: 602).
Stanley Klein and Shaun Nichols (2012) describe a more recent case of a traﬃc
accident victim R.B. who retained personal memory, but who (temporarily) lost his
sense of “ownership” of his personal memories.
However, R.B. experienced “full
ownership” of new memories formed after the accident (and gradually recovered
ownership of earlier memories) and probably because of that did not lack a sense
of self-continuity as in the prefrontal cortical damage cases described by Wheeler.
Nevertheless, both kinds of cases show that there can be personal memory without
aﬀective memory. The converse—that is, impersonal aﬀective memory—appears less
likely (and I’m not aware of any evidence for its existence), so this would mean that
we only need to add one row to table 2, resulting in table 3.
While the evidence for the aﬀective/personal distinction implies the need for a
third row in the table, it does not specify whether that row crosses with all columns.
In other words, it still needs to be established whether the aﬀective dimension is in-
dependent from the modal dimension, and whether aﬀective memory can be amodal
(g) or pseudo-modal (h) as well as modal (i), similar to personal and impersonal
memory. Although paradigm cases of aﬀective memory appear to be modal, there is
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Aphantasia, SDAM, and Episodic Memory
25
vantages. Firstly, there is probably a limit to how much information can be concep-
tualized (or “semanticized”, or “amodalized”) and stored in amodal form. Secondly,
this process might not be entirely automatic, and thus, if the subject doesn’t remem-
ber to remember (i.e. store) something, it won’t be remembered (i.e. retrieved). And
thirdly, amodal memory might degrade faster and diﬀerently than modal memory.
In any case, pseudo-modal memory is probably a poor substitute for modal memory
in many circumstances, which explains the memory deﬁciencies of aphantasics and
people with SDAM.
6
Tulving’s list of diagnostic features was not intended as a conjunctive deﬁnition,
but if it is interpreted as such, then episodic memory is the kind of memory that has
all of those features. In other words, episodic memory is (i) in table 3. Similarly,
semantic memory is the kind of memory that has all of the features in the semantic
memory column of table 1 (or in Tulving’s table on which table 1 is based) and lacks
all of the features of episodic memory: cell (a) in table 3. The semantic/episodic dis-
tinction, then, is the (a)/(i) contrast, which raises the question what kind of memory
all the other variants in table 3 are. In practice, however, episodic memory often
appears to be operationalized disjunctively—that is, memory that is modal or per-
sonal or aﬀective tends to be treated as episodic memory. In laboratory research, for
example, episodic memory is sometimes operationalized as memory of pictures, which
just requires (c) (or (b), perhaps) in table 3. In such a disjunctive understanding,
everything except (a) would be episodic memory.
Perhaps, such apparent disjunctive understandings of episodic memory are the
consequence of an implicit assumption that of the nine varieties of memory in table
3, only (a) and (i) exist. Under that assumption, which has been shown to be false
above, the conjunctive and disjunctive understandings of episodic memory necessarily
coincide—then all and only modal memory is episodic memory, and therefore, picture
memory is episodic memory.
A similar assumption seems to play a key role in many—perhaps, even all—
explanations of the evolutionary advantage of episodic memory.
(See Michaelian
2016 for a critical review.) That is, the supposed evolutionary advantages of episodic
memory and the related ability of mental time travel into the future are never advan-
tages of just (i) but equally of one or more other variants in table 3. For example, for
the abilities to avoid past mistakes and/or to plan and prepare for an uncertain future
(d) or (e) are suﬃcient, although lacking the aﬀective dimension the subject may be
disinterested in avoiding mistakes or in planning for the future. In any case, modal
imagination—which is a supposed core aspect of episodic memory—is not necessary
(but this is also evident from the fact that aphantasics are just as (in-) capable of
— 25 —
BROASA-8v1.pdf — page 19

Aphantasia, SDAM, and Episodic Memory
27
some kind of unconscious modal memory when remembering does not imply that
aphantasics don’t have unconscious modal memory at all. See section 4.)
If semantic memory is (a) and episodic memory is (i) or some other union of cells
in table 3 that excludes more than just (a)—as in the what/where/when interpreta-
tion and in Cheng and Werning’s deﬁnition—then it is unclear how the remaining
varieties of memory should be classiﬁed. These remaining varieties include impersonal
modal memory (c) and its semanticized counterpart (b), as well as personal amodal
memory (d) and its aﬀective counterpart (g), but depending on the exact deﬁnition
of episodic memory, they may also include (e), (f), and (h). Denying the existence of
these varieties is hardly an option given the evidence reviewed in previous sections,
but that doesn’t automatically imply that they are really diﬀerent kinds of memory in
addition to episodic and semantic memory: they might be variants or applications of
episodic memory that just don’t make use of everything episodic memory can do, for
example. In that case, someone lacking some of these variants or applications would
have defective episodic memory. (“Defective” in the sense that some of the functions
of episodic memory don’t “work”.) The plausibility of this suggestion depends on
whether it can be shown that a single mental faculty is involved in everything but
(a) and that aphantasics and people with SDAM have a defect in this single mental
faculty explaining their lack of modal memory. In other words, it depends on ex-
planatory and causal uniﬁcation of episodic memory, and thus, on whether episodic
memory is a natural kind.
7
Something is a natural kind—in the here relevant sense—if (1) the entities be-
longing to that kind share a large set of inductively and explanatorily relevant prop-
erties and (2) that kind is the largest class whose members share those properties
due to some underlying causal mechanism14. These two criteria (1 and 2) are indi-
vidually necessary and collectively suﬃcient conditions for attributing natural kind
status. The ﬁrst criterion demands explanatory uniﬁcation of the kind in question;
the second criterion demands its causal uniﬁcation.
According to Cheng and Werning (2016) episodic memory satisﬁes both criteria,
and therefore, is a natural kind. The underlying causal mechanism—criterion (2)—
they identify is the hippocampus. However, while there is broad consensus that the
thing like crypto-modal memory (although I’m not aware of any evidence for this),
but even if this is the case, the notion appears to have little explanatory value, and
adding a fourth column to table 3 to accommodate it is, therefore, not necessary.
14 As observed in footnote 1, one could further weaken the notion of natural kinds by giv-
ing up (or signiﬁcantly relaxing) one of these criteria, but the resulting notion would
almost certainly be too weak to be explanatorily useful. And therefore, whether such
kinds could be justiﬁably considered natural kinds is doubtful.
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28
Lajos Brons
Vol. 28
hippocampus is essential for (key aspects of) episodic memory, it plays an equally im-
portant role in a large number of other cognitive contexts, and there is no consensus
about the exact function of the hippocampus. In a recent review Arne Ekstrom and
Charan Ranganath (2017) provisionally conclude that the hippocampus’s function
may be to cut up experience into spatial, temporal, or other kinds of chunks that
have low variance internally. Episodes would be one kind of such chunk (but only
one kind). Furthermore, there is evidence that hippocampal damage is related to a
deﬁciency of imagery (reviewed in Ekstrom and Rangarath 2017), and Palombo and
colleagues (2015) found a subtly reduced right hippocampal volume in their SDAM
cases.
However, “the hippocampus is all over the cognitive map” (Ekstrom and Ran-
garath 2017) and its function is (or functions are) not nearly speciﬁc enough to identify
it as the underlying causal mechanism of episodic memory. Moreover, the cases of
deﬁcient aﬀective memory described by Wheeler (2000) and Klein and Nichols (2012)
involved prefrontal cortical damage suggesting that the prefrontal cortex rather than
the hippocampus is essential for aﬀective memory. In other words, for causal uniﬁ-
cation of episodic memory, the role of the hippocampus is both too broad and too
narrow.
The problem of narrowness can be avoided, however, by dissociating the aﬀective
dimension from episodic memory. The cases of deﬁcient aﬀective memory then have
normal episodic memory and have an unrelated memory deﬁciency. Given that Cheng
and Werning’s deﬁnition does not explicitly involve an aﬀective aspect, this response
is available to them.
Episodic memory would then be (f), personal modal mem-
ory, and (i), the kind of memory that is more commonly identiﬁed as paradigmatic
episodic memory, would be a combination of episodic-memory-as-(f) and aﬀective
memory15. This doesn’t solve the broadness problem, however, and given that the
causal uniﬁcation criterion requires the kind to be the largest class that shares the
supposed causal mechanism, this problem appears to be fatal.
The hippocampus
cannot possibly provide the kind of causal uniﬁcation required.
Furthermore, even if, despite these objections, the hippocampus would be iden-
tiﬁed as the underlying causal mechanism of episodic memory, this would not be
suﬃcient to classify episodic memory as a natural kind. The other criterion, explana-
tory uniﬁcation, requires that the things that make up the supposed natural kind also
share a large set of inductively and explanatorily relevant properties (due to the un-
derlying causal mechanism). There is no such set of properties, however. Impersonal
modal memory (c) has almost nothing in common with personal amodal memory (d)
or aﬀective amodal memory (g), and certainly nothing inductively or explanatorily
15 If episodic memory is (f), then it may be the case that many animals have full-ﬂedged
episodic memory. At least, replay in rats seems to be modal and personal, and thus
(f) (e.g. Buhry, Azizi, & Cheng 2011).
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30
Lajos Brons
Vol. 28
The episodic memory construct suggests that there is a single mental faculty
responsible for very diﬀerent kinds and uses of memory such as impersonal modal
memory and aﬀective amodal memory. There is no such single mental faculty, how-
ever, and consequently, the episodic memory construct obscures more than it clariﬁes.
There is no such thing as episodic memory.
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— 32 —
La DGA livre le premier drone de surface de guerre des mines à la Marine nationale dans le cadre du programme SLAM-F _ Ministère des Armées et des Anciens combattants.pdf — page 1

La DGA livre le premier drone de surface
de guerre des mines à la Marine nationale
dans le cadre du programme SLAM-F
Drones
Marine nationale
Direction : DGA / Publié le : 21 janvier 2025
Le 19 décembre 2024, la Direction générale de l’armement (DGA) a livré le premier
drone de surface de guerre des mines à la Marine nationale.
Ce système initie le renouvellement de la capacité de guerre des mines porté par le
programme SLAM-F (système de lutte anti-mines marines futur). Il comprend un drone
de surface et un sonar tracté associés à un centre d’opération projetable, installé à
Brest (29).
Voir le fil d'ariane
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La DGA livre le premier drone de surface de guerre des mines à la Marine nationale dans le cadre du programme SLAM-F _ Ministère des Armées et des Anciens combattants.pdf — page 2

SLAM-F - © DGA
Réalisé dans le cadre de la coopération franco-britannique « MMCM » (Maritime Mine
Counter Measures), ce programme est porté par la société Thales Underwater
Systems, sous maitrise d’ouvrage déléguée à l’OCCAr (organisation conjointe de
coopération en matière d’armement).
Ce système constitue une étape majeure dans le renouvellement de la capacité de
guerre des mines de la Marine nationale, marquant une rupture technologique dans la
conduite des opérations dans ce domaine. Véritable concentré de technologie, le
drone de surface cumule dans un format compact et aérotransportable, l’ensemble
des fonctions dévolues auparavant à des bâtiments plus imposants.
La livraison de ce drone constitue une première étape avant l’atteinte d’une véritable
capacité opérationnelle en fin d’année 2025.
Dans cette perspective, ce drone sera associé à cinq drones de surface
supplémentaires, constituant ainsi la première capacité de systèmes autonomes de
surface de la Marine nationale.
En parallèle des essais d’acceptation, les formations initiées à l'été 2024 se sont
poursuivies afin de permettre à la Marine nationale de mettre en œuvre le système
dès sa livraison et d’être en mesure de l'accompagner dans sa mise en service. Le
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drone de surface a passé avec succès sa mise en condition de navigation (MECNAV), le
16 janvier 2025, l’autorisant à naviguer en mode inhabité télé opéré et ainsi à débuter
sa première phase de montée en compétence exploratoire.
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