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Memory
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Eye movements disrupt episodic future thinking
Stefania de Vitoab, Antimo Buonocorec, Jean-François Bonnefond & Sergio Della
Salae
a Centre de Recherche de l'Institut du Cerveau et de la Moelle épinière, INSERM,
Paris, France
b Laboratory of Experimental Psychology, Suor Orsola Benincasa University, Naples,
Italy
c Department of Psychology and Cognitive Sciences, Center for Mind/Brain
Sciences, Trento University, Trento, Italy
d CLLE, Maison de la Recherche, Toulouse, France
e Human Cognitive Neuroscience, Psychology, University of Edinburgh, Edinburgh,
UK
Published online: 17 Jun 2014.
To cite this article: Stefania de Vito, Antimo Buonocore, Jean-François Bonnefon & Sergio Della Sala (2014): Eye
movements disrupt episodic future thinking, Memory, DOI: 10.1080/09658211.2014.927888
To link to this article: http://dx.doi.org/10.1080/09658211.2014.927888
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Eye movements disrupt episodic future thinking
Stefania de Vito
1,2
, Antimo Buonocore
3
, Jean-François Bonnefon
4
, and
Sergio Della Sala
5
1
Centre de Recherche de l’Institut du Cerveau et de la Moelle épinière, INSERM, Paris,
France
2
Laboratory of Experimental Psychology, Suor Orsola Benincasa University, Naples, Italy
3
Department of Psychology and Cognitive Sciences, Center for Mind/Brain Sciences,
Trento University, Trento, Italy
4
CLLE, Maison de la Recherche, Toulouse, France
5
Human Cognitive Neuroscience, Psychology, University of Edinburgh, Edinburgh, UK
(Received 27 February 2014; accepted 20 May 2014)
Remembering the past and imagining the future both rely on complex mental imagery. We considered
the possibility that constructing a future scene might tap a component of mental imagery that is not as
critical for remembering past scenes. Whereas visual imagery plays an important role in remembering the
past, we predicted that spatial imagery plays a crucial role in imagining the future. For the purpose of
teasing apart the different components underpinning scene construction in the two experiences of
recalling episodic memories and shaping novel future events, we used a paradigm that might selectively
affect one of these components (i.e., the spatial). Participants performed concurrent eye movements
while remembering the past and imagining the future. These concurrent eye movements selectively
interfere with spatial imagery, while sparing visual imagery. Eye movements prevented participants from
imagining complex and detailed future scenes, but had no comparable effect on the recollection of past
scenes. Similarities between remembering the past and imagining the future are coupled with some
differences. The present findings uncover another fundamental divergence between the two processes.
Keywords:Episodic future thinking; Prospection; Eye movements; Visual imagery; Spatial mental
imagery.
There is not only one time:
There are many ribbons that slide parallel
often in the opposite sense
(Eugenio Montale)
People can withdraw from the current moment and
mentally project themselves to an alternative time
and place, as they remember their past or imagine
their future (Szpunar, 2011). Importantly, the cog-
nitive and neuralprocesses involved in remembering
thepastseemtobethesameasthecognitiveand
neural processes involved in imagining the future
(episodic future thinking,Atance&O’Neill, 2001;
Buckner & Carroll, 2007; de Vito & Della Sala,
2011). In this article, we show that even though both
remembering the past and imagining the future
depend on mental imagery, they involve a different
mix of spatial and visual mental imagery.
The neural activity underpinning the remem-
brance of the past is strikingly similar to the
Address correspondence to: Stefania de Vito, Centre de Recherche de l’Institut du Cerveau et de la Moelle épinière, INSERM,
U 1127, 47-83 Boulevard de l’Hôpital, F-75013 Paris, France. E-mail: stefaniadv29@libero.it
© 2014 Taylor & Francis
Memory, 2014
http://dx.doi.org/10.1080/09658211.2014.927888
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neural activity underpinning episodic future
thinking (Buckner & Carroll, 2007; Irish &
Piguet, 2013; Schacter et al., 2012). The set of
cognitive processes sustaining these two functions
is thought to overlap considerably (Addis, Wong, &
Schacter, 2007;D’Argembeau & Van der Linden,
2004; Levine, Svoboda, Hay, Winocur, & Mos-
covitch, 2002; Manning, Denkova, & Unterber-
ger, 2013). Nonetheless, relevant neuroimaging
(Addis et al., 2007; Okuda et al., 2003), behavi-
oural (Addis, Musicaro, Pan, & Schacter, 2010;
D’Argembeau & Van der Linden, 2004; Gamboz,
Brandimonte, & de Vito, 2010) and neuropsycho-
logical studies (Berryhill, Picasso, Arnold, Dro-
wos, & Olson, 2010; de Vito et al., 2012) have
reported marked differences or dissociations
(Irish, Addis, Hodges, & Piguet, 2012) between
the ability of remembering the past and that of
imagining the future.
Both functions reflect the construction of
mental scenes that involve complex mental
imagery (Hassabis & Maguire, 2007; Schacter &
Addis, 2007). However, mental imagery is a mul-
tifarious cognitive tool, which relies on at least
two components, a spatial component and a
depictive (Kosslyn & Thompson, 2000), also
labelled visual, component (Reisberg & Heuer,
2002). We need to carefully consider the possib-
ility that these various components might be
differentially involved in remembering the past
and in imagining the future.
While it seems reasonably clear that remem-
bering the past crucially requires visual imagery
(Rubin, Schrauf, & Greenberg, 2003), much
remains to be elucidated about the mix of visual
and spatial imagery required to imagine the
future (de Vito, 2012).
One possible means to address this issue is to
explore the disruptive effect of voluntary eye
movements on episodic future thinking. Volun-
tary eye movements are known to disrupt mental
imagery (Postle, Idzikowski, Della Sala, Logie, &
Baddeley, 2006).
Early studies (e.g., Perky, 1910) indicated a
tight link between eye movements and mental
images. Neisser (1967) then argued that eye
movements are necessary to the construction of
a visual image, and Baddeley (1986) posited that
voluntary eye movements interfere with visuo-
spatial mental imagery. This hypothesis is sup-
ported by experimental data (Hale, Myerson,
Rhee, Weiss, & Abrams, 1996; Laeng & Teodor-
escu, 2002; Lawrence, Myerson, Oonk, &
Abrams, 2001; Pearson & Sahraie, 2003; Postle
et al., 2006). Further studies showed that eye
movements (specifically, endogenously generated
smooth pursuit) reduce the vividness and emo-
tional impact of personal recollections (Andrade,
Kavanagh, & Baddeley, 1997). This effect extends
to upsetting visual images of feared future events
(Engelhard, van den Hout, Janssen, & van der
Beek, 2010).
A close examination of the literature, however,
suggests that only spatial mental imagery has
been shown to be disrupted by concurrent eye
movements. The visual component of mental
imagery has rarely been investigated under sim-
ultaneous eye movements (see, e.g., Exp 4 in
Postle et al., 2006). Pearson and Sahraie (2003)
demonstrated that concurrent voluntary eye
movements reduce spatial memory task signifi-
cantly more than equivalent covert attention
shifts or limb movements. Indeed, all experiments
showing impairment of mental imagery due to
concurrent eye movements employed spatially
loaded tasks (Lawrence et al., 2001; Pearson &
Sahraie 2003; Postle et al., 2006). Even more
tellingly, Postle et al. (2006, Study 4), as well as de
Vito, Buonocore, Bonnefon, and Della Sala
(2014), presented participants with tasks tapping
either the visual or spatial component of mental
imagery, and showed that voluntary eye move-
ments impaired performance on the latter, but
not on the former. Postle et al. (2006) asked
participants for the delayed recognition of the
shape of previously provided targets, and for the
delayed recognition of the location of previous
targets. After the presentation of the target,
participants underwent a “distraction period”in
which they were asked either to continuously
move their eyes or to read some words appearing
on the screen. The results indicated that saccadic
distraction affects spatial working memory per-
formance, but not performance on a non-spatial
task that is equally difficult. On the contrary,
word reading disrupts working memory for
shape, but not for locations. de Vito et al. (2014)
observed that an additional task of concurrent
eye movements perturbed performance for the
iconic version of a spatial imagery test (Brooks
matrices) but not for the iconic versions of visual
imagery tests (Animal tails task and Curvy Let-
ter task).
Accordingly, the question of whether remem-
bering the past and imagining the future depend
on the same mix of mental imagery can be
explored by investigating the disruptive effects
of voluntary eye movements.
2 DE VITO ET AL.
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To this end, we instructed participants to per-
form cue-dependent memory tasks as well as
future-thinking tasks, concurrently with two dif-
ferent secondary tasks: eye movement and hand
tapping. This latter condition was added because
previous studies suggested that it could interfere
with mental imagery tasks (e.g., Farmer, Berman, &
Fletcher, 1986; Logie & Marchetti, 1991;Moscov-
itch, 1994; Salway & Logie, 1995;Smyth,Pearson,
& Pendleton, 1988). Its inclusion thus ensured that
our results would not simply reflect the unspecific
effect of any attention-demanding concurrent task.
We posit that spatial imagery serves the ability
of future thinking to a greater extent than the
ability of remembering past events. Indeed, rel-
ative to autobiographical memory, future thinking
requires a more extensive constructive process
(Schacter et al., 2012). Thus, concurrent voluntary
eye movements are likely to disrupt future think-
ing, while sparing episodic memory.
METHOD
Participants
Fourteen young adults (9 men) entered this
experiment. Participants were right-handed stu-
dents recruited at the University of Edinburgh.
Their average age was 31.14 years (SD = 2.24).
None was under psychoactive pharmacological
treatment or had a history of neurological or
psychiatric disorder. Participants did not receive
any compensation. Before starting the testing
session, participants signed an informed consent
form. The study procedures were approved by
the local ethical committee and were carried out
in accordance with the Declaration of Helsinki.
Materials
Participants were initially briefed that they
would be required to mentally re-experience and
pre-experience 12 autobiographical episodes
(6 occurred in the past; 6 occurring in the future
and never occurred in the past), in response to
randomly presented cue words. This technique of
open-ended cueing paradigms has been largely
used in most of the previous future-thinking
studies on healthy participants and has been
proved to be sensitive to future-imagining deficits
in patients (Squire et al., 2011). Participants were
given an explicit temporal frame with each future/
past cue (i.e., next few years/last few years).
Aiming at eliciting past and future events, two
sets of eight words, matched for familiarity,
frequency, imageability and concreteness, were
selected (Burani, Barca, & Arduino, 2001). Within
each list, the words were randomly assigned to
the two temporal directions and rotated in the
past/future conditions. Then, each participant was
given one of these two sets. The experimenter
further explained that the events had to be
remembered or imagined in as much detail as
possible. Participants also were encouraged to
produce temporally and contextually specific
events and to vividly imagine novel and plausible
future episodes, given their current plans. When
constructing future episodes, participants were
explicitly instructed not to describe a memory or
any part of it, or something they planned to do,
but rather to imagine something completely new.
This procedure follows those of D’Argembeau
and van der Linden (2004) and of Addis et al.
(2007). The order of presentation of temporal
connotation (i.e., past and future) was
counterbalanced.
The cues were read, one at a time, by the
experimenter with the instructions about the tem-
poral direction (remember or imagine). Once an
episode had been recalled or imagined, it was
recounted by the participant. There was no time
limit. Participants were allowed to keep on verb-
ally illustrating the event until they thought that
nothing else could be added. We maintained
constantly the prompting procedure for the parti-
cipants in all the experimental conditions. When
participants stopped talking, the experimenter
asked only once whether there was any further
detail that they would have liked to add.
Recollections and simulations were digitally
recorded to enable later transcriptions and sub-
sequent scoring of participants’responses.
After the transcription, a trained rater, who
was blind to the hypothesis of the study, used the
standardised scoring procedure developed by
Levine et al. (2002) to systematically parse the
details generated in the past and future events.
This allowed the rater first to segment the main
event (i.e., the most talked about, with a brief
time frame) into details and then to distinguish
between (1) internal details (i.e., episodic
information pertaining to the main event, specific
to time and place) and (2) external details
(general knowledge related to the event). A
second rater, trained for this purpose, then scored
the protocols of 10 participants. The inter-rater
EYE MOVEMENTS DISRUPT EPISODIC FUTURE THINKING 3
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reliability (r) between the original rater and the
new rater was .96, p< .001 for the number of
internal details and r= .98, p< .001 for the
number of external details.
Internal details were further categorised into:
(1) event (happenings, individuals present, phys-
ical/emotional actions and reactions and weather),
(2) place (information about the environment
where the event occurred), (3) time (date, season,
month, day of the week and time of day), (4)
perceptual (sensory information and body posi-
tion) and (5) emotion (emotional state and
thoughts). External details were categorised into:
(1) external event (specific details from other
incidents, from all of the above categories,
external to the main event), (2) semantic (general
knowledge or facts, ongoing events and extended
states of being), (3) repetition (unsolicited repe-
tition of details) and (4) other (metacognitive
statements and editorialising).
Procedure
Testing was carried out in one single session. All
participants were tested individually and sat facing
the same experimenter in a quiet testing environ-
ment. They performed the task in three experi-
mental conditions. Participants were required to
mentally re-experience and pre-experience four
autobiographical episodes (two past and two future)
in each condition. The “control”condition was a
free-viewing condition not involving a concurrent
task. In the “hand-tapping”condition participants
performed the main task while concurrently tap-
ping a square on a board with their right hand. The
tapping task was paced by a metronome, which
was set on “Largo”, at 40 bpm, to equate the speed
of the dot-moving on the screen in the “eye
movement”condition. The participants’hands
were covered so that movements were performed
without visual processing.
Finally, in the critical “eye movement”condi-
tion, the task was performed concurrently with
lateral, continuous and voluntary eye movements.
Red fixation and green target stimuli on a white
background were presented on a 17-inch cathode
ray tube monitor (1024 × 768 pixels) at 100 Hz.
Participants were seated with their head in a chin
rest and their eyes horizontally and vertically
aligned with the centre of the screen at a distance
of 80 cm. Eye movements were recorded with
the EyeLink 1000 system (detection algorithm:
pupil and corneal reflex, 1000-Hz sampling).
A five-point horizontal–vertical calibration was
run at the start of the experiment. Each trial
began with a drift correction and a tone accom-
panying the onset of a 0.5° red dot presented on
the left side of the screen at an eccentricity of 8.5°
of visual angle. The experimenter started each
trial by pressing the space bar. As soon as the
experimenter started the trial, the dot became
green and moved continuously from left to right
at a frequency of 0.6 Hz, spanning a total distance
of 17° of visual angle. Participants were required
to fixate the dot until it was red and then to
follow it with their gaze as soon as became green
and started moving. The experimenter stopped
the trial when a single episode was recounted.
Participants were also asked to perform a base-
line condition in which they were instructed solely
to follow the dot for 60 seconds.
The tapping task was voluntary and exogen-
ously driven to match the fundamental character-
istics of the eye movement task and was
introduced to tease apart the disruptive effect of
a motor task and the disruptive effect that might
be specific for eye movements. Thus, the tapping
task was used to ensure that future thinking
was not simply disrupted by any additional motor
task.
The order of presentation of the three concur-
rent tasks was fully counterbalanced across the
participants.
RESULTS
The performance in the future-thinking task, in
each condition, is shown in Figure 1.A3
(Concurrent task: Eye movements vs. Tapping
vs. Control) × 2 (Direction of time travel: Past vs.
Future) analysis of variance (ANOVA), with all
variables as within-subjects factors, was carried
out on the mean number of internal details.
The results revealed main effects of both
Concurrent task, F(1, 13) = 13.96, MSE =
445.36, p< .001, and Direction of time travel,
F(1, 13) = 14.2, MSE = 966.96, p< .005. These
indicated that participants generated a greater
number of internal details during the control
(M= 27.64, SD = 13.72) and the hand-tapping
(M= 26.76, SD = 13.99) conditions than in the
eye movement condition (M= 20.33, SD = 12.72),
and that, overall, more internal details were
uttered for the past events (M= 28.3, SD =
13.94) than for future events (M= 21.52,
SD = 10). A post hoc power analysis using the
4 DE VITO ET AL.
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software package, GPower (Faul & Erdfelder,
1992), was conducted on these results. The
sample size of 14 was used for the statistical
power analyses. The alpha level used for this
analysis was p< .05. The post hoc analyses
revealed that the statistical power for this study
was .949 for detecting the effect size (g2
p
¼:522)
related to the main effect of Direction of time
travel and .947 for detecting the effect size
(g2
p
¼:518) related to the main effect of Concur-
rent task. Thus, there was more than adequate
power (i.e., power = .94) at our effect size levels.
A significant interaction between Concurrent
task and Direction of time travel, F(1, 13) = 4.78,
MSE = 195.77, p< 0.05, indicated that a lower
number of internal details was produced in future
episodes in the eye movement condition (M=
13.92, SD = 5.35) than during the hand-tapping
condition (M= 25.28, SD = 12.56), t(13) = 4.96,
MSE = 2.28, p< .001, and the control condition
(M= 25.35, SD = 13.75), t(13) = 4.24, MSE = 2.69,
p< .005. No significant difference in the number
of internal details was observed between the
hand-tapping condition and the control condition
in the future conditions.
Furthermore, no significant difference in the
number of internal details produced when
remembering past events was observed between
the eye movement, the tapping and the control
conditions.
A separate 3 (Concurrent task: Eye move-
ments vs. Tapping vs. Control) × 2 (Direction of
time travel: Past vs. Future) ANOVA was con-
ducted on the mean number of external details
and showed a main effect of the Concurrent task,
F(1, 13) = 4.12, MSE = 25.64, p< .05, and
Direction of time travel, F(1, 13) = 6.16, MSE =
21.5, p< .05. These indicate that a greater
number of external snippets was uttered during
the eye movement condition (M= 3.58, SD =
4.19), if compared to the tapping (M= 2.53,
SD = 3.25) and the control conditions (M= 1.67,
SD = 1.61), and that more external details were
generated in future (M= 3.1, SD = 3.83) than in
past episodes (M= 2.09, SD = 2.5).
The interaction between Concurrent task and
Direction of time travel was also significant,
F(1, 13) = 17.53, MSE = 44.86, p< .001, indicating
that the number of external details generated in
future episodes was greater in the eye movement
condition (M= 5.53, SD = 4.96) than in the
control condition (M= 1.67, SD = 1.89), t(13) =
3.2, MSE = 1.2, p< .01 and the hand-tapping con-
dition (M= 2.1, SD = 2.92), t(13) = 4.13, MSE =
3.1, p< .005.
No significant difference in the number of
external details produced when remembering
past events was observed between the eye move-
ment, the tapping and the control conditions.
Finally, the subcomponents of internal details
(i.e., events, place, time, perceptual details and
emotions) were separately analysed. We com-
pared, both in past and future episodes, the
number of details for each subcomponent in the
three conditions (Eye movements vs. Tapping vs.
Control), by means of ttests. The Bonferroni
adjustment was applied, α= .016, to correct for
multiple comparisons. No differences were found
in any of the subcomponents in past episodes. On
the contrary, for what concerns future episodes,
Figure 1. Performance (expressed in mean number of internal details produced) on past and future tasks in all the conditions.
Error bars show standard error of the mean.
EYE MOVEMENTS DISRUPT EPISODIC FUTURE THINKING 5
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the following significant differences were found
in the components of the events, place and
emotions.
Events. The number of details was significantly
lower in the eye movement conditions (M= 4.03,
SD = 1.64), when compared to the tapping
condition (M= 9.35, SD = 4.88), t= 4.29, MSE =
1.23, p<.005, and the control condition (M=
9.25, SD = 4.68), t= 4.33, MSE = 1.2, p<.005.
Place. The number of details was significantly
lower in the eye movement conditions (M= 2.00,
SD = 1.00), when compared to the tapping con-
dition (M= 3.21, SD = 1.08), t= 6.04, MSE = .2,
p<.001, and the control condition (M= 3.6,
SD = 1.94), t= 3.82, MSE = .41, p<.005.
Emotions. The number of details was signifi-
cantly lower in the eye movement conditions
(M= 1.39, SD = 1.86), when compared to the
control condition (M= 2.85, SD = 2.44), t= 4.09,
MSE = .35, p<.005.
Eye-tracking data can also be useful to inter-
pret our results. In the eye movement condition,
we recorded the mean “error”distance (in mm),
between the position of a participant’s gaze and
the position of the dot on the screen. The higher
the conflict between eye movements and the main
task, the greater this error distance should be. We
decided to remove the unique outlier who scored
3 SDs above the mean of the group for these
analyses. The error distance during future think-
ing (M
mm
= 22.87, SD = 14.74) was significantly
greater than that observed in the baseline condi-
tion (M
mm
= 10.30, SD = 4.67), t(12) = 2.82, MSE =
4.44, p< .05. Similarly, the error distance during
episodic memory (M
mm
= 19.55, SD = 10.6) was
significantly greater than that observed in the
baseline condition, t(12) = 2.95, MSE = 3.12, p<
.05. No significant differences were observed
between the error distance during episodic mem-
ory and future-thinking conditions.
DISCUSSION
Event construction plays a pivotal role in remem-
bering the past (Bartlett, 1932; Tulving, 2002).
Moreover, the two most influential hypotheses on
the cognitive underpinning of episodic future
thinking contend that scene construction plays a
crucial role also in foresight, although they inter-
pret this role in different ways (Hassabis &
Maguire, 2007; Schacter & Addis, 2007). The
“constructive simulation hypothesis”(Schacter &
Addis, 2007) contends that foresight relies on
episodic memory. To contemplate the infinite
array of elaborated simulations of possible
upcoming episodes, people need to mentally
manipulate and rearrange the items that unfolded
in the past. Thus, according to this theory, the
ability to make mental excursions in the future
was a driving force in the evolution of the scene
construction at the bases of episodic memory
(Tulving, 2002). On the other hand, the “scene
construction hypothesis”(Hassabis & Maguire,
2007) maintains that the mental scene construc-
tion underpins the creation of settings where both
past and future events can unfold, and suggests
that “real memories are reconstructed along very
similar lines to the way imagined events are
constructed”(Hassabis, Kumaran, & Maguire,
2007, p. 14371).
Our findings stand partly in contrast with the
scene construction hypothesis which states that
episodic memory and future thinking rely on the
same mechanism of scene construction. We sug-
gest that the construction of new future imaginary
experiences requires spatial imagery, while the
(re)construction of personal past episodes does
not, at least not to the same extent.
Despite strong evidence that the two abilities
of forecasting and remembering personal past
share a number of similarities (Schacter & Addis,
2007; for a review see Irish & Piguet, 2013), it is
feasible that constructing a future scene might
require crucial components, which are not funda-
mental in (re)constructing a personal memory.
When reconstructing a personal past event, we
need to look for a unique combination of details.
On the contrary, future thinking is more “open-
ended and generative”(Suddendorf & Corballis,
2007, p. 302) so that the number of future
scenarios that might be envisaged is potentially
infinite.
Therefore, future thinking might rely on some
components of mental imagery more than on
others. For the purpose of teasing apart the
different components underpinning scene con-
struction in the two experiences of recalling
episodic memories and shaping novel future
events, we used a paradigm that disrupted one
of these components (spatial) relatively sparing
the other one (visual). Our results showed that
voluntary eye movements disrupt future thinking,
while having no effect on the recollection of past
episodic memories. In particular, this effect is
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selective for the subcomponents of the internal
details strictly pertaining to the event, the place
and the emotions, whereas the perceptual and the
temporal subcomponents are relatively spared.
The effect of concurrent eye movements was not
selective for the spatial component of future
event representations. This is not surprising.
In fact, a difficulty in manipulating the spatial
components of a recollection may reasonably
determine a difficulty in manipulating the
“events”, which have intrinsic spatio-temporal
features. As to the emotions, we expected a
reduced emotional impact of future events ima-
gined during concurrent eye movements (Engel-
hard et al., 2010).
In parallel with the failure to produce internal
details, we observed an increment of external
details, when participants generated future epi-
sodes during the eye movement condition. These
data are similar to those reported on heterogen-
eous populations of patients (Addis, Sacchetti,
Allyc, Budson, & Schacter, 2009; de Vito et al.,
2012; Gamboz, de Vito, et al., 2010; Irish et al.,
2012). It has been shown that, when a cognitive
function that is crucial for future thinking is
impaired, people are prone to rely on alternative
strategies that help them to enrich their narratives
(Addis et al., 2009). Thus, it is probable that,
since the generation of future internal details was
hindered, participants tended to fill the gap in
their recollections by providing a greater amount
of tangential, off-target snippets.
The performance in visually tracking a dot
proved similar in future thinking and autobio-
graphical memory task, thus excluding that our
findings could be simply due to a trade-off effect.
Furthermore, although our sample size is rela-
tively small, the findings clearly reveal a strong
effect of eye movements on future thinking.
A number of studies suggested that eye move-
ments during imagery allow to correctly position
each part of a scene (e.g., de Vito et al., 2014;
Postle et al., 2006), while having no effect on the
visual component of mental imagery. The exact
nature of the spatial process that distinguishes the
disruption exerted by eye movement seems to
rely on the fact that “commands to the eyes for
each fixation are stored along with the visual
representation and are used as spatial index in a
motor-based coordinate system for the proper
arrangement of parts of an image”(Laeng &
Teodorescu, 2002, p. 207). Laeng, Bloem,
D’Ascenzo, and Tommasi (2014) observed that,
when asked to retrieve the image, participants
were likely to fixate the same regions of space as
those fixated during the perceptual scrutiny of the
shape. Johansson and Johansson (2014) also
showed that constraining eye movements to a
central fixation cross or to an incongruent loca-
tion (i.e., incongruent with the original location of
the to-be-remembered object) more readily affec-
ted memory for the spatial arrangement between
two objects than memory concerning the visual
orientation of an object. Consequently, concur-
rent eye movements might selectively interfere
with spatial imagery, while sparing visual
imagery. These two types of imagery are said to
play a different role in autobiographical memory.
Visual imagery plays a key role (see for instance
Johnson & Raye, 1981). In particular, one com-
ponent of visual imagery, i.e., long-term visual
memory, is fundamental for autobiographical
memory (Greenberg & Rubin, 2003). The preval-
ence of visual imagery in autobiographical mem-
ories has long been acknowledged (Brewer, 1988;
Galton, 1883). More recently, visual images have
been identified as the “main representational
format of episodic memories”(Conway, 2009,
p. 2308). Indeed, a loss of the ability to generate
visual images may determine a retrograde amnesia
(e.g., Conway, 2005). On the contrary, spatial
deficits do not produce profound global autobio-
graphical amnesia (Barr, Goldberg, Wasserstein, &
Novelly, 1990). According to Conway (2009), the
information contained in the visual images is “con-
figural”, i.e., the objects represented in the visual
images are already in relation to each other. This
pre-existing configuration may be sufficient when
retrieving an episodic memory, but may not be
enough when distinct details are to be collected
from distinct memories and recombined together,
as in the case of future thinking. In this case, the
objects that are contained in a visual image need to
be differently configured. We may suggest that,
when foreseeing, it is crucial to break down the pre-
existing relations between the objects present in the
autobiographical memories in order to alternatively
arrange each part. Spatial imagery may be very
important in serving this dynamic process. Indeed,
our results confirm that voluntary eye movements
do not hamper the recollection of autobiographical
memories. Eye movements might blur the image
(Andrade et al., 1997), though leaving it still
accessible. On the contrary, crucially, we demon-
strated that eye movements prevent participants
from imagining complex and detailed future scenes.
In sum, it has been widely acknowledged that
episodic memory is particularly important for the
EYE MOVEMENTS DISRUPT EPISODIC FUTURE THINKING 7
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ability of future thinking. It has been also suggested
that the images derived from experience serve to
provide specific content to more abstract scripts to
be projected in the future (Conway, 2009). How-
ever, our findings suggest that such a specific
evidence may not be projected into the future as it
is, but rather that it needs to be further processed.
To the purpose of imagining novel future events,
people need to spatially reorganise the pre-existent
configuration of mental images of the past. There-
fore, whereas episodic memory is dominated by
visual imagery, episodic future thinking is likely to
be dominated by spatial imagery. This implies that
past and future are not constructed in the same
manner. Future directions, which may unfold from
the present work, should include neuropsychologi-
cal studies aiming at investigating whether or not
patients with specific impairments of spatial
imagery may be still capable to project themselves
into novel future scenarios.
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