video games improve performance

instructions:

Measurement. How to measure the X (independent) and Y (dependent) variables? What methods have been used

in previous studies? Try to be as specific as possible so that the audience know exactly how to measure

them. It is fine to skip some details, but make sure to refer to proper references so that the audience

can find the details there. If there are multiple measures from different studies, suggest adding a table

to summarize them.

Major findings. What is known from the literature? Regarding the research questions, what are the answers?

For example, some factors may have significant effects on Y, but some other factors may not. Are there

enough evidences to support any conclusion? If there are contradicting results, what could be the reason?

Discussion and implication. Are the research results expected or surprising? What are potential reasons

for the results? How can people use the findings from the literature? For example, is there any value for

industrial design, education, daily life, or academic research? • Limitation. Any

limitation in the previous studies? Is there any way to improve? What kinds of future studies are needed?

Any new research questions that you identified?
Conclusion. Concisely summarize the major points in the current review.

Restorative Neurology and Neuroscience 26 (2008) 435–446 435
IOS Press
Video games as a tool to train visual skills
R.L. Achtman*, C.S. Green and D. Bavelier
Department of Brain & Cognitive Sciences, Center for Visual Sciences, University of Rochester, RC 270268,
Meliora Hall, Rochester, NY 14627-0268, USA
Abstract. Purpose: Adult brain plasticity, although possible, is often difficult to elicit. Training

regimens in adults can produce
specific improvements on the trained task without leading to general enhancements that would improve

quality of life. This paper
considers the case of playing action video games as a way to induce widespread enhancement in vision.
Conclusions: We review the range of visual skills altered by action video game playing as well as the game

components important
in promoting visual plasticity. Further, we discuss what these results might mean in terms of

rehabilitation for different patient
populations.
Keywords: Video games, perceptual learning, plasticity, visual attention, rehabilitation
1. Introduction
There is much interest in understanding the factors
that promote learning and brain plasticity. We are all
waiting for the ultimate training experience where for
a few hours of our time we could restore our eyesight,
augment our attentional abilities and speed up
our decision-making. The status quo in the field of
training-induced plasticity is unfortunately more sobering.
Whereas individuals can improve at a given task
by training on that very task for hours on end, skill
enhancement is typically limited to the trained task and
shows little to no generalization to different, even highly
related, tasks. This specificity is best illustrated in
the field of perceptual learning which documents that
perceptual learning can be specific to the trained eye,
direction of motion or even retinal location (Fahle et
al., 2002). Such specificity is a major stumbling block
when it comes to rehabilitation of function. Indeed,
the goal of a rehabilitation regimen is to ensure that
it improves the quality of life of the patient, thus calling
for training that will generalize to a wide array of
situations and tasks.
Developing methods of overcoming known limitations
in the capacity of the human nervous system to
*Corresponding author. Tel.: +1 585 273 5323; Fax: +1 585 442
9246; E-mail: rachtman@bcs.rochester.edu.
reorganize has become a major challenge in the field
of neuroplasticity. Various approaches are being investigated
which fall roughly into two main domains:
direct pharmaceutical manipulations (Hensch, 2005),
and training-induced learning (Levi, 2005; Sabel, 1999;
Taub & Uswatt, 2006). Here we consider the case
of video games as a tool to promote training-induced
learning. Over the past decade, the possibility that perceptual
and cognitive abilities are enhanced in video
game players has raised much attention (for a review,
see Green & Bavelier, 2006c). Indeed, it is striking to
learn the variety of different skills and the degree to
which they are modified in video game players: improved
hand-eye coordination (Griffith et al., 1983), increased
processing in the periphery (Green & Bavelier,
2006a), enhanced mental rotation skills (Sims&Mayer,
2002), greater divided attention abilities (Greenfield et
al., 1994) and faster reaction times (Castel et al., 2005),
to name a few. Although intriguing, this literature has
little to say about rehabilitation unless the causal effect
of game playing is unambiguously established. Unfortunately,
only very few studies have established a
causal link between video game play and changes in
performance. This review focuses exclusively on this
small literature.
First, we will describe the range of visual skills altered
by video game playing; in particular, we will focus
on a specific subset of video games known as action
0922-6028/08/$17.00 ? 2008 – IOS Press and the authors. All rights reserved
436 R.L. Achtman et al. / Video games as a tool to train visual skills
video games, as those games seem most efficient for visual
learning. Second, we will review the type of video
games that seem best in promoting visual plasticity.
Third, we will discuss the possible reasons why action
video games may be an efficient tool when it comes to
promoting brain plasticity and visual learning. And, finally
we will consider what these results might mean in
terms of rehabilitation for different patient populations.
2. Visual skills and video game training
2.1. Visuo-spatial attention
The efficiency with which attention is distributed
across the visual field can be measured using a visual
search task (something akin to looking for a set of keys
on a cluttered desk). One such task, called the Useful
Field of View paradigm (UFoV) (Ball et al., 1988) was
adapted to this purpose by Green and Bavelier (2003).
Subjects were asked to localize a briefly presented peripheral
target in a field of distracting objects (Fig. 1a).
The experimental display was then heavily masked before
subjects were presented with a probe display where
they were asked to determine on which of the 8 possible
spokes the target had been presented. Participants were
male action video game players (VGPs) who played at
least 5 hours a week for the previous six months, and
male non-gamers (NVGPs) who had little (preferably
no) video game experience in the previous six months.
VGPs could more readily identify targets in a cluttered
field than NVGPs (Fig. 1b). Interestingly, these effects
extended to eccentricities beyond ones typically subtended
during video game play, indicating generalization
of learning to untrained locations.
These results demonstrate a performance difference
between VGPs and NVGPs. Of course, it is not enough
simply to document enhanced abilities in video game
players. After all, it might be a case of a self-selecting
population, where individuals who are innately better at
these particular skills find it easier and therefore more
enjoyable to master the video games. The only way to
fully demonstrate causation, that playing action video
games leads to increases in perceptual and cognitive
skills, is to train a random sample of non-gamers on a
video game and measure changes in their performance
before and after training. Crucially, the amount of improvement
induced by this training should be compared
to a baseline treatment that controls for test-retest improvements
and the Hawthorne effect (that individuals
who are paid close attention tend to perform better). In
the training studies we have performed, subjects trained
on action video games (e.g.,Unreal Tournament, Medal
of Honor) improved more on the experimental tasks
than subjects trained on non-action games (e.g., Tetris,
The Sims). In this review, we will focus on studies
that have included a training aspect in order to assure a
causal role for video game play, as this is critical when
talking about the use of video game training in practical
applications.
In the UFoV experiment, non-gamers trained on action
video games were better able to identify targets in a
cluttered field than those trained on a non-action game
(Fig. 1c), although these training effects are smaller
than the differences between VGPs and NVGPs (see
also Feng et al., 2007 for a replication and extension
of these results). As with VGPs, the effects seen in
the training study also extended to eccentricities beyond
the video game training set-up, again indicating
generalization of learning to untrained locations.
2.2. Dynamics of visual attention
The dynamics of visual attention can be measured
with the attentional blink paradigm (AB) which tests
how quickly attentional resources recover after being
directed to a target (Raymond et al., 1992). Subjects
are presented with a stream of quickly presented letters
(one at a time, each for 100 ms) and are told to
identify the letter in white (only one is white among
all black letters). They are also told that 50% of the
time the letter ‘X’ will appear somewhere in the stream
of letters following the white letter (anywhere from
directly after it to 8 letters after it; see Fig. 2a). At
the end of each trial, subjects are asked to report the
identity of the white letter as well as to say whether
or not an ‘X’ was presented. For most subjects, when
the ‘X’ is presented very soon after the white letter it
is missed. It is thought that the subject fails to detect
the ‘X’ because attentional resources are allocated toward
processing the identity of the white letter and are
therefore unavailable to process any new information.
If the subject has already processed the white letter his
attentional resources will be free to detect the ‘X’. The
amount of time it takes before being able to process
the ‘X’ is called the attentional blink. VGPs show a
smaller blink – both in terms of duration and magnitude
(Fig. 2b). VGPs can process a rapid stream of visual
information with increased efficiency as compared
to NVGPs. In training studies, participants trained on
action video games recover faster from the attentional
blink than those trained on a control game (Fig. 2c).
R.L. Achtman et al. / Video games as a tool to train visual skills 437
Fig. 1. Measure of attention over space using the useful field of view paradigm. (a) Sequence of displays.

After a heavy mask, participants
indicated the spoke on which the small target (filled shape within a circle) appeared. The spatial

distribution of attention was tested by placing
the target at different eccentricities. (b) Localization accuracy for VGPs & NVGPs. VGPs showed large

enhancements in localization ability at
all eccentricities. The superiority of VGPs at 30 degrees indicates that the enhancement of spatial

attention observed in this population is not
limited to trained locations. (c) Performance before (
, ) and after (,•) training. At each

eccentricity, the group trained on an action
video game (open symbols, dashed lines) improved significantly more from their pre-test scores than did

the control group trained on a non-action
video game (closed symbols, solid lines). Error bars denote SEMs, **= P <0.01. (From Green & Bavelier,

2003).
a b c
Fig. 2. Measure of attention over time using the attention blink paradigm. (a) Black letters were rapidly

presented sequentially at fixation. At a
random time in the stream, a white letter was presented. After this first target, an ‘X’ was presented at

some point in the remainder of the trial,
50% of the time. After the trial, participants reported the identity of the white letter and indicated

whether or not the ‘X’ was presented. Of interest
is the performance of participants on detecting the ‘X’, given that they correctly identified the white

letter. (b) VGP & NVGP performance. At
early lags, VGPs performed better (less blink) than NVGPs; as lag increased, the effect of the attentional

bottlenecks decreased, and, as expected,
the performances of the two populations were comparable. (c) Performance before and after training. The

group trained on an action video game
recovered faster from the attentional blink than did the group trained on a non-action video game. Error

bars denote SEMs, *= P < 0.05,
**= P <0.01. (From Green & Bavelier, 2003).
2.3. Number of objects of attention
Another property of attention is the ability to track
several objects at once, as when keeping track of friends
through a crowd. Previous research indicates that only
a limited number of visual events (about 4) can be
attended to simultaneously in this fashion. To measure
the capacity of this attentional tracking system,
the multiple object tracking paradigm (MOT) was used
(Pylyshyn & Storm, 1988). The MOT task measures
the maximum number of moving items that can be successfully
tracked within a field of distracting moving
items. In this task, participants are presented a number
of randomly moving circles. At the beginning of the
trial, some subset of the circles is cued. The cues then
disappear and participants are required to keep track of
the previously cued circles (nowvisually indistinguishable
from uncued circles) as they continue to move
around the screen. The moving circles must be tracked
for several seconds before one is highlighted and the
participant must make a yes (was initially cued) or no
(was not initially cued) decision. On average,VGPs are
able to track ~2 more items than NVGPs. Training on
action video games likewise increases a non-gamer’s
capacity to track multiple objects (see Fig. 3, Green &
Bavelier, 2006b).
438 R.L. Achtman et al. / Video games as a tool to train visual skills
0.5
0.6
0.7
0.8
0.9
1
1 2 3 4 5 6 7
% Correct
Post-test (N=16)
Pre-test (N=16) Pre-test (N=16)
Post-test (N=16)
Action Control
**
**
Number of circles Number of circles
0.5
0.6
0.7
0.8
0.9
1
1 2 3 4 5 6 7
NVGP (N=10)
VGP (N=10)
**
**
*
0.5
0.6
0.7
0.8
0.9
1
1 2 3 4 5 6 7
Number of circles
a b c
Fig. 3. Measure of overall attentional capacity using multiple object tracking. (a) VGP & NVGP

performance. VGPs demonstrate a substantial
increase in the accuracy with which multiple items can be tracked compared to NVGPs. The effect is most

pronounced for the 3–5 item range.
(b) Pre- and post-training performance of the action video game group. Participants show a marked

improvement with training. (c) Pre-and
post-training performance of the non-action video game group. Performance was identical before and after

training in the control group. Error
bars denote SEMs, *= P < 0.05, **= P < 0.001. (From Green & Bavelier, 2006b).
Enhancement of the number of attended objects in
action gamers has also been confirmed using a counting
task in which participants are presented with a random
number of objects (from 1 to 12) for a short period of
time and asked to report howmany have been presented.
The accuracy of VGPs stayed near ceiling for larger
numerosities than that of NVGPs indicating a better
ability at apprehending displays with large numerosity.
This enhanced accuracywas observed in the absence of
changes in reaction times suggesting that action gamers
may be able to attend to more objects thanks in part
to a more efficient visual short-term memory system
(Green & Bavelier, 2006b).
2.4. Other aspects of attention
Not all aspects of attention seem to be equally affected
by action game play. For example, exogenous
attention, or the efficiency with which a salient cue in
the environment captures attention, does not appear to
change with video game play (Dye et al., submitted).
Using a Posner cueing paradigm called the attentional
network task (Fan et al., 2002), participants are asked to
detect the orientation of a target arrow (pointed left or
right) presented either above or below a central fixation
point while the speed and accuracy of their responses
are measured. A given trial may be cued as to the timing
of the target presentation, or cued to its location. By
contrasting each of these cued conditions with a no cue
baseline, one can measure alerting (the ability to allocate
attention at a given time), and orienting (the ability
to allocate attention to a given location). While there is
a baseline reaction time difference between VGPs and
NVGPs (overall VGPs have faster RTs than NVGPs),
the way an exogenous cue initially controls the allocation
of attention was found to be comparable in VGPs
and NVGPs. The lack of orienting and alerting effects
are especially intriguing seeing as playing action video
games relies heavily on being alert and orienting efficiently
to any abrupt changes in the environment. It is
exactly these types of results thatmake the field of training
rehabilitation challenging; simply because something
is present in the training phase, does not guarantee
it will be altered with training. Video games are
full of exogenous events (enemies appearing at random
locations and times, grabbing your attention), and yet
playing action video games does not impact exogenous
attention (see also, Castel et al., 2005).
Overall, action video game training greatly enhances
several aspects of visual attention, such as the ability to
effectively distribute attention over space and time, as
well as the number of items that can be attended. Yet,
few changes are observed in the way an exogenous cue
initially captures attention. These results call for more
studies to better characterize those aspects of attention
that are changed and those that are not, with the aim of
understanding the mechanisms by which video game
experience enhances visual skills.
The next important question for visual learning is
whether or not playing action video games can produce
more fundamental changes in visual functions. Indeed,
action video game training will be most useful for rehabilitation
if it not only enhances different aspects of visual
attention, but also alters more fundamental aspects
of visual processing. Although work in this area is
only very recent, the available data suggest that action
game playing, by modifying the spatial and temporal
resolution of visual processing, may affect rather basic
visual skills, such as visual acuity in the presence of
flankers.
R.L. Achtman et al. / Video games as a tool to train visual skills 439
2.5. Spatial resolution of visual processing
Identification of a small letter in the middle of a
white page is easier than if the same letter is surrounded
by other letters. This phenomenon, termed crowding,
reflects an important limitation of our visual ability.
Patients with poor vision, such as amblyopes (Bonneh
et al., 2004) often complain of not being able to read
small print, with letters being unstable and jumbled
as they stare at the page. Crowding can be measured
by having subjects identify the orientation of a letter
flanked by other letters, and determining the smallest
distance between target and distractors at which the
target can be correctly identified. It has been shown
that this measure of spatial resolution is enhanced (i.e.,
crowding is reduced; Fig. 4) by playing action video
games (Green & Bavelier, 2007). Accordingly, Green
and Bavelier (2007) have shown that distractors have to
be brought nearer to the target in action game players
than in control participants before target processing is
disrupted. These increases in spatial resolution were
seen at both central and peripheral locations and, interestingly,
even at locations beyond the trained region of
space (i.e., covering a larger visual area than the video
game training set-up), again suggesting generalization
of the effect to untrained locations.
In the same experiment, Green and Bavelier (2007)
showed that visual acuity, a measure of the fine detail
that can be seen, is superior in VGPs than in NVGPs,
not only in peripheral vision but also in central vision
(acuity was measured at 0, 10, and 25 degrees eccentricity).
Although suggestive, there was no effect of action
video game training on foveal or peripheral visual
acuity in a 30-hour training study, limiting the practical
implications of this result. Training effects are
generally much smaller than ‘expert’ (gamer vs. nongamer)
effects, so it is possible that a skill as basic as
visual acuity may be modifiable by training, but only
with many more hours of training than the other skills
studied thus far. It is certainly the case that the VGPs
enrolled in our studies have many more than 30 hours
of training (most likely in the range of thousands of
hours).
2.6. Temporal resolution of visual processing
Ongoing research indicates that temporal aspects of
early visual processing are altered along with the spatial
characteristics reviewed above. Temporal masking
studies provide a measure of the time needed for visual
processing. For instance, one can measure the contrast
threshold of a gabor patch flanked in time (as opposed
to space) by other gabor patches. In particular, it is well
known that the visibility of a briefly presented target is
disrupted when a mask is presented shortly thereafter
(Bonneh et al., 2007; Polat&Sagi, 2006). Using such a
visual backward masking paradigm, Li and colleagues
(2006) have shown that action video game playing results
in reduced backward masking, suggesting faster
integration time of visual processing.
Changes in the spatio-temporal dynamics of visual
processing could allow for greater sensitivity, and thus
changes in aspects of vision as basic as contrast sensitivity
or flicker fusion. These possibilities are presently
being investigated. For now, the available studies
indicate a clear shift in the spatio-temporal properties
of visual processing at least in conditions where target
and distractors compete in space or in time. Such effects
are compatible with a large-scale change in the
functional connectivity of the networks of neurons that
support vision. Indeed, the generalization of learning
observed across visual tasks and visual stimuli points
to a common mechanism at the source of these effects.
One appealing hypothesis is that action video game
play leads to more efficient integration of sensory information,
and therefore enhanced visual skill performance
(Green et al., 2007). As yet, it remains too early
to say whether these enhancements may be due to better
noise exclusion, signal enhancement, or a combination
of both (Dosher & Lu, 1998; Lu et al., 2006).
3. Not all video games are created equal
Not all types of video games change visual functions.
Thework reviewed above focuses exclusively on action
video games. Training studies in which performance
of the experimental group (trained on an action video
game) shows greater improvement than that of the control
group (also trained on a video game), clearly show
that action video games have an edge when it comes
to visual plasticity. What is it about certain games that
contribute to changes in vision? Surely, the characteristics
of the game itself are directly related to the types
of processes that are modified by playing the game
(e.g., ability to effectively ignore distractors, speed of
processing, monitoring of the periphery, tracking multiple
moving objects, etc.). To tease apart which facets
of a video game contribute to the types of enhancements
we have been discussing, Cohen and colleagues
(2007) surveyed the literature and looked at the effects
of playing different video games on visual attention.
440 R.L. Achtman et al. / Video games as a tool to train visual skills
0 deg
25 deg
10 deg
a
3
2.5
2
1.5
1
0.5
Log Crowding Threshold
*
*
*
b
Action Training
*
*
*
Control Training
VGP
NVGP
Post
Pre
Post
Pre
0 10 25
Eccentricity (deg)
*
*
3
2.5
2
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1
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2
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NVGP / VGP
0 10 25
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0 10 25
Eccentricity (deg)
d
Fig. 4. (a) Crowding stimuli consisted of three T shapes randomly oriented either right side up or upside

down. Participants indicated the
orientation of the central T. In separate blocks, three eccentricities were tested (0, 10, 25 degrees).

The flanking Ts were presented first away
from the central T and then brought nearer and nearer until the participant’s performance threshold was

reached. (b) VGP & NVGP performance.
VGPs demonstrate a significantly reduced crowding threshold compared to NVGPs, meaning they can resolve

the central T orientation with
closer flanking Ts. (c & d) Pre- and post-training performance of the action video game group and the

control group. Participants in the
action-trained group show a marked reduction in crowding with training. For the control group performance

was identical before and after
training. (*= P < 0.05). (From Green & Bavelier, 2007).
They describe a gradient of efficiency across the games
used – with games requiring precise but rapid visual
analysis to guide accurate aiming movements appearing
to be the most efficient. We review here the effects
of playing different video games on visual learning.
Games that have been studied so far fall broadly into
five categories.
The first category concerns first-person or third person
action games, like Unreal Tournament or Medal of
Honor. These games place heavy demands on visual
attentional systems as players are constantly monitoring
the periphery for frequent, widely distributed, unpredictable
events that require quick and accurate aiming
responses. To do well, players need to track many
fast moving objects while ignoring distractors. Perhaps
most importantly, these games require motor actions
that are spatially aligned with the detailed visual world
of the game; for instance, the precise visuo-motor control
needed when aiming at small moving targets. Importantly,
the stakes of missing the target are high as the
gamer’s character may die. Finally, these games have
the advantages of having many entry levels ensuring
that the gamers will face a challenging yet doable game
experience. Not all games labeled action video games
are equally efficient though. For example, individuals
trained on an interactive version of America’s Army
played over the internet improved less on the attentional
skills measured than individuals trained on Unreal
Tournament. Two factors are suspected to have led to
decreased learning in that case. First, the interactive
version of the game made it difficult to control the pace
of the game as well as the skill level of the opponent.
The inability to tailor the training paradigm to the level
of the player probably contributed to the reduced effects.
Second, significant portions of America’s Army
are devoid of the fast-paced, visually-guided aiming actions
believed to trigger visual learning (such as when
the player needs to learn the code of conduct within the
military).
The second category concerns sports or racing
games. Anecdotal evidence from the study of children
who play sports/racing games suggests these games
may provide some visual enhancements (see also Trick
et al., 2005). However, 12 hours of training on the
sports game Harry Potter: QuidditchWorld Cup, led to
no clear enhancements of visual skill. Whether different
sports/racing games that have faster motion (e.g.,
Need for Speed), more objects to keep track of (e.g.,
NBA 2k7), or greater emphasis on peripheral processing
(e.g., FIFA 07) would lead to different results is an
open question.
The third category concerns games that require fast
visuo-motor control, like the game Tetris, but in which
the visual analysis does not require target identification
amongst distractors and the motor control part is not
focused on visually-guided aiming. Pastwork indicates
lesser improvement after playing Tetris than playing an
action game. Tetris differs from action video games in
several ways. First, there are only a limited number
of objects for players to attend to at any one time.
Second, the spatial location of these objects is highly
predictable. Thus, although attentionally demanding,
the player knows where and when to pay attention at all
times. Third, only a limited number of shapes are used
R.L. Achtman et al. / Video games as a tool to train visual skills 441
throughout the game allowing the learner to memorize
spatial configurations and moves, rather than having to
adapt to a constantly changing environment (Destefano
& Gray, 2007; Sims & Mayer, 2002). This last feature
allows for the development of excellent expertise at
the game itself, but what is learned is less likely to
generalize to other environments. Yet, it isworth noting
that Tetris has been reported to improve visual attention
slightly more than slower games (see below) suggesting
that the pace of the game is an important determinant of
learning, with fast-paced games showing an edge when
it comes to enhancing aspects of vision.
The fourth category is strategy games, like SimCity
or Civilization, which a number of our studies have
used as control games. These simulation and roleplaying
games are not fast-paced. The displays can
be visually complex, and while there may be multiple
things to keep track of in these games, it is never in
a way that is taxing to the visual system, but rather in
terms of cognitive tactics and planning. These games
make it clear that being confronted with a complex
visual environment is not enough to guarantee visual
learning. It remains possible that if the games were
sped up, strategy games could also show benefits on
visual function.
Lastly, the fifth category consists of various computer
puzzle and card games (e.g., Solitaire, Hearts,
Minesweeper, Free Cell). In these games, players can
choose how to allocate their attention. At no point are
there unexpected events one needs to react to. Responses
do not have to be particularly quick or spatially accurate,
but rather rely on the development of good problem
solving strategies often assisted by excellent use of
mental imagery. As expected, these games trigger no
changes in visual attention.
Clearly, action video games produce the greatest enhancements
(both spatial and temporal) to the visual
system. Given our present knowledge, we can list a
number of video game features that seem desirable for
promoting visual learning. The games should be fastpaced
and unpredictable. The fast pace requires frequent
interaction and allows for multiple opportunities
for learning, as each action made is met with some
form of behavioural reinforcement. The lack of predictability
(events of unknown time of arrival and location)
enforces distributed attention and leads to enough
errors to signal that adjustments in behaviour are needed,
promoting a high level of active engagement and
learning. It goes without saying that the game needs to
be motivating, as boredom will lead to non-compliance
in a rehabilitation regimen. Thus, the difficulty of the
game should be fully adaptable, as each player should
be engaged at a level that is challenging yet not overwhelming.
Indeed, task difficulty has been demonstrated
to be a significant predictor of the generalization of
learning (Ahissar & Hochstein, 2004). The factors listed
so far should not come as a surprise to scholars of
the field of learning. The notion of entry level is solidly
routed in the principle of incremental learning, nicely
illustrated by the work of Knudsen and colleagues in
the barn owl (Linkenhoker & Knudsen, 2002). Adult
barn owls are able to acquire new interaural time difference
(ITD) maps, important for sound localization, after
wearing prismatic spectacles that horizontally shift
the visual field, but only when the prismatic shift is
experienced in small increments. The use of large increments
leads to systematic learning failures. Similarly,
the importance of providing the system with an
error message and of having motivating reward values
associated with each action is well-documented in the
reinforcement learning literature (Dayan, 2001; Sutton
& Barto, 1998). Rather the new insights on learning
brought about by video game training studies are twofold.
First is the possibility that the whole is more than
the sum of its parts; video game training includes several
factors that promote learning within a single training
regimen. While each of the factors on its own may have
only a weak effect, when combined together they can
lead to widespread changes. Second, the video game
work shows that significant perceptual enhancements
can be brought about when the perceptual part of the
training is tightly linked to perceptually guided actions
such as aiming. Certainly, the fact that the outcome of
these actions is associated with high reward values also
helps. Another study in barn owls (Bergan et al., 2005)
nicely illustrates these points. Two groups of adult owls
were fit with prismatic spectacles for 10 weeks. One
group was provided with food, while the other group
had to hunt live prey to feed themselves. The auditory
maps of the group that hunted showed much greater
adaptive shifts (by a factor of 5) in their auditory maps
even though the experiences of the two groups differed
for only short periods of time each day. These findings
highlight the idea that the use of sensory information to
guide reaching or aiming movements can dramatically
increase the amount of plastic change induced.
Much remains to be done to precisely unpack how
different types of experiences affect different perceptual
and cognitive functions. A detailed analysis of
the component processes engaged during action video
game play would be extremely useful as a way to
document factors that facilitate visual learning. Oth442
R.L. Achtman et al. / Video games as a tool to train visual skills
er dimensions such as the role of immersive, multisensory
or multi-modal games on learning should also
be explored. Although enriched environments are often
thought to be beneficial for brain plasticity (which
in turn leads to the prediction that richer, more immersive
games would lead to better learning), most of the
previous studies have been carried out in animal models
and have compared deprived to normally-raised animals
(Bergan et al., 2005). Therefore, the extent to
which this principle is applicable to the approach being
considered with video games is unknown. As these
types of questions are addressed, the potential efficacy
and specificity of a video game training regimen will
almost certainly increase.
4. How video game play might enhance learning
The variety of different skills and the degree to which
they can be altered by playing action video games is
surprising, especially considering the lack of generalization
and transfer reported in the perceptual learning
literature. Action video games differ from standard
perceptual learning paradigms in several ways, but perhaps
most importantly in the type of motor responses
required. As reviewed above, the motor responses used
when playing action video games are not simple yes/no
button presses, but more refined and coordinated aiming
motions. Players are essentially acting through an
avatar, constantly moving around the scene and aiming
at different targets. Why would implicating the motor
system be important for inducing plastic changes?
In contrast to the field of perceptual learning, many
studies have documented large-scale training-induced
changes in motor functions following extensive motor
training, such as in musicians, athletes and braille readers.
For example, using MEG, Elbert and colleagues
(1995) demonstrated that practiced string players (e.g.,
violin, cello, guitar players) have an increased cortical
representation of the fingers of their left (string)
hand. And in braille readers, there is an increase in the
motor cortex representation of the finger muscles most
used during braille reading (Pascual-Leone et al., 1993;
Pascual-Leone & Torres, 1993). This work establishes
that cortical circuits, at least those involved in motor
programming and execution, are capable of exhibiting
sizeable plastic reorganization. The video gaming
training literature raises the question of whether one
can capitalize on these plastic capabilities and induce
visual plasticity through intensive visuo-motor training.
Perhaps it is the pairing of the two systems (motor
and visual), which is enhancing visual learning in video
game training. Today there are newer generations of
games (e.g., NintendoWii) that are even more embodied,
with controllers that allow players to respond with
more realistic motor responses depending on the demands
of the game. This type of visuo-motor enrichment,
combined with the rewarding feedback of games
could prove to be even more beneficial.
Of interest are not only the perceptual and cognitive
consequences of training on video games, but also
the underlying neural factors that might be involved
in learning. Koepp and colleagues (1998) studied the
neurochemical consequences of video game play using
positron emission tomography (PET). They measured
the amount of dopamine released when subjects play an
action video game. Dopamine is a neurotransmitter that
allows the modulation of information to be passed from
brain area to brain area and is thought to play a role in a
wide range of human behaviours (e.g., addiction, pleasure,
and learning). For example, most addictive drugs
produce pleasure by increasing the amount of dopamine
in the brain. They found a massive amount of dopamine
released in the brain during video game play, in particular
in areas thought to control reward and learning. Importantly,
research in rats shows that apart from providing
the well-known sensation of excitement, dopamine
may be important in facilitating brain plasticity following
perceptual training (Bao et al., 2001). In this
study, one group of rats experienced the paired presentation
of a 9 kHz tone with stimulation of dopamine
neurons. Another group received the tone alone. After
training, Bao and colleagues observed an expansion
of the part of the primary auditory cortex devoted to
the tone only in the group of rats that had dopamine
neurons simultaneously stimulated, leading to the hypothesis
that the dopamine neurons play a critical role
in perceptual learning. Large surges of dopamine seen
in people while playing video games could play a similar
role as in the rat study just described – faster
and more widespread learning. Other neuromodulators
such as acetylcholine and norepinephrenine, which like
dopamine, have been implicated in both reward/arousal
and increased cortical plasticity (Bao et al., 2001; Kilgard&
Merzenich, 1998) may also play a role. Regardless
of the exact mechanism, a better understanding
of the neuroanatomical and neurochemical substrates
of video game play and of the learning it induces will
aid in the development of training and rehabilitation
possibilities.
R.L. Achtman et al. / Video games as a tool to train visual skills 443
5. Video game training and rehabilitation
The differences that we measure in the laboratory
elicited by training on action video games (e.g., faster
RTs, increased ability to track multiple objects, faster
attentional recovery time, less crowding), may not have
huge influences on quality of life for most people, but
there are several subsets of the population that could
greatly benefit from these improvements, specifically,
populations that have experienced a deficit in visual
processing due to central nervous system deficiencies
(such as amblyopes, stroke patients with visual field
deficits, and the elderly). As we alluded to earlier, one
of the major obstacles in developing efficient rehabilitation
methods is the specificity of most perceptual learning
paradigms. Yet, as we have just described, playing
action video games changes several aspects of visual
attention (spatial, temporal, and overall capacity),
as well as other types of visual processing (crowding,
temporal masking). Thus, for once, there seem to be
positive effects that can be of use in real life situations.
Amblyopia is a developmental visual disorder, cortical
in nature, and characterized by several functional
abnormalities of spatial vision, including reduced contrast
sensitivity, increased effects of crowding, and abnormal
contour integration. While the long-standing
view was that these visual deficiencies are irreversible
after childhood, more recently, researchers have been
availing themselves of the effects of perceptual learning
to train adults with amblyopia (Levi, et al., 1997; Li &
Levi, 2004; Li et al., 2005; Polat, Ma-Naim et al., 2004;
Zhou et al., 2006). These training techniques sometimes
involve many thousands of controlled trials on
spatial vision tasks over the course of several months.
Although performance on such tasks as Vernier acuity,
positional acuity, letter recognition and contrast sensitivity
does improve, most enhancements are very specific
(e.g., with limited transfer to the untrained eye
at the trained location for Vernier acuity – Levi et al.,
1997). These sessions can be repetitive and boring for
patients and so compliance to the training regimen is an
issue. Research is ongoing in several laboratories to investigate
the extent to which some form of game playing
may be beneficial to this patient population. For
instance, Waddingham and colleagues have developed
the Interactive Binocular Treatment system (I-BiTTM)
for the treatment of amblyopia (Eastgate et al., 2006;
Waddingham et al., 2006) which puts forward an interesting
idea. Subjects play video games in a modified
virtual reality set-up where the “interesting” part
of the game is primarily displayed to the amblyopic
eye while the fellow eye receives information about
the background, with common elements in both eyes
to allow for fusion, thereby training binocularity in an
engaging way. This is a particularly appealing method
as it has the potential to both improve vision in the
amblyopic eye as well as teach the patient to use both
eyes in concert rather than relying on only one eye at a
time.
There is also much interest in developing training
regimens aimed at diminishing the visual deficits
caused by stroke. Two categories of therapy for stroke
patients with blind fields are presently available. In
scanning compensatory therapy, patients are trained
to make compensatory eye and head movements to
bring items from the missing to the intact visual field
(Kerkhoff et al., 1992; Nelles et al., 2001; Pambakian
& Kennard, 1997; Zihl, 1995). While this type of
compensatory therapy is not aimed at changing the
boundaries of the blind field, it does lead to notable
improvements in everyday tasks such as reading, with
patients demonstrating both increases in reading speed
and a reduction in reading errors (Kerkhoff et al., 1992).
The second category includes different types of vision
restoration therapies whereby the so-called ‘border
zone’ of the blind field is systematically stimulated
in an effort to diminish the visual field deficit (Huxlin
et al., 2007; Marshall et al., 2007; Sabel et al., 2004;
Sahraie et al., 2006). The restorative therapies tend to
be similar to the perceptual learning studies in that they
use training regimens comparable to the experimental
tests that are used to assess the amount of improvement.
A number of these studies report improvement on the
trained task in the blind field, but it remains unclear
whether such changes improve the quality of life of
the patient. A training regimen that has received much
interest recently is vision restoration therapy (VRT)
which requires patients to train their peripheral vision
everyday by using a software package loaded at home
on their personal computer (Sabel et al., 2004). The
idea behind VRT is that regular stimulation at the border
of the blind field may recruit surviving neurons and
shift their receptive fields to represent part of the lost
field, especially just inside the scotoma boundary. The
relative success of each type of therapy is still very
much a question of debate. A review by Booumeester
and colleagues (2007) concluded that the efficacy of
VRT depended on the method of the perimetric measurements
and on the fixation control used. Whether
VRT-trained patients may improve because of cortical
plasticity or of advantageous eye movements for the
learned task is still quite controversial (Glisson, 2006;
444 R.L. Achtman et al. / Video games as a tool to train visual skills
McFadzean, 2006; for a reply see Kasten et al., 2006).
Of course from the patient’s perspective any improvement
is good, regardless of its underlying cause. A
critical issue for training therapies whose goal is to alter
cortical functioning – be it VRT or possibly video
game playing – is to determine whether neurons within
the ischemic zone may indeed be salvaged through
stimulation. To the extent that the action video game
training discussed here is believed to alter the efficiency
of processing within the visual cortex, it does hold
promise for inducing cortical changes. However, it is
not known whether damaged cortex, be it by a stroke
or trauma, can be recruited in such a fashion.
Another population that might benefit from traininginduced
increases of transfer of learning and plasticity
is the elderly. There is a natural decline in many processing
capabilities with age. These include decreases
in manual dexterity, hand-eye coordination, ability to
respond quickly (RTs), and general cognitive abilities
(e.g., short-term memory). One obvious practical implication
of video game training for the elderly might
be to maintain or improve the ability to drive, as many
of the skills useful for driving safely are enhanced by
video game training. The question remains whether or
not training might help to slow, stop, or even reverse
some of these age-related effects.
6. Conclusions
The adult nervous system retains the capacity for
plasticity both with everyday experience and following
injury; yet, this plastic potentiality often remains difficult
to reveal. While it is possible to show improvements
on nearly any task with practice on that very
task, training that produces performance enhancement
in a range of situations remains elusive. It is, however,
this transfer of learning that is key for efficient
rehabilitation. One possible training regimen that has
shown generalizable enhancements in terms of visual
attention and more basic visual processing is playing
action video games, offering a new avenue for visual
rehabilitation.
A better understanding of the neural mechanisms underlying
the effects of video game play and perceptual
learning will lead to improved clinical treatments and
the potential of training regimens with favourable outcomes.
The difficulty is in choosing the right gaming
experience, as not all video games affect visual processing
equally. Currently, the largest enhancements to
visual processing are seen with training on action video
games. These games most likely combine a number
of factors that when implemented together allow for
extensive reshaping of visual functions. As such, they
offer a unique opportunity to improve our understanding
of the factors that promote brain plasticity and visual
learning. Video games are not a panacea however;
further research is needed into the link between a given
brain function and the type of experience needed to enhance
it. As the lack of effect of gaming on exogenous
attention makes clear, not all brain functions are equally
amenable to plastic changes. The challenge in the field
of training-induced plasticity lies in understanding both
the experiential factors that foster plasticity as well as
the intrinsic constraints that may limit its expression.
Acknowledgements
This research was supported by grants to DB from
the National Institutes of Health (EYO16880) and the
Office of Naval Research (N00014-07-1-0937).
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