ORIGINAL ARTICLE

Practice makes transfer of motor skills imperfect

Arnaud Boutin • Arnaud Badets • Robin N. Salesse •

Udo Fries • Stefan Panzer • Yannick Blandin

Received: 12 April 2011 / Accepted: 2 June 2011 / Published online: 14 June 2011

� Springer-Verlag 2011

Abstract We investigated the practice-effects on motor

skill transfer and the associated representational memory

changes that occur during the within-practice and between-

practice phases. In two experiments, participants produced

extension–flexion movements with their dominant right

arm for a limited or prolonged practice session arranged in

either a single- or multi-session format. We tested the

ability of participants to transfer the original pattern

(extrinsic transformation) or the mirrored one (intrinsic

transformation) to the non-dominant left arm, 10 min and

24 h after the practice sessions. Results showed that prac-

tice induces rapid motor skill improvements that are non-

transferable irrespective of the amount of acquisition trials.

Furthermore, the extrinsic component of the skill develops

early and remains the dominant coding system during

practice. Conversely, we found distinct between-practice

memory changes: a limited practice induces an off-line

development of the extrinsic component, whereas a pro-

longed practice session subserves the off-line development

of the intrinsic component (Experiment 2). We provided

further evidence that the long-term representation of the

motor skill also depends on the nature of the practice

session itself: the parsing of practice into multiple sessions

narrows the effector-transfer capacities in comparison to a

single session (Experiment 1). These findings yield theo-

retical and practical implications that are discussed in the

context of recent motor skill learning models.

Introduction

Growing evidence, spanning behavioural and neurophysi-

ological studies, supports the notion that the acquisition of

a new motor skill is mediated by distinct successive phases:

a fast learning, within-practice performance improvements

phase, followed by a slow learning phase consisting of

delayed (off-line), time-dependent performance improve-

ments emerging after practice (e.g., Karni, Meyer, Jezzard,

Adams, Turner, & Ungerleider, 1995; Korman, Raz, Flash,

& Karni, 2003; Robertson, Pascual-Leone, & Press, 2004b;

see also Krakauer & Shadmehr 2006; Stickgold & Walker

2007, for reviews). Current hypotheses state that a specific

and labile memory representation of the motor skill is

formed during practice. This newly memory trace will then

undergo further modifications during a period of consoli-

dation, in the absence of additional practice (e.g., Robertson,

Pascual-Leone, & Miall, 2004a; Walker & Stickgold, 2004;

see Krakauer & Shadmehr, 2006; Robertson, 2009, for a

review). Consolidation refers to the off-line process (see

McGaugh, 2000, for a review) that transforms new and

initially labile memories into more stable representations

that become integrated into the network of pre-existing

long-term motor memories ([24 h; see Krakauer &

Shadmehr, 2006, for a review).

Part of this work was presented at the conference of the North

American Society for the Psychology of Sport and Physical Activity,

Tucson (AZ), 2010.

A. Boutin � A. Badets � R. N. Salesse � Y. Blandin (&)

National Centre of Scientific Research, Centre de Recherches sur

la Cognition et l’Apprentissage, CeRCA, CNRS UMR 6234,

MSHS. Bat A5, University of Poitiers, 5, rue Theodore Lefebvre,

86000 Poitiers, France

e-mail: Yannick.Blandin@mshs.univ-poitiers.fr

U. Fries

Department of Human Movement Science,

University of Leipzig, Leipzig, Germany

S. Panzer

IfADo, Leibniz Research Centre for Working Environment

and Human Factors, Dortmund, Germany

123

Psychological Research (2012) 76:611–625

DOI 10.1007/s00426-011-0355-2

Numerous theoretical perspectives proposed that the

representation of motor skills relies on distinct and inde-

pendent coordinate or coding systems (e.g., Criscimagna-

Hemminger, Donchin, Gazzaniga, & Shadmehr, 2003;

Hikosaka, Nakahara, Rand, Sakai, Lu, Nakamura, et al.,

1999; Lange, Godde, & Braun, 2004). Each coding system

contributes to movement production and could produce

specific learning and transfer capacities. While the visually

acquired information about movement and target positions

are initially encoded in an eye-centred, extrinsic world-

based reference frame, the muscular activation patterns are

then encoded in an intrinsic, body-centred reference frame

(e.g., Colby & Goldberg, 1999; Soechting & Flanders,

1989). The intrinsic code is represented in terms of an

internal model of joint representations (Criscimagna-

Hemminger et al., 2003), musculoskeletal forces and

dynamics (Krakauer, Ghilardi, & Ghez, 1999), which takes

into the account of orientation of body segments relative to

each other (Lange et al., 2004; Soechting & Flanders,

1989). The intrinsic coding system is supposed to result in

an effector-dependent representation of the motor skill (i.e.,

without effector transfer capacity) to the extent that bio-

mechanical, neurological, and dynamic properties of the

effectors used on a transfer test are dissimilar to those used

during practice. Conversely, the extrinsic code reflects

Cartesian coordinates of the task space with respect to the

visual display. This code is represented in an effector-

independent representation (i.e., effector transfer capacity)

when the extrinsic coordinates are reinstated during an

effector transfer test even though intrinsic characteristics of

the required movement are altered (Hikosaka et al., 1999).

Many studies have investigated the capacity of indi-

viduals to transfer skills between hands/arms using inter-

manual transfer paradigms (e.g., Cohen, Pascual-Leone,

Press, & Robertson, 2005; Kovacs, Boyle, Gruetzmatcher,

& Shea, 2010; Kovacs, Han, & Shea, 2009; Panzer,

Krueger, Muehlbauer, Kovacs, & Shea, 2009). However,

the vast majority of studies have almost exclusively

focused on the long-term effects of practice on skill

transfer (e.g., Boutin, Fries, Panzer, Shea, & Blandin, 2010;

Kovacs, Muehlbauer, & Shea, 2009), on the practice-rela-

ted memory changes (e.g., Karni, Meyer, Rey-Hipolito,

Jezzard, Adams, Turner, et al., 1998; Korman et al., 2003)

and on the degree of overnight/overday improvements

(e.g., Cohen et al., 2005; Robertson, Press, & Pascual-

Leone, 2005; Witt, Margraf, Bieber, Born, & Deuschl,

2010). But the assumption that the coding systems may be

enhanced in distinct learning phases (within- and between-

practice) has not yet been directly addressed. A protocol is

lacking that allows direct assessment of both within- and

between-practice session improvements, and their relative

contribution to the development of a specific coding sys-

tem. The main purposes of this study were, therefore, to

assess the evolution of the coding systems through practice

(Experiment 1) and to further investigate the rapid and

delayed practice-dependent changes (Experiment 2) that

contribute to the formation of long-term motor skill

representations.

The questions addressed in the current study required

the use of a particular experimental design where partic-

ipants had to perform rehearsed retention and transfer tests

(i.e., testing and re-testing sessions). However, numerous

studies (see Roediger & Butler, 2010; Roediger & Kar-

picke, 2006b, for reviews) in the verbal skill literature

have shown that if the period of time devoted to learning

includes at least one test, performance on a final test is

improved. This finding is known as the testing effect (see

Roediger & Karpicke, 2006a, for a review). Recent

research provided further evidence that testing rehearsal

can be used to further promote transfer on the final test

(e.g., Butler, 2010; McDaniel, Roediger, & McDermott,

2007, for a review). In their review, Roediger and Butler

(2010) argued that testing rehearsal promotes the acqui-

sition and long-term retention of the acquired knowledge

that can be flexibly retrieved and transferred to different

contexts, thus suggesting that the mnemonics benefits of

testing extend beyond the retention of a specific response.

The retrieval of information from memory during testing

may be the central mechanism that produces learning

benefits during a final test (Butler, 2010). One possible

explanation is that combining practice with testing session

provides greater encoding variability than single practice

(McDaniel & Masson, 1985). Thereby, testing rehearsal

can be a potent memory enhancer, not just a neutral event

as usually wrongly considered (e.g., Carpenter, 2009;

Roediger & Butler, 2010; Rohrer, Taylor, & Sholar, 2010,

for similar position). It should be noted that testing-effect

studies were traditionally conducted, with very few

exceptions, using word lists (e.g., McDaniel & Masson,

1985; Wheeler et al. 2003) or educationally relevant sit-

uations (e.g., Roediger & Karpicke, 2006b; Rohrer et al.,

2010) as materials. However, to the best of our knowl-

edge, the extent to which testing rehearsal can interact

with motor skill learning and transfer remains unknown.

Therefore, a condition without testing rehearsal was also

included in all experiments.

We used a continuous dynamic arm movement task that

required participants to make a sequence of extension-

flexion movements with their dominant right arm to

reproduce a specific pattern of displacement over time. To

test whether the contribution of the extrinsic and intrinsic

coding systems to skill learning and transfer depends on the

amount of practice, performance on retention and transfer

tests was systematically evaluated after both limited and

prolonged practice sessions. We used a retention test

requiring the participants to produce the spatial–temporal

612 Psychological Research (2012) 76:611–625

123

pattern with the same arm that was used during the practice

trials and two effector transfer tests with the unpractised

arm (see Kovacs et al., 2009; Panzer et al., 2009 for a similar

procedure). In the ‘‘intrinsic transformation’’ test, the origi-

nal pattern was mirrored so that the sequential movements

remain the same when transferred to the non-dominant left

arm (i.e., the same pattern of muscle activation and limb joint

angles). This test assessed the contribution of the intrinsic

component to transfer and learning. In the ‘‘extrinsic trans-

formation’’ test, the original pattern was preserved but per-

formed with the non-dominant left arm (i.e., the same goal

movement pattern). This test assessed the contribution of the

extrinsic component to transfer and learning because it

implicated the same spatial positions but a different pattern

of muscle activation compared with that used during prac-

tice. It should be noted that ineffective transfer performance

for one or both effector transfer tests suggests that

the extrinsic and/or intrinsic components of the motor skill

were not the dominant coding system(s) for sequence

production.

Experiment 1

The primary purpose of Experiment 1 was to investigate

the evolution of the coding systems with practice. We

evaluated retention and effector transfer performances after

a limited (18 acquisition trials) and a prolonged (135

additional acquisition trials) practice session. This design

involved performing rehearsed retention and transfer tests

(repeated testing condition). Therefore, we included a

condition that required participants to complete the same

amount of practice without retention/transfer tests

between-practice sessions (non-repeated testing condition).

Our predictions for Experiment 1 were based upon

previous theoretical perspectives (e.g., Bapi, Doya, &

Harner, 2000; Hikosaka et al., 1999, 2002; Keele, Ivry,

Mayr, Hazeltine, & Heuer, 2003; Keele, Jennings, Jones,

Caulton, & Cohen, 1995), which suggested that the repre-

sentation of motor skills evolves from an extrinsic (effec-

tor-independent) to an intrinsic (effector-dependent)

dominant coding system with practice. Thus, we predicted

that a limited practice session would yield better perfor-

mance on both the retention and extrinsic transformation

tests than on the intrinsic transformation test. Conversely,

we expected an opposite pattern of results for prolonged

practice with better performance on the intrinsic transfor-

mation test than on the extrinsic transformation test.

Finally, the repeated testing condition should favour

incremental gains in performance from testing to retesting

and, consequently, could modify the relationship between

the amount of practice and the type of coding used to

produce the task (e.g., Roediger & Butler, 2010).

Method

Participants

Thirty self-declared right-handed undergraduate students

(mean age 19.1 years, SD 0.9 years; 12 women) volun-

teered to participate in this study. Each participant was

requested to read and sign an informed consent form prior

to participation in the experiment. None of the participants

had previous experience with the experimental task, and

they were unaware of the specific purposes of the study. A

local ethics committee approved the protocol.

Apparatus

The apparatus consisted of a horizontal lever supported at

one end by a vertical axle that turned in a ball-bearing

support in a manner that was almost frictionless. The

support was fixed on a table facing the participant, allow-

ing the lever to move in the transversal plane over the table

surface. At the other end of the lever, a vertical handle was

fixed. The handle’s position could be adjusted so that when

the participant grasped the handle, his/her elbow was

aligned with the axis of rotation (Fig. 1, top left). A

potentiometer was attached to the handle’s axis of rotation

to record the position, and its output was sampled at

1000 Hz. The potentiometer data were used to provide

lever position information to the participant and stored for

later analysis. A wooden cover was placed over the table to

prevent participants from seeing the lever and their arm. A

video projector was used to display the goal movement

pattern, the on-line position of the lever and the knowledge

of results (KR) on the wall facing the participant. Partici-

pants were seated on a height-adjustable chair, about 2 m

from the wall where a 1.64 9 1.23 m image was projected,

so that their lower arm was at an approximately 80� angle

to the upper arm at the starting position. All aspects of the

experiment were programmed with the Matlab� R2008b

software from the MathWorks� (The MathWorks, Inc.,

Natick, MA), and using the Psychophysics Toolbox

extensions (Brainard, 1997; Pelli, 1997; Kleiner, Brainard,

& Pelli, 2007).

Task, experimental groups and procedures

Participants were randomly assigned to the ‘‘repeated

testing’’ (RT group; N = 15) or ‘‘non-repeated testing’’

(NRT group; N = 15) practice condition. In the RT prac-

tice condition, participants underwent 24-h delayed reten-

tion and transfer tests after both limited and prolonged

practice sessions. In the NRT practice condition, partici-

pants were merely administered 24-h delayed retention and

transfer tests following the prolonged practice session.

Psychological Research (2012) 76:611–625 613

123

Figure 1 (bottom) presents the experimental phases for

each practice condition.

Participants were individually tested in a silent and

dimly lit room. Before beginning the experiment, each

participant received written instructions and additional

verbal information about the task and procedures. They had

to perform a sequence of extension-flexion movements

with their dominant right arm to reproduce the spatial and

temporal aspects of the goal pattern projected in front of

them (Fig. 1, top). The spatial–temporal pattern was cre-

ated by summing two sine waves with similar periods but

different amplitudes. The duration of the goal pattern was

1,500 ms, and the extension–flexion movements required

three reversals. The potentiometer output was sampled for

2,000 ms, but only the first 1,500 ms was retained for later

analysis.

At the beginning of each trial, the goal movement pattern

was displayed on the wall, and participants were asked to

move the lever to the starting position (1� area at the

beginning of the goal movement pattern). One second after

achieving the start position, a tone (50 ms in duration,

3 kHz square wave) indicated that they should perform the

task. The task required moving the lever with the dominant

right arm through a pattern of extension–flexion cycles

(three reversals) to produce the required spatial–temporal

pattern. As soon as the participant started moving, the goal

movement pattern disappeared from the screen, and a cursor

representing the position of the lever was displayed. After a

2-s interval following response completion, KR was pro-

vided by superimposing the goal movement pattern (white)

over the actual pattern (green). In addition, the root-mean-

square error (RMSE) of the actual movement from the goal

movement was displayed on the screen. RMSE is the

deviation of the actual pattern from the goal pattern calcu-

lated from the onset of movement until the end of the first

1,500 ms. RMSE is sensitive to both response bias and

within-participant variability. When presented, KR was

displayed for 5 s. Participants were instructed to reproduce

the goal movement pattern as accurately as possible and

were requested to reduce the RMSE on subsequent trials.

Groups Acquisition 1 Initial testing Acquisition 2 Subsequent testing

Day 1 Day 2 Day 2 Day 2

Repeated testing 2 blocks R - Et - It 15 blocks R - Et - It

Non-repeated testing 2 blocks 15 blocks R - Et - It

Fig. 1 Schematic illustrating the limb and criterion movement

pattern used during acquisition and on the retention and transfer

tests (top). Note that the goal movement pattern was projected onto

the wall in front of the participant. Participants used their dominant

right limb during acquisition and retention. The non-dominant left

limb was used for the extrinsic and intrinsic transformation tests. The

retention test was conducted first, and the order for the two transfer

tests (extrinsic transformation and intrinsic transformation) was

counterbalanced

614 Psychological Research (2012) 76:611–625

123

Participants in the RT and NRT conditions completed

the first acquisition phase (Acquisition 1), which was

composed of two blocks of nine trials each. During this

phase, KR was provided following each trial. Approxi-

mately 24 h after the completion of Acquisition 1, partic-

ipants assigned to the RT practice condition were

administered retention and effector transfer tests, while

their NRT practice condition counterparts were not. The

retention test consisted of one block of nine trials without

KR that required the participants to produce the movement

pattern with the same limb that was used during the prac-

tice trials. With the exception that KR was not provided

during retention, all other procedures remained the same as

those used for acquisition. In addition, two effector transfer

tests without KR were administered in a counterbalanced

order after the retention test (Fig. 1, top). The transfer tests

were performed with the contra-lateral limb (i.e., non-

dominant left arm). In the ‘‘intrinsic transformation’’ test,

the original pattern becomes mirrored so that the sequential

movements remain the same when transferred to the non-

dominant left arm (i.e., the same pattern of muscle acti-

vation and limb joint angles). In the ‘‘extrinsic transfor-

mation’’ test, the original pattern was preserved but

performed with the non-dominant left arm (i.e., the same

goal movement pattern).

With the exception that participants in the NRT practice

condition did not perform retention and transfer tests on

day 2, participants in the RT and NRT conditions contin-

ued practice for an additional acquisition phase (Acquisi-

tion 2). This acquisition phase consisted of fifteen blocks of

nine trials and involved the same experimental procedures

as in Acquisition 1. Note that participants in the RT

practice condition took a 5-min rest interval following

retention and transfer before practicing Acquisition 2.

Twenty-four-hour delayed retention and transfer tests

(extrinsic transformation and intrinsic transformation) were

conducted on day 3 for all participants in the same manner

as the initial testing session experienced in the RT

condition.

Data analysis and measures

Data reduction was performed using Matlab� (The Math-

works�, Inc., Natick, MA, USA). The individual trial time

series were used to compute lever displacement. Angular

displacement time series were filtered with a 2nd order

dual-pass Butterworth filter with a cut-off frequency of

10 Hz. Root-mean-square error was computed to estimate

performance error in achieving the goal movement pattern.

Such a measure is sensitive to both amplitude and timing

errors in the produced movement pattern relative to the

goal movement pattern. To compute RMSE, the difference

between the criterion and the filtered actual movement

pattern was computed at each data point in the time series.

Next, differences for each data point in the time series were

squared, and means of the squared differences were com-

puted on a trial basis. Finally, the square root of the mean

was computed for the final measure of RMSE. Values of

RMSE for individual trials were then averaged to yield a

global estimate of RMSE for each block (nine trials).

Results

Acquisition

Acquisition data were separately analysed. First, Acquisi-

tion 1 data were submitted to a 2 (practice conditions:

repeated testing, non-repeated testing) 9 2 (blocks 1–2)

analysis of variance (ANOVA) with repeated measures on

the last factor. The second analysis was a 2 (practice

conditions: repeated testing, non-repeated testing) 9 15

(blocks 3–17) ANOVA with repeated measures on block

using data from Acquisition 2. All significant effects were

reported at p \ 0.05, unless otherwise stated, and Duncan’s

multiple range test was used for post hoc comparisons.

Partial eta square (gp2) is the effect size reported for all

significant effects (Cohen, 1988). Outliers were removed

from the analysis (±2 SD: about 4%). Mean RMSEs during

the acquisition, retention and transfer phases is displayed in

Fig. 2.

Fig. 2 Mean RMSEs during acquisition (Acquisition 1 and 2) and on

the retention (R), extrinsic transformation (Et) and intrinsic transfor-

mation (It) tests for the repeated testing and non-repeated testing

groups in Experiment 1. Error bars reflect standard error of the mean

Psychological Research (2012) 76:611–625 615

123

Acquisition 1

The analysis detected a main effect of block, F(1, 28) =

75.34, gp2 = 0.72, indicating higher RMSE on block 1

(M = 100.84) than on block 2 (M = 71.10). The main

effect of practice condition, F(1, 28) \ 1, and the practice

condition 9 block interaction were not significant, F(1,

28) \ 1.

Acquisition 2

The analysis detected a main effect of block, F(14,

392) = 13.43, gp2 = .32. Duncan’s multiple range test

revealed higher RMSE on block 3 (M = 64.31) compared

with blocks 4–7 (from M = 56.04 to M = 51.18, respec-

tively), which were not different from each other but higher

than blocks 8–17 (from M = 47.44 to M = 41.43,

respectively), which did not differ from each other. The

analysis failed to detect neither a main effect of practice

condition, F(1, 28) \ 1, nor a practice condition 9 block

interaction, F(14, 392) \ 1.

Retention and transfer

Repeated testing group: from testing to retesting

To assess the evolution of the long-term representation of

motor skills with practice, we compared performances of

the RT group on the retention and transfer tests following

limited and prolonged practice. Mean RMSEs on the

retention and transfer tests were analysed in a 2 (amounts

of practice: limited practice, prolonged practice) 9 3

(tests: retention, extrinsic transformation, intrinsic trans-

formation) ANOVA with repeated measures on the two

factors. The analysis indicated main effects of amount of

practice, F(1, 14) = 31.11, gp2 = 0.68, and test, F(2,

28) = 6.17, gp2 = 0.30, but failed to detect a significant

amount of practice 9 test interaction, F(2, 28) = 1.78.

RMSE was higher following the limited (M = 74.59) than

the prolonged practice (M = 54.58). For the main effect of

test, Duncan’s multiple range test indicated that RMSE was

significantly higher on the intrinsic transformation test

(M = 71.03) than on the retention (M = 58.26) and

extrinsic transformation tests (M = 64.47), which did not

differ from each other.

Repeated and non-repeated testing groups: subsequent

testing

Performances of the RT and NRT groups on the retention

and transfer tests following the prolonged practice session

were compared to show evidence for/against a testing

effect. RMSE was analysed in a 2 (practice conditions:

repeated testing, non-repeated testing) 9 3 (tests: reten-

tion, extrinsic transformation, intrinsic transformation)

ANOVA with repeated measures on the last factor.

The analysis revealed main effects of practice condition,

F(1, 28) = 8.09, gp2 = 0.22, test, F(2, 56) = 28.09,

gp2 = 0.50, and a significant practice condition 9 test

interaction, F(2, 56) = 5.03, gp2 = 0.15. RMSE on the

retention tests were not significantly different between the

RT (M = 47.82) and NRT groups (M = 50.59). However,

lower RMSE was found for the RT group than for the NRT

group on the extrinsic and intrinsic transformation tests.

Specifically, for the RT group, post hoc comparisons

indicated that RMSE was significantly lower on the

retention test (M = 47.82) than on the extrinsic (M =

56.78) and intrinsic transformation tests (M = 59.15),

which did not significantly differ from each other. For the

NRT group, RMSE was also significantly lower on the

retention test (M = 50.59) than on the extrinsic

(M = 68.06) and intrinsic transformation tests (M = 79.06).

However, in contrast to the RT practice condition, the anal-

ysis displayed higher RMSE on the intrinsic transformation

test compared with that on the extrinsic transformation test

(p \ 0.05) for participants assigned to the NRT group.

Discussion

Results for the acquisition indicated that the RT and NRT

groups performed similarly on the first and second practice

sessions (Acquisition 1 and Acquisition 2, respectively),

suggesting that participants in both groups improved their

performance during practice. Importantly, this finding

demonstrates that improvements during Acquisition 2 were

not testing-dependent. Indeed, participants in the NRT

practice condition did not express worse performance

during Acquisition 2 compared with their RT practice

condition counterparts. Our findings revealed that testing

rehearsal did not interact with motor skill acquisition.

Similar conclusions can be drawn regarding motor skill

retention. As revealed by performances during retention at

subsequent testing, RMSE on retention tests were identical

for the RT and NRT groups.

However, different patterns of results were observed at

subsequent transfer tests for the RT and NRT groups. This

indicates that the initial testing session, performed in the

RT practice condition, has influenced effector transfer

capacities. This is in line with previous research in the

testing-effect literature (e.g., Butler, 2010; Rohrer et al.,

2010; see Roediger & Butler, 2010; Roediger & Karpicke,

2006a, for reviews), and extend the findings from the

verbal to the motor domain. Specifically, transfer data for

the NRT group indicated that practice produced an effec-

tor-dependent representation (lower RMSE on the retention

616 Psychological Research (2012) 76:611–625

123

test compared with the transfer tests) that remained

extrinsic (lower RMSE on the extrinsic than on the intrinsic

transformation test). Conversely, testing rehearsal resulted

in a multiple coding representation (similar performances

for the RT group on the extrinsic and intrinsic transfor-

mation tests). Interestingly, this finding suggests that test-

ing rehearsal promotes the development of a multiple

coding representation that can be flexibly used from

dominant to non-dominant limb.

Because testing rehearsal interacts with motor skill

transfer, it is therefore not surprising that we did not find

any amount of practice 9 test interaction when analysing

data of the RT group. Indeed, one could assume that

retrieval practice at initial testing might have enhanced

motor skill transfer at subsequent testing, thus precluding

the possibility of additional analysis regarding the evolu-

tion of the motor skill representation from testing to

retesting. Therefore, to assess the motor skill representation

after limited practice, we further conducted a 3 (tests:

retention, extrinsic transformation and intrinsic transfor-

mation) ANOVA with repeated measures on test using the

RT group’s data at initial testing. Analysis revealed a main

effect of test, F(2, 28) = 4.47, gp2 = 0.24, with lower

RMSE on the retention (M = 68.71) and extrinsic trans-

formation tests (M = 72.16) than on the intrinsic trans-

formation test (M = 82.91). These results agree with the

theoretical perspective that an effector-independent repre-

sentation of an extrinsically transformed skill is developed

after few practice trials (Hikosaka et al., 1999, 2002; Keele

et al., 2003, 1995).

To summarise, a key finding of Experiment 1 is that the

long-term representation of the motor skill after multises-

sion practice was qualitatively (i.e., reliance on a particular

coding system) different when participants were confronted

with testing rehearsal or with a single delayed testing

session. Neither the delay between testing sessions nor the

multisession format per se could explain such differences

because the experimental design was exactly the same for

the RT and NRT practice conditions. Two issues could be

considered when interpreting these results: the opportunity

for testing rehearsal and/or the process of motor memory

consolidation that took place during the 24-h interval fol-

lowing the first and second acquisition phase. Therefore,

Experiment 2 sought to further clarify the relative contri-

bution of testing rehearsal and/or the process of memory

consolidation to motor skills coding. An additional purpose

of Experiment 2 was to investigate the rapid and delayed

practice-related memory changes that contribute to the

formation of long-term motor skill representations, using

single practice sessions composed of either 18 acquisition

trials (limited practice) or 153 acquisition trials (18 ? 135;

prolonged practice).

Experiment 2

Experiment 2 was designed to extend the findings of

Experiment 1 from multisession to single session and to

evaluate the off-line practice-related memory changes

following a single practice session. The results of Experi-

ment 1 revealed that testing rehearsal might be an effective

memory enhancer when the testing sessions are adminis-

tered between-practice sessions. Experiment 2 aimed at

determining whether off-line testing-dependent memory

enhancements of the motor skill could be observed from

testing to retesting in the absence of further task

engagement.

Participants from two groups were required to reproduce

the spatial–temporal pattern used in Experiment 1 for either

18 or 153 acquisition trials in a single practice session

before being evaluated on both 10-min and 24-h delayed

retention and transfer tests. As in Experiment 1, two other

groups practised the same goal pattern for either 18 or 153

acquisition trials but with the exception that no 10-min

retention/transfer tests were conducted, thus avoiding a

potential testing effect from 10-min testing to 24-h delayed

retesting. We expected rapid representational memory

changes with practice, as evaluated by 10-min retention

and transfer tests, with the dominance of the extrinsic

coding system after limited practice and conversely of the

intrinsic one after prolonged practice. Additionally, we

predicted that the rapid and practice-dependent memory

changes would extend beyond the practice session, i.e.,

from 10-min to 24-h testing. More specifically, a limited

practice session would favour the off-line development of

the extrinsic component of the motor skill while in con-

trast, a prolonged practice session would emphasize the

off-line development of the intrinsic coding system.

Method

Participants

Sixty self-declared right-handed undergraduate students

(mean age 21.1 years, SD 1.5 years; 21 women) volun-

teered to participate in this study. Each participant was

requested to read and sign an informed consent form prior

to participation in the experiment. None of the participants

had previous experience with the experimental task, and

they were unaware of the specific purposes of the study. A

local ethics committee approved the protocol.

Apparatus

The apparatus was identical to that used in Experiment 1.

Psychological Research (2012) 76:611–625 617

123

Task, experimental groups and procedures

Participants were randomly assigned to one of four groups

(N = 15) defined by the practice condition (repeated testing

or non-repeated testing) and the amount of practice (limited

or prolonged). While assigned to the ‘‘repeated testing’’

(RT) practice condition, participants underwent both

immediate and 24-h delayed retention and transfer tests

following either a limited or a prolonged practice session.

Conversely, while assigned to the ‘‘non-repeated testing’’

(NRT) practice condition, participants were merely

administered 24-h delayed retention and transfer tests fol-

lowing either a limited or a prolonged practice session (see

Table 1). Task and procedures for the acquisition, retention

and transfer tests were conducted in the same manner as

described in Experiment 1, except as noted.

Data analysis and measures

Data reduction was performed in the same manner as in

Experiment 1.

Results

Acquisition

Acquisition data were separately analysed. First, the lim-

ited practice data were submitted to a 2 (practice condi-

tions: repeated testing, non-repeated testing) 9 2 (blocks

1–2) ANOVA with repeated measures on the last factor.

The second analysis was a 2 (practice conditions: repeated

testing, non-repeated testing) 9 17 (blocks 1–17) ANOVA

with repeated measures on block using data from the pro-

longed practice groups. All significant effects were repor-

ted at p \ 0.05, unless otherwise stated, and Duncan’s

multiple range test was used for post hoc comparisons.

Partial eta square (gp2) is the effect size reported for all

significant effects (Cohen, 1988). Outliers were removed

from the analysis (±2 SD: about 4%). Mean RMSEs during

acquisition for the limited and prolonged practice groups

are displayed in Fig. 3.

Limited practice

The analysis revealed a main effect of block, F(1,

28) = 59.89, gp2 = 0.68, indicating that RMSE was higher

on block 1 (M = 102.01) than on block 2 (M = 68.59).

The main effect of practice condition, F(1, 28) \ 1, and the

practice condition 9 block interaction, F(1, 28) \ 1, were

not significant.

Prolonged practice

The analysis detected a main effect of block, F(16,

448) = 36.29, gp2 = 0.56. Duncan’s multiple range test

revealed that RMSE was higher on block 1 (M = 98.54)

than on block 2 (M = 69.59). Further, analysis found

higher RMSE on block 2 than on blocks 3–4 (from

M = 63.18 to M = 57.63, respectively), which was not

different from each other but higher than on blocks 5–13

(from M = 53.90 to M = 47.12, respectively), which did

not differ from each other. From block 14, RMSE remained

stable until the end of acquisition (from M = 45.02 to

M = 43.91, for blocks 14–17 respectively). The analysis

failed to detect neither a main effect of practice condition,

F(1, 28) = 2.37, nor a practice condition 9 block inter-

action, F(16, 448) \ 1.

Retention and transfer

Mean RMSEs on the retention and transfer tests were

analysed in several ways. To assess the coding systems’

time course during practice and memory consolidation, we

separately analysed performances of the RT groups (a) at

10-min testing and performances of the RT and NRT

groups at 24-h testing after (b) limited and (c) prolonged

practice (Fig. 3). Additionally, to investigate the contri-

bution of the consolidation process to the quantitative and

qualitative memory changes, we compared performance

(d) at 10-min testing to performance at 24-h retesting using

data from the RT groups (Fig. 4).

Repeated groups: 10-min testing

Mean RMSEs on the retention and transfer tests were

analysed in a 2 (amounts of practice: limited practice,

prolonged practice) 9 3 (tests: retention, extrinsic trans-

formation, intrinsic transformation) ANOVA with repeated

measures on the last factor. The analysis indicated a main

Table 1 Experimental phases for the repeated testing and non-

repeated testing groups in Experiment 2

Groups Acquisition Immediate

testing

24-h

testing

Day 1 Day 1 Day 2

Limited practice

Repeated testing 2 Blocks R–Et–It R–Et–It

Non-repeated testing 2 Blocks R–Et–It

Prolonged practice

Repeated testing 17 Blocks R–Et–It R–Et–It

Non-repeated testing 17 Blocks R–Et–It

R retention, Et extrinsic transformation, It intrinsic transformation

(order counterbalanced)

618 Psychological Research (2012) 76:611–625

123

effect of test, F(2, 56) = 30.05, gp2 = 0.52. Post hoc

comparisons revealed lower RMSE on the retention test

(M = 52.92) compared with that on the extrinsic trans-

formation (M = 69.87), which is also significantly lower

than on the intrinsic transformation test (M = 78.49). The

analysis failed to detect neither a main effect of amount of

practice, F(1, 28) \ 1, nor an amount of practice 9 test

interaction, F(2, 56) = 2.10.

Limited practice: repeated and non-repeated testing

groups (24-h testing)

Mean RMSEs on the retention and transfer tests were

analysed in a 2 (practice conditions: repeated testing, non-

repeated testing) 9 3 (tests: retention, extrinsic transfor-

mation, intrinsic transformation) ANOVA with repeated

measures on the last factor. The analysis indicated a main

effect of test, F(2, 56) = 11.27, gp2 = 0.28. Duncan’s

multiple range test revealed that RMSE was higher on the

intrinsic transformation test (M = 77.71) than on the

retention (M = 63.66) and extrinsic transformation tests

(M = 66.70), which did not differ from each other. The

analysis failed to detect neither a main effect of practice

condition, F(1, 28) = 2.64, nor a practice condition 9 test

interaction, F(2, 56) \ 1.

Prolonged practice: repeated and non-repeated testing

groups (24-h testing)

Mean RMSEs on the retention and transfer tests were

analysed in a 2 (practice conditions: repeated testing, non-

repeated testing) 9 3 (tests: retention, extrinsic transfor-

mation, intrinsic transformation) ANOVA with repeated

measures on the last factor. The analysis indicated a main

effect of test, F(2, 56) = 8.47, gp2 = 0.23, with lower

RMSE on the retention test (M = 53.40) than on the

extrinsic transformation (M = 64.26) and intrinsic trans-

formation tests (M = 65.39), which did not differ from

each other. The main effect of practice condition, F(1,

Fig. 3 Mean RMSEs during acquisition and on the retention (R),

extrinsic transformation (Et) and intrinsic transformation (It) tests for

the repeated testing and non-repeated testing groups performing a

limited (blocks 1–2; left panel) and a prolonged practice session

(blocks 1–17; right panel) in Experiment 2. Error bars reflect

standard error of the mean

Fig. 4 Off-line improvements are defined as the average RMSE

difference (10-min testing minus 24-h testing) on the retention (R),

extrinsic transformation (Et) and intrinsic transformation (It) tests

following a limited (left panel) and a prolonged practice session (rightpanel) for the repeated testing groups. Error bars reflect standard

error of the mean

Psychological Research (2012) 76:611–625 619

123

28) \ 1, and the practice condition 9 test interaction, F(2,

56) \ 1, was not significant.

Off-line improvements (from testing to retesting): repeated

testing groups

We compared performance on tests conducted immediately

and tests conducted following a 24-h delay among partic-

ipants who had received either a limited or prolonged

practice session. The difference between these measures

(testing minus retesting) highlighted the off-line develop-

ment of the motor skill; a positive value reflects improved

performance. We measured off-line improvements for the

RT groups using two amounts of practice (limited practice,

prolonged practice) and three retention/transfer tests

(retention, extrinsic transformation, intrinsic transforma-

tion), resulting in a 2 9 3 factorial design with repeated

measures on the last factor. Results are depicted in Fig. 4.

The analysis indicated a main effect of test, F(2, 56) =

6.70, gp2 = 0.19, and a significant amount of practice 9 test

interaction, F(2, 56) = 3.10, gp2 = 0.10. Duncan’s multiple

range test revealed higher off-line improvements after

limited practice on the extrinsic transformation test

(M = 10.58) compared with the retention (M = -0.09)

and intrinsic transformation tests (M = 4.71), which did

not differ from each other. In contrast, following prolonged

practice, post hoc comparisons revealed higher off-line

improvements on the intrinsic transformation test (M =

17.63) than on the retention (M = -1.67) and extrinsic

transformation tests (M = 7.67), which did not differ from

each other.

Discussion

Participants demonstrated a significant decrease in RMSE

across acquisition blocks, suggesting that RT and NRT

groups similarly improved their performances during both

limited and prolonged practice sessions. In addition, anal-

ysis of the retention/transfer data at 24-h testing failed to

detect a significant interaction between the practice con-

ditions and the tests for both limited and prolonged prac-

tice. This suggests that testing rehearsal did not interact

with the off-line development of the coding systems. Our

findings argue for the evidence that testing rehearsal per se

does not induce representational memory changes of the

motor skill if no additional practice trials are performed

between testing sessions. To our knowledge, this is the first

demonstration of the interactive influences between mul-

tisession practice and testing rehearsal on the evolution of

motor skill memories.

However, although the off-line learning phase was not

influenced by testing rehearsal following a single practice

session, we found evidence that the long-term representa-

tion of motor skills depends on the amount of prior prac-

tice. Following a limited practice session, we showed a

significant advantage at 24-h testing of effector transfer for

an extrinsic transformation of the goal movement pattern

(i.e., the same spatial–temporal pattern) compared with an

intrinsic transformation (i.e., the same pattern of muscle

activation and limb joint angles). In contrast, no transfer

capacities were observed for an extrinsic or intrinsic

transformation of the original pattern following a pro-

longed practice session (similar performances on the

extrinsic and intrinsic transformation tests). Interestingly,

these findings revealed that the long-term representation of

a motor skill is based on an extrinsic coding system and at

an effector-independent level after a limited single practice

session, whereas a prolonged single practice session

resulted in a multiple coding and effector-dependent

representation.

Distinct consolidating mechanisms appear therefore to

be dependent on prior practice experience (see also

Trempe & Proteau, 2010). More specifically, we found

robust delayed gains expressed at retesting on the

extrinsic transformation test after a limited single prac-

tice session and on the intrinsic transformation test after

a prolonged single practice session. The present data are

consistent with our initial predictions, which were based

on the rationale that distinct coding systems develop off-

line and at different practice scales. We showed

between-practice memory enhancements involving an

off-line developing effector-independent component that

is represented in extrinsic coordinates early in practice,

and an off-line developing effector-dependent component

that is represented in intrinsic coordinates late in

practice.

General discussion

The main questions addressed by the present study were (1)

whether motor skill learning is mediated by different

coding systems, and (2) how those coding systems evolve

during the rapid and slow learning phases depending on the

organisation of practice and testing sessions. This study

sought to determine the underlying processes that mediate

the formation of motor skill memories. As expected, in two

experiments we showed that practice triggers within-prac-

tice and between-practice session reorganisations of the

motor skill representation, yielding distinct transfer

capacities. Our findings revealed that practice induces rapid

and non-transferable (i.e., effector-dependent representa-

tion) motor skill improvements irrespective of the amount

of acquisition trials. We found that the extrinsic component

of the skill develops early and remains the dominant coding

620 Psychological Research (2012) 76:611–625

123

system during practice. Conversely, results revealed latent

and practice-dependent reorganisations of the motor skill

during the off-line period: a limited practice induced an

off-line development of the extrinsic component, whereas a

prolonged practice session improved an off-line develop-

ment of the intrinsic component. Additionally, we provided

evidence that the long-term representation of the newly

acquired skill is also dependent on the nature of the prac-

tice session itself. Specifically, the parsing of practice into

multiple sessions provides participants with a stronger

intrinsic skill representation, which is less susceptible to

transfer in comparison to the outcome of a single practice

session. Importantly, however, we found interactive influ-

ences between multisession practice and testing rehearsal.

Results suggest that the alternation between-practice and

testing sessions provides greater transfer capacities than

does the mere repetition of practice sessions themselves.

Each of these issues will be discussed in the following

sections.

Practice and its effects on motor skill transfer

To investigate the rapid (10-min testing) and latent (24-h

testing) reorganisations of the motor skill representation

and the practice-effects on motor skill transfer, we eval-

uated the ability of participants to transfer the original

spatial–temporal pattern (extrinsic transformation) or the

mirrored one (intrinsic transformation) to the unpractised

non-dominant left arm following limited and prolonged

practice. It is important to note that the present findings

are considered for dominant arm practice but may not

generalize to practice with the non-dominant arm. Indeed,

we used unidirectional transfer tests from the dominant

practised arm to the non-dominant unpractised arm. Con-

sequently, the present finding can only be interpreted for a

motor improvement of the dominant arm. In the same

vein, recent studies (e.g., Kovacs et al., 2009; Sainburg,

2005; Stockel, Weigelt, & Krug, 2011; Wang & Sainburg,

2006) provided evidence for inter-manual transfer asym-

metries depending on the limb used during practice, i.e.,

from the dominant limb to the non-dominant limb or vice

versa.

Thus, on the one hand, our results indicated an early

setting-up of an effector-dependent representation, as

revealed by the 10-min retention/transfer tests (Experi-

ment 2). Specifically, the better performances observed on

the retention test compared with the extrinsic and intrinsic

transformation tests provide evidence for within-practice

improvements during the acquisition of skilled perfor-

mance, which is a fast and non-transferable (unpractised

arm) process. This rapid motor skill’s reorganisation arises

irrespective of the amount of practice. On the other hand,

unlike the rapid learning phase, we showed latent and

practice-dependent reorganisations of the motor skill.

After limited practice, the slow learning phase enables the

latent reorganisation of the skill memory towards an

effector-independent representation of the extrinsically

transformed skill. Conversely, following prolonged prac-

tice, the slow learning phase maintained the transfer

capacities to an effector-dependent level based on a mul-

tiple coding representation of the motor task (similar

performances on the extrinsic and intrinsic transformation

tests).

Lange et al. (2004) reported findings about the neural

processes underlying the acquisition and effector transfer

of motor skills. For instance, when participants performed

the original motor task with their unpractised left arm (here

referred to as the extrinsic transformation test), they found

increased neural activity in restricted cortical regions and

decreased activation of cortical networks. They concluded

that processes involved in the modification of the intrinsic

motor skill component included fronto-central areas as well

as the supplementary motor area. Conversely, when par-

ticipants performed the mirrored motor task with their left

arm (here referred to as the intrinsic transformation test),

they indicated that the processes underlying the modifica-

tion of the extrinsic motor skill component are controlled

by intensified parieto-frontal information flow. The pro-

duction of the mirrored motor task was associated with

suppressed cortical activity, which presumably reflects the

inhibited recall of the learned extrinsic motor skill

component.

This interpretation gains support from our results but

only during the rapid learning phase. Indeed, we showed

that the extrinsic component of the motor skill develops

early and remains the dominant coding system during

practice. Because the acquired extrinsic component is not

the appropriate coding system to perform the intrinsic

transformation test, the worse performances observed on

the intrinsic transformation test might reflect the inhibition

of the learned extrinsic component. In contrast, we

observed distinct and practice-dependent representations of

the motor skill in long-term memory, suggesting that

practice initiates latent and distinct processes during con-

solidation. The process of memory consolidation during the

off-line period is therefore differently affected by the

amount of prior practice experience.

Distinct consolidating mechanisms

The present findings confirmed the relevance of the slow

learning phase for the formation of long-term motor skill

representations. The effectiveness of the consolidation

process for motor skill learning has been extensively

Psychological Research (2012) 76:611–625 621

123

documented in the literature (e.g., Diekelmann & Born,

2010; McGaugh, 2000, for reviews). It is suggested that

consolidation refers to a process that transforms new and

labile memories encoded during practice into more stable

representations that become integrated into the network

of pre-existing long-term memories. In this view, the

present study shows for the first time that practice trig-

gers distinct consolidating mechanisms during the off-line

period. Indeed, we observed an off-line developing

effector-independent component that is represented in

extrinsic coordinates following few practice trials, and an

off-line developing effector-dependent component that is

represented in intrinsic coordinates with extensive

practice.

Recent research using imaging techniques suggested

that motor memory consolidation involves a reorganisation

of the motor skill representation residing predominantly in

M1 (e.g., Li et al. 2001; Sanes & Donoghue, 2000). The

off-line representational memory changes, presumably

initiated during practice, could be mediated by functionally

distinct subpopulations of neurons within M1 (Steele &

Penhune, 2010) or by the recruitment of additional M1

units into a local network that specifically represents the

trained motor skill with prolonged practice (Karni et al.,

1995). We therefore propose that the motor memory con-

solidation is not a single process. There might be multiple

routes to support off-line learning and engagement of these

distinct mechanisms (coding systems) is determined by

prior practice experience. It is plausible that both of these

mechanisms operate together to mediate off-line memory

processing, with one tuned to the more rapidly learned

extrinsic component of the task (following limited practice)

and the other tuned to the more slowly learned intrinsic

component of the task (following prolonged practice). This

off-line memory processing could provide the key basis for

the formation of motor skill representations in long-term

memory.

Therefore, the current study provides a critical insight

into the off-line memory processing framework. Observing

motor skill memory improvements after a single practice

session challenges the prevailing notion that the released

time is critical for motor memory consolidation. However,

it appears that single and multiple practice sessions make

distinct contributions to long-term motor skill memory

during the off-line period.

Single versus multisession practice

In the present study, we demonstrated that the long-term

representation of motor skills after multisession practice

(Experiment 1) was more resistant to transfer compared

with a single practice session (Experiment 2) when no

testing rehearsal was allowed between-practice sessions

(i.e., NRT groups).1 The combined results of Experiments

1 and 2 revealed that a single practice session promotes the

development of a multiple coding representation of the

motor skill, while the parsing of practice into multiple

sessions restricts the development of the intrinsic coding

system. This demonstrates that the long-lasting multises-

sion practice improvements cannot be conceptualised as

the sum of incremental gains expressed following single

practice sessions. That is, we postulate that distinct long-

lasting practice gains would be observed depending on

whether the amount of acquisition trials is performed

during a unique single practice session or over multiple

practice sessions.

Furthermore, we showed in Experiment 1 that the long-

term representation of the motor skill underwent qualitative

changes when comparing participants who rehearsed

retention and transfer tests (RT condition) with those who

only performed single delayed retention and transfer tests

(NRT condition). In accordance with previous research in

the testing-effect literature (e.g., Butler, 2010; Rohrer et al.,

2010), our results revealed that testing rehearsal promotes

the development of a multiple coding representation of the

motor task. This suggests that each of the extrinsic and

intrinsic codes potentially contribute to retention and

transfer performance (see also Kovacs et al., 2009). Thus,

performing several practice sessions could sustain the

development of a multiple coding representation based on

extrinsic and intrinsic components, but only when partici-

pants rehearsed retention and transfer tests between-prac-

tice sessions. In this condition, the retention and transfer

performances were determined by multiple coding systems

that acted together to enhance motor skill performance

rather than the pure dominance of a single most salient

coding system.

Our results in Experiment 1 suggest that the reactivation

and updating of existing consolidated motor memories (i.e.,

during the initial retention and transfer tests, respectively)

may be critical for further memory modifications.

1 1. We compared retention and transfer performances of the NRT

groups following a prolonged practice session arranged in a single

and multisession format (Experiments 2 and 1, respectively). We

conducted a 2 (practice formats: multisession, single session) 9 3

(tests: retention, extrinsic transformation, intrinsic transformation)

ANOVA with repeated measures on test using data from the NRT

groups. The analysis revealed a main effect of test, F(2, 56) = 18.28,

gp2 = 0.39, and a practice format 9 test interaction, F(2, 56) = 3.46,

gp2 = 0.11. Duncan’s multiple range test indicated that RMSE was

significantly higher on the intrinsic transformation test following

multisession practice (M = 79.06) than following a single practice

session (M = 66.96). No performance difference was observed

between groups on the retention (M = 56.20 and 50.59 following a

single and multisession practice, respectively) and extrinsic transfor-

mation tests (M = 65.69 and 68.06 following a single and multises-

sion practice, respectively). The main effect of practice format was

not significant, F(1, 28) \ 1.

622 Psychological Research (2012) 76:611–625

123

Likewise, recent research suggests that following their

initial acquisition and consolidation, memories can be

further modified (reconsolidated) after being reactivated

during retrieval or after additional practice. Specifically,

the reactivation of an existing motor memory yields addi-

tional strengthening and off-line gains (Walker et al. 2003).

This process, known as ‘‘reconsolidation’’ (e.g., Dudai &

Eisenberg, 2004; Przybyslawski & Sara, 1997; Stickgold &

Walker, 2007), has been suggested to enable the updating

of the internal neural representation of a previously

acquired memory (e.g., Dudai, 2006; Sara, 2000). The

phenomenon of memory reconsolidation led Censor et al.

(2010) to propose a model for human motor memory

modification. This model differentiates between what the

authors referred to as the ‘‘executing storage domain’’

(primary motor cortex) and the ‘‘core storage domain’’. The

brain areas supposed to be involved as a part of the core

storage domain which may include the cerebellum, stria-

tum and/or other motor-related cortical areas (e.g., Doyon,

Song, Karni, Lalonde, Adams, & Ungerleider, 2002;

Ungerleider, Doyon, & Karni 2002; Shadmehr & Holcomb,

1997) and the hippocampus (e.g., Albouy, Sterpenich,

Balteau, Vandewalle, Desseilles, Dang-Vu, et al., 2008).

According to this model, when the memory is reactivated,

recurrent output from the core storage domain to the exe-

cuting storage domain (which interacts with the environ-

ment) enables further memory modifications. In light of

this model, our findings suggest that testing rehearsal, when

combined to more than a single practice session, enables

the modification of existing consolidated motor memories.

This implies that testing rehearsal influences the repre-

sentation of motor skills through the process of memory

reconsolidation.

Finally, the present findings demonstrated that the

combination of practice and testing sessions provides

greater effector transfer capacities than does practice

alone–an important finding in light of the potential

behavioural and motor-related applications of the testing

effect. Indeed, our findings are important not only for

theoretical but also for practical reasons related to training

protocols designed to improve learning, as in the case

where one limb is injured, for instance. From a practical

standpoint, this research has the potential to impact the

design of training and learning therapy programs, and thus

to (re)shape the development of new learning and

relearning programs. More specifically, when elaborating

training protocols on multiple practice sessions, alternating

practice and testing sessions seems to be the best condition

for long-lasting retention of skill memories and for

enhancing transfer capacities. Obviously, the benefits of

testing rehearsal on motor skill transfer have yet to be fully

exploited.

Summary

Our findings revealed that practice does trigger rapid

(within-practice) and latent (between-practice) reorganisa-

tions of the new motor skill representation, yielding distinct

transfer capacities. While the extrinsic component of the

motor skill develops early and remains the dominant cod-

ing system during practice, we showed that practice leads

to the off-line development of distinct coding systems.

Only few practice trials induces an off-line development of

the extrinsic component of the motor skill, whereas

extensive practice subserves the off-line development of

the intrinsic component. Another important finding is that

practice makes transfer of motor skills imperfect, irre-

spective of the amount of acquisition trials and the practice

session format (single session vs. multisession practice).

Our results indicated, however, that the alternation between

practice and testing sessions provides greater transfer

capacities than does the mere repetition of practice

sessions.

Acknowledgments This work was supported by a grant from the

German Research Foundation (PA 774/8-1) and the Agence Nationale

de la Recherche (ANR-08-FASHS-14).

References

Albouy, G., Sterpenich, V., Balteau, E., Vandewalle, G., Desseilles,

M., Dang-Vu, T., et al. (2008). Both the hippocampus and

striatum are involved in consolidation of motor sequence

memory. Neuron, 58, 261–272.

Bapi, R. S., Doya, K., & Harner, A. M. (2000). Evidence for effector

independent and dependent representations and their differential

time course of acquisition during motor sequence learning.

Experimental Brain Research, 132, 149–162.

Boutin, A., Fries, U., Panzer, S., Shea, C. H., & Blandin, Y. (2010).

Role of action observation and action in sequence learning and

coding. Acta Psychologica, 135, 240–251.

Brainard, D. H. (1997). The psychophysics toolbox. Spatial Vision,10, 433–436.

Butler, A. C. (2010). Repeated testing produces superior transfer of

learning relative to repeated studying. Journal of ExperimentalPsychology. Learning, Memory, and Cognition, 36, 1118–1133.

Carpenter, S. K. (2009). Cue strength as a moderator of the testing

effect: The benefits of elaborative retrieval. Journal of Exper-imental Psychology. Learning, Memory, and Cognition, 35,

1563–1569.

Censor, N., Dimyan, M. A., & Cohen, L. G. (2010). Modification of

existing human motor memories is enabled by primary cortical

processing during memory reactivation. Current Biology, 20,

1545–1649.

Cohen, J. (1988). Statistical power analysis for the behavioralsciences (2nd ed.). Hilsdale, Nj: Erlbaum.

Cohen, D. A., Pascual-Leone, A., Press, D. Z., & Robertson, E. M.

(2005). Off-line learning of motor skill memory: a double

dissociation of goal and movement. Proceedings of the NationalAcademy of Sciences of the United States of America, 102,

18237–18241.

Psychological Research (2012) 76:611–625 623

123

Colby, C. L., & Goldberg, M. E. (1999). Space and attention in

parietal cortex. Annual Review of Neuroscience, 22, 319–349.

Criscimagna-Hemminger, S. E., Donchin, O., Gazzaniga, M. S., &

Shadmehr, R. (2003). Learned dynamics of reaching movements

generalize from dominant to nondominant arm. Journal ofNeurophysiology, 89, 168–176.

Diekelmann, S., & Born, J. (2010). The memory function of sleep.

Nature Reviews Neuroscience, 11, 114–126.

Doyon, J., Song, A. W., Karni, A., Lalonde, F., Adams, M. M., &

Ungerleider, L. G. (2002). Experience-dependent changes in

cerebellar contributions to motor sequence learning. Proceedingsof the National Academy of Sciences of the United States ofAmerica, 99, 1017–1022.

Dudai, Y. (2006). Reconsolidation: the advantage of being refocused.

Current Opinion in Neurobiology, 16, 174–178.

Dudai, Y., & Eisenberg, M. (2004). Rites of passage of the engram:

reconsolidation and the lingering consolidation hypothesis.

Neuron, 44, 93–100.

Hikosaka, O., Nakahara, H., Rand, M. K., Sakai, K., Lu, X.,

Nakamura, K., et al. (1999). Parallel neural networks for

learning sequential procedures. Trends in Neuroscience, 22,

464–471.

Hikosaka, O., Rand, M. K., Nakamura, K., Miyachi, S., Kitaguchi, K.,

Sakai, K., et al. (2002). Long-term retention of motor skill in

macaque monkeys and humans. Experimental Brain Research,147, 494–504.

Karni, A., Meyer, G., Jezzard, P., Adams, M. M., Turner, R., &

Ungerleider, L. G. (1995). Functional MRI evidence for adult

motor cortex plasticity during motor skill learning. Nature, 377,

155–158.

Karni, A., Meyer, G., Rey-Hipolito, C., Jezzard, P., Adams, M. M.,

Turner, R., et al. (1998). The acquisition of skilled motor

performance: fast and slow experience-driven changes in

primary motor cortex. Proceedings of the National Academy ofSciences of the United States of America, 95, 861–868.

Keele, S. W., Ivry, R., Mayr, U., Hazeltine, E., & Heuer, H. (2003).

The cognitive and neural architecture of sequence representation.

Psychological Review, 110, 316–339.

Keele, S. W., Jennings, P., Jones, S., Caulton, D., & Cohen, A.

(1995). On the modularity of sequence representation. Journal ofMotor Behavior, 27, 17–30.

Kleiner, M., Brainard, D., & Pelli, D. G. (2007). What’s new in

Psychtoolbox-3? Perception, 36 (ECVP Abstract Supplement).

Korman, M., Raz, N., Flash, T., & Karni, A. (2003). Multiple shifts in

the representation of a motor sequence during the acquisition of

skilled performance. Proceedings of the National Academy ofSciences of the United States of America, 100, 12492–12497.

Kovacs, A. J., Boyle, J., Gruetzmatcher, N., & Shea, C. H. (2010).

Coding of on-line and pre-planned movement sequences. ActaPsychologica, 133, 119–126.

Kovacs, A. J., Han, D.-W., & Shea, C. H. (2009a). The representation

of movement sequences is related to task characteristics. ActaPsychologica, 132, 54–61.

Kovacs, A. J., Muehlbauer, T., & Shea, C. H. (2009b). The coding of

movement sequences. Journal of Experimental Psychology:Human Perception and Performance, 35, 390–407.

Krakauer, J. W., Ghilardi, M. F., & Ghez, C. (1999). Independent

learning of internal models for kinematic and dynamic control of

reaching. Nature Neuroscience, 2, 1026–1031.

Krakauer, J. W., & Shadmehr, R. (2006). Consolidation of motor

memory. Trends in Neurosciences, 29, 58–64.

Lange, R. K., Godde, B., & Braun, C. (2004). EEG correlates of

coordinate processing during intermanual transfer. ExperimentalBrain Research, 159, 161–171.

Li, C. S. R., Padoa-Schioppa, C., & Bizzi, E. (2001). Neuronal

correlates of motor performance and motor learning in the

primary motor cortex of monkeys adapting to an external force

field. Neuron, 30, 593–607.

McDaniel, M. A., & Masson, M. E. J. (1985). Alterning memory

representations through retrieval. Journal of Experimental Psy-chology. Learning, Memory, and Cognition, 11, 371–385.

McDaniel, M. A., Roediger, H. L., I. I. I., & McDermott, K. B.

(2007). Generalizing test-enhanced learning from the laboratory

to the classroom. Psychonomic Bulletin & Review, 14, 200–206.

McGaugh, J. L. (2000). Memory—a century of consolidation.

Science, 287, 248–251.

Panzer, S., Krueger, M., Muehlbauer, T., Kovacs, A. J., & Shea, C. H.

(2009). Inter-manual transfer and practice: coding of simple

motor sequences. Acta Psychologica, 131, 99–109.

Pelli, D. G. (1997). The VideoToolbox software for visual psycho-

physics: transforming numbers into movies. Spatial Vision, 10,

437–442.

Przybyslawski, J., & Sara, S. J. (1997). Reconsolidation of memory

after its reactivation. Behavioural Brain Research, 84, 241–246.

Robertson, E. M. (2009). From creation to consolidation: A novel

framework for memory processing. PLoS Biology, 7, 11–19.

Robertson, E. M., Pascual-Leone, A., & Miall, R. C. (2004a). Current

concepts in procedural consolidation. Nature Reviews Neurosci-ence, 5, 576–582.

Robertson, E. M., Pascual-Leone, A., & Press, D. Z. (2004b).

Awareness modifies the skill-learning benefits of sleep. CurrentBiology, 14, 208–212.

Robertson, E. M., Press, D. Z., & Pascual-Leone, A. (2005). Off-line

learning and the primary motor cortex. The Journal of Neuro-science, 25, 6372–6378.

Roediger, H. L., I. I. I., & Butler, A. C. (2010). The critical role of

retrieval practice in long-term retention. Trends in CognitiveSciences, 15, 20–27.

Roediger, H. L., I. I. I., & Karpicke, J. D. (2006a). Test-enhanced

learning: taking memory tests improves long-term retention.

Psychological Science, 17, 249–255.

Roediger, H. L., I. I. I., & Karpicke, J. D. (2006b). The power of

testing memory: basic research and implications for educational

practice. Perspectives on Psychological Science, 3, 181–210.

Rohrer, D., Taylor, K., & Sholar, B. (2010). Tests enhance the

transfer of learning. Journal of Experimental Psychology.Learning, Memory, and Cognition, 36, 233–239.

Sainburg, R. L. (2005). Handedness: differential specializations for

control of trajectory and position. Exercise and Sport SciencesReviews, 33, 206–213.

Sanes, J. N., & Donoghue, J. P. (2000). Plasticity and primary motor

cortex. Annual Review of Neuroscience, 23, 393–415.

Sara, S. J. (2000). Retrieval and reconsolidation: toward a neurobi-

ology of remembering. Learning and Memory, 7, 73–84.

Shadmehr, R., & Holcomb, H. H. (1997). Neural correlates of motor

memory consolidation. Science, 277, 821–825.

Soechting, J. F., & Flanders, M. (1989). Errors in pointing are due to

approximations in sensorimotor transformations. Journal ofNeurophysiology, 62, 595–608.

Steele, C. J., & Penhune, V. B. (2010). Specific increases within

global decreases: a functional magnetic resonance imaging

investigation of five days of motor sequence learning. TheJournal of Neuroscience, 30, 8332–8341.

Stickgold, R., & Walker, M. P. (2007). Sleep-dependent memory

consolidation and reconsolidation. Sleep Medicine, 8, 331–343.

Stockel, T., Weigelt, M., & Krug (2011). Acquisition of a complex

basketball dribbling task in school children as a function of

bilateral practice order. Research Quarterly for Exercise andSport, 82, 188–197.

Trempe, M., & Proteau, L. (2010). Distinct consolidation outcomes in

a visuomotor adaptation task: off-line leaning and persistent

after-effect. Brain and Cognition, 73, 135–145.

624 Psychological Research (2012) 76:611–625

123

Ungerleider, L. G., Doyon, J., & Karni, A. (2002). Imaging brain

plasticity during motor skill learning. Neurobiology of Learningand Memory, 78, 553–564.

Walker, M. P., Brakefield, T., Hobson, J. A., & Stickgold, R. (2003).

Dissociable stages of human memory consolidation and recon-

solidation. Nature, 425, 616–620.

Walker, M. P., & Stickgold, R. (2004). Sleep-dependent learning and

memory consolidation. Neuron, 44, 121–133.

Wang, J., & Sainburg, R. L. (2006). Interlimb transfer of visuomotor

rotations depends on handedness. Experimental Brain Research,175, 223–230.

Wheeler, M. A., Ewers, M., & Buonanno, J. F. (2003). Different rates

of forgetting following study versus test trials. Memory, 11,

571–580.

Witt, K., Margraf, N., Bieber, C., Born, J., & Deuschl, G. (2010).

Sleep consolidates the effector-independent representation of a

motor skill. Neuroscience, 171, 227–234.

Psychological Research (2012) 76:611–625 625

123