Post on 03-Feb-2023
www.elsevier.com/locate/cogbrainres
Cognitive Brain Researc
Research Report
Indexing strategic retrieval of colour information with
event-related potentials
E.L. Wilding*, C.S. Fraser, J.E. Herron
School of Psychology, Cardiff University, Cardiff, CF10 3AT Wales, UK
Accepted 9 April 2005
Available online 31 May 2005
Abstract
Event-related potentials (ERPs) were acquired during two experiments in order to determine boundary conditions for when recollection of
colour information can be controlled strategically. In initial encoding phases, participants saw an equal number of words presented in red or
green. In subsequent retrieval phases, all words were shown in white. Participants were asked to endorse old words that had been shown at
encoding in one colour (targets), and to reject new test words as well as old words shown in the alternate colour (non-targets). Study and test
lists were longer in Experiment 1, and as a result, the accuracy of memory judgments was superior in Experiment 2. The left-parietal ERP
old/new effect—the electrophysiological signature of recollection—was reliable for targets in both experiments, and reliable for non-targets
in Experiment 1 only. These findings are consistent with the view that participants were able to restrict recollection to targets in Experiment 2,
while recollecting information about targets as well as non-targets in Experiment 1. The fact that this selective strategy was implemented in
Experiment 2 despite the close correspondence between the kinds of information associated with targets and non-targets indicates that
participants were able to exert considerable control over the conditions under which recollection of task-relevant information occurred.
D 2005 Elsevier B.V. All rights reserved.
Theme: Neural basis of behaviour
Topic: Learning and memory systems and functions
Keywords: Event-related potential; Colour information; Episodic memory; Recollection; Exclusion task
1. Introduction
Studies of retrieval from episodic memory in which
event-related potentials (ERPs) were recorded have led to
the identification of several modulations of scalp-recorded
neural activity that index distinct classes of retrieval process
(for reviews, see [16,43,53]). The most common contrast in
ERP studies of memory retrieval is between the electrical
activity that is evoked by old (previously studied) and new
items to which correct memory judgments have been made.
The differences revealed by these contrasts will be referred
to here as ERP old/new effects.
0926-6410/$ - see front matter D 2005 Elsevier B.V. All rights reserved.
doi:10.1016/j.cogbrainres.2005.04.012
* Corresponding author. Fax: +44 2920874858.
E-mail address: wildinge@cardiff.ac.uk (E.L. Wilding).
URL: http://www.cardiff.ac.uk/psych/home/wildinge/index.html
(E.L. Wilding).
There is a family of old/new effects, and the individual
effects are distinguishable on the basis of their time courses,
scalp distributions, and sensitivity to experimental variables
[11]. The old/new effect to which probably the most attention
has been paid is largest at parietal electrode locations,
typically larger over the left than the right hemisphere, and
comprises a relatively greater positivity for old than for new
test items to which correct judgments have been made [37].
This left-parietal ERP old/new effect onsets approximately
500 ms post-stimulus, and commonly lasts between 200 and
700 ms, the duration being influenced by task demands [10].
It is now widely accepted that the left-parietal ERP old/
new effect indexes recollection (for recent discussion, see
[5,15]). Recollection is defined here as successful recovery
of contextual information about a prior event [56], which
might include one or more of information sources such as
where or when the event occurred, the modality through
h 25 (2005) 19 – 32
E.L. Wilding et al. / Cognitive Brain Research 25 (2005) 19–3220
which information was perceived, and/or what actions were
completed during the event [28].
The data that support the link between the parietal effect
and recollection include the following: (1) patients with
deficits in recollection (as revealed by behavioural mea-
sures) exhibit attenuated or absent left-parietal ERP old/new
effects relative to appropriately matched controls [13,39,
46,47]; (2) the magnitude of the effect is correlated
positively with the amount of contextual information that
is retrieved, as inferred from the numbers of correct source
judgments that are made on retrieval tasks [50,51]; and (3)
the effect is larger for correct old judgments associated with
Remember (R) rather than with Know (K) judgments
[12,45]. R judgments are held to be based upon recollection
while K judgments are not [13].
While this brief summary provides arguably a compelling
case for a link between the parietal old/new effect and
recollection, some recent findings, at least at a first pass, jar
with this account. These findings have come from exclusion
tasks [23,24], in which ERPs were acquired time-locked to
test stimuli. In the study phases of exclusion tasks, items are
typically associated with one of two contexts. In subsequent
retrieval phases, items associated with one context are
designated as targets, while items from the other are
designated as non-targets. Participants are asked to respond
on one key to targets, and on another to non-targets as well as
to genuinely new test items. The exclusion task was
introduced as one component of the process-dissociation
procedure (PDP; [23–25]), and while the details of that
procedure are not important here, the critical point for present
purposes is that accurate target/non-target judgments have
been assumed to be based upon recollection of information
associated with targets and with non-targets [23].
If this assumption is correct, then correct target as well as
non-target judgments will be accompanied by reliable left-
parietal ERP old/new effects. In one recent study, however,
Herron and Rugg [20] reported a somewhat different pattern
of effects. They acquired ERPs during the retrieval phases
of two exclusion tasks. For both experiments, the first
encoding phase involved generating sentences incorporating
single words that were presented at study, while the second
encoding phase differed across the two experiments. In the
first experiment, participants rated words for pleasantness,
while in the second, participants were asked simply to read
words aloud. Targets were designated as words that were
rated for pleasantness in Experiment 1, and words that were
read aloud in Experiment 2. Thus, the non-targets were
associated with the same encoding task in both experiments,
and while reliable parietal ERP old/new effects were obtained
for targets in both experiments, for non-targets, a reliable left-
parietal effect was revealed in Experiment 2 only.
This finding is striking, because in both experiments,
the information associated with non-targets is likely to be
highly similar, since they were encoded using the same
task (sentence generation), and in keeping with this
observation, the accuracy of non-target judgments was
equivalent in the two experiments. To the extent that
participants were equally likely to have recollected non-
targets in both experiments, therefore, the absence of a
left-parietal ERP old/new effect in Experiment 1 might be
seen to call into question the link between the parietal ERP
old/new effect and recollection (see also [21]).
Whether these results challenge current views of the
functional significance of the left-parietal ERP old/new
effect, however, depends upon the assumption that partici-
pants did in fact recollect information about non-targets
equally often in the two experiments. Herron and Rugg
[20] questioned this assumption, noting that recollection of
non-targets is not always necessary for successful comple-
tion of the exclusion task. The reason for this is that the
failure to recollect information that would identify a test
item as a target is one basis upon which a correct response
to non-targets and new words can be made. Herron and
Rugg [20] suggested that implementation of this strategy
was the reason for the absence of the non-target old/new
effects in Experiment 1: participants were successful in
restricting recollection to information diagnostic of the
target status of an item and did not recollect information
about non-targets.
In extending this account to explain why non-targets
were associated with a reliable left-parietal ERP old/new
effect in Experiment 2, Herron and Rugg noted that the
reliability of the strategy described above decreases along
with the likelihood of recollecting information about targets.
They noted that target judgments in Experiment 2 were less
accurate than in Experiment 1 and proposed that because of
this, participants attempted to recollect information about
both targets and non-targets in order to ensure successful
completion of the task.
There are several implications of the findings of Herron
and Rugg, one of which is the way in which these data impact
on assumptions concerning the use of the exclusion task and
the process-dissociation procedure [20,24,57,58]. A second
implication, and the principal focus here, concerns the
boundary conditions for when a strategy of recollecting
information associated with targets only can be implemented.
The experiments that are presented here are concerned with
these boundary conditions, and are motivated by findings
suggesting that under some circumstances, even when the
accuracy of target judgments is relatively high, recollection
of information associated with non-targets occurs. The
critical data come from studies in which the target/non-target
distinction was based upon study voice (male or female;
[52,54]) or the colour in which pictures were presented at
study (red or green; [7–9]). In the case of both of these
manipulations, and in contrast to the findings of Herron and
Rugg described previously, the researchers have reported
reliable non-target ERP old/new effects (also see [19]).
One way to reconcile these findings is to assume that the
precision with which recollection can be controlled depends
upon the relationship between the information that either is
or is not to be recollected. That is, in the case of the voice
E.L. Wilding et al. / Cognitive Brain Research 25 (2005) 19–32 21
and colour studies described above, one explanation for the
presence of the non-target ERP old/new effects is that the
high degree of similarity between the target and non-target
information precluded the restriction of recollection to
information associated with targets only. In Experiment 1
of Herron and Rugg [20], meanwhile, the cognitive opera-
tions underlying sentence generation and ratings for
pleasantness were sufficiently distinct to permit recollection
to be restricted to the latter only.
While this explanation for the colour and voice data is
reasonable, the majority of the foregoing inferences about
the conditions under which recollection of non-targets
occurs in the colour and voice studies are based only on
informal observations of the correspondences between
electrophysiological as well as behavioural data across
studies. In the case of the colour and voice data, moreover,
the published non-target old/new effects have, at least on the
basis of visual inspection, been of smaller magnitude than
the target old/new effects. The reason that this is important
is that this pattern of findings raises the possibility that
larger non-target old/new effects (relative to target old/new
effects) might be obtained as target accuracy—hence, the
likelihood of target recollection—decreases. This pattern of
findings would be consistent with the view that at least
partial control of recollection of non-target material can be
exerted even when the information associated with targets
and with non-targets corresponds closely. There are, how-
ever, no studies to date in which the outcomes of the
appropriate contrasts—those between target and non-target
old/new effects for the same kinds of perceptual information
and separated according to levels of target accuracy—have
been reported.
The two experiments presented here were designed in
order to address this disparity, and in both experiments, the
colour of visually presented words was the contextual
information that was designated as being important for the
target/non-target distinction in subsequent retrieval phases.
The two experiments differed only in the number of study–
test cycles and the number of words per cycle. Experiment 1
contained fewer study–test blocks and more study and test
words per block than Experiment 2. This difference was
introduced in order to encourage more accurate performance
in Experiment 2, thereby permitting an analysis of the
left-parietal ERP old/new effects for the same forms of
information under conditions in which target accuracy
differed.
In addition, the lengths of study and test lists in the two
experiments were set at a level that ensured the accuracy of
target judgments was higher (Experiment 2) and lower
(Experiment 1) than in the majority of previous ERP studies
in which voice or colour has been the source of information
on which target/non-target judgments were to be made.
Non-target left parietal ERP old/new effects of smaller
amplitude in Experiment 2 than Experiment 1 (relative to
the relevant target effects in each case) would suggest that
participants can exert some degree of control over recollec-
tion of colour information even under conditions where
target recollection also depends on accessing colour
information. Equivalent non-target ERP old/new effects
across the two experiments would provide important
information concerning limits on the resolution with which
control over recollection can be exerted.
2. Methods
Due to the similarity of the two experiments, they are
described jointly.
2.1. Participants
Twenty participants (12 female, mean age = 21 years)
took part in Experiment 1. The data from two participants
(one male) were discarded due to insufficient trials in at
least one response category of interest because of excessive
EOG artefacts. Eighteen participants (eight female, mean
age = 22 years) took part in Experiment 2. No participant
took part in both experiments. All participants had normal or
corrected to normal vision and were right-handed, as
assessed by writing-hand. No participants reported suffering
from red/green colour blindness, all were native English
speakers, and each gave informed consent before complet-
ing the task. The data for Experiment 1 were collected prior
to the data for Experiment 2.
2.2. Materials
The stimuli comprised low-frequency words (MRC
psycholinguistic database: frequency 1–9/million); 240
words were used in Experiment 1 and 180 words were
used in Experiment 2. All words were open-class and
ranged between four and nine letters in length. Words were
presented visually on a monitor 1.2 m from the participant,
in red or green text in the study phases and white text in the
test phases. A black background was used during all study
and test phases. The stimuli subtended maximum visual
angles of 0.5- (vertical) and 2.2- (horizontal).
2.3. Design and procedure
Participants were fitted with an electrode cap before the
experiment (see below) and were seated in a sound-
attenuated room facing a monitor with their thumbs resting
on two response keys. There was a short practice session
before the experiment and short breaks between each
study–test cycle. There were 8 study–test cycles in Expe-
riment 1, and 12 cycles in Experiment 2. In Experiment 1,
the 240 words were divided randomly into 8 equal blocks,
creating 8 study–test cycles each containing 20 study words
and 30 test words (an equal number of old red, old green
and new words). In Experiment 2, the 180 words were
divided randomly into 12 equal blocks creating 12 study–
1 These and all subsequent analyses of variance incorporated the
Geisser–Greenhouse correction for non-sphericity where necessary [18].
Corrected degrees of freedom are shown where appropriate.
E.L. Wilding et al. / Cognitive Brain Research 25 (2005) 19–3222
test cycles, each containing 10 study words and 15 test
words (again, an equal number of old red, old green, and
new words). In both experiments, the words in each block
were rotated so that, across participants, each word was
encountered as an old red word, an old green word, and a
new word. This manipulation resulted in the creation of
three complete task-lists in each experiment, and an equal
number of participants completed each list. The order of
word presentation at both study and test within each study–
test cycle of each list was determined randomly for each
participant.
Prior to commencing the experiments, participants were
informed that, in each study cycle, they would see some
words presented in red and some in green, and that they
were to make key presses with either their right or left hand
based upon the colour in which the words were presented.
They were instructed that, in each test phase, words
presented in one colour at study (targets) would require a
key press with one hand, while a key press with the other
hand would be required for words presented in the other
colour (non-targets) as well as for words that were new to
the experiment. Participants were also informed that target
designation would only be revealed at the start of each test
phase, and that no words would appear in more than one
study–test cycle.
In both experiments, each study trial began with an
asterisk (*), which was displayed for 500 ms and followed by
a blank screen (200 ms), after which the study word was
presented for 300 ms. Half of the study words were presented
in red/green in a random order. Participants indicated the
colour in which each word was presented, and the next trial
began 500 ms after the response. An interval of approxi-
mately 1 min intervened between each study and test phase,
during which participants were informed of the Ftarget_response requirements for the test phase.
Each test trial also began with an asterisk (500 ms
duration), and 200 ms then intervened before the presen-
tation of a test word. Each word was visible for 300 ms
and then the screen remained blank until 500 ms after the
response of the participant, at which time the asterisk
signalling the start of the next trial appeared. Participants
were asked to make a target or non-target/new judgement
via key press when each test word appeared. For each
participant, the first half of the study–test cycles (4 in
Experiment 1 and 6 in Experiment 2) had the same target
designation (red or green) and the remainder had the
alternate designation. Blocking of designation was
employed in order to reduce the number of times in
which the response requirements changed for participants
during the experiments. The order of target designation
was balanced across participants, as were the hands
required for the binary red/green judgment at study and
the binary target/non-target/new judgment at test. Partici-
pants were encouraged to respond while balancing speed
and accuracy equally. Test responses faster than 650 ms
were treated as errors.
2.4. Electrophysiological recording procedure
EEG was recorded from 25 silver/silver chloride electro-
des housed in an elastic cap. They were located at midline
(Fz, Cz, Pz) and left/right hemisphere locations (FP1/FP2,
F7/F8, F5/F6, F3/F4, T3/T4, C5/C6, C3/C4, T5/T6, P5/P6,
P3/P4, O1/O2). Additional electrodes were placed on the
mastoid processes, and in Experiment 2, a further electrode
was placed on the nose-tip. EEG was recorded continuously
at 166 Hz (6 ms per point) with Fz as the reference
electrode, and was re-referenced computationally off-line to
a linked mastoid reference into epochs of 1536 ms (256 data
points), each including a 102-ms pre-stimulus baseline
relative to which all post-stimulus amplitudes were mea-
sured. EOG was recorded from above and below the right
eye (VEOG) and from the outer canthi (HEOG). Trials
containing large EOG artefact were rejected, as were trials
containing A/D saturation or baseline drift exceeding T80AV. Other EOG blink artefacts were corrected using a linear
regression estimate [44].
Averaged ERPs were formed for correct judgments at test
to target, non-target, and new words for each participant in
each experiment. Participants were excluded if they did not
contribute at least 16 artefact-free trials to each response
category [51,55]. The ERPs were collapsed across colour,
on the basis of null results for this factor in preliminary
analyses of both the behavioural and the electrophysiolog-
ical data (in keeping with the findings of Cycowicz et al.
[8]). On average, less than 20% of trials per participant per
response category were rejected due to artefact. In Exper-
iment 1, the mean numbers of trials per category were 39,
47, and 65 for correct responses to target, non-target, and
new words, respectively. The equivalent values in Experi-
ment 2 were 39, 40, and 50. The averaged ERPs for each
participant and for each category of interest in each
experiment were subjected to a 7-point binomially weighted
smoothing filter prior to analysis.
3. Results
3.1. Behavioural data
The probabilities of correct responses to red and green
words during the study phases of both experiments were
high and statistically equivalent, as assessed by ANOVA1
with between and within factors of experiment and colour,
respectively (Experiment 1: red = 0.98, green = 0.99;
Experiment 2: red = 0.99, green = 0.99). In two further
analyses, the reaction times for the colour judgments at
study were analysed separated according to whether they
Table 1
Probabilities of correct responses and reaction times (RT) to target, non-
target, and new words in Experiments 1 and 2 (SD in brackets)
Target Non-target New
Experiment 1
P (correct) 0.63 (0.14) 0.76 (0.07) 0.95 (0.05)
RT 1040 (279) 1126 (387) 886 (246)
Experiment 2
P (correct) 0.78 (0.06) 0.82 (0.06) 0.97 (0.02)
RT 977 (258) 1118 (338) 871 (279)
E.L. Wilding et al. / Cognitive Brain Research 25 (2005) 19–32 23
were designated as targets or non-targets in the subsequent
test phase(s). These analyses were restricted to the blocks
where participants had completed three previous blocks with
the same target designation (data from blocks 4 and 8 in
Experiment 1 and data averaged across blocks 4–6 and 10–
12 in Experiment 2). Separate analyses were conducted on
the data from each experiment, including the factors of
subsequent target designation and block (4 vs. 8 in Exp. 1,
4–6 vs. 10–12 in Exp. 2). No reliable effects were revealed
in either analysis. The mean study RTs for targets and non-
targets in Experiment 1 were 875 and 850 ms, respectively,
for block 4, and 865 and 840 ms for block 8. In Experiment
2, the values were 1070 and 1101 ms (blocks 4–6) and 1143
and 1113 ms (blocks 10–12)2. The reason for these
restricted block analyses was to determine whether there
was any evidence to support the view that, as the task
unfolded, participants treated study items differentially,
which might impact upon the patterns of ERP data that
were acquired in subsequent retrieval phases. We return to
this issue in the Discussion.
Table 1 shows the mean probabilities of, and reaction
times (RTs) for, correct responses to target, non-target, and
new words in Experiments 1 and 2. Correct responses to
targets and non-targets will be referred to as target hits and
non-target hits, respectively. The term old words will refer
to targets and non-targets jointly. In each experiment, the
probabilities of a target hit were reliably greater than the
probabilities of a target response to a non-target [Experi-
ment 1: t(17) = 6.85, P < 0.001; Experiment 2: t(17) =
14.89, P < 0.001] or a new word [Experiment 1: t(17) =
13.11, P < 0.001; Experiment 2: t(17) = 31.10, P < 0.001].
The analysis of the accuracy data [factors of experiment
(between) and response category (within)] revealed a main
effect of experiment [F(1,34) = 9.24, P < 0.01] and an
interaction between this factor and category [F(1.6,55.4) =
4.31, P < 0.05]. Post hoc analyses (Newman–Keuls)
revealed that only target accuracy was superior in Experi-
ment 2 to Experiment 1. RT varied according to response
category only [F(1.8,62.4) = 38.40, P < 0.001], and post
hoc analyses revealed that RTs for correct judgments to new
words were reliably faster than those for targets, which were
in turn reliably faster than those for non-targets.
3.2. Results: ERPs
The ERPs from a 3 � 3 array of 9 electrode sites for
Experiments 1 and 2 are shown in Fig. 1. The figure
shows the ERPs associated with correct judgments to
target, non-target, and new words. The fact that this
selection of electrode locations permits inspection of the
principal divergences between response categories is
attested to by the data shown in Fig. 2, which comprises
2 We are grateful to an anonymous referee for suggesting this specific
analysis.
the scalp distributions of the ERP old/new effects for
targets and for non-targets in the two experiments over 4
time windows: 300–500, 500–700, 700–900, and 900–
1400 ms. These scalp maps are derived from the difference
scores obtained by subtracting the ERPs evoked by new
words from those evoked by targets and non-targets,
respectively. Fig. 3 shows the same data as for the lower
half of Fig. 1, with the exception that the data is referenced
to nose-tip. We return to the importance of this figure in
the Discussion.
3.2.1. Analysis of left-parietal ERP old/new effects
The initial directed analysis of the ERPs was conducted
in order to determine the relationships between the left-
parietal ERP old/new effects that were obtained in the two
experiments. This analysis was restricted to the P5 electrode
location, and included the factors of experiment and
response category (correct responses to target, non-target,
and new test words). The analysis revealed an interaction
between these two factors [F(1.8,60.9) = 5.02, P < 0.025]
and was followed up by separate analyses of the target and
non-target ERP old/new effects in each experiment. These
revealed that the ERPs evoked by old words were reliably
more positive than those evoked by new words with the
exception of the non-target vs. new contrast in Experiment 2
[Exp. 1: targets F(1,17) = 48.08, P < 0.001, non-targets
F(1,17) = 14.42, P < 0.01; Exp. 2: targets F(1,17) = 24.40,
P < 0.001, non-targets F < 1]. Target old/new effects were
also reliably larger than non-target effects in both experi-
ments [Experiment 1: F(1,17) = 17.84, P < 0.01;
Experiment 2: F(1,17) = 32.39, P < 0.001].
3.2.2. Global analyses
The directed analyses were followed by a series of
analyses conducted using data from the 9 electrodes shown
in Fig. 1 (F5, Fz, F6, C5, Cz, C6, P5, Pz, P6). The analyses
incorporated the factors of location in the anterior/posterior
(AP: anterior, central, posterior) and left–right (LR: left-
hemisphere, midline, right-hemisphere) planes. They were
conducted separately for each experiment in order to
determine the correspondence between the ERP old/new
effects in these experiments and those reported in previous
studies, as well as to license subsequent between-experi-
ment analyses [42,54]. They were conducted employing
Fig. 1. Grand average ERPs associated with correct judgments to target, non-target, and new words in Experiments 1 (upper panel) and 2. The data are shown
for nine sites at anterior (from left to right: F5, Fz, F6), central (C5, Cz, C6), and posterior (P5, Pz, P6) scalp locations.
E.L. Wilding et al. / Cognitive Brain Research 25 (2005) 19–3224
data from the 300–500, 500–700, 700–900, and 900–1400
ms time windows, selected in order to encompass the
epochs in which ERP old/new effects have been reported
previously (e.g., [54]), as well as to capture the differences
between experiments that are evident in Figs. 1 and 2.
For each experiment, an initial analysis was conducted
incorporating data from all three response categories as well
as the factor of epoch, in addition to the site factors (AP and
LR) described above. Both analyses revealed interactions
between epoch (EP) and response category (RC), including
in each case a four-way interaction between these two
factors, AP and LR [Exp. 1: F(7.4,126.0) = 5.08, P < 0.001;
Exp. 2: F(6.0,101.9) = 2.20, P < 0.05]. For each expe-
riment, these analyses were followed up by paired contrasts
for the data from successive epochs. All other factors were
as described above, and the outcomes of these analyses
(restricted to interactions involving epoch and response
category) are shown in Table 2, where it can be seen that
there are either reliable or marginal interactions between the
relevant factors for each of the paired epoch contrasts.
The purpose of the analyses that included epoch as a
factor (see Table 2) was to establish that the epochs
employed in this analysis section are the ones that likely
separate the ERP data into periods during which reliably
different patterns of ERP old/new effects occurred. In order
to establish the profile of the old/new effects within each
epoch, these initial analyses were followed by separate
analyses within each epoch. The analyses comprised all
possible paired contrasts of the ERPs associated with correct
judgments to targets, non-targets, and new test words (see
Tables 3 and 4: main effects or interaction terms that do not
include the factors of response category are not shown as
they are not the outcomes of principal interest here). The
following description of the outcomes of these analyses is
restricted to the highest-order interactions that were obtained
in each case.
Fig. 2. Scalp distributions of the ERP old/new effects for targets and for non-targets in Experiments 1 and 2. The data are shown for four post-stimulus epochs:
300–500, 500–700, 700–900, and 900–1400 ms. The maps were computed from the scores obtained by subtracting mean amplitudes from the ERPs evoked
by new words from those evoked by targets and non-targets. The paired values below each map denote the maxima and minima of the amplitude differences
between response categories, which can be interpreted relative to the bar on the left-hand side of the figure.
E.L. Wilding et al. / Cognitive Brain Research 25 (2005) 19–32 25
3.2.3. Experiment 1 — see Table 3
For all epochs, the contrasts involving new words
revealed interactions between response category, AP, and
LR. For the 300–500 and 500–700 ms epochs, these
interactions reflect the vertex maximum of the positive-
going ERP old/new effects, and the left-lateralisation of the
Fig. 3. Grand average ERPs associated with correct judgments to target, non-target
as for Fig. 1.
effects at posterior electrodes, as Fig. 2 illustrates. The same
posterior lateralisation is evident in the 700–900 ms epoch,
while at frontal locations over this time window, the small
positive-going old/new effect is distributed relatively more
evenly across the two hemispheres. In the 900–1400 ms
epoch, the right-lateralised ERP old/new effects at anterior
, and new words in Experiment 2, referenced to nose-tip. Electrode locations
Table 2
Results of the paired epoch contrasts between the ERPs evoked by correct judgments to target, non-target, and new words in Experiments 1 and 2
Effect df 300–500 vs. 500–700 500–700 vs. 700–900 700–900 vs. 900–1400
F E F E F E
Experiment 1
EP � RC 2,34 7.79** 0.89 13.75*** 0.94 7.70** 0.78
EP � RC � LR 4,68 3.24* 0.72 12.27*** 0.55 4.13* 0.61
EP � RC � AP 4,68 3.53* 0.54 3.56* 0.44 12.66*** 0.50
EP � RC � AP � LR 8,136 5.42*** 0.45 7.65*** 0.63 2.18& 0.52
Experiment 2
EP � RC 2,34 ns 11.11*** 0.82 ns
EP � RC � LR 4,68 ns 11.68*** 0.70 ns
EP � RC � AP 4,68 ns ns 4.56* 0.51
EP � RC � AP � LR 8,136 2.58& (P = 0.05) 0.45 ns ns
EP = epoch, RC = response category, AP = anterior/central/posterior, LR = left/midline/right. &P < 0.1, *P < 0.05, **P < 0.01, ***P < 0.001, E = epsilon value.
E.L. Wilding et al. / Cognitive Brain Research 25 (2005) 19–3226
locations are accompanied by a negative-going old/new
effect with a posterior midline (Pz) maximum.
The direct contrast between targets and non-targets re-
vealed that the ERPs evoked by targets are more positive-
going from 500 to 900 ms, with this positivity being most
pronounced at the midline for the 500–700 ms epoch,
reflected in a RC � LR interaction. The RC � AP � LR
interaction over the 900–1400 ms epoch reflects the fact that
the greater relative positivity for targets is larger at midline
and right than at left anterior locations, while at Pz, the ERPs
evoked by non-targets are relatively more positive-going.
3.2.4. Experiment 2 — see Table 4
For the target vs. new contrast, the interactions between
RC, AP, and LR from 500 to 900 ms and the marginal
interaction in the 900–1400 ms epoch come about for
similar reasons to those described above for Experiment 1
for the contrasts involving new words. In the 300–500 ms
Table 3
Results of the paired contrasts between ERPs evoked by correct judgments to targe
700–900, and 900–1400 ms epochs
Effect df 300–500 500–700
F E F
Target vs. new
RC 1,17 35.93*** 42.26***
RC � AP 2,34 ns ns
RC � LR 2,34 4.78* 0.88 9.92**
RC � AP � LR 4,68 4.26* 0.69 9.48***
Non-target vs. new
RC 1,17 31.15*** 10.49**
RC � AP 2,34 ns ns
RC � LR 2,34 8.85** 0.86 5.23*
RC � AP � LR 4,68 4.36* 0.57 10.64***
Target vs. non-target
RC 1,17 ns 23.68***
RC � AP 2,34 ns ns
RC � LR 2,34 ns 3.86*
RC � AP � LR 4,68 ns ns
Abbreviations and meanings of symbols are as for Table 2.
epoch, the same three-way interaction reflects the vertex
maximum of the old/new effect. For the non-target versus
new contrast, there were no reliable ERP old/new effects
between 500 and 900 ms. The analyses in the early (300–
500 ms) epoch revealed a main effect of response category
only—despite the apparent anterior maximum of the ERP
old/new effect—and reflects the relatively greater positivity
for non-targets. For the 900–1400 ms epoch, the RC�AP�LR interaction revealed in the non-target vs. new contrast
reflects primarily the fact that the differences between the
ERPs are restricted to midline central and posterior scalp
locations, where the ERPs evoked by new test words are
more positive-going than those evoked by non-targets.
For the target vs. non-target contrast, the RC � AP and
RC � LR interactions for the 300–500 ms epoch reflect the
fact that the greater positivity for targets is smaller at
anterior than at central and posterior locations, and larger at
the midline than at left and right hemisphere locations. For
t, non-target, and new words in Experiment 1 over the 300–500, 500–700
700–900 900–1400
E F E F E
12.80** ns
ns 23.22*** 0.62
0.89 2.97& 0.96 10.26*** 0.99
0.72 6.61** 0.69 8.29*** 0.71
5.62* ns
ns 10.02** 0.68
0.97 3.49* 0.88 4.21* 0.97
0.75 5.35** 0.78 3.20* 0.73
5.21* ns
ns 7.43** 0.64
0.92 ns ns
2.47& 0.63 2.84** 0.75
,
Table 4
Results of the paired contrasts between ERPs evoked by correct judgments to target, non-target, and new words in Experiment 2
Effect df 300–500 500–700 700–900 900–1400
F E F E F E F E
Target vs. new
RC 1,17 51.31*** 14.98** ns ns
RC � AP 2,34 3.04& 0.59 ns ns 4.92* 0.71
RC � LR 2,34 13.37** 0.64 3.15& 0.84 ns 4.03* 0.90
RC � AP � LR 4,68 2.85* 0.70 4.78** 0.66 3.15* 0.74 2.24& 0.73
Non-target vs. new
RF 1,17 13.51** ns ns 4.86*
RC � AP 2,34 ns ns ns 7.49** 0.74
RC � LR 2,34 3.18& 0.91 ns 3.34& 0.99 7.10** 0.92
RC � AP � LR 4,68 ns 2.42& 0.82 ns 3.54** 0.75
Target vs. non-target
RC 1,17 14.56** 14.92** ns 3.71&RC � AP 2,34 5.66* 0.68 16.03*** 0.62 3.56& 0.59 ns
RC � LR 2,34 8.13** 0.84 4.39* 0.93 ns ns
RC � AP � LR 4,68 ns 2.73* 0.81 2.92& 0.60 ns
Abbreviations and meanings of symbols are as for Table 2.
E.L. Wilding et al. / Cognitive Brain Research 25 (2005) 19–32 27
the 500–700 ms epoch, the RC � AP � LR interaction for
the contrast between the two classes of old word is due to
reasons similar to those responsible for the same interaction
term that was revealed in the target vs. new contrast: the fact
that the greater relative positivity for targets is most
pronounced at left hemisphere central and posterior scalp
locations.
3.2.5. Between-experiment analyses
These comprised direct contrasts of the ERP old/new
effects from the two experiments, and were completed on
mean amplitudes computed from subtraction waveforms
obtained by subtracting the ERPs evoked by correct
responses to new words from those evoked by target and
non-target hits. The initial analyses were completed sepa-
rately for targets and for non-targets, and were restricted to
targets for the 500–700 and 700–900 ms epochs as the
within-experiment analyses described above revealed no
reliable old/new effects for non-targets over these epochs in
Experiment 2. The analyses each included factors of
experiment, AP and LR, using the same epochs and electrode
locations described above. Where these analyses revealed
interactions between experiment and scalp locations, they
were followed up by analyses of rescaled data in order to
determine whether the interactions came about because of
differences between the scalp distributions of the ERP old/
new effects, or simply because of amplitude differences [33].
The data were rescaled using the vector length method [33],
and the rescaling was computed over all 25 sites from which
data were collected, although the analyses included the same
factors and electrode locations that were employed for the
data that were analysed prior to rescaling.
For the 300–500 ms epoch, the only reliable effect
involving experiment was an interaction with the LR
dimension for targets [F(1.6,54.2) = 3.83, P < 0.05],
reflecting the fact that the old/new effects in Experiment 1
are larger than those from Experiment 2 at left hemisphere
locations but smaller at the midline. This interaction was not
reliable for the analysis of rescaled data. For the 500–700
and 700–900 ms epochs, the target old/new effects in
Experiment 1 were larger than those from Experiment 2
[500–700: F(1,34) = 5.76, P < 0.05; 700–900: F(1,34) =
8.66, P < 0.01]. For the 900–1400 ms epoch, the contrast
for non-targets revealed a main effect of experiment
[F(1,34) = 4.31, P < 0.05], reflecting the fact that the
positive-going old/new effects at anterior locations were
larger in Experiment 1, while the negative-going effects
at posterior locations were larger in Experiment 2. The
contrast for targets over this epoch revealed an interaction
between experiment and the anterior/posterior dimension
[F(1.4,47.1) = 4.17, P < 0.05], reflecting the fact that while
the negative-going ERP old/new effects at posterior
electrodes differ minimally across experiments, at anterior
electrode locations the positive-going old/new effects are
markedly larger in Experiment 1 than in Experiment 2. This
interaction was not, however, reliable for the analysis of
rescaled data.
4. Discussion
Participants were able to discriminate between targets
and non-targets in both experiments, but the proportion of
correct target judgments was higher in Experiment 2 than in
Experiment 1. This pattern of behavioural data indicates that
participants were able to use recollection of the colour of
study presentation as a basis for distinguishing between
targets and non-targets, and that the amount or quality of
information available for this discrimination was greater in
the second experiment.
E.L. Wilding et al. / Cognitive Brain Research 25 (2005) 19–3228
In and of themselves, however, the behavioural findings in
these experiments do not support unequivocally the assump-
tion that participants recollected information about both
targets and non-targets in order to make judgments at test.
Succeeding or failing in the recollection only of colour
information for targets can also serve as the basis for
distinguishing targets from non-targets and new words
[19,20]. As noted in the Introduction, this strategy becomes
increasingly effective as the likelihood of recollecting
information associated with targets increases, and the analysis
of ERPs evoked by test stimuli in these two experiments
provides an opportunity to assess the contribution of recol-
lection during the completion of exclusion tasks that differed
primarily in terms of the accuracy of target judgments.
Reliable left-parietal ERP old/new effects were obtained
for targets in both experiments, but for non-targets in
Experiment 1 only, suggesting that participants depended
upon recollection of information associated with non-targets
to a greater degree in Experiment 1 than in Experiment 2.
Since the accuracy of task judgments was superior in the
second experiment, this finding is consistent with Herron
and Rugg’s proposal that a strategy of depending primarily
on recollection of target information for task judgments is
employed when the likelihood of recollecting information
about targets is high [14,19,20].
It is also of critical importance here that this evidence for
selective recollection was obtained in tasks where the
principal feature distinguishing targets from non-targets
was colour. Thus, participants were able to restrict recol-
lection of information associated with non-targets, while in
both experiments, recollecting colour information about
targets. These results suggest that a considerable degree of
control can be exerted over what is and what is not
recollected, even under circumstances when there is a close
correspondence between these two classes of information.
A second important aspect of the findings in Experiment
1 is the fact that the left-parietal ERP old/new effect for non-
targets, while reliable, was smaller than the effect for targets.
This finding raises the possibility that, while relying on
recollection of non-target colour information to a greater
extent in Experiment 1 than Experiment 2, participants in
Experiment 1 also relied upon recollection of target colour
information to a greater degree than upon recollection of
non-target colour information. This could have come about
because of variability within participants with respect to the
retrieval strategy that was adopted during the course of the
retrieval phases, or because of variability across participants,
whereby some but not all participants in Experiment 1
depended solely upon the success or failure of recollection
of colour information about targets in order to make task
judgments [52,54].
While the present data do not permit a clear separation of
these alternatives, the accuracy of either does not challenge
two central claims. First, that the degree of dependence
upon recollection of colour information associated with non-
targets is correlated inversely with the accuracy of target
judgments. Second, that this strategic control of retrieval can
occur despite an apparently close correspondence between
the sources of information associated with targets and with
non-targets.
Whether the same conclusions hold for auditory source
information remains to be determined. As noted in the
Introduction, reliable non-target ERP old/new effects were
reported by Wilding and Sharpe [54] in two experiments
where target designation was based on the voice (male/
female) in which words were spoken at study and target
accuracy was�0.70. Whether these non-target effects would
be attenuated as accuracy increased to the levels achieved by
participants in Experiment 1 is a question for future research,
as is the question of whether there are other forms of
information for which selective recollection does not or
cannot occur during completion of the exclusion task [21].
It is also important to note that the analyses of the study-
phase RT data provide no support for the possibility that
some of the differences between the ERPs at test in Expe-
riments 1 and 2 came about because of differential encoding
of targets and of non-targets. In both experiments, the
colour of words designated as targets was changed halfway
through the experiment—after four study–test blocks in
Experiment 1 and 6 study–test blocks in Experiment 2.
Participants were not informed of target designation until
the start of each test phase, they were not informed of the
total number of study–test blocks in each experiment, and
they were told that target designation might change for each
retrieval phase. Despite these aspects of the design,
however, the possibility remains that participants made
assumptions about likely target designation and encoded
information at study differentially on the basis of these
assumptions.
In order to assess this possibility, the RTs for words
presented during the study phases in the blocks where the
same target designation had been required in the three
preceding blocks were analysed after being separated
according to whether they were designated subsequently
as targets or non-targets. The analyses revealed no effects
involving block position or target designation, a finding
consistent with the view that the differences between the
ERPs at test can be ascribed to factors operating at retrieval
rather than at encoding2. Support for the claim that the test
data is a function of strategies adopted at test also stems
from the fact that qualitatively similar patterns of target and
non-target ERP old/new effects have been obtained in
studies where there was only one study phase [20,21].
A second challenge for the conclusions drawn above
stems from the consideration that there may be variations
across the two experiments in the levels of confidence
associated with task judgments. Johnson et al. [29] reported
that ERPs elicited during a recognition memory task may be
sensitive to variations in response confidence, and in their
study, these variations manifested themselves as an increased
positivity with increasing confidence, the effects being
largest at left-central scalp locations (see also [15]). Due to
E.L. Wilding et al. / Cognitive Brain Research 25 (2005) 19–32 29
the fact that these modulations linked with decision confi-
dence were identified at scalp locations and in time periods
(¨500–900 ms post-stimulus) that overlap with those in
which the left-parietal ERP old/new effect is typically
observed, it is possible that variations in decision confidence
may be responsible for the patterns of ERP old/new effects
that were obtained in the experiments reported here.
For the following reason, however, this account seems
unlikely. Response confidence may on average have been
greater in Experiment 2 than in Experiment 1 because of
superior response accuracy. In Experiment 2, however, left-
parietal ERP old/new effects were non-significant for non-
targets, while the effects for the same category were reliable
in Experiment 1. Given that the data indicating ERP
sensitivity to response confidence predict relatively greater
positivity with increasing confidence [15,29], and the
reasonable inference that the confidence in judgments
increases with response accuracy, this pattern of data
suggests that variations in confidence do not explain
satisfactorily the pattern of data across the two experiments:
for non-targets, the left-parietal ERP old/new effects are
larger in the experiment where response confidence is if
anything likely to be lower. Rugg et al. [40], moreover,
show data illustrating that ERP old/new effects at left-
parietal scalp locations differ little according to response
confidence (see also [36,38]).
What mechanisms might operate during retrieval tasks in
order to permit control over episodic retrieval? Common to
several conceptual frameworks is the assumption that
processes engaged before and/or after an interaction bet-
ween a retrieval cue and a memory trace can influence what
information is available and/or employed for memory
judgments [3,35,48]. Anderson and Bjork [2] identified
two classes of process that operate prior to this interaction
and which might support selective retrieval (also see [1,30]).
The first, target bias, describes processes that operate
directly on memory representations themselves. This class
of process enables selective retrieval by making some
representations more likely to interact with an appropriate
retrieval cue than others. A second class of process
described by Anderson and Bjork is cue bias, which
describes processes that operate directly on retrieval cues,
increasing the likelihood that they will interact with some
memory representations rather than with others. As for
target bias processes, cue bias operations are engaged prior
to a cue/trace interaction and influence the nature of that
interaction. A third class of process discussed by Anderson
and Bjork—attention bias—has a different locus, operating
downstream of any interactions between a retrieval cue and
a memory trace. This class of process enables selective
retrieval by ensuring that processing resources are allocated
only to task-relevant material that becomes available as a
result of the cue/trace interaction.
There is to date no electrophysiological data that dis-
tinguish unequivocally between these classes of bias
mechanism, although it has been argued that target bias
mechanisms are likely to be maintained throughout a
retrieval task and thus will not be revealed in time-locked
and baseline-corrected event-related potential measures of
neural activity [22]. Herron and Rugg [19] favoured a cue-
bias account of the ERP data they acquired in a task where
the encoding phase comprised presentation of words and
pictures. Test stimuli were words, and the old words were
either re-presentations of words, or of words corresponding
to the objects shown in the pictures. In separate retrieval
phases, targets were designated as old words encountered
either as words or pictures at encoding.
There were reliable parietal old/new effects for targets in
both target designations, but reliable parietal effects for non-
targets only when pictures were designated as targets.
Herron and Rugg [19] noted that these data could not be
accommodated straightforwardly within an attention bias
account, but could be within a cue-bias account if it was
assumed that: (1) in the word target condition, participants
were able to process cues sufficiently selectively to restrict
recollection to information associated with studied words,
perhaps because of the perceptual match for the target
stimuli, while (2) in the picture target condition, the absence
of the perceptual match for target stimuli meant that
processes engaged to recover information about studied
pictures involved processing operations that also resulted in
recollection of information associated with studied words.
This account does not preclude the possibility that a
combination of these classes of bias mechanism is typically
responsible for selective episodic retrieval, nor whether the
extent to which these processes act in concert varies
according to factors such as the content that is to be retrieved
and the structure of retrieval tasks. Identification of boundary
conditions for when selective retrieval can occur—a goal of
the study described here—is a precursor to attempts to
delineate further the mechanisms that enable selective
retrieval of episodic information to be accomplished.
Over and above the implications of the pattern of left-
parietal ERP old/new effects in these two experiments for
the resolution with which recollection can be constrained,
the contrasts between the target and non-target ERP old/new
effects revealed other modulations of the electrical record
that have been linked to memory processes. The analyses of
the ERP old/new effects provided no evidence for qualita-
tive differences between the ERP old/new effects in the two
experiments, but there were amplitude differences of note.
In the 300–500 ms post-stimulus time window, a fronto-
central modulation comprising a greater positivity for
correctly identified old than for new items has been linked
to familiarity [4,6,34,41,59], which according to dual-
process accounts of recognition memory is one basis for
making old/new recognition memory judgments [23,32,57].
Although the scalp maps in Fig. 2 show that there are some
differences according to experiment and target/non-target
status in this epoch, these were not borne out by the
analyses, which revealed only quantitative differences
between the ERP old/new effects for targets.
E.L. Wilding et al. / Cognitive Brain Research 25 (2005) 19–3230
A disparity between the ERP old/new effects in the two
experiments that does receive statistical support is evident
primarily at frontal electrode locations, where the right-
lateralised ERP old/new effects were markedly more
prominent in Experiment 1 than in Experiment 2, and larger
for targets than for non-targets. According to one account of
the right-frontal ERP old/new effect, it indexes processes
responsible for monitoring retrieval processing in service of
task goals [42,43]. The current data are broadly compatible
with this account, in so far as the relatively lower level of
memory accuracy in Experiment 1 might well have en-
couraged a greater degree of content and/or response
monitoring than in Experiment 2, where the superior level
of memory accuracy may have precluded requirements for
extensive monitoring.
A further notable aspect of the ERP old/new effects is the
fact that common to both experiments is the relatively focal
negativity for old compared to new words that is evident
primarily during the 900–1400 ms epoch, and which has a
posterior midline maximum. While Fig. 1 shows that there
are small differences between these posterior negativities for
targets and for non-targets across experiments, the principal
divergence is between the ERPs evoked by new words and
those evoked by both classes of old word. This late posterior
negativity is evident in a number of recent ERP studies of
source memory (for examples, see [27,31]), and the func-
tional significance of the modulation is a matter of
continuing debate. In a series of studies, Cycowicz, Fried-
man, and colleagues [7–9] have reported pronounced
posterior negativities in tasks where the information to be
retrieved was the colour (red/green) in which pictures were
presented in a prior study phase. In their experiments, the
effect did not differ reliably according to the accuracy of
source judgments, leading to the proposal that it reflects
processes linked closely to the search for and/or retrieval of
colour information [7], or perhaps processes that are linked
with retrieval and/or evaluation of source information but
not necessarily restricted to colour [17].
The data in this experiment contribute in two ways to
questions about the functional significance of this posteri-
orly distributed old/new effect. First, the fact that the effect
is of comparable magnitude across the two experiments
while the right-frontal ERP old/new effect is markedly
larger in Experiment 1 is consistent with the view that the
two effects are functionally dissociable (see also [49]). The
second point stems from the fact that the ERP waveforms in
the studies of Cycowicz and colleagues have been displayed
with respect to a nose-tip reference only, with the exception
of one recent publication [17]. In the majority of ERP
memory studies, a linked mastoid reference has been
employed. The data from Experiment 2 are relevant in this
regard, as EEG was also acquired from the nose-tip,
permitting the data to be re-referenced to that site. The
outcome of this procedure is shown in Fig. 3, where it can
be seen that the consequence of this change of reference is a
considerable increase in the amplitude of the late posterior
negativity, and a small reversal of the positive-going ERP
old/new effects at anterior electrodes.
The data referenced to linked mastoids that is shown in
Figs. 1 and 2 bear strong similarities to that which has been
reported for different kinds of source information such as
voice [51] or study task [49]. One interpretation of this
correspondence is that the posterior negativity is not linked
strongly to colour-specific processing, given the apparent
match between the data reported here and in other studies in
which a linked mastoid reference has been employed and in
which retrieval of different kinds of source information has
been encouraged. The data in Fig. 3 support this account in
so far as when a nose-tip reference is employed, the pattern
of data resembles closely that reported previously by
Cycowicz and colleagues [7–9]. In combination, therefore,
the data provide little support for a colour-specific account
of the late posterior negativity.
From this perspective, Johannsen and Mecklinger’s
recent proposal that one aspect of the posterior negativity
reflects processes related to maintaining and/or forming
representations of attribute conjunctions is parsimonious,
since it makes no claims about the content of those
conjunctions [17,26]. It is important to observe, however,
that these suggestions are based on informal comparisons
across studies, and in determining the functional signifi-
cance of this late posterior modulation, it will be
important in future studies to contrast ERPs associated
with retrieval of different contents while equating all other
factors [17].
To summarise, the principal findings in these two
experiments concern the pattern of left-parietal ERP old/
new effects—the electrophysiological signature of recollec-
tion. In the first experiment, overall task accuracy was
inferior to that in the second experiment, and targets as well
as non-targets were associated with reliable left-parietal
ERP old/new effects. In the second experiment, only targets
were associated with the effect. In combination, these
findings are consistent with Herron and Rugg’s proposal
that relying upon the success or failure of recollection of
information associated with targets only is a strategy that is
adopted when memory for targets is high [19,20]. In
addition, the findings in these two studies demonstrate that
control over what is and what is not recollected can be
exercised with a high degree of precision, as attested to by
the fact that the data in Experiment 2 suggest that
participants were able to recollect some colour information
while not recollecting other highly similar information.
Acknowledgments
This research was supported by the UK Biotechnology
and Biological Sciences Research Council (BBSRC). We
would like to thank Mariam Dzulkifli and Nazanin
Azimian-Faridani for comments on a draft of the
manuscript.
E.L. Wilding et al. / Cognitive Brain Research 25 (2005) 19–32 31
References
[1] M.C. Anderson, Rethinking interference theory: executive control
and the mechanisms of forgetting, J. Mem. Lang. 49 (2003)
415–445.
[2] M.C. Anderson, R.A. Bjork, Mechanisms of inhibition in long term
memory, in: D. Dagenbach, T.H. Carr (Eds.), Inhibitory Processes in
Attention, Memory, and Language, Academic Press, San Diego, CA,
1994, pp. 265–325.
[3] P.W. Burgess, T. Shallice, Confabulation and the control of recollec-
tion, Memory 4 (1996) 359–411.
[4] T. Curran, Brain potentials of recollection and familiarity, Mem. Cogn.
28 (2000) 923–938.
[5] T. Curran, Effects of attention and confidence on the hypothesized
ERP correlates of recollection and familiarity, Neuropsychologia 42
(2004) 1088–1106.
[6] T. Curran, A.M. Cleary, Using ERPs to dissociate familiarity from
recollection in picture recognition, Cognit. Brain Res. 15 (2003)
191–205.
[7] Y.M. Cycowicz, D. Friedman, Source memory for the color of
pictures: event-related brain potentials (ERPs) reveal sensory-specific
retrieval-related activity, Psychophysiol. 40 (2003) 455–464.
[8] Y.M. Cycowicz, D. Friedman, J.G. Snodgrass, Remembering the
colour of objects: an ERP investigation of source memory, Cereb.
Cortex 11 (2001) 322–334.
[9] Y.M. Cycowicz, D. Friedman, M. Duff, Pictures and their colors: what
do children remember? J. Cogn. Neurosci. 15 (2003) 759–770.
[10] D.I. Donaldson, M.D. Rugg, Recognition memory for new associa-
tions: electrophysiological evidence for the role of recollection,
Neuropsychologia 36 (1998) 377–395.
[11] D.I. Donaldson, E.L. Wilding, K. Allan, Fractionating retrieval from
episodic memory using event-related potentials, in: A.E. Parker, E.L.
Wilding, T.J. Bussey (Eds.), The Cognitive Neuroscience of
Memory: Episodic Encoding and Retrieval, Psychology Press, Hove,
2003, pp. 39–58.
[12] E. Duzel, A.P. Yonelinas, G.R. Mangun, H.J. Heinze, E. Tulving,
Event-related brain potential correlates of two states of conscious
awareness in memory, Proc. Natl. Acad. Sci. U. S. A. 94 (1997)
5973–5978.
[13] E. Duzel, F. Vargha-Khadem, H.J. Heinze, M. Mishkin, Brain
activity evidence for recognition without recollection after early
hippocampal damage, Proc. Natl. Acad. Sci. U. S. A. 98 (2001)
8101–8106.
[14] A. Dzulkifli, E.L. Wilding, Electrophysiological indices of strategic
episodic retrieval processing, Neuropsychologia 43 (2005) 1152–1162.
[15] S. Finnigan, M.S. Humphreys, S. Dennis, G. Geffen, ERP ‘‘old/new’’
effects: memory and decisional factor(s), Neuropsychologia 40 (2002)
2288–2304.
[16] D. Friedman, R. Johnson Jr., Event-related potential (ERP) studies of
memory encoding and retrieval: a selective review, Microsc. Res.
Tech. 51 (2000) 6–28.
[17] D. Friedman, Y.M. Cycowicz, M. Bersick, The late negative episodic
memory effect: the effect of recapitulating study details at test, Cognit.
Brain Res. 23 (2005) 185–198.
[18] G.W. Greenhouse, S. Geisser, On methods in the analysis of repeated
measures designs, Psychometrika 49 (1959) 95–112.
[19] J.E. Herron, M.D. Rugg, Retrieval orientation and the control of
recollection, J. Cognit. Neurosci. 15 (2003) 843–854.
[20] J.E. Herron, M.D. Rugg, Strategic influences on recollection in the
exclusion task: electrophysiological evidence, Psychon. Bull. Rev. 10
(2003) 703–710.
[21] J.E. Herron, E.L. Wilding, An electrophysiological investigation of
factors facilitating strategic recollection, J. Cognit. Neurosci. 17
(2005) 1–11.
[22] M. Hornberger, A.M. Morcom, M.D. Rugg, Neural correlates of
retrieval orientation: effects of study– test similarity, J. Cognit.
Neurosci. 16 (2004) 1196–1210.
[23] L.L. Jacoby, A process dissociation framework: separating auto-
matic from intentional uses of memory, J. Mem. Lang. 30 (1991)
513–541.
[24] L.L. Jacoby, Invariance in automatic influences of memory: toward a
user’s guide for the process-dissociation procedure, J. Exper. Psychol.,
Learn., Mem., Cogn. 24 (1998) 3–26.
[25] L.L. Jacoby, C. Kelley, Unconscious influences of memory: dissocia-
tions and automaticity, in: A.D. Milner, M.D. Rugg (Eds.), The
Neuropsychology of Consciousness, Academic Press, London, 1992,
pp. 201–233.
[26] M. Johannson, A. Mecklinger, The late posterior negativity in ERP
studies of episodic memory: action monitoring and retrieval of
attribute conjunctions, Biol. Psychol. 64 (2003) 91–117.
[27] M. Johansson, G. Stenberg, M. Lindberg, I. Rosen, Memory for
perceived and imagined pictures—An event-related potential study,
Neuropsychologia 40 (2002) 986–1002.
[28] M.K. Johnson, S. Hashtroudi, D.S. Lindsay, Source monitoring,
Psychol. Bull. 114 (1993) 3–28.
[29] R. Johnson Jr., K. Kreiter, B. Russo, J. Zhu, A spatio-temporal
analysis of recognition-related event-related brain potentials, Int. J.
Psychophysiol. 29 (1998) 83–104.
[30] B.J. Levy, M.C. Anderson, Inhibitory processes and the control of
memory retrieval, Trends Cognit. Sci. 6 (2002) 299–305.
[31] P.A. Leynes, M.L. Bink, Did I do that? An ERP study of memory for
performed and planned actions, Int. J. Psychophysiol. 45 (2002)
197–210.
[32] G. Mandler, Recognising: the judgment of previous occurrence,
Psychol. Rev. 87 (1980) 252–271.
[33] G. McCarthy, C.C. Wood, Scalp distributions of event-related
potentials: an ambiguity associated with analysis of variance models,
Electroencephalogr. Clin. Neurophysiol. 62 (1985) 203–208.
[34] A. Mecklinger, Interfacing mind and brain: a neurocognitive model of
recognition memory, Psychophysiology 37 (2000) 565–582.
[35] D.A. Norman, D.G. Bobrow, Descriptions: an intermediate stage in
memory retrieval, Cogn. Psychol. 11 (1979) 107–123.
[36] S.R. Rubin, C. Van-Petten, E.L. Glisky, W.M. Newberg, Memory
conjunction errors in younger and older adults: event-related
potential and neuropsychological data, Cogn. Neuropsychol. 16
(1999) 459–488.
[37] M.D. Rugg, ERP studies of memory, in: M.D. Rugg, M.G.H.
Coles (Eds.), Electrophysiology of Mind: Event-Related Brain
Potentials and Cognition, Oxford University Press, London,
1995, pp. 132–170.
[38] M.D. Rugg, M.C. Doyle, Event-related potentials and recognition
memory for low- and high-frequency words, J. Cognit. Neurosci. 4
(1992) 69–79.
[39] M.D. Rugg, R.C. Roberts, D.D. Potter, C.D. Pickles, M.E. Nagy,
Event-related potentials related to recognition memory. Effects of
unilateral temporal lobectomy and temporal lobe epilepsy, Brain 114
(1991) 2313–2332.
[40] M.D. Rugg, C.J.C. Cox, M.C. Doyle, T. Wells, Event-related
potentials and the recollection of low and high frequency words,
Neuropsychologia 33 (1995) 471–484.
[41] M.D. Rugg, R.E. Mark, P. Walla, A. Schloerscheidt, C.S. Birch, K.
Allan, Dissociation of the neural correlates of implicit and explicit
memory, Nature 392 (1998) 595–598.
[42] M.D. Rugg, K. Allan, C.S. Birch, Electrophysiological evidence for
the modulation of retrieval orientation by depth of study processing,
J. Cognit. Neurosci. 12 (2000) 664–678.
[43] M.D. Rugg, J. Herron, A. Morcom, Electrophysiological studies of
retrieval processing, in: L.R. Squire, D.L. Schacter (Eds.), Neuro-
psychology of Memory, Guilford Publications, New York, 2002,
pp. 154–165.
[44] H.V. Semlitsch, P. Anderer, P. Schuster, O. Presslich, A solution for
reliable and valid reduction of ocular artifacts, applied to the P300
ERP, Psychophysiology 23 (1986) 695–703.
[45] M.E. Smith, Neurophysiological manifestations of recollective expe-
E.L. Wilding et al. / Cognitive Brain Research 25 (2005) 19–3232
rience during recognition memory judgements, J. Cognit. Neurosci. 5
(1993) 1–13.
[46] M.E. Smith, E. Halgren, Dissociation of recognition memory
components following temporal lobe lesions, J. Exper. Psychol.,
Learn., Mem., Cogn. 15 (1989) 50–60.
[47] I. Tendolkar, A. Schoenfeld, G. Golz, G. Fernandez, K. Kuhl, R.
Ferszt, H. Heinze, Neural correlates of recognition memory with and
without recollection in patients with Alzheimer’s disease and healthy
controls, Neurosci. Lett. 263 (1999) 45–48.
[48] E. Tulving, Ecphoric processes in episodic memory, Philos. Trans. R.
Soc., London B302 (1983) 361–371.
[49] E.L. Wilding, Separating retrieval strategies from retrieval success: an
event-related potential study of source memory, Neuropsychologia 37
(1999) 441–454.
[50] E.L. Wilding, In what way does the parietal ERP old/new effect index
recollection? Int. J. Psychophysiol. 35 (2000) 81–87.
[51] E.L. Wilding, M.D. Rugg, An event-related potential study of
recognition memory with and without retrieval of source, Brain 119
(1996) 889–905.
[52] E.L. Wilding, M.D. Rugg, Event-related potentials and the recognition
memory exclusion task, Neuropsychologia 35 (1997) 119–128.
[53] E.L. Wilding, H. Sharpe, Episodic memory encoding and retrieval:
recent insights from event-related potentials, in: A. Zani, A. Mado-
Proverbio (Eds.), The Cognitive Electrophysiology of Mind and Brain,
Academic Press, San Diego, 2003, pp. 169–196.
[54] E.L. Wilding, H.L. Sharpe, The influence of response– time demands
on electrophysiological correlates of successful episodic retrieval,
Cognit. Brain Res. 18 (2004) 185–195.
[55] E.L. Wilding, M.C. Doyle, M.D. Rugg, Recognition memory with and
without retrieval of context: an event-related potential study, Neuro-
psychologia 33 (1995) 743–767.
[56] A.P. Yonelinas, The nature of recollection and familiarity: a review of
the 30 years of research, J. Mem. Lang. 46 (2002) 441–517.
[57] A.P. Yonelinas, I. Dobbins, M.D. Szymanski, H.S. Dhaliwal, L. King,
Signal-detection, threshold, and dual-process models of recognition
memory: ROCs and conscious recollection, Conscious. Cogn. 5
(1996) 418–441.
[58] A.P. Yonelinas, N.E. Kroll, I. Dobbins, M. Lazzara, R.T. Knight,
Recollection and familiarity deficits in amnesia: convergence of
remember-know, process dissociation and receiver operating charac-
teristic data, Neuropsychology 12 (1998) 323–339.
[59] G. Yovel, K.A. Paller, The neural basis of the butcher-on-the-bus
phenomenon: when a face seems familiar but is not remembered,
NeuroImage 21 (2004) 789–800.