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The Effects of Context on Recognition and Memory
Matthew Canning
Cognitive Psychology – Human Learning & Memory
Dr. Gordon Hayman
Lakehead University
Tuesday, 30 November 2004
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The Effects of Context on Recognition and Memory
In the realm of cognitive psychology, a frequently studied subject is the
effect context has on recognition and memory. The context in which a person
learns material often plays an important role in how well he or she remembers it
or if memory is possible at all. For example, if the learning context is similar to
the context at time of testing, this may be involved in aiding successful recall.
Similarly, the more the context at time of test deviates from the learning context,
the less likely a subject is to successfully recall the learning material. Related to
the concept of context dependent memory is environmental context, which is
defined as the environmental setting with which events are originally experienced
in as well as remembered. There are other related concepts such as state
dependent memory, in which case greater success in memory is attributed to the
state in which a person learned the required material. Both changes in state of
the subject and changes in environmental context from study phase to test phase
may have an effect on memory. Environment is also able to affect state as
environmental stressors will yield a certain state of mind in some cases. Many
experiments have been performed on this topic, several of which will be
examined throughout this research paper. Godden & Baddeley (1975)
performed an experiment in which divers learnt lists of words in two natural
settings: on dry land and underwater. The words were later recalled in either
same of different- context settings. The four possible conditions were DD (Learn
Dry, Recall Dry); DW (Learn Dry, Recall Wet); WW (Learn Wet, Recall Wet) and
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WD (Learn Wet, Recall Dry). In a later study performed by Murnane & Phelps
(1993), environmental context was manipulated as a combination of foreground
colour, background colour, and location of words on a computer screen. The
purpose of the change in context was to determine if there would be a related
change in hit rate (HR) and false alarm rate (FAR). The Hit Rate is calculated as
the proportion of observed measures that are predicted and the False Alarm
Rate as the proportion of observed non-measures that are predicted as
measures related to the study. In a later study (2002), Macken examined the
role of recollection and familiarity on environmental context and recognition. In
his first experiment, he used an AB-X design in which half the study items were
presented in context A and half in context B. During the testing phase of the
experiment, half the items presented in context A at study were again presented
in context A (same context condition) and half in the novel context X (changed
context condition). Finally, in a study by McKenzie & Tiberghien (2000) the role
of familiarity and recollection was examined on context effects in recognition
memory.
Godden & Baddeley (1975) performed an experiment on context
dependent memory in two natural settings; on dry land and underwater. After
initial learning took place, participants were required to recall the lists of words in
either environment, allowing for the following combinations: DD (Learn Dry,
Recall Dry); DW (Learn Dry, Recall Wet); WW and WD. Divers learnt lists of 36
words (different two and three syllable words). The words were chosen at
random from the Toronto word bank and recorded on tape. Due to the
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requirement for efficient auditory perception in both dry and wet land
environments, the presentation of the material was grouped. To allow each diver
to adopt a comfortable breathing pattern, each list was presented in blocks of
three words, within which words were spaced at two second intervals. Breathing
took place within blocks of words, where four seconds was allotted for subjects to
exhale, inhale, and hold their breath while the next block of words were
presented. It was ensured that subjects were breathing correctly before the first
word of the list appeared. At the beginning of each tape, a similar pattern to the
list pattern was presented with the letter “z” in place of words in a list. After each
block of three z’s, subjects were instructed by tape to breath. Once the word list
was presented, the command to breath was dropped, as it was adapted by
subjects at this point. This gave subjects a chance to become familiar with the
requirements which would be present during time of testing. When the
experiment was performed, for each tape, the relevant list was presented twice,
in between which, a time period of 15 seconds was allotted for uncontrolled
breathing, which allowed subjects to catch their breath before the second list
session took place, which reverted back to the scheduled breathing pattern.
Upon the completion of the second list of words, subjects were required to copy
15 digits at the rate of 15 seconds per digit. Afterwards they were given an
instruction to ascend to the shore station, where they were to write as many of
the words as possible in two minutes after a four minute delay upon arrival. This
post learning interval and testing phase occurred in all four conditions. All 16
subjects practiced both the breathing technique and the task itself before the
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experiment took place, using a practice list of words. This was done in order to
ensure subjects could perform the actual task successfully during time of testing.
Subjects experienced one condition per diving session, with sessions separated
by 24 hours. The order of both the remaining four lists with the four conditions,
and the temporal orderings of the conditions for each of the four groups were
arranged according to a Graeco-Latin square design. All group members started
each session in the same state for the most part (cold and wet). Subjects in the
wet environment dived to a length of 20 feet, taking the materials described
above required for writing. Subjects in the dry environment sat by the edge of
the water, masks tipped back, breathing tubes removed, and receivers in place
for instructions.
The results showed that the effect of learning and recall environment was
highly significant (F=22.0; d.f. = 1, 12; P = <0.001) (Godden & Baddeley, 1975).
No other interactions proved significant. As well, for learning in the dry
environment, recall was better in the dry environment than in the wet
environment, and for learning in the wet environment, recall was better in the wet
environment than recall in the dry environment. There was no significant
difference in recall between conditions DD and WW, nor between conditions DW
and DW.
Murnane & Phelps (1993) performed several experiments to get a more
enriched understanding of recognition performance with change in environmental
context from context at time of study to context at time of test. According to
global activation theories of recognition, if the test context is different from the
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context at study, hit rates (HR) and false alarm rates (FAR) should decrease.
There were two purposes to their first experiment. The first purpose was to
determine whether the predictions proposed by global activation theory held. In
order to establish this, test context was manipulated. This was to determine if hit
rates and false alarm rates would be lower in the different context conditions at
test as opposed to the same context.
Lists contained items which were presented on either, one, two, three, or
six learning contexts. The context effect expected by the global activation theory
should be absent in the one-learning-context condition if mental reinstatement
occurred. By manipulating learning contexts, the mental reinstatement
phenomenon could be investigated. This phenomenon offers a method in which
individuals can avoid the problems associated with differing environmental
contexts and stressors. According to this principle, there is a change present
when learning and testing context are different; that being that the effect of
changing the environment decreases the extent to which the subjects are
expectant to mentally reinstate the context that was current at learning while they
are testing. When the context is sufficiently different, it does not aid in the
retrieval of information because no memory cues are triggered. In the onelearning condition, the context effect predicted by global activation theories
should be absent if mental reinstatement occurred. An effect caused by context
was predicted in the six-learning-context experiment condition because mental
reinstatement of the learning context when different context items could have
appeared in any one of the six contests would be difficult. For learning which
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took place in the two or three context conditions, context effects were expected
to show variation depending on the difficulty of mentally reinstating the context at
learning.
The experiment was set up so that 10 lists of 36 word pairs were
presented per experimental session. Following the ten lists were 24 intactrearranged, “old-new” recognition tests for the words which it contained. Pairs of
words which were shown together during the study period were targets. Both
pairs were intact. Words which appeared in different pairs during the study were
“distractors”. They were constructed from two words, as were the targets.
During testing, words which were used as one word in a distractor pair were not
tested. In order to prevent retrieval from either short term or working memory, 30
to 40 seconds of backward counting were included between study time and test
time. The lists were learned in, one, two, three, or six learning contexts. An
equal number of subjects were present in each of the four conditions, and the
total number of learning contexts was manipulated using a between subjects
factor. Screen location, as well as the colour of both the foreground and the
background defined the context. Lists contained an equal number of pairs in
each learning context when items were learned in two, three, or six learning
contexts. Test context was manipulated as a within-subjects factor. Exactly half
of both targets and distractors from each list were tested in study context. The
remaining half of the distractors from each list was tested in the same context
seen at study. The remaining half of the targets and distractors were tested in a
new context. In this new context, all characteristics were different. Two words
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from different study pairs which had also not appeared in the same learning
context were used to construct distractors. Each subject had a randomized order
for lists, study items, and test items during presentation. The statistical design of
the experiment was a two-factor, repeated measures, mixed design. The
between-subjects factor was the number of learning contexts, and the withinsubjects factor was the test context (either same or different), as well, subjects
were assigned to the number of learning context conditions randomly. In order to
construct word pairs, 720 English nouns were used (Francis & Kucera, 1982).
There were some restrictions present; if both members in a pair were easily
associated (ie, car wash), they were not used. As well, pairs which both had the
same initial letter (ie, hand hobby) were also not used. In either case, an unfair
advantage would be given on remembering those words due to association,
which would be visibly undesirable for the purposes of the experiment. Each of
the 10 lists was assigned pairs. Two versions of the stimulus materials were
created. Within each list, the two word pairs were randomly assigned to either
study or test context (same or different), and item type (target item or distractor
item). In both versions, the two word pairs were identical. Version was
counterbalanced across number of learning contexts and subjects. Personal
computers (PCs) were placed in the individual subject booths to manage the
experiment. Subjects were informed via instructions of the experimental
procedure, basis of the study items, and the intact-rearranged recognition test.
Subjects were instructed to form association between both of the words in each
study pair. They were then told that the screen colours and locations of the pairs
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were subject to change. Depending on whether or not the two words had
appeared together on the list of study items, subjects were told to respond either
“new” or “old” to said test pairs. This was the case not considering either screen
location or colour. Before the time of experimentation, subjects were first
familiarized with the procedure through a practice session. The purpose of this
practice session was to ensure subjects would perform the instructions
successfully in order for the study to achieve optimal results. The initiation of list
presentation was self-paced in this session. During the learning phase of each
list, pairs of study items were first presented for three seconds followed by 300 m
seconds of blank screen. Once all 36 study pairs were presented, a backward
counting task was announced by a message. The task involved subjects
counting backward mentally from a specified three digit number by a specified
single digit number for a total of eight seconds. From there, they received a
prompt for a response, where they entered their answer on a keypad present.
Subjects were allowed seven seconds to enter this answer. Three such
backward counting tasks were first presented, followed by a message
announcing the test phase of the experiment. Each test pair remained on the
screen until the subject provided a response. If no response was provided, a
total of three seconds was allowed. Additional test pairs appeared following 300
ms of blank screen. Mapping of recognition response to response key was
equivalent across subjects and versions (Murnane & Phelps, 1993). Subjects for
the experiment consisted of 80 undergraduate students enrolled in introductory
psychology, and volunteered for the study in return for course credit for their
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participation. Using the mean rate of both hit rate and false alarm rate, separate
statistical analyses were carried out, and individual subject d’ was used as
dependent measures There were no significant differences found between the
two versions of the stimulus materials split across both experimental factors
when assessed using t tests. From that, individual version was excluded from all
additional analyses. Data were analyzed 4X2 mixed-factors multivariate analysis
of variance (MANOVA). Four represented the number of learning contexts, while
two was the number of test contexts. With a design that is repeated measures,
the levels of within-subject variable may be treated as multiple dependent
variables in MANOVA. A MANOVA was considered ideal for this experiment. In
order to examine the effect of test context for each number of learning contexts,
planned comparisons using within-subject t tests were conducted. Statistical
tests were deemed significant at the .05 level. There were significant main
effects of text context for both targets, F (1, 76) = 13.99, p < 0.0005, and
distractors F(1, 76) = 39.51, p<0.0005. This experiment provided no evidence
that subjects mentally reinstated the learning context when performing in the text
context. Neither the main effect of the number of learning contexts X test context
interaction nor the main effect of the number of learning contexts was significant
for either distractor or target items. Mean differences in the hit rate and false
alarm rate were determined by collapsing over the four number of learning
context conditions (0.041 and 0.056 for HR and FAR, respectively). Global
activation theories predict that recognition is sensitive to changes in
environmental context between learning and test. For this experiment, there was
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a failure to find evidence in favour of mental reinstatement of the learning context
in the one-learning-context condition. In the one-learning-context condition,
subjects saw 36 word pairs per list on a magenta screen in the upper left-hand
corner. During the testing phase, without warning, a word pair appeared on a
cyan screen in black in the centre. It would be unexpected if subjects did not
recognize the difference and remember the green colours and location presented
when the list was learned as a result. Retrieving information about the learning
context from memory at time of retrieval should have been adequate to permit
use of this information in different-context conditions present at time of test. It
may have been that the mental reinstatement strategy simply did not occur to
subjects in Experiment 1.
In 2002, Macken studied the effect of study and study-context change on
recollection and familiarity in several experiments. The first experiment was
in part a replication and in part a natural extension of the approach used
previously (and described in this research paper) by Murnane and Phelps (1993).
An AB-X design was used, and half the study items were presented in context A
and half in context B. During the testing phase, half of the items which are
presented in context A at study are once more presented in context A (same
context condition), and half are presented in context X (changed-context
condition). For each study item presented in context B, half of them are
presented once again in the same context at time of testing. The other half
remaining is presented in the novel context (X). Subjects were required to make
judgments when they recognize an item as either old or new, and whether they
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know it occurred before in the study list, or if they suspect that it had (if it seems
familiar). This helped to measure recollection and familiarity. Subjects were
undergraduate students from the School of Psychology at Cardiff University.
Participation allowed students to fulfill a course requirement. 13 female students
and seven male students participated. One hundred twenty words with a
frequency of 50 or less per million (Paivio, Yuille, & Madigan, 1968) were divided
into two lists randomly. 80 words served as study items and 40 served as
distractors at test. All stimuli were presented on a computer screen. The
experiment consisted of a total of three contexts. Context A consisted of a green
background and the presentation of red letters in the bottom right corner of the
screen. Context B consisted of a brown background and the presentation of
yellow letters in the top left corner of the screen. Context X was the novel
context, which was only presented during the time of test. This context consisted
of a pink background and the presentation of blue letters in the centre of the
screen. Items were split in half for both Contexts A and B, with 40 being
presented in each. During the testing phase, 20 of each of the set of items
presented in either learning contexts A or B were presented once again in the
same-context condition as was the original and 20 were presented in the
changed context (X). A total of 40 distractor items were used and 10 of them
were presented in contexts A and B. The remaining 20 of them being presented
in the novel context X. During the study phase, 20 words were presented in
context X and 10 in both contexts A and B. These words were presented on the
screen for a period of five seconds each, with a two second gray screen inserted
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between the presentations of each word. Subjects received instructions to learn
the words presented as their memory for the items would be tested later.
Subjects were solely aware that testing would take place, where specific details
of the testing procedure were omitted. Subjects were told that words would
appear differently in the test phase compared to the study phase (locations,
colours, backgrounds). They were strictly told to tend to the words. During the
testing phase, words were presented for a period of three seconds, followed by
prompt for the subject to type an R in their keypad provided if they recognized
the item based on feelings of familiarity. Subjects were to type an N if they felt
the item had not been present during the study phase. As with before, they were
told that the same words would appear with variance in location, colour and
background colour. Judgments were to be made purely on the basis of whether
they recognized the word from before. The assignment of words to either same
or changed context conditions, as well as study words to either of the learning
contexts was counterbalanced across participants. Each subject received a
different order of presentation of words at study and at test. The probability of R
responses was taken as a measure of recognition together with recall in both the
same and changed context conditions. In the same- and changed- context
conditions, whereas the measure of familiarity independent of the level of
recollection was calculated as K/(1-R) for each participant in each of the
conditions (Macken, 2002). This variation was carried out for both hits and false
alarms. However, there was a low level of false alarm rates associated with R
responses, and so the corrected false-alarm rate for distractors differed very
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little from the false K rate. The single high-threshold statistic, q, was taken as a
measure of the sensitivity of the recollection process, with the false-alarm rate
providing the associated bias measure (Macken, 2002). Sensitivity and bias
measures were derived from R responses to targets and distractors, because the
level of R responding is taken here as a direct measure. To provide sensitivity
and bias measures to correspond, d' and c were calculated for familiarity scores.
For the familiarity scores, d’ and c were calculated to provide the corresponding
sensitivity and bias measures. In this case, the measure of the
contribution to recognition of the familiarity process is not given straight
from the raw K scores, so the K/(1-R)-transformed hit and false-alarm rates
were used to draw from sensitivity and bias of the familiarity process for every
participant in each condition. In the same-context condition, the mean value of q
was 0.58 (SD = 0.18) and in the changed-context condition, the mean value of q
was 0.48 (SD=0.17), showing significantly greater recollection in the previous,
t(19) = 2.72, p < .02. The results determined that context had no effect on the
false-alarm rate, t(19) = 1.55, p > .05, which suggests that response bias was
equal across conditions. Mean d’ values in the same- and changed-context
condition were 1.35 (SD = 1.13) and 1.44 (SD = 0.89), respectively, showing no
effect of context condition on familiarity, t(19) = 0.38, p > .05, and there was no
effect on response bias, with the values of c in same- and changed-context
conditions being 1.23 (SD = 0.61) and 1.23 (SD = 0.49), respectively, t(19) =
0.02, p > .05.
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Based on the statistical results from this experiment, primary evidence for
a potential explanation for the ephemeral nature of context effects in recognition
is shown; since it is known that changed contexts affects only recognition when
accompanied by recollection, if overall performance is mainly based on familiarity
of the item, which is not noticeably affected by context change, then effects of
changed context will insignificant or absent. The effect of changed context on
recollection is mostly insignificant. This experiment failed to find an effect of
changed context for recognition. This poses some problems for the global
activation approach discussed earlier in this paper. A measure of familiarity
independent of level of recollection was calculated, but a true effect may have
been hidden based on low levels of raw K scores. But the basic finding still has a
reasonable amount of weight.
In 2000, McKenzie & Tiberghien studied the effects of familiarity and
recollection. As with the studies above, the primary goal was to determine a
relationship between context effects in recognition memory. Specifically, the
research aimed to determine if manipulations of context affect one or both of the
familiarity and search processes as described in the dual process model of
recognition. Subjects first studied a list of word pairs (context word and target
word), followed by a recognition test where target words were presented in either
the same or different contexts, as well as in the same or different form as study
(singular form or plural). Subjects were then asked to recognize any target word
independent of changes in the form, or to present words that were recognized in
the same form (inclusion or exclusion).
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Subjects who participated in the first experiment of the study were 24
students from the Universite Pierre Mendes-France, Grenoble, France, who
spoke all spoke French fluently. Incentive to participate in the experiment was in
the form of course credit, or on a voluntary basis. Words used in the study were
selected from a word pool consisting of 2000 French words. Each of the words
(total of 533) were nouns that had one or two syllables, were between 3 and 11
letters long, and each occurred more frequently than 100 per million. In order to
establish conditions that would produce conclusions about recognition responses
made when the contribution of recollection was either substantially compacted or
completely available the choice of temporal parameters for the manipulation of
response signal lag was of vital importance. Hintzmann and Curran (1994) found
that at lags of approximately 30 ms, changes in the pattern of recognition
responses to signal words took place, as opposed to longer response lags of
more than 1500 ms. In the current experiment, the appearance of pairs of words
at test was involved. The context word appeared first for 1000 ms followed by
the presentation of the context and target together for 750 ms. A 1250 ms delay
took place in the short lag condition before the response signal through which no
response was accepted. The data were analyzed using a 2X(2X2X3) ANOVA on
the number of YES responses for the different conditions. Long or short lag was
the between subjects variable, and the remaining factors were within subject
variables, inclusion or exclusion instructions, same or different contexts, and old,
similar, or new type of test item. A correct comparison of YES responses to old
items (hits) and incorrect YES responses to new items (false alarms) was
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permissible by analyzing YES responses, for both inclusion and exclusion tests.
A YES response to a comparable item would be classified as a hit under the
inclusion instructions and a false alarm under exclusion instructions. The
manipulations of the test instructions produced the intended effect indicated by
significant main effects of instruction (F(1, 22) = 38.68, MSE = 5.79, p < .001)
and type of test item (F(2, 44) = 291.90, MSE = 4.71, p < .001) and a reliable
interaction between instruction and type of test item (F (2, 44) = 50.41, MSE =
3.14, p < .001) (McKenzie & Tiberghien, 2004). After these analyses were done,
the number of YES responses given under inclusion and exclusion were
compared with each type of item using modified Bonferroni correction applied at
alpha = .033). Significantly more YES responses were made to similar items in
the inclusion condition (M = 5.69, SD = 1.27) than in the exclusion condition (M =
2.34, SD = 1.34, t(23) = 7.83, p < .001. However, no significant differences were
found for the old items (M = 6.10, SD = 1.06) vs. M = 5.78, SD = 1.05 for
inclusion and exclusion tests, respectively, t(23) = 1.36, p > .033), and new items
(M = .70, SD = .60 vs M = .61 for inclusion and exclusion tests, respectively, t(23)
= .79, p > .033). However, significantly more YES responses were made to
items which were similar in the inclusion condition (M = 5.69, SD = 1.27) than in
the exclusion condition (M = 2.34, SD = 1.34, t(23) = 7.83, p < .001).. Thus,
subjects were capable of following the test instructions to exclude items that had
changed in form from time of study to time of test.
Within context, a significant main effect was found (F(1, 22) = 10.78, MSE
= 1.61, p < .005) showed that, overall, reinstating YES responses were increased
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when the study context was reinstated. This pattern of context effects differed as
a function of item type (F(2,44) = 5.96, MSE = .90, p < .01). Subsequent analysis
(α = .033) showed the context reinstatement effect was trustworthy for old items
(M = 6.30, SD = .80 vs M = 5.58, SD = 1.12), same and different context,
respectively, t(23) = 4.27, p < .001) and new items (M = .78, SD = .62 vs M = .53,
SD = .58, same and different context respectively, t(23) = 2.48, p < .03) but not
for items which were similar to one another (M = 4.05, SD = .97 vs M = 3.98, SD
= .78 for same and different context respectively, t(23) < 1). The exclusion
condition which had slightly fewer YES responses made in the same context
condition than in different context condition seemed to cause the negligible effect
of context on similar items (McKenzie & Tiberghien, 2004).
The realm of cognitive psychology is an extensive one, and topics such as
the effects of environmental context on recognition, while extensive, are still
fields of science currently in progress. However, many conclusions can be
generally accepted as good predictors of memory. In the study by Godden &
Baddeley (1975), it was determined that lists of words learnt underwater were
best recalled underwater, and lists of words learnt on dry land were best recalled
on dry land. In a later study performed by Murnane & Phelps (1993), it was
determined that changes in context resulted in reduced hit and false alarm rates,
which is what we would expect by global activation theories. In 2002, William
Macken’s study suggested that effects of environmental context will only be
found when recognition is accompanied by conscious recollection of the material
and further, that this effect is due to a specific item-context association. Finally,
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McKenzie & Tiberghien (2000) performed a study which suggests that context
effect demonstrated can be attributed to the influence of familiarity on
recognition, whereas the effect of recollection was less clear. Taken together,
there is good support for the claim that recollection may be improved if
environmental context at time of test is the close to environmental context at time
of study. The physical environment can provide valuable cues that help
individuals remember material which they have previously learned within the
same or similar setting. This can have positive effects both in the laboratory and
in the classroom, and are important for both memory researchers and everyday
learners to bear in mind.
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References
Francis, W.N., & Kucera, H. (1982). Frequency analysis of English usage:
Lexicon and grammar. Boston: Houghton Mifflin.
Godden, D. R., & Baddeley, A. D. (1975). Context-dependent memory in two
natural environments: On land and underwater. British Journal of
Psychology, 66, 325-331.
Hintzman, D.L., & Curran, T. (1994). Retrieval dynamics of recognition and
frequency judgments: Evidence for separate processes of familiarity and
recall. Journal of Memory and Language, 33, 1-18,
doi:10.1006/jmla.1994.1001.
Macken, W. J. (2002). Environmental context and recognition: The role of
recollection and familiarity. Journal of Experimental Psychology: Learning,
Memory, and Cognition, 28, 153-161.
McKenzie, W. A., & Tiberghien, G. (2004). Context effects in recognition
memory: The role of familiarity and recollection. Consciousness and
Cognition 13, 20-38.
Murnane, K., & Phelps, M. P. (1993). A global activation approach to the effect
of changes in environmental context on recognition. Journal of
Experimental Psychology: Learning, Memory, and Cognition, 19, 882894.
Paivio, A., Yuille, J.C., & Madigan, S.A. (1968). Concreteness, imagery and
meaningfulness for 925 nouns. Journal of Experimental Psychology, 76,
(1, Pt. 2) 1-25