Encoding Organizational Source and Associative Source under Incidental and Intentional Learning Conditions

doi:10.4236/psych.2013.49096

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Psychology

2013. Vol.4, No.9, 677-681

Published Online September 2013 in SciRes (http://www.scirp.org/journal/psych) http://dx.doi.org/10.4236/psych.2013.49096

Encoding Organizational Source and Associative Source under

Incidental and Intentional Learning Conditions

Lei Zhu

Department of Psychology, Fudan University, Shanghai, China

Email: [email protected]

Received May 24th, 2013; revised July 15th, 2013; accepted August 6th, 2013

License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original

work is properly cited.

The present study aimed at providing a plausible answer for the controversy whether organizational

source or associative source could be encoded in a more automatic manner through incidental learning. In

the experiment, subjects were asked to learn organizational and associative sources under incidental or

intentional learning conditions. It turned out that only associative source accuracy increased when sub-

jects were instructed to intentionally learn that source, which implied that associative source might be

encoded in a more effortful way, whereas processing of organizational source might be performed inci-

dentally.

Keywords: Organizational Source; Associative Source; Incidental Learning; Intentional Learning

Introduction

People encounter lots of information from various sources

every day. Sometimes, when they retrieve the remembered

information, they are also required to identify the related source

of this information. In the typical source memory tasks, sub-

jects were presented with items from at least two different

sources (e.g., Zhu et al., 2010). The items to be learned include

words, pictures, statements, and so on. And the source refers to

a variety of characteristics which specify the conditions under

which the learning items are presented, such as their color,

shape, size, spatial location, temporal order and the media or

modality of presentation.

In the recent decades, there is increasing evidence which sug-

gested that source memory might be fundamentally different

from memory for the item. That is, compared to memory for-

mation for item, encoding source is a more effortful task which

is performed intentionally and requires considerable attentional

resources (Spencer & Raz, 1995; Troyer & Craik, 2000). For

example, the population with decline of frontal executive sys-

tems and reduced attentional resources, such as older adults and

amnesia patients showed more deficits in remembering the

sources than in remembering the items (Schacter, 1987; Schac-

ter et al., 1991; Ferguson et al., 1992; Hashtroudi et al., 1994;

Chalfonte et al., 1996; Wegesin et al., 2000). In addition, en-

coding source was interfered more severely by the secondary

tasks under divided attention condition than was encoding item

(Troyer et al., 1999; Troyer & Craik, 2000). Similarly, com-

pared with intentional learning conditions, source accuracy

decreased under incidental learning conditions (Chalfonte &

Johnson, 1996; Marsh et al., 2004; Kuo & Van Petten, 2006;

Uncapher & Rugg, 2009).

However, not all the source is encoded in the same way. One

insight comes from the dichotomy between automatic and ef-

fortful processes proposed by Hasher and Zacks (1979). Ac-

cording to Hasher and Zacks (1979), automatic memory proc-

esses which require minimal attentional resources can occur

without intention and do not benefit from practice. Contrarily,

effortful memory processes such as rehearsal or elaborative

mnemonic activities which require considerable attentional

resources are initiated intentionally and show benefits from

practice. Based on that, Hasher and Zacks (1979) further pro-

posed that different from other source, spatial locations, tem-

poral orders tend to be encoded incidentally by automatic

memory processes. Yet, on the contrary, other researchers clas-

sified source into two categories (Geiselman & Bjork, 1980;

Baddeley, 1982; Moscovitch, 1992; Spencer & Raz, 1995;

Staresina & Davachi, 2008). Opposite to Hasher and Zacks

(1979), source, such as spatial locations or temporal orders, is

thought to be extrinsic to the item and not be encoded concur-

rently with the item. Thus, more intentional effort is required to

bind it to the item. This type of source has been named as ex-

trinsic (Geiselman & Bjork, 1980; Baddeley, 1982), organiza-

tional (Moscovitch, 1992), spatiotemporal (Spencer & Raz,

1995), or item-context (Staresina & Davachi, 2008) source. On

the other hand, source, such as color, font, shape, is likely to be

encoded automatically without conscious intention, because it

is directly bound to the item itself and is encoded concurrently

with the item. This type of source is denominated as intrinsic

(Geiselman & Bjork, 1980; Baddeley, 1982), associative (Mos-

covitch, 1992), stimulus bound (Spencer & Raz, 1995), or item-

feature (Staresina & Davachi, 2008) source. Thus, it is still an

open question whether organizational source or associative

source could be encoded in a more automatic manner through

incidental learning.

To test this, participants were asked to encode organizational

source (i.e., location) and associative source (i.e., color) under

incidental or intentional learning conditions. They first studied

a list of colored objects presented in the top or bottom of the

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computer screen during three tasks (Figure 1). In the item-

oriented task, participants judged whether the items depicted in

pictures were animate. In the color-oriented task, they judged

whether the item-color conjunctions were plausible (red hat) or

not (green orange) in real life. In the location-oriented task,

they judged whether it was plausible in the real life that the

item appeared in the sky when the item was presented in the top

of the screen and judged whether it was plausible in the real life

that the item appeared in the ground when the item was pre-

sented in the bottom of the screen. Thus, organizational source

was intentionally learned in location-oriented task, but was

incidentally learned in the other two tasks, whereas associative

source was intentionally learned in color-oriented task, but was

incidentally learned in the other two tasks. It should be noted

that such manipulation of intentional and incidental learning is

different from the traditional Craik and Lockhart (1972) defini-

tion for item memory. The Craik and Lockhart (1972) distin-

guish intentional and incidental learning by explicit instruction

to learn specific item, whereas the present study distinguish

intentional and incidental learning by the encoding task. After

that, participants took a surprised subsequent memory test

where they first gave old/new decision, and then, for items

called old, they gave source (color and location) judgment. It is

predicted that if the associative source needs to be encoded

intentionally by effortful memory processes, then the source

accuracy of color would benefit from intentional learning. On

the other hand, if organizational source is encoded through

intentional learning, the source accuracy of location would

differ for three tasks.

Method

Participants

Fourteen right-handed Chinese volunteers from the univer-

sity community with normal or corrected-to-normal vision (three

Figure 1.

Experimental Design. (a) Encoding phase. The task cues were

varied between trials and participants were instructed to conduct

location-oriented task, color-oriented task or item-oriented task

according to the task cue; (b) Subsequent memory test. For the

items judged as “old” in the item memory test, their source mem-

ory for location and color was further assessed.

males, aged from 19 to 29, M = 22.00, SD = 3.11) participated

in this experiment. All the participants were naïve about the

purpose of the experiment and were paid 20 RMB for their

participation.

Materials

Two hundred and forty gray pictures of common objects

were randomly selected from the revised Snodgrass and Van-

derwart’s object pictorial set (Rossion & Pourtois, 2004) as

materials, 180 of which were randomly selected to serve as

learning items with 60 for each task condition and 60 of which

served as lures during the memory test. The learning items in

each condition were randomly transferred into two different

colors (red [RGB: 255, 0, 0] or blue [RGB: 0, 0, 255]), with 30

items in each color. Then, 30 items in each color for each task

were randomly assigned to two locations, with 15 items in each

location. Complexity, agreement, imagery and familiarity of the

items were counterbalanced across different conditions, differ-

ent colors and different locations. The pictures subtended about

10˚ vertical and horizontal visual angles in the encoding phase

and 12˚ in the test phase at the viewing distance of about 50 cm.

All the stimuli were presented on a white screen with a resolu-

tion of 640 × 480 pixels.

Procedures

The participants were not informed about the subsequent

memory test before the task. During the encoding phase, 180

learning items were presented sequentially (Figure 1). For each

encoding trial, a 1 s task cue was presented at first, followed by

a 3 s colored item. The task cues were varied between trials and

participants were required to judge whether it was plausible to

encounter the item appearing in the sky (when the item appear

in the top) or ground (when the item appear in the bottom)

when viewing “LOCATION PLAUSIBLE?” (location-oriented

task), but judge whether it was plausible to encounter the item

appearing in the given color in real life when viewing “COLOR

PLAUSIBLE?” (color-oriented task). They were also asked to

judge whether the item depicted in the picture was animate

when viewing “ANIMATE?” (item-oriented task). Reponses

were given via participant’s key press. The order of presenta-

tion sequence was randomized across participants.

About five minutes after the encoding phase, participants

were given a surprised self-paced memory test. 240 gray ob-

jects were presented sequentially in a random order across par-

ticipants. Participants were instructed to indicate whether the

object was old (presented during the encoding phase) or new

(not presented during the encoding phase). If they responded as

“old”, they were then required to indicate the related location

and color of the object. The order of the location and color

judgments were counterbalanced between participants.

Results

Encoding Task

The encoding trials with no responses (0.16% ± 0.34% of tri-

als) were excluded from further analyses. As is shown in Table

1, the location-oriented trials and the color-oriented trials pro-

duced similar rates of “YES” responses (judged to be plausible

and animate for all the trials, t(13) = 0.49, p > .05, 1 − β = 0.07),

whereas the proportions of “YES” responses in both tasks were

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Table 1.

Behavioral performance during encoding and subsequent memory test.

Task “YES” proportion

(%)

Encoding RT

(ms)

Recognition

(hit rate %)

Location-oriented 56.79 ( 9.57) 1330 (190) 73.33 (14.75)

Color-oriented 54.34 (16.18) 1431 (217) 78.94 (10.34)

Item-oriented 32.29 ( 6.04) 1072 (184) 67.69 (14.48)

Note: Standard errors are given in parentheses. Average “yes” proportions and

recognition hit rates (%) across participants is shown as a proportion of all valid

encoding trials within each task.

higher than that in the item-oriented task (ts > 4.71, ps < .05

with Bonferroni correction for multiple comparison). Besides,

participants responded faster in the item-oriented task than in

the location-oriented task (t(13) = 9.50, p < .05 with Bonferroni

correction for multiple comparison) and responded faster in the

location-oriented task than in the color-oriented task (t(13) =

2.46, p < .05 with Bonferroni correction for multiple compari-

son).

Memory Test

Turning to the subsequent memory performance during test,

the learning items were recognized at a rate of 73.32% ±

11.63% and lures were correctly rejected at a rate of 86.31% ±

7.34%. As shown in Table 1, the mean recognition hit rate in

the color-oriented task was significantly higher than that in the

item-oriented task (t(13) = 3.87, p < .05 with Bonferroni cor-

rection for multiple comparison). The difference of hit rates

between the color-oriented and the location-oriented, the loca-

tion-oriented and the item-oriented conditions did not reach

statistical significance.

Last, the source accuracy of location and color in three tasks,

taken as the proportion of correctly recognized trials, are illus-

trated in Figure 2. A 3 task * 2 source ANOVA revealed that

the main effect of source (F(1, 13) = 60.12, p < .01), the main

effect of task (F(2, 26) = 14.54, p < .01) and the interaction

(F(2, 26) = 18.64, p < .01) were significant. This result indi-

cated that the source accuracy of location was higher than that

of color. Further analysis revealed the source accuracy in the

color-oriented task was higher than in the other two tasks (ts >

4.14, ps < .05 with Bonferroni correction for multiple compari-

son), whereas the difference of source accuracy between the the

location-oriented and the item-oriented tasks did not reach sta-

tistical significance (t(13) = 1.44, p > .05, 1 − β = 0.27). Be-

sides, simple effect analysis of the task effect revealed that the

effect did not differ from zero for location judgment (F(2, 26) =

1.67, p > .05, 1 − β = 0.32), but was significantly greater than

zero for color judgment (F(2, 26) = 30.35, p < .01). Further

analysis revealed that the source accuracy of color in the

color-oriented task was higher than that in the other two tasks

(ts > 5.98, ps < .05 with Bonferroni correction for multiple

comparison), whereas the difference of source accuracy of

color between the location-oriented and the item-oriented tasks

did not reach statistical significance (t(13) = 0.41, p > .05, 1 − β

= 0.07). These findings suggested that the associative source

(i.e., color) needs to be encoded intentionally because its source

accuracy benefited from intentional learning, whereas the or-

ganizational source (i.e., location) could be encoded in a more

automatic manner.

Figure 2.

Average source accuracy of location and color in three tasks.

Eorror bars indicates +/− standard errors.

Discussion

The present study aimed at providing a plausible answer for

the controversy whether organizational source or associative

source could be encoded in a more automatic manner through

incidental learning. Consistent with Hasher and Zacks (1979),

the results implied that organizational source might be encoded

in a more automatic manner through incidental learning, but

associative source might be encoded in a more effortful way,

since only associative source accuracy increased when subjects

were instructed to intentionally learn that source. However, as

Hasher and Zacks’s (1979) viewpoint, automatic and effortful

memory processes can be distinguished from three aspects:

whether it requires considerable attentional resources; whether

it can occur without intention; and whether it benefits from

practice. The present study tested whether the processes in-

volved in encoding organizational or associative source could

occur without intention. Whether encoding organizational or

associative source requires considerable attentional resources or

whether it benefits from practice remains to be tested.

The findings that relative to associative source, organiza-

tional source might be encoded in a more automatic manner

through incidental learning does not comply with the predic-

tions by many other researchers, who argued that organizational

source should be encoded in a more effortful manner, since it is

extrinsic to the item and more intentional effort is required to

bind it to the item (Geiselman & Bjork, 1980; Baddeley, 1982;

Moscovitch, 1992; Spencer & Raz, 1995; Staresina & Davachi,

2008). This inconsistency might be due to the superiority of

learning and memory associated with location. Location changes

may involve eye movements, which may facilitate learning and

memory (Mayr, 1996) and counteract the interruption of main

task in the present study. Further investigation could focus on

the dissociation between associative sources and other organ-

izational sources, such as time.

Besides, the results of the present study could be used to ex-

plain the results from previous studies using incidental learning

task. Previous studies demonstrated that organizational source

accuracy was higher than associative source accuracy during

incidental learning (i.e., participants were not informed what

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would be tested later and the related source was not a part of

the demand of encoding task) (Staresina & Davachi, 2008,

Uncapher et al., 2006). Based on the present results, it is sug-

gested that organizational source is encoded concurrently with

the main task, which produces significantly higher performance

than associative source. Consistently, our data also showed that

organizational source accuracy was higher than associative

source accuracy in the item-oriented task (t(13) = 6.07, p < .05

with Bonferroni correction for multiple comparison).

It should be noted that the results of the present study could

not merely be explained by congruency effect. According to

congruency effect, congruous items eliciting “yes” answers

(e.g., “is ELEPANT animate?”) will result in better subsequent

memory than incongruous items eliciting “no” answers (e.g.,

“is TABLE animate?”, e.g., Schulman, 1974; Craik & Tulving,

1975; Staresina et al., 2009), because unlike incongruous items,

the congruous items have a preexisting relationship with the

question context. This relationship is thought to prompt addi-

tional relational binding processes to combine the context and

the item as an integrated unit, which in turn strengthens the

memory trace. The present study found the location-oriented

task and the color-oriented task produced more “YES” re-

sponses than the item-oriented task, which might foster addi-

tional relational binding processes and strengthen the memory

trace. However, although the source accuracy in the color-ori-

ented task was higher than in the item-oriented task, such supe-

riority in source memory did not appear for the location-ori-

ented task.

Finally, it should also be noted that the results of the present

study might not be strategy-derived. The present experiment

used a mixed trials approach at encoding phase (i.e., asking

participants to make different types of judgments from trial-to-

trial), which might lead participants to more intentionally en-

code all aspects of the stimulus in each trial and develop strate-

gies relating to the perceived importance of location, color, and

animacy. Correspondingly, one might argue that the present

results might be strategy-derived, rather than truly representing

the difference between incidental and intentional encodings.

However, our experimental methods rule out such possibility.

In the experiment, the frequency of each task (1/3) remains the

same during encoding phase. Such manipulation, which has

been informed to the participants before the experiment, might

result in equal perceived importance of three aspects (location,

color, and animacy).

In sum, the present findings suggested that associative source

might be encoded in more effortful way, whereas processing of

organizational source might be performed incidentally.

Acknowledgements

This research was supported by National Natural Science

Foundation of China (31100728), Projects Planning in Shang-

hai Philosophy and Social Sciences Research (2012JJY001).

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