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The Relative Effectiveness of Mixed, Explicit and Implicit

Feedback in the Acquisition of English Articles

Abstract

This article reports on a study that compares the effectiveness

of three oral negative feedback types in the acquisition of

English articles. A mixed feedback treatment, in which

learners' errors were corrected, first, through explicit

feedback, then through implicit feedback, was compared to

implicit-only (i.e., recasts) and explicit-only (i.e., explicit

correction) feedback treatments. The study followed a

pretest/posttest/delayed posttest experimental design. Eighty

English-as-a foreign language learners, whose proficiency level

ranged from beginner to intermediate, were randomly assigned

into explicit-only feedback, implicit-only feedback, mixed

feedback, reduced-explicit feedback and no-feedback control

groups. The learners and researcher met two times for the

treatment sessions. In each treatment session, the learners and

researcher carried out three oral production tasks, where

learner errors on the English indefinite and definite articles

were treated according to their group assignments. The

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differences between the groups in performance were measured

using oral production tasks. The results of the study revealed

that the explicit-only feedback and mixed feedback groups

outperformed all the other groups on the immediate posttest,

but there was no difference between the explicit-only and mixed

feedback groups on either of the posttests. This result was

interpreted as indicating that mixed-feedback can be as

effective as explicit-only feedback.

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1. Introduction

In the field of Second Language Acquisition (SLA), recent

years have witnessed increased research interest in the

investigation of the question of what type of negative feedback

is more effective for L2 development. A group of researchers

has advocated for implicit feedback types that are less likely

to interrupt the flow of communication (e.g., Doughty, 2001;

Doughty and Williams, 1998; Long, 2007; Long and Robinson,

1998). Another group (e.g., Carroll, 2001; Lyster, 1998) has

argued in favor of feedback types that are more explicit,

asserting that the relative salience of explicit feedback can

make it easier for learners to recognize the corrective intent

behind them, which is a necessary step to benefit from negative

evidence according to some researchers (e.g., Carroll, 2001).

Previous research has shown that groups receiving explicit

feedback tend to outperform groups receiving implicit feedback

(Author, XXXX; Carroll and Swain, 1993; Ellis, 2007; Ellis,

Loewen and Erlam, 2006; Sheen, 2007). Despite these results

speaking to the general effectiveness of explicit feedback,

relatively little is known as to what extent a feedback

treatment including both explicit and implicit feedback would

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be effective. An examination of the comparative effects of a

mixed feedback treatment involving both explicit and implicit

feedback to feedback treatments consisting of only one of the

feedback types is important because it could shed light on 1)

the extent to which explicit feedback is necessary to invoke

the desired level of salience, and 2) whether the salient

nature of explicit feedback can help learners interpret

subsequent implicit feedback more efficiently.

2. Literature Review

Disagreement exists about the role of negative feedback in

second language (L2) acquisition. Some researchers (e.g.,

Schwartz, 1993; Truscott, 1996) have argued that negative

feedback can only produce a superficial form of L2 knowledge,

not affecting learners’ competence. The majority of researchers

(e.g., Gass, 1991; Long, 2007), however, does believe that

negative feedback has potential for affecting learners’

competence. Previous meta-analyses comparing groups that

received oral negative feedback to groups that did not receive

feedback have provided supportive evidence for this second

position by showing that negative feedback has a medium-to-

large effect on L2 acquisition (Li, 2010; Lyster and Saito,

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2010; Mackey and Goo, 2007). Aside from the absolute effect of

negative feedback, researchers have also been interested in the

relative effectiveness of different feedback types. Although

there are different ways to classify feedback types (e.g.,

Lyster and Saito, 2010), a widely accepted classification

method involves deciding where along an explicit/implicit

continuum feedback types fall (Ellis, 2001). Two features,

metalinguistic information and directness, play role in the

decision of whether a feedback type leans towards the explicit

or implicit end of the continuum. Feedback types conveying

metalinguistic information (e.g., metalinguistic feedback)

and/or directly informing learners about the accuracy of their

utterances (e.g., explicit correction) have been considered

explicit. The ones, however, lacking metalinguistic

information and/or directness (e.g., clarification requests and

recasts) have been considered implicit.

Recasts, broadly defined as targetlike reformulations of

leaners’ non-targetlike utterances, are considered a form of

implicit feedback. Descriptive studies have shown that recasts

are the most frequently occurring feedback type in language

classrooms (Ellis, Basturkmen and Loewen, 2001; Lyster and

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Ranta, 1997; Panova and Lyster, 2002; Sheen, 2004). For

example, Sheen (2004) reported that recasts accounted for 60%,

whereas explicit feedback (i.e., metalinguistic or explicit

correction) accounted for between 5.8% and 7% of all the

feedback moves provided in different contexts (i.e., second

language, foreign language, immersion). This difference

between implicit and explicit feedback in frequency could be

attributed to teachers’ feedback preferences. Seedhouse (2001)

carried out a conversation analytic study on a database of 330

lessons or fragments of lessons and concluded that teachers

preferred using non-threatening and mitigated implicit feedback

such as recasts.

Despite being a preferred form of feedback, recasts have

been found to be less effective than more explicit feedback

types. Several descriptive studies have carried out a frequency

analysis of learners’ reactions to teachers feedback moves,

i.e., uptake, as a measure for feedback effectiveness. Although

it has been shown that learner uptake and the extent to which

learners benefit from feedback (as measured by posttests) might

not necessarily be related (Mackey and Philp, 1998), the

presence of uptake, at least, indicates that the learner has

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noticed the corrective intent behind the feedback (Mackey, Gass

and McDonough, 2000). Sheen (2004) reported that the average

uptake rates for explicit feedback types (explicit correction,

63%, and metalinguistic feedback, 83%) were considerably higher

than the average uptake rate for recasts (48.2%).

Experimental and quasi-experimental studies investigating

the relative effectiveness of feedback types that differ in

metalinguistic information have revealed that whenever there is

a statistical difference between recasts and metalinguistic

feedback, this difference is in favor of metalinguistic

feedback (Carroll and Swain, 1993; Ellis, 2007; Ellis et al.,

2006; Sheen, 2007). This result, however, should be interpreted

cautiously in light of the following two observations. First,

the findings were not consistent across studies. For example,

Loewen and Nabei’s study (2007), where 66 EFL learners received

recasts, metalinguistic feedback, or clarification requests,

did not show any differences between the groups. Second, there

was considerable methodological variability among the studies:

treatment tasks employed, operationalizations of feedback

types, outcome measures, target structure choice, design

features (e.g., whether learners are assigned randomly to

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experimental groups), number of treatment sessions, duration of

the treatment sessions, consistency in providing feedback for

each error (see Author, XXXX and Ellis et al., 2006 for an

extended list of features).

Much less research has been conducted to compare the

relative effectiveness of oral feedback types that differ in

directness. The only study to date is that by Author (XXXX),

who investigated the relative effectiveness of explicit

correction (direct) versus recasts (indirect), using an

experimental design with two posttests (immediate and delayed).

Forty-eight participants self-selected themselves for the study

on the basis of (1) being a native speaker of English, (2) not

having taken any linguistics course, and (3) not having been

exposed to Turkish. The participants were asked to learn 50

Turkish words in order to carry out the rest of the study.

After learning the words, they carried out two communication

games with the researcher. Learner errors on two Turkish

morphemes (i.e., locative and plural) were corrected according

to group assignment. Oral production, comprehension and

recognition tests were administered to measure learners’

resulting performance. Results revealed that explicit

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correction was more effective than recasts on the oral

production and comprehension tasks. When these results are

considered together with the results of the previous studies

that compared metalinguistic feedback versus recasts, it can be

claimed that not only explicit feedback in the form of

metalinguistic feedback but also explicit feedback in the form

of explicit correction is more effective than recasts.

Researchers have attributed the positive results for

explicit feedback to its relatively more salient nature.

Carroll (2001), among others (e.g., Lyster and Ranta, 1997),

has argued that in order for feedback to be beneficial for

learners, learners should recognize the corrective intent so

that they could shift their attention from meaning to form.

Carroll hypothesized that the recognition of the corrective

intent is facilitated by a failure to find relevance between

the feedback and the ongoing topic of the conversation. Drawing

on Carroll’s ideas, Author (XXXX) pointed out that the explicit

correction used in his study, which included explicit verbal

indicators (i.e., x is wrong, you should say y), could have made

the corrective intent more salient because it was not relevant

to the ongoing talk.

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In sum, research on the relative effects of explicit and

implicit feedback has shown that explicit feedback types are

generally more effective and that this effect might be due to

the way explicit feedback makes the corrective intent salient

for the learner. However, what previous research has not been

able to show so far is the extent to which each feedback

instance in a feedback treatment should be explicit in order to

reach the desired level of effectiveness. Should an learners

receive explicit feedback whenever they produce erroneous

utterance? Or would it be sufficient for learners to receive a

few initial explicit feedback instances and then implicit

feedback instances? One way of seeking answers to these

questions is using a research design where a mixed feedback

treatment including both explicit and implicit feedback can be

compared to single feedback type treatments (i.e., explicit-

only or implicit-only). So far, no attempt has been made to

investigate the effect of a mixed feedback treatment on L2

development by treating it as part of a feedback type variable.

Previous experimental and quasi-experimental studies have

investigated the relative effectiveness of the feedback types

by exposing learners to a single feedback type. Each learner

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throughout these studies received either explicit or implicit

feedback depending on their experimental group. To address this

gap in the negative feedback research, the present study aims

to examine the effectiveness of a mixed feedback (explicit +

implicit) treatment relative to implicit-only and explicit-only

feedback treatments. In such an investigation, it is important

to tease apart whether any effect for the mixed treatment is

attributable to explicit feedback only or to both explicit and

implicit feedback. For this reason, the use of a fourth group

(i.e., reduced-explicit group) receiving as many explicit

feedback instances as the mixed group without any implicit

feedback is necessary. If one can show that the mixed group

performs significantly better than the reduced-explicit group,

one can deduce that explicit feedback alone cannot be

responsible for the overall effectiveness of the mixed feedback

treatment. The research questions were the following:

1- Is there a difference between the oral performance of

the group that receives explicit feedback (i.e., explicit-

only group) and the oral performance of the group that

receives implicit feedback (i.e., implicit-only group)?

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2- Is there a difference between the oral performance of

the group that receives both explicit and implicit

feedback (i.e., mixed group) and the oral performance of

the implicit-only group?

3- Is there a difference between the mixed and explicit-

only groups in oral performance ?

4- Is the oral performance of the mixed feedback group

attributable to the explicit feedback instances provided

during the mixed feedback treatment?

3. Method

3.1. Participants and Context

One hundred twenty students EFL students who were taking

either a 3-hour general English course or a 6-hour English

Speaking course with the researcher volunteered for the study.

The general English course is a requirement for all first-year

university students in Turkey. The course targeted beginner

level students and aimed to improve their vocabulary knowledge

and conversational skills. The English Speaking course was one

of the four courses that the preparatory year students in the

English Language Teaching program are required to take.

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Throughout this course, the learners were engaged in group and

whole-class discussions, individual and group presentations as

well as communicative tasks on topics presented by the course

book. Neither course included any formal grammar teaching. Out

of 120 students who volunteered to participate, 40 students

were screened out because they scored higher than the preset

criterion (20%) on the pretest. The average age of the

remaining 80 participants (28 male and 52 female) was 19.77 (SD

= 1.01). Participants took 7.88 years of English language

instruction on average (SD = 1.82). To measure learners’ general

level of English, the Michigan English Placement Test (EPT) was

administered. The results of the EPT revealed that the levels

of the participants ranged between beginner and intermediate (M

= 35.42, SD = 9.49). Participants were pursuing undergraduate

degrees in math, science, preschool education or English

language teaching.

3.2. Target structure

The English definite and indefinite articles were selected

as the target linguistic structures for the present study. The

motivation for this selection was that English articles have

been considered an important learning challenge for learners

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whose first languages lack articles (García Mayo and Hawkins,

2009). The L1 of the participants in this study was Turkish,

which does not have morphological determiners (Öztürk, 2005)i.

Master (2002) discusses three factors contributing to this

challenge. First, the fact that the articles occur very

frequently in English makes the consistent application of

conscious rules very difficult. Second, noticing the articles

in the spoken mode is challenging because they are unstressed.

Finally, articles resist learners’ tendency to look for a one-

to-one overlap between form and function because they serve for

multiple functions.

Because the choice of an article depends on multiple

factors (e.g., linguistic and pragmatic factors), following

Sheen (2007), the current study has limited the obligatory

contexts for each article to one major function of the

indefinite and definite articles: a as first-mention and the as

anaphoric reference (e.g., we made a cake yesterday. My brother

liked the cake very much). Simply put, the rule can be

expressed as follows. Noun phrases referring to entities that

are introduced in the discourse are preceded by an indefinite

article (first-mention), whereas a particular entity that has

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already been introduced in the discourse is preceded by a

definite article (anaphoric reference).

The learners participating in the study did not receive

explicit instruction or corrective feedback on English articles

in their regular classrooms during the semester they

participated in the study.

3.3. Research design

The study followed a pretest/posttest/control group

between-subjects design with a delayed posttest. Participants

were randomly assigned to one of five conditions: Explicit-only

(N = 16), implicit-only (N = 16), mixed (explicit + implicit;

N = 16) reduced-explicit feedback (N = 16) and no-feedback

control (N = 16) groups. The independent variable was feedback

group, and the dependent variable was oral performance as

measured by oral production tasks.

3.4. Materials

Different versions of an Oral Production Elicitation Tool

(OPET) were used in the tests and feedback sessions. Each OPET

includes three distinct oral production tasks. It has been

argued that learner performance in articles varies depending on

the task used (Muranoi, 2000). Therefore, as an attempt to

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obtain a more reliable representation of learners’ oral

language performance on the target structures, the study

measured oral performance in as many different contexts as

feasible for the study. In order to form different OPETs,

different versions of each individual oral production task were

developed. These oral production tasks were a guided oral

production task, a spot-the-difference task and a story-

retelling task. Task stimuli in each of these individual tasks

were presented through computers.

In the guided oral production tasks (GOP), learners

completed a communication game with the researcher. In order to

fill in the information missing from his task sheet, the

researcher had to elicit some answers from the learner. The

learner’s task was to provide the researcher with the necessary

information by looking at a series MS Power Point slides

containing different objects. The learners saw 24 objects in

two different contexts. They were instructed to name the object

when they saw it for the first time and to talk about one of

the three features (i.e., color, size and price) of it when

they saw it for a second time. These questions created 24

obligatory contexts for the use of each target structure.

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In the spot-the-difference task (SD), the learner and

researcher performed an information gap task that was based on

two room pictures with eight objects. The learner was asked to

describe the picture to help the researcher find the

differences between the two pictures. Although spot-the-

difference tasks have been generally considered two-way

information gap tasks in the SLA literature (e.g., Gass, Mackey

& Ross-Feldman, 2005) in this study, the information flow was

kept one way in order to prevent learners from receiving

positive evidence. As a result, the researcher’s task was to

identify whether the dyad had the same objects in their

pictures, and if they did, whether their locations were the

same. The SDs created eight obligatory contexts for the use of

each target structure.

The story retelling task (RET) asked learners to retell a

story after reading its L1version on a computer screen for ten

seconds. A pilot testing revealed that this time limit was long

enough for learners to comprehend the story and short enough to

keep them away from memorizing the story word for word. Then,

they were asked to retell the story in English using a list of

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English words. Each story created 4-5 obligatory contexts for

the use of each article. Each OPET included two stories.

3.5. Procedure

To prevent lack of vocabulary knowledge from interfering

with task performance, learners were provided with a list of 90

English words prior to the study and asked to study it. No

attempt was made to include words that were relevant for the

courses that the learners were enrolled in. The words were

retrieved from MRC Psycholinguistic Database (Coltheart, 1981)

using the parameters for the following word properties: number

of letters, 3 – 8; number of syllables, 1-2 ; Brown verbal

frequency, 1-1500; concreteness, 600-700; imageability, 600-

700. These properties were selected to ensure that the words

can easily be depicted and to prevent the difficulty in

learning or producing the words from interacting with learners’

performance on the target structures. At the beginning of each

meeting, learners were asked to say the English name of the

objects that were shown to them through a PowerPoint slide

show. Learners could proceed to the next stage if they were

100% accurate in this task. In the first meeting, following the

vocabulary test, the learner and researcher performed two

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OPETs, one for the pretest and one for the first treatment

session. The dyad met for a second time 7-10 days after the

first meeting to perform two more OPETs (one for the second

feedback session and one for the immediate posttest). Two

months after the second meeting, the dyad met for the third

meeting and carried out another OPET as the delayed posttest.

Also in the third meeting, learners filled out a background

questionnaire.

During the OPETs that were administered as tests (i.e.,

pretest, immediate and delayed posttests), the dyad interacted

as much as necessary, but no feedback was provided. During the

OPETs that were used as feedback treatment, the learners in the

explicit-only, implicit-only, mixed and reduced-explicit groups

received negative feedback when they produced non-targetlike

utterances in article use. The feedback provided to these

learners was of two types: explicit or implicit. Explicit

feedback was operationalized through explicit correction.

Explicit correction was defined as the presentation of the

targetlike reformulation of the erroneous segment of the

learner’s production in a direct manner. In explicit

correction, the incorrect segment of the learner’s production

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is, first, directly rejected together with the noun following

it, and then, the correct alternative is directly indicated

together with the noun following the article (see Table 1). The

learners’ L1 was used in the explicit correction because of the

learners’ low proficiency level. Implicit feedback was

operationalized through recasts. A recast was defined as the

targetlike reformulation of the erroneous segment of the

learner’s production . The reformulated utterance also

contained the noun following the article. This recast type has

been referred to as partial recasts in the negative feedback

literature (Loewen and Philp, 2006). Feedback was provided

without any special intonation.

<Insert Table 1 about here>

The feedback groups received either only one type of

feedback, as in the explicit-only, implicit-only and reduced-

explicit groups, or they received a combination of both as in

the mixed group (see Table 3). Below is a description of each

condition.

Explicit-only. The learners in the explicit group received

explicit feedback in the form of explicit correction whenever

they produced a non-targetlike utterance throughout the tasks

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<Insert Table 2 about here>

Implicit-only. The learners in the implicit group received

implicit feedback in the form of recasts whenever they produced

a non-targetlike utterance throughout the tasks.

Mixed. Mixed feedback was defined as the combination of

explicit and implicit feedback, where implicit feedback

followed explicit feedback (Table 3). Learners’ non-targetlike

utterances in the first two obligatory contexts for each

structure in each individual task were corrected through

explicit feedback, whereas learners’ non-targetlike utterances

in the remaining obligatory contexts were corrected through

implicit feedback. The decision of providing explicit feedback

only in the first two obligatory contexts was based on the

prediction that two initial instances of explicit feedback

would be enough to obtain the desired level of salience.

Reduced Explicit. The learners in the reduced-explicit group

received explicit feedback on their non-targetlike utterance in

the first two obligatory contexts in each task (Table 3). The

remaining non-targetlike utterances were left uncorrected.

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No Feedback. In the no-feedback group, the learners

received no feedback but performed the same tasks as the

learners in the other groups. All sessions were audio recorded

for analysis.

<Insert Table 3 about here>

3.6. Scoring

Each task was coded for obligatory contexts, correct

response in obligatory contexts, and suppliance in non-

obligatory contexts. Another rater listened to and coded 10% of

the recorded data from each task. Interrater reliability was

measured by both percentage agreement and Cohen’s Kappa

coefficient (where applicable). Interrater reliability was

acceptable (see Table 4). Next, a target-language use (TLU)

score for each learner was calculated for each target structure

and test following the formula explained in Pica (1983). When

calculating the scores, the individual tasks constituting OPETs

were considered together. Accordingly, correct responses were

added, and then, the sum was divided by the sum of number of

obligatory contexts and suppliance of the target structure in

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non-obligatory contexts, in which the use of the target

structure was inappropriate.

<Insert Table 4 about here>

4. Results

The descriptive statistics, as shown in Table 5 below,

revealed that the mean definite and indefinite scores for each

treatment group were close to each other on the pretest. The

scores of the feedback groups started to differ on the

immediate posttest. On the delayed posttest, there is a

noticeable decrease in the performance of all the feedback

groups. The highest scoring groups were the mixed and explicit-

only in both structures and on both posttests. Before running

the necessary tests to find out whether there were statistical

differences between the groups, pretest, immediate and delayed

posttest scores on both structures were checked for normality.

Pretest scores failed to conform to normality as indicated by

the results of a series Kolmogorov-Smirnov (KS) tests for both

the definite (explicit-only, Z(16) = 1.91, p < . 01; implicit-

only, Z(16) = 2.07, p < . 01; mixed, Z(16) = 1.92, p < . 01;

no-feedback, Z(16) = 1.92, p < . 01; reduced-explicit, Z(16) =

1.57, p = . 02) and the indefinite (explicit-only, Z(16) =

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2.07, p < . 01; implicit-only, Z(16) = 2.15, p < . 01; mixed,

Z(16) = 2.15, p < . 01; no-feedback, Z(16) = 2.04, p < . 01;

reduced-explicit was constant). Therefore, a Kruskal-Wallis

test, a non-parametric equivalent of a one-way ANOVA, for each

structure was carried out to check whether groups differed on

their pretest scores. Neither tests revealed a statistical

difference among groups, indefinite, χ2(4)=2.63, p = .62,

2= .03; definite, χ2(4)=2.32, p = .68, 2= .03. These results

indicate that all groups began on an equal footing with respect

to their pretest scores on both target structures.

<Insert Table 5 about here>

Next, immediate and delayed posttest scores on each of the

target structures were checked for normality. It was found that

data largely conformed to normalityii. Then, two separate

Bonferroni-adjusted, one-way ANOVAs for each target structure

were run. The ANOVA with the immediate posttest indefinite

scores as the dependent variable and Group as the independent

variable revealed an effect for Group F(4, 75) = 26.88, p

< .001. Tukey’s post hoc multiple comparisons revealed that the

explicit-only and mixed groups outperformed all the other

groups with large effect sizes (ranging from d = 1.05 to d =

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5.03), but the difference between the two was not statistical

and small in effect size, d = .24 (see Table 6 for the post hoc

results). It was also shown that the implicit-only and reduced-

explicit groups outperformed the no-feedback group with large

effect sizes (implicit-only, d = 2.05; reduced-explicit, d =

1.98), but there was no statistical difference between the

implicit-only and reduced-explicit groups (in fact, the mean

scores of these groups were the same). The ANOVA with the

delayed indefinite scores as the dependent variable and Group

as the independent variable revealed an effect for Group F(4,

75) = 9.06, p < .001. Tukey’s post hoc multiple comparisons

showed that the explicit-only, mixed, implicit-only and

reduced-explicit groups outperformed the no-feedback group with

large effect sizes (ranging from d = 1.63 to d = 2.91). The

scores of the explicit-only and mixed groups were not

statistically higher than the reduced-explicit and implicit

groups at this time even though the mean scores of the

explicit-only and mixed groups were still higher than the mean

scores of the reduced-explicit and implicit-only groups. The

magnitude of the difference between the mixed and reduced-

explicit as well as the magnitude of the difference between the

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mixed and implicit-only groups were noteworthy as shown by

medium effect sizes (d = .55 and d = .72, respectively).

<Insert Table 6 about here>

The ANOVA with the immediate posttest definite scores as

the dependent variable and Group as the independent variable

revealed an effect for Group, F(4, 75) = 45.01, p < .001.

Tukey’s post hoc multiple comparisons (see Table 6) showed that

the explicit-only and mixed groups outperformed all the other

groups with large differences between the scores (effect sizes

ranging from d = 1.17 to d = 14.41), but there was no

statistical difference between the two, with the magnitude of

the difference being small (d = .15). The implicit-only and

reduced-explicit groups outperformed the no-feedback control

group with large effect sizes (implicit-only, d = -3.15;

reduced-explicit, d = 2.29), but there was no statistical

difference between the two, with the magnitude of the

difference being small (d = .20). The ANOVA with the delayed

posttest definite scores as the dependent variable and Group as

the independent variable revealed an effect for Group, F(4, 75)

= 9.70, p < .001. Tukey’s post hoc multiple comparisons showed

that the explicit-only, mixed, implicit-only and reduced-

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explicit groups outperformed the no-feedback group with large

effect sizes (values ranging from d = 1.22 to d = 2.54). On the

delayed posttest, the scores of the explicit-only and mixed

were not statistically higher than the scores of the reduced-

explicit and implicit-only. However, the mean scores for the

explicit-only and mixed groups were still larger than the mean

scores for the reduced-explicit and implicit-only groups, and

the magnitude of these differences were noteworthy as shown by

medium effect size values (ranging from d = .39 to d = .75).

Finally, the difference between the implicit-only and reduced-

explicit groups was not statistical and small in effect size, d

= .29.

<Insert Figure 1 about here>

<Insert Figure 2 about here>

5. Discussion

The results of the study revealed that all feedback groups

outperformed the no-feedback control group in both structures

on both posttests with large effect sizes (d values ranging

from 1.22 to 14.41). This finding is in line with previous

findings that negative feedback groups consistently performed

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better than no-feedback control groups (Author, XXXX; Ammar and

Spada, 2006; Carroll, 2001; Carroll and Swain, 1993; Doughty

and Varela, 1998; Ellis et al., 2006; Loewen and Nabei, 2007;

Mackey and Philp, 1998; Sheen, 2007). The first research

question of the study was about the relative performance of the

explicit and implicit feedback groups. Results showed that the

explicit feedback was more effective than the implicit feedback

on the immediate posttest, but not on the delayed posttest. The

magnitude of the difference between the explicit and implicit

feedback (d= 1.07) was large. This finding is in line with the

findings of the previous studies that have shown that learners

benefit more from explicit feedback than implicit feedback

(Author, XXXX; Ellis, 2007; Ellis et al. 2006; Sheen, 2007).

However, as mentioned earlier, most of the previous studies

(Ellis, 2007; Ellis et al., 2006; Sheen, 2007) operationalized

explicit feedback through metalinguistic feedback in their

comparisons. Therefore, the consistency between the findings of

AUTHOR (XXXX) and the findings of the current study becomes

especially important because although these two studies

targeted different structures and languages, they

operationalized explicit and implicit feedback in the same way

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(e.g., explicit correction and recasts). In addition, the fact

that the magnitude of the difference between the feedback types

in AUTHOR’s study (oral production, d = 1.00; recognition, d

= .87) was considerably close to the one found in this study (d

= 1.07) adds validity to the findings of these studies.

The second and third research questions asked about the

performance of the mixed feedback relative to the implicit and

explicit groups, respectively. It was found that the mixed

group performed significantly better than the implicit-only on

the immediate, but not on the delayed posttest. In addition,

results revealed that there was no statistical difference

between the mixed and explicit-only groups. Based on these

results, it can be argued that the mixed group performed as

well as the explicit-only group. Both groups performed better

than the implicit-only on the immediate posttest, and there was

no statistical difference between the two on both posttets. The

fourth research question asked whether the oral performance of

the mixed group could be attributed to the explicit feedback

instances provided during the mixed feedback treatment. Because

the mixed group outperformed the reduced-explicit group, it is

possible to claim that the resulting performance of the mixed

30

group could not be due to the few instances of explicit

feedback that the reduced-explicit and mixed groups had in

common. As Appendix D shows, the learners in the mixed group

continued to make errors after receiving explicit feedback and

received implicit feedback on these errors ( indefinite, M =

10.69; definite, M = 9.31). It seems, then, most probable

that the resulting performance was due to the combined effect

of explicit and implicit feedback instances.

A possible reason for this finding may be that the

salience of the implicit feedback (i.e., recasts) in the mixed

feedback treatment increased due to the salience of the

explicit feedback. When salience is viewed as the ease of

noticing the negative evidence and the correct form conveyed

through feedback, explicit feedback has a clear advantage over

implicit feedback as evidenced by the superior performance of

the explicit-only group over the implicit-only group. Part of

this advantage might have come from the overt indicators (e.g.,

X is wrong, you should say Y) used in the explicit correction.

These indicators might have helped learners realize that the

feedback was irrelevant to the topic of the ongoing

conversation, which is considered a necessary step by Carroll

31

(2001) in order for learners to interpret the feedback as a

comment on the form of the utterance. It could be that once

learners came to be aware, through the initial explicit

feedback instances, that comments coming from the researcher

were not related to the topic of the task but about the

targetlikeness of their utterances, then, this awareness might

have facilitated the interpretation of the recasts provided

afterwards. In other words, recasts could have worked like an

elliptical discourse device. In ellipsis, some part of a

sentence is left out, but this does not interfere with its

comprehension because the learner can fill in the missing

pieces. Therefore, although the implicit feedback lacked the

directness of the explicit feedback, previously provided

explicit feedback instances might have caused learners to gain

the maximum benefit out of the implicit ones. One could argue,

then, that the effect of explicit feedback on recasts in a

mixed feedback treatment is similar to the effect of several

previously reported factors on recasts. Previous research on

recasts has shown that factors such as length, number of

changes, type of intonation, communication mode moderate the

effectiveness of recasts by increasing their salience (Author,

32

XXXX; Egi, 2007; Loewen and Philp, 2006; Sheen, 2006). Viewed

from this perspective, the provision of explicit correction

before recasts can be considered another factor that increases

the salience of recasts.

The finding that mixed feedback is comparable to explicit

feedback in effectiveness has an important pedagogical

implication. Previous descriptive classroom studies have

reported that recasts are the most frequent feedback type,

whereas explicit correction is one of the least frequent

(Ellis, et al., 2001; Lyster and Ranta, 1997; Oliver and

Mackey, 2003; Panova and Lyster, 2002; Sheen, 2004). A

potential underlying factor for this difference in frequency

could be teachers’ feedback type preferences. For example, some

teachers are reported to avoid the use of explicit feedback not

to undermine learners` confidence because they consider

explicitly pointing out errors intimidating (Yoshida, 2010).

Ironically, the most salient and effective feedback types are

the ones that are the least frequent ones (as predicted by

Carroll, 2001). To put it differently, the feedback types

avoided by some teachers because of their obtrusive and

intimidating nature are the most effective ones. This means

33

that no matter which type of feedback is chosen to be used

exclusively, the decision will entail a compromise, either from

teacher preferences or from salience. The effectiveness of

mixed feedback in the present study, however, shows that it is

possible to provide negative evidence through feedback

treatments that are closer to what learners and teachers are

already used to without compromising salience. In other words,

the study has shown that it is not necessary to correct each

learner error with explicit correction in order to obtain the

desired level of salience.

Finally, results showed that the statistical differences

between the feedback group pairs (e.g., explicit vs. implicit)

observed on the immediate posttest vanished on the delayed

posttest. This, however, should not be taken to mean all

feedback groups performed equally on the delayed posttest. A

glance at the mean scores reveals that the explicit-only and

mixed groups performed better than the implicit-only and

reduced-explicit groups even on the delayed posttest, which was

two months after the treatment. Future research should

investigate the question of whether the differences between the

feedback groups are durable beyond immediate posttests in order

34

to rule out the possibility that observed differences between

the feedback groups in this study are probabilistically likely.

6. Limitations, Future Research, Conclusions

Several limitations should be born in mind when

generalizations are made from this study. Unlike the majority

of previous studies that operationalized explicit feedback

through metalinguistic feedback, this study operationalized

explicit feedback through explicit correction. This means that

the explicit and implicit feedback compared in the current

study differed in directness, not in metalinguistic

information. Obviously, then, the hybrid feedback treatment

used in this study was a mixture of the two feedback types that

differed in directness. Thus, results should be seen as the

outcome of these specific feedback types. Future research can

combine metalinguistic feedback and recasts and investigate the

extent to which this combination would be effective in

comparison to metalinguistic-only and implicit-only groups.

Furthermore, the study has a limited focus with respect to

the linguistic target. Therefore, claims about the relative

effectiveness of the feedback types on target structures that

35

were not the focus of this study should be made with caution.

Again related to the target structures, this study has reduced

the complexity of English articles by limiting the use of each

article to one major function, i.e., first-mention and

anaphoric reference, for the sake of experimental control. This

approach might have artificially boosted the salience of the

target structures. Therefore, it is essential for future

research to represent a broader array of functions of the

articles.

Finally, the present study has used intensive feedback

targeting pre-determined linguistic structures, as has been the

norm in laboratory studies. Therefore, the results of the study

can only be generalized to one-to-one teaching contexts (i.e.,

tutoring). In tutoring lessons aiming to improve learners’

accuracy on particular targets, instructors can implement the

mixed feedback technique by providing explicit feedback

initially and then keeping on with implicit feedback. The

extent to which the findings of this study informs the

classroom settings where feedback is incidental and provided on

a variety of structures (i.e., extensive) may be limited. In

order to determine whether the findings of this study are

36

applicable to these settings, researchers can investigate the

research questions of this study using designs that include

intact classes. In addition, future classroom studies can vary

the number of explicit feedback instances in a mixed feedback

treatment in order to find the mixture that is optimally

effective and practical.

The present study has made a unique contribution to the

research literature by investigating whether a mixed feedback

treatment would be as effective as an explicit-only feedback

treatment. The results of this study have provided support for

the emerging consensus in the field of SLA that explicit

feedback is more effective than implicit feedback in the short

term. The study has also revealed that a mixed feedback

treatment can be as effective as an explicit feedback

treatment. Because this study is the first to show that a mixed

feedback treatment could be as effective as explicit feedback

treatment, further research is necessary to confirm or

disconfirm this finding. Finally, this study targeted one small

aspect of the English language system (two uses of articles),

future research is necessary to investigate whether the

37

observed effects would apply to other aspects of language

acquisition.  

38

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44

Table 1

Feedback Episodes

Table 2

Implicit Feedback Episodes

Episode 1(Story Retelling) Episode 2 (Spot the

difference)

L: The man put the pizza in a

cupboard and leave. Girl is see

everything.

R: A girl?

L: The girl is see everything.

R: What can you see in your

picture?

L: I can see shirt

R: a shirt

L: a shirt and a pencil

R: Where are they?

Explicit Feedback (Explicit

Correction)

Implicit Feedback (Recast)

L: There is a laptop and a

vase.

R: Where are they?

L: Vase is on the coffee table.

R: Vase yanlis, the vase demen

R: What can you see in your

picture?

L: I can see shirt

R: a shirt

45

lazim.

“Vase is incorrect, you

should say the vase.”

R: What else can you see?

L: a shirt and a pencil

R: Where are they?

Table 3

Feedback Provision by Group

Group First Two OCsa Rest of the OCs

Explicit-only Explicit Explicit

Implicit-only Implicit Implicit

Mix Explicit Implicit

No Feedback No Feedback No Feedback

Reduced

Explicit

Explicit No Feedback

Note. a = Obligatory Context

46

Table 4

Interrater Reliability

Obligatory

Contexts

Correct Response Suppliance in Non-

Obligatory

Indefin

ite

Defini

te

Indefini

te

Definit

e

Indefin

ite

Definite

κ % κ % κ % κ % κ % κ %

GOP - 99.9 - 100 .9

3

99.9

6

.9

0

99.

95

- 99.9

6

- 100

SD - 100 - 100 .7

8

99.8

9

.6

2

99.

83

- 99.8

4

- 99.87

RET - 100 - 100 .8

6

99.9

3

.9

3

99.

96

- 99.9

7

- 99.96

i It should be noted that for some researchers (e.g., Goad & White, 2009) the unstressed bir is an indefinite article.ii KS test results for the indefinite posttest scores were Explicit-only, Z(16) = .79, p = .57; Implicit-only, Z(16) =.67, p = .76; Mixed, Z(16) =.86,p = .45; no-feedback, Z(16) = 1.91, p < . 01; reduced explicit, Z(16) =.68,p = .74. KS test results for definite posttest scores were Explicit-only, Z(16) = .56, p = .91; Implicit-only, Z(16) = 1.14, p = .15; Mixed, Z(16) = 1.35, p= . 05; no-feedback, Z(16) = 2.15, p < . 01; reduced explicit, Z (16) = .75, p = .63. KS test results for indefinite delayed posttest scores wereExplicit-only, Z (16) = .62, p = .84; Implicit-only, Z (16) =.95, p = .33; Mixed, Z (16) =.87, p = .43; no-feedback, the distribution had no variance,therefore a KS test could not be performed; reduced explicit, Z (16) =.68, p = .75. KS test results for definite delayed posttest scores were Explicit-only, Z (16) = 1.09, p =. 19; Implicit-only, Z (16) =.79, p= .56; Mixed, Z (16) = .94, p = .34; No-feedback, the distribution had no variance, therefore a KS test could not be performed; Reduced explicit, Z (16) =1.32, p = .60.

47

Table 5

Post Hoc Tests

Indefinite Definite

Comparison Immediate Delayed Immediate Delayed

MDb p d MD p d MD p d MD p d

Expc vs. Impd .27

*a

.01 1.07 .12 .73 .38 .26

*

.00 1.35 .17 .52 .51

Exp vs. NFe .66

*

.00 3.75 .45* .00 1.92 .85

*

.00 14.4

1

.59* .00 2.38

Exp vs. REf .27

*

.01 1.05 .09 .89 .25 .32

*

.00 1.37 .27 .09 .75

Exp vs. Mixg .05 .96 .24 -.0

8

.92 -.26 .03 1.0

0

.15 .05 .99 .15

Mix vs. Imp .32

*

.00 1.42 .20 .25 .72 .24

*

.01 1.09 .11 .82 .39

Mix vs. NF .72

*

.00 5.03 .53* .00 2.91 .82

*

.00 6.77 .54* .00 2.54

48

Indefinite Definite

Mix vs. RE .32

*

.00 1.38 .16 .42 .55 .30

*

.00 1.17 .22 .26 .65

Imp vs. NF .39

*

.00 2.05 .33* .01 1.63 .58

*

.00 3.15 .42* .00 1.91

Imp vs. RE .00 1.0

0

.00 -.0

3

1.00 2.94 .06 .91 .20 .10 .87 .29

RE vs. NF .39

*

.00 1.98 .37* .00 1.64 .52

*

.00 2.29 .32* .03 1.22

Note. a= statistically significant at an alpha level of .05. b

= mean difference, c = explicit-only, d = implicit-only, e = no

feedback, f = reduced explicit, g = mixed

49

Table 6

Post Hoc Tests

Indefinite Definite

Comparison Immediate Delayed Immediate Delayed

MDb p d MD p d MD p d MD p d

Expc vs. Impd .27

*a

.01 1.07 .12 .73 .38 .26

*

.00 1.35 .17 .52 .51

Exp vs. NFe .66

*

.00 3.75 .45* .00 1.92 .85

*

.00 14.4

1

.59* .00 2.38

Exp vs. REf .27

*

.01 1.05 .09 .89 .25 .32

*

.00 1.37 .27 .09 .75

Exp vs. Mixg .05 .96 .24 -.0

8

.92 -.26 .03 1.0

0

.15 .05 .99 .15

Mix vs. Imp .32

*

.00 1.42 .20 .25 .72 .24

*

.01 1.09 .11 .82 .39

Mix vs. NF .72

*

.00 5.03 .53* .00 2.91 .82

*

.00 6.77 .54* .00 2.54

Mix vs. RE .32

*

.00 1.38 .16 .42 .55 .30

*

.00 1.17 .22 .26 .65

Imp vs. NF .39

*

.00 2.05 .33* .01 1.63 .58

*

.00 3.15 .42* .00 1.91

50

Indefinite Definite

Imp vs. RE .00 1.0

0

.00 -.0

3

1.00 2.94 .06 .91 .20 .10 .87 .29

RE vs. NF .39

*

.00 1.98 .37* .00 1.64 .52

*

.00 2.29 .32* .03 1.22

Note. a= statistically significant at an alpha level of .05. b

= mean difference, c = explicit-only, d = implicit-only, e = no

feedback, f = reduced explicit, g = mixed

51

Figure 1.Indefinite Scores by Time and Treatment Group

Figure 2. Definite Scores by Time and Treatment Group

52

Appendix D

Number of Feedback Instances by Treatment Group and Target

Structure

Indefinite Definite

Groups M SD M SD

Implicit 24.87 9.32 23.63 10.11

Explicit 15.67 6.09 11.73 5.95

Mixed 15.12

(4.44

+10.69)a

6.17

(1.90+5.4

5)

14.00

(4.69 +9.31)

7.28

(3.07+5.92)

No Feedback - - - -

Reduced

Explicit

6.87 3.25 6.93 3.13

Note. a = The figures in parenthesis show the breakdown of the

related category according to explicit correction (first

figure) and recasts (second figure).