Investigating the Role of Selective Attention in Implicit Learning Using Overlapping Letter Strings Daisuke Tanaka (
[email protected]) Department of Cognitive and Behavioral Science, Graduate School of Arts and Sciences University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902, Japan
Sachiko Kiyokawa (
[email protected]) Center for Research of Core Academic Competences Graduate School of Education, University of Tokyo, Hongo 7-3-1 Bunkyo-ku, Tokyo 113-0033, Japan
Ayumi Yamada (ayumi.yamada @ gakushuin.ac.jp) Department of Psychology, Faculty of Letters, Gakushuin University, 1-5-1 Mejiro Toshima-ku, Tokyo 171-8588, Japan
Kazuo Shigemasu (
[email protected]) Department of Cognitive and Behavioral Science, Graduate School of Arts and Sciences University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902, Japan
In this study, the role of selective attention in implicit artificial grammar (AG) learning was investigated using the overlapping procedure; this novel procedure has been invented in order to exclude the methodological problems in the dual-task procedure. The results reveal that selective attention plays an important role in AG learning, although a possibility still remains that participants can learn AG without attention.
Selective attention has also been discussed as a more sophisticated concept; for instance, Jiang and Chun (2001) investigated the effect of selective attention on implicit learning by using a visual search task. However, studies using the AG learning procedure have not been conducted. Therefore, the aim of this experiment was to examine the effect of selective attention on AG learning by using a new procedure.
Purposes
Methods
Abstract
Exposure to a structured stimulus results in the induction of representations of that structure. This ability is known as implicit learning (Reber, 1989). In the context of research on implicit learning, the artificial grammar (AG) learning procedure is a commonly used paradigm. AG is generally defined as the finite-state Markovian rule system (Figure 1). In the standard procedure of AG learning, the participants are exposed to a series of letter strings generated from AG. As a result, the participants can appropriately determine the grammaticality of the novel strings, even though the participants cannot verbalize their criteria. In terms of the relationship between attention and implicit learning, studies using a serial reaction time task have primarily investigated the influence of a secondary task on implicit learning or have compared conditions in which different types of secondary tasks were used (e.g., Nissen & Bullemer, 1987; Stadler, 1995). Relatively rare studies using AG learning also used the dual-task procedure (Dienes, Broadbent, & Berry, 1991). The results showed that the existence of secondary task decreased the participants’ performance in implicit learning. From these results, the researchers draw largely the same conclusion that attention plays an important role in implicit learning, especially in organizing an abstract pattern from stimuli (Stadler, 1995). However, the concept of attention used in these studies is rather broad.
Participants Twenty-six undergraduates participated in this study.
from
Senshu
University
S5 S3
T
J S2
S1
T
S5
S1
N
V
S2
T
V
X N
J
S4
V
X
X
J
S4
N
S3
J
Figure 1: The two AGs used in this study.
Figure 2: An example of overlapping strings.
Stimuli The two AGs used in this experiment were identical to those used by Knowlton and Squire (1996) in terms of their abstract grammar structures. One letter was added to each 205
The 40 pairs were presented in a random order to each participant. A pair of stimuli was presented as long as a participant pressed one of the two specific keys. This procedure of the test phase was repeated twice.
AG to avoid the sharing of bigrams between the two grammars, i.e., Grammar A and Grammar B. We developed two AGs comprising 5 letters—J, N, T, V, and X—with the constraint that these AGs did not have the same bigrams. Next, the letters B, F, L, Y, and Z were systematically substituted for J, N, T, V, and X, respectively in Grammar B. This translation clarified the difference between Grammars A and B since these two grammars shared neither letters nor bigrams at the superficial level. Eighteen grammatical strings were constructed by 3 through 6 letters from each grammar to use in the learning phase. Eighteen pairs of strings were constructed with the constraint that the length of both strings in the pair should be the same. For the test phase, 40 strings were constructed from each grammar. The 80 strings thus constructed were not identical to any of the strings that were used in the learning phase. These strings were called “grammatical strings.” We also constructed non-grammatical strings by replacing one or two letters from the grammatical strings; this was done to deviate from the two AGs with the constraint that the newly replaced letters were also letters included in the ex-grammar. In other words, the participants could not select grammatical strings using their knowledge of the letters that were used in constructing the strings. Two types of pairs were created for the test phase. The first type was a pair of grammatical and non-grammatical strings based on Grammar A; the second type was a pair of grammatical and non-grammatical strings based on Grammar B. Each type comprised 20 such pairs.
Results and Discussion The difference in the selection rates of the grammatical strings between the attended (M = .754) and unattended (M = .635) grammars was significant (t(25) = 4.21, p < .001). This result reveals that attention facilitates implicit learning. This suggestion that attention plays an important role in implicit learning consists with the results of previous studies using different tasks and /or procedures. However, the results of the t-tests (one-tailed) that compared the selection rates of the grammatical strings with the chance levels in each condition were also significant in the cases of the attended grammar (t(25) = 11.49, p < .001) and the unattended grammar (t(25) = 7.36, p < .001). These results could be interpreted as the results of implicit learning from an unattended feature in the visual field. However, an alternative hypothesis suggests that the participants could have selected the grammatical strings using the unattended grammar based on their knowledge of the attended grammar. In fact, the knowledge of the abstract structure of learned grammar was found to be intact even if superficial characters were replaced with others (Reber, 1969). Although the two AGs used in this experiment differed in their letters, the abstract structures of the two grammars were rather similar. In addition to the need for precise research on the role of selective attention in implicit learning, the possibility of the transfer of knowledge acquired from the attended grammar to the unattended grammar needs to be investigated in the future.
Procedures This experiment consisted of two phases—the learning phase and the test phase. In the learning phase, the “+” sign written in 10.5 pt masks the rectangular region (20 cm width × 3.5 cm height) in which two strings were presented. After the presentation of the masks, the two strings were displayed in the rectangular region. These strings were slightly misaligned in relation to each other. This misalignment was intentionally done to ensure that the participants read both the strings perfectly. The duration for which a pair of the strings was presented was 6 s. The strings were painted with different colors—white and red—on a black back screen. The participants were instructed to write down the string of a specific color on a sheet. The grammar extracted from the written strings was designated “attended grammar.” The other grammar comprising ignored strings was designated “unattended grammar.” The string pairs were presented six times. After the learning phase, the participants were exposed to the test phase, which was the grammaticality selection task. The participants were informed that two strings would be presented in the upper and lower regions of the display. Further, they were also informed about the existence of the rules used to construct the strings and that one of a pair followed the rules, whereas the other did not. Then, they were required to press one of two specific keys in order to select which string presented in the display was grammatical.
References Dienes, Z., Broadbent, D., & Berry, D. (1991). Implicit and explicit knowledge bases in artificial grammar learning. Journal of Experimental Psychology: Learning, Memory, and Cognition, 17, 875-887. Jiang, Y., & Chun, M. M. (2001). Selective attention modulates implicit learning. The Quarterly Journal of Experimental Psychology, 54A, 1105-1124. Knowlton, B. & Squire, L. R. (1996). Artificial grammar learning depends on implicit acquisition of both abstracted and exemplar-specific information. Journal of Experimental Psychology: Learning, Memory, and Cognition, 22, 169-181. Nissen, M., & Bullemer, P. (1987). Attentional requirements of learning: Evidence from performance measures. Cognitive Psychology, 19, 1-32. Reber, A. S. (1989). Implicit learning and tacit knowledge. Journal of Experimental Psychology: General, 118, 219235. Stadler, M. A. (1995). Role of attention in implicit learning. Journal of Experimental Psychology: Learning, Memory, and Cognition, 21, 674-685.
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