Acta Psychologica 130 (2009) 1–10
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Transfer of learning in choice reactions: Contributions of specific and general components of manual responses Motonori Yamaguchi *, Robert W. Proctor Department of Psychological Sciences, Purdue University, 703 Third Street, West Lafayette, IN 47907-2081, United States
a r t i c l e
i n f o
Article history: Received 10 June 2008 Received in revised form 5 September 2008 Accepted 12 September 2008 Available online 25 October 2008 PsycINFO classification: 2330 Keywords: Transfer of learning Response mode Simon effect Cognitive processes
a b s t r a c t Manifestations of learned skills and knowledge are known to be context-dependent. However, a study of perceptual-motor learning [Tagliabue, M., Zorzi, M., & Umiltà, C. (2002). Cross-modal re-mapping influences the Simon effect. Memory and Cognition, 30, 18–23] reported context-independent transfer of a learned stimulus–response (S–R) mapping to a task in which the mapping is no longer relevant. Although similar results were observed in subsequent studies, these studies also provided an indication that the transfer is context-dependent. The present study investigated the issue of context-dependence of the transfer of a learned S–R mapping. In experiment 1, groups of participants performed choice-reaction tasks with either the same or different response modes (keypresses or joystick movements) in the practice and transfer sessions. Smaller transfer effects were observed for those who switched response mode in the transfer session than for those who did not, indicating that transfer of the learned mapping is context-dependent. However, transfer also occurred for the former group, indicating that the transfer effect is dependent on both general and specific response components. In experiment 2, the same task conditions were examined, but with action effects consistent across the practice and transfer sessions, which were assumed to introduce a contextual feature that was common to the two sessions. The influence of action effects on transfer depended on the practiced response. The results are discussed in terms of feature overlap between the learning and test contexts, and an association network model of learning and response selection. Ó 2008 Elsevier B.V. All rights reserved.
1. Introduction Transfer of newly acquired skills and knowledge to novel task settings is of great interest in educational, occupational, and military research. Training has little utility if trainees fail to apply newly acquired skills outside of the trained context; classroom knowledge should eventually yield practical applications in solving problems in people’s lives, not just problems on a course exam. In spite of this need for generality of skills and knowledge, transfer of learning is known to be context-dependent. In particular, the knowledge and skills are manifested better when the contexts in which learning occurs and is tested are more similar (Bouton, 1993; Godden & Baddeley, 1975; Healy, Wohldmann, Parker, & Bourne, 2005; Healy, Wohldmann, Sutton, & Bourne, 2006). The context-dependence of transfer of learning is explained by way of associations established between some contextual cues and responses during learning (Bouton, 1993). Alternatively, it is explained by the effectiveness of retrieval cues: Contextual factors during learning determine specific encoding operations and thus * Corresponding author. Tel.: +1 765 494 6861. E-mail address:
[email protected] (M. Yamaguchi). 0001-6918/$ - see front matter Ó 2008 Elsevier B.V. All rights reserved. doi:10.1016/j.actpsy.2008.09.008
how learned events are represented in memory; in turn, how events are stored in memory determines how effective retrieval cues present at test are (Tulving & Thomson, 1973). In any case, a change in the context has a potentially harmful consequence for learned skills and knowledge in most cases. The context-dependence of transfer can be expressed in the following way (Nairne, 2002): Suppose that the practice and test contexts are summarized as vectors of unique features, CP = (X1, . . ., Xm) and CT = (Y1, . . ., Yn), respectively. An event E1 of the practice context is associated with the contextual features Xi during the practice. Thus, the effectiveness of the contextual features as retrieval cues for the event E1 can be expressed as f ðE1 ; X i Þ; where f is some function that represents the associative strength, or weight, of Xi to E1. Thus, f ðE1 ; X i Þ ¼ 0 if they are not associated, and f ðE1 ; X i Þ > 0 if they are associated. The activation of E1 in the presence of the contextual feature Yj of the test context is given by
Pm i¼1 f ½E1 ; SðX i ; Y j Þ UðE1 j Y J Þ ¼ P P ; m i¼1 f ½Ek ; SðX i ; Y j Þ k
ð1Þ
where S is a similarity function. Then, the overall activation of E1 is given by
2
UðE1 j C T Þ ¼
M. Yamaguchi, R.W. Proctor / Acta Psychologica 130 (2009) 1–10 n X
UðE1 j Y j Þ:
j¼1
Provided that the amount of activation of an event is positively related to the probability of its being retrieved, the likelihood of a contextual feature retrieving a learned event at test depends on two factors: (a) whether the feature matches with some contextual feature present during learning and (b) its associative strength with the event proportional to the sum of its associations with other events present during learning. Consequently, a match of contextual features during learning and testing is the precondition for retrieval of the learned skill and knowledge. 1.1. Transfer of learning in choice-reaction tasks Transfer of learning has been studied in choice-reaction tasks by Proctor and Lu (1999) and Tagliabue, Zorzi, Umiltà, and Bassignani (2000). In Proctor and Lu’s study, participants first practiced a task for 900 trials in which they pressed a left key when a stimulus appeared in a right location and a right key when a stimulus appeared in a left location; thus, the task defined a spatially incompatible stimulus–response (S–R) mapping. Subsequently, the participants performed a task in which they responded to a non-spatial stimulus dimension (letter identity), though the stimuli were still presented in left and right locations. Without the prior practice, responses are faster and more accurate when stimulus and response locations correspond than when they do not, a phenomenon called the Simon effect (see Lu and Proctor (1995) and Simon (1990) for reviews). However, after practice with the incompatible S–R mapping, the responses were faster for noncorresponding S–R relations than for the corresponding relations. Tagliabue et al., showed that practice of less than 100 trials with an incompatible spatial mapping was sufficient to eliminate the Simon effect in the transfer session. These observations indicate transfer of the incompatible mapping used in a prior task, despite the fact that the mapping is no longer relevant in a subsequent task. Tagliabue et al. (2000) explained the transfer of the incompatible mapping in terms of a connectionist model developed by Zorzi and Umiltà (1995). According to Tagliabue et al.’s model, response selection is performed based on response activation via two distinct S–R associations. The first association, a short-term memory (STM) link, connects between the task-relevant feature of a stimulus and a pre-specified response, whereas the second association, a long-term memory (LTM) link, connects between a task-irrelevant, spatial feature of a stimulus and a response spatially corresponding to that feature. Consequently, a spatially corresponding response receives activation from both STM and LTM links, whereas a spatially noncorresponding response receives activation only from the STM link. This is assumed to be the mechanism underlying the Simon effect. However, when participants practice a choicereaction task with the incompatible mapping prior to the Simon task, they acquire a new STM link that connects between the spatial stimulus feature and a noncorresponding response. Hence, a spatially noncorresponding response now receives activation from two STM links, which eliminates or even reverses the Simon effect, according to the strength of the newly acquired STM link. In a follow-up study also using less than 100 practice trials, Tagliabue, Zorzi, and Umiltà (2002) examined transfer of the incompatible mapping across different stimulus modalities. When participants practiced the incompatible-mapping task with auditory stimuli and then transferred to the Simon task with visual stimuli, the Simon effect was significantly reduced. Tagliabue et al., concluded, ‘‘The effects of practicing a spatially incompatible task cannot be explained by episodic/contextual factors but must be ascribed to a process of spatial remapping that is not modality
specific” (p. 22). This conclusion is counterintuitive, provided that transfer of learning is known generally to be context-dependent. 1.2. Is transfer context-dependent or context-independent? Several studies have followed up Tagliabue et al. (2002) finding (e.g., Proctor, Yamaguchi, &Vu, 2007; Vu, Proctor, & Urcuioli, 2003), but the results were not entirely clear with regard to contextdependence of the transfer effect. For instance, Vu et al., showed that when the transfer session used visual stimuli, the transfer effect was significantly smaller for participants who practiced with auditory stimuli than for those who practiced with visual stimuli. However, they also found no significant within-modality transfer effect when the transfer session used auditory stimuli, which made it difficult to unambiguously rule out the possibility that the practice with auditory stimuli was merely insufficient to produce a strong transfer effect (e.g., the learned association was weak; see also Keele, Jennings, Jones, Caulton, & Cohen, 1995; Vu, 2007). Consequently, the aim of the present study was to demonstrate context-dependence of a learned S–R mapping in choice-reaction tasks. The study closely followed the method used in the studies of Tagliabue et al. (2000, 2002) and Vu et al. (2003). However, the manipulated variable was response mode, instead of stimulus modality. Because response mode is part of the task context, the size of transfer effects should also depend on that factor. Furthermore, Vu et al., suggested that the lack of transfer effects for auditory Simon task was due to auditory stimuli yielding a stronger tendency to make a corresponding response than visual stimuli. Hence, the design has an advantage of excluding such a confounding factor by maintaining the effects of visual stimulus modality on the Simon effect. The first study was divided into two experiments (experiments 1A and 1B) according to the response mode used in the transfer session. The response mode was a standard keyboard in experiment 1A and a joystick in experiment 1B. Because the magnitude of the Simon effect might be affected by the response mode used in the transfer session, where our focus is on the transfer effect, this way of comparing the conditions seems most appropriate. Nevertheless, we provide a supplementary comparison between the two experiments, so that a higher-order interaction between practice and transfer conditions can be examined. Experiment 2 extended the finding of experiment 1 to another task context in which an additional contextual factor was introduced in the practice and transfer sessions. In particular, regardless of which mode was used, a response produced an action effect that was consistent across the practice and transfer sessions. Previous studies have shown that action effects play an important role in action planning (e.g., Elsner & Hommel, 2001; Hommel, 1993). Thus, that factor can be considered to be a contextual feature. We expected that if consistent action effects are present in the practice and transfer sessions, they increase feature overlap between the contexts and help to maintain the size of the transfer effect when response mode changes. 2. Experiment 1 Despite the fact that the manifestation of learned skills and knowledge is known to be context-dependent (e.g., Bouton, 1993; Godden & Baddeley, 1975; Healy et al., 2005; Tulving & Thomson, 1973), Tagliabue et al. (2002) argued that transfer of the incompatible mapping to a subsequent choice-reaction task was not. We examined their conclusion by manipulating the response mode used in the practice and transfer sessions. Experiments 1A and 1B used visual tasks for both practice and transfer sessions, with a keyboard (1A) or a joystick (1B) in the
M. Yamaguchi, R.W. Proctor / Acta Psychologica 130 (2009) 1–10 Table 1 Response modes used in the practice and transfer sessions of experiments 1 and 2
Experiment 1A
Experiment 1B
Experiment 2A
Experiment 2B
Practice session
Transfer session
Control (no Keyboard Joystick Control (no Keyboard Joystick Control (no Keyboard Joystick Control (no Keyboard Joystick
practice)
Keyboard
practice)
Joystick
practice)
Keyboard
practice)
Joystick
transfer session (see Table 1). In both experiments, one group of participants practiced the incompatible-mapping task with the keyboard, and another group with the joystick. Therefore, response mode of the transfer session was identical with that of the practice mode for one group and different for the other group. A third group performed no practice task and served as the control group to assess whether transfer effects were present for the two experimental groups. According to the model presented earlier (Eq. (1)), feature overlap between the practice and transfer sessions is a determinant of the transfer effect. Because change in response mode likely eliminates some of the contextual features present during practice, the probability of activating episodic associations decreases. Thus, the transfer effect should be larger (i.e., the Simon effect should be smaller) when participants practice with the keyboard than with the joystick in experiment 1A, whereas it should be larger when participants practice with the joystick than with the keyboard in experiment 1B. If the transfer effect is context-independent, little difference between the two practice conditions is expected. 2.1. Method 2.1.1. Participants Two groups of 96 participants were recruited for experiments 1A and 1B from the Introductory Psychology subject pool at Purdue University. They received partial course credits for their participation. All participants were right-handed and reported having normal color vision and visual acuity.
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from the monitor to the axis of the joystick. The base of the joystick was 4.5 cm in height, and the length of the stick was approximately 18 cm. Response time (RT) was measured as the interval between a stimulus onset and a depression of a response key or deflection of the joystick (approximately 5° to the left or right). Participants were instructed to deflect the joystick all the way (approximately 45°). 2.1.3. Procedure For both experiments, participants were randomly assigned to one of three practice conditions (N = 32 for each group; see Table 1). The first group performed the practice session with the joystick, and the second group with the keyboard. The third group was the control group, who did not perform the practice session. The practice session began with instructions displayed on the screen, which emphasized both speed and accuracy. Participants were instructed to place the left index finger on the left key and the right index finger on the right key, respectively, or hold the joystick with their dominant hand. On each trial, the fixation cross was presented on the computer screen. With a 1-s interval, an imperative stimulus appeared on the left or right of the fixation cross, which lasted until a response was made. The imperative stimuli consisted of a white circle on the left or right of the fixation cross. Participants responded to a left circle with a right response (pressing the right key or deflecting the joystick to the right) and a right circle with a left response (pressing the left key or deflecting to the left). An error tone was presented from external speakers located on the left and right sides of the monitor for an incorrect response. The tone duration was 500 ms, and its frequency was 400 Hz. The interval between a response and onset of the next trial (fixation cross) was 1500 ms for both correct and incorrect responses. The procedure for the transfer session was similar to that for the practice session, except that participants responded to a red disc with one response and a green disc with the other. The S–R mapping was counterbalanced across participants. In experiment 1A, participants performed the transfer session with the keyboard, whereas in experiment 1B, they performed the session with the joystick. There were 12 familiarization trials before each session. After the familiarization, each participant performed 84 trials in the practice session, and 156 trials in the transfer session. The first 12 test trials were considered as warm-up in both sessions and were not included in the subsequent analysis. 2.2. Results
2.1.2. Apparatus and stimuli The apparatus consisted of a personal computer and a 17-in. color monitor. The experiment was controlled by a custom program written in VisualBasic 6.0. In both experiments, the imperative stimuli were discs (1 cm diameter) presented to the left or right of the fixation cross (consisting of 0.6 cm horizontal and vertical lines). The distance between the centers of a circle and the fixation cross was approximately 6.3 cm. In the practice session, the discs were colored in white, and participants made a left response to a disc presented on the right and a right response to a disc presented on the left. In the transfer session, the discs were colored in green or red, and participants made a left response to one color and a right response to the other. The color-response mapping was counterbalanced across participants. A response was made either by pressing a left (‘z’) or right (‘/’) key of the keyboard with the left and right index fingers or by deflecting a joystick to the left or right with their dominant hand. The two response keys on the keyboard were 17 cm apart from each other, and the distance between the midpoint of these keys and the monitor was approximately 22 cm. The joystick was placed in front of the monitor at the distance of approximately 19.5 cm
Less than 0.03% and 0.09% of trials were excluded for the practice and transfer sessions, respectively, for being outside the RT boundaries of 100 and 1200 ms. 2.2.1. Experiment 1A: keyboard in transfer session For the practice session, mean RT for correct responses and percentage error (PE) were computed for each participant and submitted to independent-samples t-tests to compare the two response conditions (joystick vs. keyboard; see Table 2). For RT, responses were faster with the keyboard (M = 381 ms) than with the joystick (M = 431 ms), t(62) = 2.82, SE = 17.69, p < .006, but there was no significant difference in PE, t(62) < 0.8, SE = 0.52. For the transfer session, ANOVAs as a function of correspondence (corresponding vs. noncorresponding; within-subject) and practice condition (joystick practice vs. keyboard practice vs. control; between-subject) were conducted for RT and PE (see Table 3). For RT, the main effect of correspondence was significant, F(1, 93) = 15.34, MSE = 492, p < .001, but not that of practice condition, F(1, 93) < 1, MSE = 4994. Responses were faster for the corresponding trials (M = 455 ms) than for the noncorresponding trials
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Table 2 Mean response times (RT; in milliseconds) and percentage errors in the practice session of experiments 1 and 2, as a function of practice mode (values in parentheses are mean standard errors) Practice mode
RT
PE
Experiment 1A: keyboard in transfer session Keyboard 381 (12.59) Joystick 431 (12.42)
1.95 1.52
(0.34) (0.40)
Experiment 1B: joystick in transfer session Keyboard 368 Joystick 412
(7.00) (9.69)
2.04 1.87
(0.35) (0.38)
Experiment 2A: keyboard in transfer session Keyboard 398 (11.61) Joystick 441 (13.14)
1.82 0.74
(0.30) (0.18)
Experiment 2B: joystick in transfer session Keyboard 391 (10.36) Joystick 446 (13.64)
1.26 1.56
(0.22) (0.32)
Table 3 Mean response times (RT; in milliseconds) and percentage errors in the transfer sessions of experiments 1 and 2, as a function of correspondence and practice mode (values in parentheses are mean standard errors) Practice mode
RT
PE
Corresponding Noncorresponding Corresponding Noncorresponding Experiment 1A: keyboard in Control 456 (10.38) Keyboard 464 (11.79) Joystick 444 (9.24)
transfer session 481 (11.21) 463 (9.45) 458 (8.27)
2.22 2.74 2.21
(0.39) (0.42) (0.42)
3.82 3.13 4.17
(0.70) (0.54) (0.72)
Experiment 1B: joystick in transfer session Control 513 (11.20) 550 (12.41) Keyboard 526 (14.81) 552 (13.70) Joystick 492 (11.26) 510 (10.58)
1.91 1.30 1.69
(0.40) (0.38) (0.27)
3.69 3.60 4.47
(0.64) (0.62) (0.72)
Experiment 2A: keyboard in Control 463 (11.60) Keyboard 493 (14.14) Joystick 486 (12.19)
session (11.28) (13.06) (10.61)
1.75 2.71 2.01
(0.35) (0.35) (0.40)
3.36 1.70 3.19
(0.55) (0.32) (0.51)
Experiment 2B: joystick in transfer session Control 502 (11.63) 524 (10.70) Keyboard 557 (12.63) 564 (10.34) Joystick 552 (15.11) 558 (12.85)
1.44 2.24 1.96
(0.25) (0.45) (0.37)
3.40 2.40 2.26
(0.52) (0.44) (0.42)
transfer 482 479 492
(M = 467 ms), yielding a 12 ms Simon effect. The interaction of the two factors was also significant, F(2, 93) = 5.86, MSE = 492, p < .004. Post hoc comparisons (Bonferroni adjustment) showed that the Simon effect was significantly different between the control group
and the keyboard practice (p < .004) but not between the control group and the joystick practice (p > .3). The experimental groups were not significantly different, either (p > .1). These outcomes suggest that the Simon effect (see Fig. 1) was largest for the control group (M = 25 ms), intermediate for the joystick practice (i.e., who switched response mode; M = 14 ms), and smallest for the keyboard practice (i.e., who did not switch response mode; M = 1 ms). Therefore, transfer of the incompatible mapping did occur for both groups, but its magnitude was larger for the keyboard practice than for the joystick practice. For PE, the only significant effect was the main effect of correspondence, F(1, 93) = 9.91, MSE = 8.37, p < .002; responses were more accurate for the corresponding trials (M = 2.39%) than for the noncorresponding trials (M = 3.71%). 2.2.2. Experiment 1B: joystick in transfer session The RT and PE data were analyzed in the same manner as in experiment 1A. For the practice session (see Table 2), responses were significantly faster with the keyboard (M = 368 ms) than with the joystick (M = 412 ms), t(62) = 3.65, SE = 11.95, p < .001. There was no significant difference in PE, t(62) < 0.7, SE = 0.52. For the transfer session (see Table 3), the RT data showed the main effect of correspondence, F(1, 93) = 103.83, MSE = 345, p < .001, and the main effect of practice condition approached significance, F(1, 93) = 2.76, MSE = 9525, p < .068. Responses were faster for the corresponding trials (M = 510 ms) than for the noncorresponding trials (M = 537 ms), yielding a 27 ms Simon effect. Responses were somewhat faster for those who performed the practice session with the joystick (M = 501 ms) than for those who performed with the keyboard (M = 539 ms) or who did not perform the practice session (M = 531 ms). More important, there was a significant interaction of these two factors, F(2, 93) = 4.50, MSE = 345, p < .014. Post hoc comparisons also showed that the Simon effect was significantly different between the control group and the joystick practice (p < .014) but not between the control and the keyboard practice (p > .2). As in experiment 1A, the two experimental groups were not significantly different either (p > .4). The Simon effect (see Fig. 1) was largest for the control group (M = 37 ms), intermediate for the keyboard practice (i.e., who switched response mode; M = 27 ms), and smallest for the joystick practice (i.e., who did not switch response mode; M = 18 ms). Again, these outcomes indicate that transfer occurred for both practice groups, but it was larger for the joystick practice than for the keyboard practice. For PE, only the main effect of correspondence was significant, F(1, 93) = 32.95, MSE = 7.61, p < .001. Responses were more accu-
Experiment 1A
Experiment 1B
50
RT PE
Simon Effect
40 30 20 10 0 -10 Control
Keyboard
Joystick
Control
Keyboard
Joystick
Practice Mode Fig. 1. The Simon effects in experiment 1A (keyboard in the transfer session) and experiment 1B (joystick in the transfer session) as a function of practice mode for mean response time (RT in ms: bar) and percentage error (PE: line).
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rate for the corresponding trials (M = 1.64%) than the noncorresponding trials (M = 3.92%), yielding a 2.28% Simon effect. 2.2.3. Comparison between experiments 1A and 1B To confirm the symmetrical reductions of the transfer effects for the conditions in which response modes in the two sessions were different, an ANOVA as a function of practice condition (keyboard vs. joystick), transfer condition (keyboard vs. joystick), and correspondence was conducted for RT in the transfer sessions of the two experiments. The results showed that the 3-way interaction among those factors was significant, F(1, 124) = 5.91, MSE = 403, p < .017: The transfer effect was larger when the response modes in practice and transfer matched than when they did not. Also, the interaction between transfer condition and correspondence was significant, F(1, 124) = 10.24, MSE = 403, p < .002, indicating that the Simon effect was larger when the transfer session used the joystick (M = 22 ms) than when it used the keyboard (M = 6 ms). Similarly, the main effect of transfer condition was significant, F(1, 124) = 31.97, MSE = 7819, p < .001, showing that responses were faster with the keyboard (M = 457 ms) than with the joystick (M = 520 ms). Hence, the larger Simon effect for the joystick might be due to slower responses with that response mode. 2.3. Discussion The outcomes were consistent in experiments 1A and 1B. For RT, the Simon effect was reduced more when the response mode in the transfer session was the same as that in the practice session than when it was different. The comparison between the two experiments showed a significant interaction, providing statistical support for the cross-over of the transfer effects. Responses were faster with the keyboard than with the joystick in the practice and transfer sessions. This difference in response mode seems to have affected the overall magnitude of the Simon effect but not the pattern of the transfer effect. Experiment 1 indicates that there was context-dependence of transfer with respect to the practiced response mode. On the other hand, the Simon effect was still consistently reduced after practice even when the response mode differed in the transfer session. This outcome suggests that transfer also involved some component that is general between the two response modes. In other words, the transfer effect depends on both general and specific response components. The general component may stem from the spatial-manual mode of responding (Proctor & Wang, 1997a; Proctor & Wang, 1997b) or from an abstract spatial code (e.g., Proctor & Cho, 2006). In any case, the results of experiment 1 are consistent with the hypothesis that transfer of the incompatible mapping is context-dependent. Fig. 2 shows a schematic representation of the noncorresponding S–R association that describes the present results. The emphasis is put on the fact that a response consists of general and specific components, each of which forms an association with the stimulus. When the associated stimulus is presented, these components are activated. If response mode of the transfer session is the same as that of the practice session (Fig. 2a), both components enhance response activation. However, when the response modes of the two sessions differ (Fig. 2b), only the general component contributes to response activation. Consequently, the overall response activation is smaller in the latter condition, reducing the transfer effect. In fact, these models provide an estimate of each component effect, which will be provided in the Section 4.
a
b
S
SP
GE
R
S
SP
GE
R
Fig. 2. Schematic illustrations of hypothetical association networks acquired in the practice session for the conditions where (a) response mode did not switch and (b) the response mode switched in the transfer session of experiments 1A and 1B. Stimulus (S), response (R), general response component (GE) and specific response component (SP).
text-dependent. At the same time, the experiment indicated that the transfer effect depended on both general and specific response components. Experiment 2 further investigated the contribution of another response variable to the transfer of a newly acquired association. The correspondence between stimulus and response depends on how the performer interprets, and thus represents, the task context (e.g., Ansorge & Wühr, 2004; Ansorge & Wühr, in press; Proctor & Reeve, 1985). For instance, it has been shown that the S–R compatibility (SRC) effect can be modulated by emphasizing one stimulus dimension over the other (Vu & Proctor, 2002); the Simon effect for orthogonally arrayed stimulus–response sets can be reversed by changing response position or hand posture (Cho, Proctor, & Yamaguchi, 2008); and the Simon effect can occur based on the correspondence between the locations of stimulus and response key or that between the locations of stimulus and the effect of responding (or action effect), depending on which factor is emphasized (Hommel, 1993). Therefore, it seems possible that, if the transfer effect depends on both general and specific response components, its magnitude can be modulated by manipulating the weights of respective components in the task. Experiment 2 examined this possibility by adding a contextual feature that was assumed to aid the general response component. The design of this experiment was identical with that of experiment 1, except that the goal of participants was to produce an action effect rather than making a bilateral response. However, making a bilateral response was still required to produce an action effect, which obliged participants to perform exactly the same task as that of experiment 1. The action effects were held constant across the practice and transfer sessions. Therefore, the consistent action effects should provide an additional general component for different response modes and reduce differences in the transfer effect between the conditions in which response mode switches and in which it does not. 3.1. Method 3.1.1. Participants Two new groups of 96 participants from the same subject pool as in experiment 1 were recruited for experiments 2A and 2B. All reported having normal color vision and visual acuity.
3. Experiment 2 Experiment 1 showed that transfer of the incompatible mapping was sensitive to a change in response mode and thus con-
3.1.2. Apparatus and stimuli The apparatus was identical with that used in experiments 1A and 1B, except that there were two square boxes presented on
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the left and the right of the lower portion of the screen (2.8 cm in height and width). The distance from the center of a box to the midline of the screen was 6.3 cm, and that to the bottom of the screen was 7.5 cm. The imperative stimuli occurred 2.5 cm above the box and were identical with those used in experiments 1A and 1B. The left box was filled in white when a left response was made (i.e., left keypress or deflection of the joystick to the left), whereas the right box was filled when a right response was made, providing an action effect that spatially corresponded to the response. An action effect was presented as soon as a response was detected, and it remained on the screen for 500 ms or until the response was set to a neutral state (i.e., a response key was released or the joystick returned to the center) if it had not been done within the 500 ms interval during which the screen was paused. 3.1.3. Procedure Participants in each experiment were randomly assigned to one of the three practice conditions; control, joystick practice, keyboard practice (N = 32 for each; see Table 1). Instructions were displayed on the screen at the beginning of the practice and transfer sessions. It was emphasized that participants were to ‘‘turn on the left or right light in response to presentation of a stimulus,” rather than to press a key or deflect the joystick. The procedure closely followed that of experiments 1A and 1B in other respects. Among those who used the joystick, four participants in experiment 2A and three participants in experiment 2B were lefthanded; the remaining participants were right-handed. 3.2. Results Trials for which RT was less than 100 ms or greater than 1200 ms were discarded (0.04% and 0.51% of trials, respectively, for practice and transfer sessions). RT and PE were analyzed in the same manner as in experiments 1A and 1B. 3.2.1. Experiment 2A: keyboard in transfer session For the practice session (see Table 2), responses were faster with the keyboard (M = 398 ms) than with the joystick (M = 441 ms), t(62) = 2.48, SE = 17.54, p < .016. In contrast, responses were more accurate with the joystick (M = 0.74%) than with the keyboard (M = 1.82%), t(62) = 3.16, SE = 0.34, p < .002. For the transfer session (see Table 3), the RT data showed no significant main effect of correspondence, F(1, 93) = 1.68, MSE = 366, or practice condition, F(1, 93) < 1, MSE = 9162. However, the interaction between these factors was significant,
F(2, 93) = 12.27, MSE = 366, p < .001. As in experiment 1A, post hoc comparisons showed that the Simon effect was significantly different between the control and the keyboard practice (p < .001), but not between the control and the joystick practice (p > .1). There was also a significant difference between the two experimental groups (p < .010). The Simon effect (see Fig. 3) was largest for the control group (M = 19 ms), intermediate for the joystick practice (i.e., who switched response mode; M = 6 ms), and smallest for the keyboard practice (i.e., who did not switch response mode; M = 14 ms). Hence, the pattern of Simon effects across groups is similar to that of experiment 1A. For PE, the main effect of correspondence just missed the significance criterion, F(1, 93) = 3.86, MSE = 4.36, p < .052. Responses were more accurate for the corresponding trials (M = 2.16%) than for the noncorresponding trials (M = 2.75%), yielding a 0.59% Simon effect. The main effect of response condition was not significant, F(1, 93) < 1, MSE = 7.08, but its interaction with correspondence was, F(2, 93) = 7.26, MSE = 4.36, p < .001. Post hoc comparisons showed that the Simon effect was significantly different between the control and the keyboard practice (p < .003) but not between the control and the joystick practice (p < .1). The two experimental groups were also significantly different (p < .011), consistent with the RT data. Again, the Simon effect was largest for the control group (M = 1.61%), intermediate for the joystick practice (M = 1.18%), and smallest for the keyboard practice (M = 1.01%). 3.2.2. Experiment 2B: joystick in transfer session For the practice session (see Table 2), responses were faster with the keyboard (M = 391 ms) than with the joystick (M = 446 ms), t(62) = 3.16, SE = 17.13, p < .002. The PE data showed no significant difference between the two response conditions, t(62) < 0.8, SE = 0.38. For the transfer session (see Table 3), the main effect of correspondence was significant for RT, F(1, 93) = 13.67, MSE = 457, p < .001. Responses were faster for the corresponding responses (M = 537 ms) than for the noncorresponding responses (M = 549), yielding a 12 ms Simon effect. The main effect of practice condition was also significant, F(1, 93) = 4.63, MSE = 9244. Responses were fastest for the control group (M = 513 ms), intermediate for the joystick practice (M = 555 ms), and slowest for the keyboard group (M = 561 ms). The interaction between these factors approached significance, F(2, 93) = 2.72, MSE = 457, p < .071, and a contrast test (control vs. joystick and keyboard) showed a significant effect, t(93) = 2.32, SE = 6.54, p < .022. The Simon effect (see Fig. 3) was 22 ms for the control group, 6 ms for the joystick practice (i.e.,
Experiment 2A
Experiment 2B
30
RT PE
Simon Effect
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0
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-20
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Control
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Practice Mode Fig. 3. The Simon effects in experiment 2A (keyboard in the transfer session) and experiment 2B (joystick in the transfer session) as a function of practice mode for mean response time (RT in ms: bar) and percentage error (PE: line).
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who did not switch response mode), and 7 ms for the keyboard practice (i.e., who switched response mode). Thus, the transfer effect was equivalent between those who switched response modes and those who did not. For PE, the main effect of correspondence was significant, F(1, 93) = 9.14, MSE = 3.42, p < .003, but that of practice condition was not, F(1, 93) < 1, MSE = 7.74. Responses were more accurate for the corresponding trials (M = 1.88%) than for the noncorresponding trials (M = 2.67%), yielding a 0.79% Simon effect. The interaction between the two factors was also significant, F(2, 93) = 4.69, MSE = 3.42, p < .011. Post hoc comparisons showed that the Simon effect was significantly different between the control group and the experimental groups (ps < .045), but not between the latter groups (p > .9). The Simon effect was 1.96% for the control group, 0.30% for the joystick practice, and 0.16% for the keyboard practice. 3.2.3. Comparison between experiments 2A and 2B As in experiment 1, an ANOVA on RT as a function of practice condition, transfer condition, and correspondence was conducted. The three-way interaction of these factors was significant, F(1, 124) = 4.31, MSE = 435, p < .040. However, as seen above, this pattern does not indicate the symmetrical reductions of the transfer effects observed in experiment 1. Instead, it reflects the observation that the difference in transfer effects between the two practice conditions of experiment 2B is reliably smaller than that between the two practice conditions of experiment 2A. The interaction between practice condition and transfer condition was also significant, F(1, 124) = 4.03, MSE = 435, p < .047, which reflects the
a
GE
3.3. Discussion The Simon effect was smaller for participants who did not switch response mode between the practice and transfer sessions than for those who switched response mode in experiment 2A (with the keyboard in the transfer session). This outcome suggests specificity of transfer to the practiced response mode even when identical action effects were present in both sessions. In contrast, in experiment 2B (with the joystick in the transfer session), the interaction between correspondence and practice condition did not attain the .05 criterion, but the contrast test showed that Simon effect was significantly larger for the control group than the average of the two experimental groups, indicating that transfer of the incompatible mapping occurred. However, the transfer effect was similar for those who switched and did not switch response mode. Reflecting this observation, the comparison between experiments 2A and 2B indicated that the patterns of transfer effects differ between the experiments. Hence, transfer occurred to a similar extent for the two practice conditions in experiment 2B. One possible reason for the patterns of the transfer effects is that a change in the task context is more attention-absorbing when response mode switches from joystick to keyboard (experiment 2A) than when it switches from keyboard to joystick (experiment
b
S
SP
fact that the Simon effect was larger for the joystick (M = 6 ms) than for the keyboard (M = 4 ms). The main effect of transfer condition was also significant, F(1, 124) = 31.97, MSE = 9896, p < .001, which agreed with experiment 1 that responses were faster with the keyboard (M = 487 ms) than with the joystick (M = 558 ms).
AE
S
SP
GE
AE
R
R
c
d S
SP
GE
R
S
AE
SP
GE
AE
R
Fig. 4. Schematic illustrations of hypothetical association networks acquired in the practice session for (a) keyboard-to-keyboard, (b) joystick-to-keyboard, (c) joystick-tojoystick, and (d) keyboard-to-joystick conditions of experiments 2A and 2B. Stimulus (S), response (R), general response component (GE), specific response component (SP) and action-effect component (AE).
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2B). That is, in the latter condition, participants kept attending to action effects after the response mode switched, whereas they did not in the former condition. If one assumes that the Simon effect relied entirely on the correspondence between the action effects and stimuli, this possibility may explain the present results. However, the assumption is not supported by the observation that the magnitude of the Simon effect was smaller for those who did not switch response mode in experiment 2A (14 ms) than in experiment 2B (6 ms). If action effects fully determined encoding of response (and hence the transfer effect), these magnitudes should have been similar. Another possible reason is that the influence of action effects is contingent on the response mode used in the practice session. Participants who switched response mode in experiment 2A used the joystick in the practice session, whereas those who switched response mode in experiment 2B used the keyboard in the practice session. This explanation may be described more clearly by referring to network models of the type provided in experiment 1. As earlier, it is assumed that general and specific response components contribute to the acquisition of noncorresponding S–R associations (see Fig. 4). To describe the task conditions of experiment 2, an ‘action-effect component’ is introduced into the response code, which is assumed to have formed a noncorresponding association with the spatial feature of stimuli. Because action effects were identical for the two response modes, the role of that component is to provide an additional general component for response encoding. In Fig. 4a and c, the conditions in which response modes for the practice and transfer sessions are identical, the activation of the specific component contributes to response activation. However, in Fig. 4b and d, the conditions in which response modes for the two sessions differ, the activation of the specific component does not contribute to response activation. If the action-effect component serves as an additional general component when the response mode of the practice session is the keyboard (Fig. 4a and d) but not when it is the joystick (Fig. 4b and c), more components contribute to response activation in Fig. 4a than in Fig. 4b, whereas the difference in the number of components is small in Fig. 4c and d. Thus, the models can produce the observed pattern of the Simon effects in the present experiments. A final possible reason for the observed pattern of the transfer effects is that the degree of learning was smaller when practicing with the joystick than with the keyboard, while the influences of action effects on the transfer effects were present in all conditions. In this case, all conditions formed noncorresponding associations between stimulus and the general plus action-effect components, but the association between stimulus and the specific component contributed only for the keyboard practice group of experiment 2A. A smaller amount of learning for the joystick practice groups might have occurred because performing the incompatible-mapping task was more difficult with the joystick than with the keyboard in the presence of the action effect. An indication would be the observation that RT in the practice condition was longer with the joystick than with the keyboard. However, experiment 1 also showed this pattern. Another indication would be that PEs were significantly different between the joystick and keyboard groups in the practice session of experiment 2A. Again, this does not seem to support the difficulty hypothesis, because experiment 2B did not reveal a significant difference, and because experiment 2A showed that the joystick group performed better than the keyboard group in terms of PE. Although these results do not completely reject the difficulty hypothesis, we favor the response-contingency hypothesis over the difficulty hypothesis because, as shown later, estimations of component effects derived from the models are consistent with the results of experiments 1 and 2.
4. General Discussion This study examined context-dependence of transfer of the incompatible mapping. Previous studies (Proctor & Lu, 1999; Tagliabue et al., 2000) showed that the Simon effect is reduced or even reversed after practice with the incompatible-mapping task, indicating transfer of the noncorresponding S–R association. Having shown that the Simon effect with visual stimuli was also reduced after practice with auditory stimuli, Tagliabue et al. (2002) argued that the transfer effect was context-independent. However, subsequent studies provide an indication that seems to contradict their conclusion (e.g., Proctor, Yamaguchi, & Vu, 2007; Vu, 2007; Vu et al., 2003). The present experiments provided unambiguous results that suggest context-dependence of the transfer effect. Experiment 1 showed that the transfer effect was reduced when response modes differed between the practice and transfer sessions, compared to when response mode was the same. Thus, the results support context-dependence of the transfer effect. At the same time, however, the transfer effect was still evident in the condition where response mode switched. Hence, the effect is dependent on both general and specific response components. In experiment 2, the influence of response mode was also examined in the presence of action effects that were consistent across the practice and transfer sessions, with the assumption that action effects would provide an additional general component and thus reduce the influence of the specific response component on the transfer effect. With keyboard responses in the transfer session, the pattern of the Simon effects was similar to that observed in experiment 1, indicating little evidence that the action effects provided an additional general response component. In contrast, with joystick responses in the transfer session, the presence of action effects appeared to have prevented a reduction of the transfer effect when response mode switched, indicating that the action effect served as an additional general response component. Based on these observations, association network models were constructed for the respective conditions. Given the models in Figs. 2 and 4, it is possible to estimate the effect sizes of the components on the transfer of the incompatible mapping. For instance, in experiments 1A and 1B, the general component is assumed to exert its influence in the conditions where response mode switched and where it did not, whereas the specific component exerts its influence only in the latter condition. Thus, the effect size of the specific component on the transfer effect can be obtained by comparing the magnitudes of the Simon effect for those conditions. Assuming additive effects of the general and specific response components, we obtain 15 ms of the specific-component effect for experiment 1A and 10 ms for experiment 1B. These effect sizes are, respectively, those attributable to the specific component of the keyboard and of the joystick. In turn, from comparisons between the control group and those who switched response mode, the effect size of the general component is estimated to be 11 ms in experiment 1A and 10 ms in experiment 1B. These highly similar effect sizes provide convincing support for the models. Similarly, Fig. 4a and b provide a joint effect of the specific (keyboard) and action-effect components as 20 ms in experiment 2A. Provided that the specific-component effect of the keyboard is 15 ms, the effect size of the action-effect component is 5 ms. Also, comparison of the control group and those who switch response modes (Fig. 4b) provides a 13 ms effect of the general component, which is close to the values estimated in experiments 1A and 1B. In the same manner, experiment 2B provides a joint effect of specific (joystick) and general components of 16 ms (control vs. Fig. 4c), which the results of experiment 1B show as 20 ms (10 ms effect for each component). At the same time, the joint effect of general
M. Yamaguchi, R.W. Proctor / Acta Psychologica 130 (2009) 1–10
and action-effect components is 15 ms (control vs. Fig. 4d), which is predicted based on the 10 ms effect of the general component derived from experiment 1B and the 5 ms effect of action-effect component derived from experiment 2A. Therefore, these results are reasonably consistent across the experimental conditions and can be taken as a support for the articulated models. Because these are rough estimates without statistical tests, we leave the final judgment to the readers. Though the influence of action effects on transfer was minimal in experiment 2B, despite the fact that they provided additional feature overlap between the practice and transfer contexts, this observation is not necessarily at odds with the retrieval model of Eq. (1). The selective influence of action effect on transfer can be incorporated into the function f. That is, its associative strength is greater when practicing with the keyboard than with the joystick. Influences of action effects in action planning are typically attributed to integration by way of anticipating the consequences of responding (Hommel, 1996; Hommel, Müsseler, Aschersleben, & Prinz, 2001). Consistent with this explanation, previous studies showed that there is a compatibility effect between action effect and response (Koch & Kunde, 2002; Kunde, 2001). Wang, Proctor, and Pick (2003) showed that when wheel rotation controlled movement of a visual cursor, the Simon effect was determined by the correspondence between the stimulus location and the direction of the cursor movement, but when wheel rotation only triggered a cursor movement, the movement direction did not determine the Simon effect. Furthermore, Wang, Proctor, and Pick (2007) showed that, having performed with the controlled-cursor condition, the triggered-cursor could also affect the Simon effect, indicating transfer of a reference frame to a subsequent task. Hence, certain action effects seem to be integrated better with a particular response mode, and their influences can be transferred to a subsequent task. Several studies have demonstrated the importance of action effects for learning in sequential and choice-reaction tasks (e.g., Elsner & Hommel, 2001; Elsner & Hommel, 2004; Hommel, 1996; Ziessler, 1998). Because there are several factors that differ between the keyboard and joystick responses, the present study does not point out a single factor responsible for selective influence of action effects. Therefore, the results suggest a need for future studies on this issue. 5. Conclusion The importance of transfer studies of the present type is that, whereas the influence of irrelevant stimulus features on performance is often considered to be robust (hard-wired or overlearned), it is easily overridden by small amounts of practice (Proctor et al., 2007). The present experiments provide clear evidence consistent with the general notion that transfer of learning is context-dependent (e.g., Healy et al., 2005; Tulving & Thomson, 1973). Especially, they suggest that feature overlap between the practice and transfer sessions is an important factor for transfer of learning to occur. Ansorge and Wühr (in press) recently showed that transfer of the Simon effect from a choice-reaction task to a go/no-go task was sensitive to chromatic similarity of stimuli used in the tasks, consistent with the feature overlap account. In any case, given that the transfer of a learned S–R mapping is contextdependent, the transfer paradigm used in the present study is useful for investigating the extent to which particular contextual factors contribute to learning.
Acknowledgements This research was supported in part by Grant W911NF-05-10153 from the Army Research Office. We thank Ulrich Ansorge, Ir-
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ing Koch, and Jeroen Smeets for helpful comments on an earlier version of this manuscript. References Ansorge, U., & Wühr, P. (2004). A response-discrimination account of the Simon effect. Journal of Experimental Psychology: Human Perception and Performance, 30, 365–377. Ansorge, U., & Wühr, P. (in press). Transfer of response codes from choice responses to go-nogo tasks. Quarterly Journal of Experimental Psychology. Bouton, M. E. (1993). Context, time, and memory retrieval in the interference paradigms of Pavlovian learning. Psychological Bulletin, 114, 80–99. Cho, Y.-S., Proctor, R. W., & Yamaguchi, M. (2008). Influences of response position and hand posture on the orthogonal Simon effect. Quarterly Journal of Experimental Psychology, 61, 1020–1035. Elsner, B., & Hommel, B. (2001). Effect anticipation and action control. Journal of Experimental Psychology: Human Perception and Performance, 27, 229–240. Elsner, B., & Hommel, B. (2004). Contiguity and contingency in action-effect learning. Psychological Research, 68, 138–154. Godden, B. R., & Baddeley, A. D. (1975). Context-dependent memory in two natural environments: On land and underwater. British Journal of Psychology, 66, 325–331. Healy, A. F., Wohldmann, E. L., Parker, J. T., & Bourne, L. E. Jr., (2005). Skill training, retention, and transfer: The effects of a concurrent secondary task. Memory and Cognition, 33, 1457–1471. Healy, A. F., Wohldmann, E. L., Sutton, E. M., & Bourne, L. E. Jr., (2006). Specificity effects in training and transfer of speeded responses. Journal of Experimental Psychology: Learning, Memory and Cognition, 32, 534–546. Hommel, B. (1993). Inverting the Simon effect by intention. Psychological Research, 55, 270–279. Hommel, B. (1996). The cognitive representation of action: Automatic integration of perceived action effects. Psychological Research, 59, 176–186. Hommel, B., Müsseler, J., Aschersleben, G., & Prinz, W. (2001). The theory of event coding (TEC): A framework for perception and action planning. Behavioral and Brain Science, 24, 849–937. Keele, S. W., Jennings, P., Jones, S., Caulton, D., & Cohen, A. (1995). On the modularity of sequence representation. Journal of Motor Behavior, 27, 17–30. Koch, I., & Kunde, W. (2002). Verbal response–effect compatibility. Memory and Cognition, 30, 1297–1303. Kunde, W. (2001). Response–effect compatibility in manual choice reaction tasks. Journal of Experimental Psychology: Human Perception and Performance, 27, 387–394. Lu, C.-H., & Proctor, R. W. (1995). The influence of irrelevant location information on performance: A review of the Simon and spatial Stroop effects. Psychonomic Bulletin and Review, 2, 174–207. Nairne, J. S. (2002). The myth of the encoding-retrieval match. Memory, 10, 389–395. Proctor, R. W., & Cho, Y. S. (2006). Polarity correspondence: A general principle for performance of speeded binary classification task. Psychological Bulletin, 132, 416–442. Proctor, R. W., & Lu, C.-H. (1999). Processing irrelevant location information: Practice and transfer effects in choice-reaction tasks. Memory and Cognition, 27, 63–77. Proctor, R. W., & Reeve, T. G. (1985). Compatibility effects in the assignment of symbolic stimuli to discrete finger responses. Journal of Experimental Psychology: Human Perception and Performance, 11, 623–639. Proctor, R. W., & Wang, H. (1997a). Differentiating types of set-level compatibility. In B. Hommel & W. Prinz (Eds.), Theoretical issues in stimulus–response compatibility (pp. 11–37). Amsterdam: North-Holland. Proctor, R. W., & Wang, H. (1997b). Set- and element-level stimulus–response compatibility effects for different manual response sets. Journal of Motor Behavior, 29, 351–365. Proctor, R. W., Yamaguchi, M., & Vu, K.-P. L. (2007). Transfer of noncorresponding spatial associations to the auditory Simon task. Journal of Experimental Psychology: Learning, Memory, and Cognition, 33, 245–253. Simon, J. R. (1990). The effects of an irrelevant directional cue on human information processing. In R. W. Proctor & T. G. Reeve (Eds.), Stimulus– response compatibility: An integrated perspective (pp. 31–86). Amsterdam: North-Holland. Tagliabue, M., Zorzi, M., & Umiltà, C. (2002). Cross-modal re-mapping influences the Simon effect. Memory and Cognition, 30, 18–23. Tagliabue, M., Zorzi, M., Umiltà, C., & Bassignani, F. (2000). The role of LTM links and STM links in the Simon effect. Journal of Experimental Psychology: Human Perception and Performance, 26, 648–670. Tulving, E., & Thomson, D. M. (1973). Encoding specificity and retrieval processes in episodic memory. Psychological Review, 80, 352–373. Vu, K.-P. L. (2007). Influences on the Simon effect of prior practice with spatially incompatible mappings: Transfer within and between horizontal and vertical dimensions. Memory and Cognition, 35, 1463–1471. Vu, K.-P. L., & Proctor, R. W. (2002). The prevalence effect for two-dimensional S–R compatibility is a function of the relative salience of the dimensions. Perception and Psychophysics, 64, 815–828. Vu, K.-P. L., Proctor, R. W., & Urcuioli, P. (2003). Effects of practice with an incompatible location-relevant mapping on the Simon effect in a transfer task. Memory and Cognition, 31, 1146–1152.
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M. Yamaguchi, R.W. Proctor / Acta Psychologica 130 (2009) 1–10
Wang, D.-Y. D., Proctor, R. W., & Pick, D. F. (2003). The Simon effect with wheelrotation responses. Journal of Motor Behavior, 35, 261–273. Wang, D.-Y. D., Proctor, R. W., & Pick, D. F. (2007). Coding controlled and triggered cursor movements as action effects: Influences on the auditory Simon effect for wheel-rotation responses. Journal of Experimental Psychology: Human Perception and Performance, 33, 657–669.
Ziessler, M. (1998). Response-effect learning as a major component of implicit serial learning. Journal of Experimental Psychology: Learning, Memory, and Cognition, 24, 962–978. Zorzi, M., & Umiltà, C. (1995). A computational model of the Simon effect. Psychological Research, 58, 193–205.
