The Activation and Instantiation of Instrumental Inferences

Transcription

1 Discourse Processes, 46: , 2009 Copyright Taylor & Francis Group, LLC ISSN: X print/ online DOI: / The Activation and Instantiation of Instrumental Inferences Mary Harmon-Vukić Department of Psychology Providence College Sabine Guéraud Department of Psychology University of Paris-8 Karla A. Lassonde Department of Psychology Minnesota State University, Mankato Edward J. O Brien Department of Psychology University of New Hampshire Participants read a series of passages containing an action that required the use of an instrument. In Experiment 1, a naming task failed to detect activation of a target instrument when that instrument was supported in the preceding text. In Experiment 2, reading times were slow on a target sentence that contradicted the inferential information, indicating that instrument information had been activated. The combination of the results from Experiments 1 and 2 are consistent with the view that activation involves a set of features of a concept, not a specific lexical item. The results from Experiment 3 and 4 demonstrated the role of contextual support in the activation and instantiation of instrumental inferences. Correspondence concerning this article should be addressed to Mary Harmon-Vukić, Department of Psychology, Providence College, 1 Cunningham Square, Providence, RI mharmon@providence.edu 467

2 468 HARMON-VUKIĆ, GUÉRAUD, LASSONDE, O BRIEN When composing text, writers understand that the flow of information should be smooth; that is, incoming information should integrate easily with what came before. On the one hand, if a writer leaves too many gaps between ideas, then comprehension becomes difficult. On the other hand, if a writer leaves no gaps explicitly stating every detail the text becomes overly redundant. Comprehension is best when text contains gaps that can be quickly and easily filled in by the reader on the basis of his or her general world knowledge. Most theories of reading comprehension recognize that making inferences to fill gaps between explicitly stated information is a critical component of the reading process (e.g., Graesser, Singer, & Trabasso, 1994; McKoon & Ratcliff, 1992; van Dijk & Kintsch, 1983; Zwann & Radvansky, 1998). However, these theories differ regarding the types of inferences that become activated and the conditions under which inferential processing occurs. The types of inferences that become available during reading fall into two broad categories: necessary and elaborative. Necessary inferences are those that are required for comprehension to proceed smoothly. In contrast, elaborative inferences simply expand on the explicitly stated information and are not essential for complete comprehension. There is general agreement that inferences necessary for comprehension become available to readers during normal reading. Examples of necessary inferences include bridging inferences (Clark & Sengul, 1979; Haviland & Clark, 1974), anaphoric inferences (McKoon & Ratcliff, 1980; O Brien, Duffy, & Myers, 1986), and causal inferences (Keenan, Baillet, & Brown, 1984; Graesser et al., 1994; Singer, Graesser, & Trabasso, 1994; Trabasso & Sperry, 1985). There is also converging agreement that with sufficient contextual support, elaborative inferences become activated; that is, although elaborative inferences are not necessary for comprehension, with sufficient context they become available and can influence comprehension. For example, O Brien and Albrecht (1991) found that with high contextual support, a target antecedent was inferred upon reading a category anaphor. This was true even when an alternative antecedent had been explicitly stated in the text. More recent studies have also provided evidence for the activation of predictive inferences when supported by a strong context (e.g., Cook, Limber, & O Brien, 2001; Murray, Klin, & Myers, 1993; Peracchi & O Brien, 2004). For example, when readers are presented with information about an angry man throwing a delicate porcelain vase against the wall, the concept break becomes activated (Klin, Guzman, & Levine, 1999; Peracchi & O Brien, 2004). Despite the growing evidence that contextual support is a key component in detecting activation of such elaborative inferences, the role of context in the activation of instrumental inferences, another form of elaborative inference, is less clear (Dosher & Corbett, 1982; McKoon & Ratcliff, 1981). Early work suggested that instrumental inferences are not typically activated during reading (Corbett & Dosher, 1978; Dosher & Corbett, 1982; Singer, 1979). For example,

3 INSTRUMENTAL INFERENCES 469 Dosher and Corbett presented sentences containing a verb that implied the use of an instrument (e.g., He pounded the nail ). After each sentence, an instrument was presented that was either appropriate (e.g., hammer) or inappropriate (e.g., broom) to the action mentioned in the sentence. They found that response times were the same for the appropriate and inappropriate instruments, indicating that instrumental inferences had not been activated. However, in a subsequent study, they detected activation of the appropriate instrument when they explicitly instructed participants to identify the appropriate instrument for the action mentioned in the text. Dosher and Corbett concluded that instrumental inferences were not automatically activated but could become available if readers were encouraged to engage in strategic processes. In contrast to the findings of Dosher and Corbett (1982), there is evidence that with sufficient context, instrumental inferences become activated without explicit instruction to do so (Garrod & Sanford, 1981; Lucas, Tanenhaus, & Carlson, 1990; McKoon & Ratcliff, 1981). For example, McKoon and Ratcliff (1981) presented participants with passages such as the following: Bobby got a saw, hammer, screwdriver, and square from his toolbox. He had already selected an oak tree as the site for the birdhouse. He had drawn a detailed blueprint and measured carefully. He marked the boards and cut them. Then Bobby pounded/stuck the boards together with nails/glue (p. 674). Note that the final sentence of the text contained a verb that expressed an action that was either appropriate (e.g., pounded the boards together with nails) or inappropriate (e.g., stuck the boards together with glue) to the instrument that had been explicitly mentioned earlier in the passage (e.g., hammer). Recognition times on the target instrument were faster following the appropriate condition compared to the inappropriate condition, suggesting that the instrument had been activated. However, when the target instrument was replaced with an object that was less related to the action (e.g., mallet), they were unable to detect activation of the instrumental inference. McKoon and Ratcliff (1981) concluded that instrumental inferences became activated only when the target instrument was highly related to the main action in the sentence. The lack of a consistent finding regarding the activation of instrumental inferences at the level of the situation model (i.e., the level that captures the representation of what the text is about) is somewhat surprising. This is especially true because at the level of individual sentences, there is considerable evidence that the semantic relations between verbs and agents (e.g., instruments) increase the activation of potential, but unstated, instruments (e.g., Garrod & Sanford, 1981; McRae, Cree, Westmacott, & de Sa, 1999; McRae, Ferretti, & Amyote, 1997; McRae, Hare, Elman, & Ferretti, 2005). McRae et al. (2005) noted that, verbs as they are accessed, should immediately activate highly specific knowledge about

4 470 HARMON-VUKIĆ, GUÉRAUD, LASSONDE, O BRIEN entities that typically participate in the event that they encode (p. 1176). For example, certain verbs (e.g., sweep, color, and shave) may constrain activation of likely instruments (e.g., broom, crayon, and razor) simply because of the semantic relation between the two. In fact, McRae et al. (2005) showed that the degree to which verbs constrain activation of related instruments at the sentence level is likely to vary due to the differences in the strength of these relations. Within the situation model, the verb should continue to contribute to constraining activation to a limited number of instruments; the additional contextual support necessary to further constrain activation to a specific instrument would come from the contextual support from the surrounding text. Lack of sufficient contextual support from the surrounding text may be the critical difference between studies that have provided evidence for the activation of an instrumental inference and those that have not. Those studies that detected activation of an instrumental inference included an explicit mention of the to-beinferred instrument (e.g., Lucas et al., 1990; McKoon & Ratcliff, 1981), whereas those studies that failed to detect activation did not include an explicit mention of the to-be-inferred instrument (e.g., Dosher & Corbett, 1982; Singer, 1979). Explicitly mentioning the instrument may provide the additional contextual support necessary to result in activation of the instrumental inference; that is, it may not be the explicit mentioning of the target instrument per say instead, it may be the additional contextual support the explicit mentioning provided. In studies that did not find activation for a specific instrumental inference (e.g., Dosher & Corbett, 1982; Singer, 1979), it may be that a subset of the features associated with a particular instrumental inference was activated, but that activation was relatively weak and, therefore, could not be detected by facilitation in response times to a specific target word. For example, reading the sentence, The actor swept the floor in the garage (Dosher & Corbett, 1982), may activate a set of features consistent with the concept broom such as brush, sweep, dirt, and so forth, but the actual lexical item broom may not have received sufficient activation to be detected. This would be consistent with McKoon and Ratcliff s (1986) minimal-inferencing hypothesis in which inference activation is often general rather than specific (for a similar argument at the situation model level, see Cook et al., 2001; for a similar argument at the sentence level, see McRae et al., 2005; and for a similar argument of the activation of emotional inferences, see Blanc, 2006; Gygax, Garnham, & Oakhill, 2004; Gygax, Oakhill, & Garnham, 2003). The goal of this set of experiments was to further assess the relation between contextual support and the activation of instrumental inferences. In Experiment 1, a word-naming task replicated previous work, which suggested that instrumental inferences were not activated when the target instrument was not explicitly stated in the previous text. Experiment 2 investigated if something more general had been activated, such as a set of features, by measuring reading time on a critical

5 INSTRUMENTAL INFERENCES 471 sentence. Experiment 3 was designed to show that increasing the contextual support, without including an explicit mention of the instrument, was sufficient to produce measurable activation of an instrumental inference. Experiment 4 assessed whether the activation obtained in Experiment 3 was transient or if the activation resulted in the inference being encoded into long-term memory. EXPERIMENT 1 The purpose of Experiment 1 was to replicate previous work (e.g., Lucas et al., 1990; McKoon & Ratcliff, 1981) showing that activation of instrumental inferences was only detected when an explicit mention of the instrument was provided in an earlier portion of the text. Participants read a series of passages and were asked to name the target instrument at the end of each passage. Each passage appeared in each of three experimental conditions: the implicit condition, the explicit condition, or the control condition. An example is presented in Table 1 (see the Appendix for additional examples). In the implicit condition, the text was supportive of a target instrument, but the instrument was not explicitly stated. In the explicit condition, the text was also supportive of the target instrument, and the instrument was explicitly stated. The control condition contained an object unrelated to the target instrument while remaining consistent with the passage. Naming time on the target instrument was recorded. Based on previous results (Dosher & Corbett, 1982; Lucas et al., 1990; McKoon & Ratcliff, 1981), the TABLE 1 Sample Passage From Experiment 1 Introduction Carol had been working on a quilt for some time. Her daughter had requested that she make one for her new baby. She did all of her work by hand, which of course took longer. Implicit Inference-Evoking Sentence Carol focused on sewing each stitch very carefully. Explicit Sentence Carol focused on sewing each stitch very carefully with a needle. Control Sentence Carol focused on attaching the seams together carefully with a glue gun. Probe Word needle Comprehension Question Was Carol making a sweater?

6 472 HARMON-VUKIĆ, GUÉRAUD, LASSONDE, O BRIEN instrumental information should only be active when the target instrument was explicitly stated in the text. Method Participants. Participants included 36 undergraduate students from the University of New Hampshire, who received partial course credit for their involvement in the experiment. Materials. The materials were 24 narrative passages. Each passage began with an introduction that described the setting and character of the story. The introduction contained a mean of words, with a range of 32 to 36 words. This was followed by one of three experimental sentences: an implicit inferenceevoking sentence, an explicit sentence, or a control sentence. The explicit sentence stated the use of an instrument, whereas the implicit inference-evoking sentence implied its use. The control sentence mentioned an object unrelated to the target instrument while remaining consistent with the passage. The mean length for the implicit and explicit sentences, and the control sentences were 9.20, 11.95, and words, respectively. Each passage was followed by a target instrument word that participants named out loud. After naming the probe word, a comprehension question was presented to ensure that participants were reading the passages carefully. The questions were focused on details from the passage unrelated to the instrument. In addition, there were an equal number of yes and no questions. Three material sets were constructed. Each set contained eight passages in each of the three experimental conditions, plus an additional 24 filler passages to divert participants attention from the fact that the passages and probes involved instruments. A non-instrument probe was presented after each filler passage, followed by a comprehension question. Across the three material sets, each passage appeared only once in each of the three conditions. Procedure. Participants were randomly assigned to one of the three material sets. All participants were run individually in a session that lasted approximately 1 hr. All materials were presented on a video monitor controlled by a 2 Dell 386 microcomputer. Each trial began with the word READY in the middle of the screen. Participants were instructed to press a line-advance key when ready. Each press of the key erased the current line of text and presented the next line. Participants were instructed to read at a normal and comfortable reading rate. Following the last line of each passage, the cue XXXX appeared for 500 ms. The cue was then replaced by a probe word. Participants were instructed to name the probe word aloud as quickly as possible. When the probe was named, a voice key

7 INSTRUMENTAL INFERENCES 473 triggered, the probe word was erased from the screen, and the naming time for the probe was recorded. After the probe word, the cue QUESTIONS appeared in the middle of the screen for 2,000 ms. This was followed by a comprehension question to which participants responded by either pressing a yes or no key. On the trials where participants made errors, the word ERROR appeared in the middle of the screen for 750 ms. Before beginning the experimental passages, participants read three practice passages with the experimenter present to ensure that they were familiarized with and understood the procedure. Results and Discussion In all analyses reported, F 1 always refers to tests against an error term based on participant variability, and F 2 always refers to tests against an error term based on item variability. All analyses were significant at an alpha level of.05, unless otherwise indicated. All response times beyond 2.5 SDs from the mean were eliminated from the analyses. Across all experiments, this resulted in the elimination of less than 2.2% of the data. In addition, all voice key failures when naming times were recorded were eliminated; this resulted in the additional elimination of less than 5.3% of the data. The mean naming times for probe words in Experiment 1 are presented in Table 2. There was a significant effect of explicitness of instrument mention: F 1 (2, 66) D 19.61, MSE D ; F 2 (2, 42) D 19.26, MSE D Planned comparisons confirmed that naming times were faster when the probe word followed the explicit sentence than when it followed either the control sentence, F 1 (1, 33) D 33.92, MSE D and F 2 (1, 21) D 34.67, MSE D ; or the implicit inference-evoking sentence, F 1 (1, 33) D 23.84, MSE D and F 2 (1, 21) D 26.83, MSE D Naming times did not differ significantly between the implicit and control conditions (p s >.51). TABLE 2 Mean Response Times (in Milliseconds) and Standard Deviations as a Function of Explicitness of Instrument Mention in Experiments 1 and 2 Instrument Mention Control Implicit Explicit Variable M SD M SD M SD Naming time (Experiment 1) Reading time (Experiment 2) 2, , ,

8 474 HARMON-VUKIĆ, GUÉRAUD, LASSONDE, O BRIEN As expected, mean naming times for probe words were the fastest when the instrument had been explicitly stated in the passage. Also, naming times were equally slow when the instrument followed the implicit inference-evoking and control sentences. Thus, the pattern of results was consistent with past research demonstrating that activation of instrumental inferences was not detected if the instrument had not been explicitly mentioned in the text (Dosher & Corbett, 1982; Lucas et al., 1990). As previously discussed, this absence of facilitation in naming the probe instrument when the use of the instrument was implied and not explicitly stated could reflect activation of only a small subset of the features of a specific instrument; that is, activation was relatively weak and could not be detected by facilitation in naming times for a specific target word. It is possible that the naming task is only sensitive to activation of a specific lexical item and, therefore, activation of the inference went undetected. Experiment 2 was designed to test this possibility. EXPERIMENT 2 The results from Experiment 1 suggested that instrumental inferences were not activated, unless the text contained an explicit mention of the instrument. However, one possible explanation is that the naming task only measured the activation of a specific lexical item and that inference activation is often general rather than specific (e.g., Cook et al., 2001; McKoon & Ratcliff, 1986; McRae et al., 2005). If inferential information consists of a subset of features of an instrument then the naming task may not be an accurate measure of what was currently activated. Thus, Experiment 2 employed a reading task to assess whether the type of activation that occurs is something more general, such as a set of features. In this experiment, participants read the passages used in Experiment 1. The passages were modified so that the inference-evoking or control sentences were immediately followed by a critical sentence (see Table 3 for a sample passage and the Appendix for additional examples). This sentence was designed to contradict the use of the instrument stated in the explicit sentence (e.g., The job would be easier if Carol had a needle ). The assumption when using the reading time paradigm is that comprehension of a sentence that is consistent with the inference will be faster when an inference has been activated than when no inference has been activated. However, the use of reading time has been criticized as an inaccurate measure of inference activation (McKoon & Ratcliff, 1980). There are several other factors that cause reading times to fluctuate including lexical priming, repetition effects, coherence breaks, or the results of spillover effects from the preceding text

9 INSTRUMENTAL INFERENCES 475 TABLE 3 Sample Passage From Experiment 2 Introduction Carol had been working on a quilt for some time. Her daughter had requested that she make one for her new baby. She did all of her work by hand, which of course took longer. Implicit Inference-Evoking Sentence Carol focused on sewing each stitch very carefully. Explicit Sentence Carol focused on sewing each stitch very carefully with a needle. Control Sentence Carol focused on attaching the seams together carefully with a glue gun. Critical Sentence The job would be easier if Carol had a needle. Closing Section She tried hard to keep working patiently. She thought about how exciting it would be to have a grandchild. It was her first grandchild and she couldn t wait to have a new baby around. Comprehension Question Was Carol making a sweater? (McKoon & Ratcliff, 1980). Furthermore, using reading times to detect the activation of elaborative inferences often involves using null results to support inference activation (Keenan, Potts, Golding, & Jennings, 1990). To avoid such problems, passages in Experiment 2 contained a target sentence that contradicted the inference (Garrod & Sanford, 1981; Keenan et al., 1990; O Brien & Albrecht, 1992). The underlying assumption of this paradigm is that reading times on the contradictory sentence would be slow only if the inference had been previously activated. Thus, while a contradictory sentence not only avoids the standard issues surrounding the reading time paradigm, it may also serve as a more sensitive measure of inferential information that becomes available during reading (O Brien & Albrecht, 1992). Reading times for the critical sentence should be fastest following the control sentence because the material in the control sentence and the critical sentence is consistent. A slowdown in reading is expected on the critical sentence when it is presented after the explicit sentence because the critical sentence is inconsistent with what is explicitly stated in the text. Finally, the result of interest is reading time on the critical sentence when it immediately follows the implicit inferenceevoking sentence. If the instrumental inference is activated, reading times on the critical sentence should be slower than when the control sentence is presented because the critical sentence is inconsistent with the inference. However, if the inference is not activated when the implicit inference-evoking sentence is

10 476 HARMON-VUKIĆ, GUÉRAUD, LASSONDE, O BRIEN presented, reading times on the critical sentence should be the same as in the control condition. Method Participants. Participants included 45 undergraduates from the University of New Hampshire enrolled in introductory psychology courses, who had not participated in Experiment 1. Participants received partial course credit for their involvement in the experiment. Materials. The materials were the same passages used in Experiment 1, with one modification (see Table 3 for a sample passage). A critical sentence was added immediately after the explicit, implicit inference-evoking, and control sentences. This critical sentence contained information that was inconsistent with information in the explicit sentence but remained consistent with the control sentence. When the implicit inference-evoking sentence was presented, the critical sentence was only contradictory if the inference had, in fact, been activated. The mean character length for the critical sentence was 37.75, with a range of 35 to 42 characters. The passages ended with a brief closing section with an average of words. Each passage was then followed by the same comprehension question that was used in Experiment 1. Three material sets were constructed. Each set contained eight passages that appeared in each of the three conditions. Across the three material sets, each passage appeared only once in each of the three conditions. Twenty-four filler passages were added to divert participants attention from the contradictory information in some of the passages. Procedure. The procedure for Experiment 2 was the same as Experiment 1, except that no probe word was presented. Reading times were recorded for the critical sentence. Comprehension time was measured as the time between key presses. Results and Discussion The mean reading times for the critical sentence appear in Table 2. The effect of explicitness of the instrument mention was significant: F 1 (2, 84) D 19.21, MSE D 192,153.66; F 2 (2, 42) D 8.68, MSE D 249, Planned comparisons showed that reading times for the critical sentence were faster when it followed the control sentence than when it followed the explicit sentence, F 1 (1, 42) D 25.16, MSE D 541, and F 2 (1, 21) D 14.43, MSE D 595,776.99; and the implicit inference-evoking sentence, F 1 (1, 42) D 4.12, MSE D 208, and

11 INSTRUMENTAL INFERENCES 477 F 2 (1, 21) D 5.72, MSE D 508, In addition, reading times were faster when the implicit inference-evoking sentence was presented compared to when the explicit sentence was presented. This difference was significant when tested against participant variability, F 1 (1, 42) D 19.00, MSE D 402,918.30; but was only marginally significant when tested against item variability, F 2 (1, 21) D 3.82, MSE D 395,136.59, p D.06. The slow down in reading when the instrument was implicitly stated indicated that some instrumental information became available to readers. The combined results of Experiments 1 and 2 demonstrate that the inferential information available to the reader was not sufficient to be detected in naming times for a specific lexical item but was sufficient to disrupt reading times. In addition, these results also demonstrated the legitimacy of using the reading time paradigm in measuring the activation of an elaborative inference. EXPERIMENT 3 In Experiment 1, it is possible that the failure to detect activation of a specific instrument with a naming time measure was due to the lack of sufficient contextual support in the implicit inference-evoking condition. If correct, increasing the contextual support, without including an explicit mention of the instrument, should serve to increase the activation of an instrumental inference to a level that can be detected by a facilitation in naming time. In Experiment 3, the amount of contextual support for the target instrument was varied to determine if the explicit mention of the target instrument was a necessary condition to detect activation of instrumental inferences with a lexical item (e.g., naming task), or if simply increasing contextual support was the key factor. To investigate the influence of contextual support on the activation of instrumental inferences, we varied the level of information supporting the targeted instrumental inference. The low-context condition included the same introduction used in the passages in Experiment 1, without the inclusion of an explicit mention. We labeled this condition the low-context condition because in Experiment 1, this context was not sufficient to produce a facilitation in naming time for the target instrument. The high-context condition contained information that was more strongly supportive of the target instrument. If increasing the contextual support without explicitly mentioning the target instrument is sufficient to activate a lexical item, then naming times for the target instrument should be faster when following the implicit inference-evoking sentence than when following the control sentence. However, this should occur only in the high-context version; a lack of facilitation in naming time for the low-context version would be consistent with the results of Experiment 1.

12 478 HARMON-VUKIĆ, GUÉRAUD, LASSONDE, O BRIEN Method Participants. Participants were 60 University of New Hampshire undergraduates enrolled in introductory psychology courses, who had not participated in the previous experiments. Participants received partial course credit for their involvement in the experiment. Materials. The materials were 24 passages from Experiment 1 (see Table 4 for a sample passage and the Appendix for additional examples). Each passage began with an introduction that was either supportive (e.g., low-context) or highly supportive (e.g., high-context) of the target instrument. The low-context introduction was the same as the introduction in the passages from the previous experiments. The high-context version was created by altering the introduction so that it contained additional concepts (i.e., contextual support) related to the targeted instrumental inference. Within each passage, the high-context and lowcontext introductions were always exactly the same length. Across passages, the mean length of the introduction was words, with a range of 34 to 36 words. The introduction was followed by either the implicit inference-evoking sentence or the control sentence. Both sentences were identical to those used in previous experiments. Immediately after the implicit inference-evoking sentence or the control sentence, participants were asked to name the target instrument word out loud. TABLE 4 Sample Passage From Experiment 3 Low-Context Introduction Carol had been working on a quilt for some time. Her daughter had requested that she make one for her new baby. She did all of her work by hand, which of course took longer. High-Context Introduction Carol had been working on a quilt for some time. She was careful to use a thimble because she was always pricking herself. The thimble kept the sharp point from puncturing her in her thumb. Implicit Inference-Evoking Sentence Carol focused on sewing each stitch very carefully. Control Sentence Carol focused on attaching the seams together carefully with a glue gun. Probe Word needle Comprehension Question Was Carol making a sweater?

13 INSTRUMENTAL INFERENCES 479 Four material sets were constructed. Each set contained six passages in each of the four experimental conditions. Across the four sets, each passage occurred only once in one of the four conditions. As in Experiments 1 and 2, 24 filler passages were included in the materials. Procedure. The procedure was the same as in Experiment 1. Results and Discussion The mean naming times for probe words are presented in Table 5. Naming times were shorter when the probe word followed the implicit inference-evoking sentence than when it followed the control sentence: F 1 (1, 56) D 5.79, MSE D ; F 2 (1, 20) D 5.07, MSE D However, this was only true in the high-context condition. The interaction between context and sentence condition was significant when tested against participant variability, F 1 (1, 56) D 6.70, MSE D ; but failed to reach significance when tested against item variability (p D.21). Planned comparisons confirmed that naming times were faster in the high-context implicit condition than in the high-context control condition: F 1 (1, 56) D 13.01, MSE D ; F 2 (1, 20) D 6.05, MSE D In contrast, this difference was not reliable in the low-context version when tested against participant variability or item variability (p s >.54). The pattern of naming times in the high-context condition indicates that activation of instrumental inferences can be detected with a word-naming task. Thus, with sufficient contextual support, activation of an instrumental inference can be constrained to the point where activation can be detected with a single lexical item. This result shows that contextual support from an explicit mention of the instrument in text is not the only condition required to detect activation of instrumental inferences with a single lexical item. Rather, as previous studies on elaborative inferences have shown (Cook et al., 2001; McKoon & Ratcliff, 1986; O Brien, Shank, Myers, & Rayner, 1988), activation of an instrumental inference TABLE 5 Mean Naming Times (in Milliseconds) and Standard Deviations as a Function of Context Condition and Sentence Condition in Experiment 3 Context High Low Variable M SD M SD Implicit inference-evoking sentence Control sentence

14 480 HARMON-VUKIĆ, GUÉRAUD, LASSONDE, O BRIEN is also dependent on the degree of contextual support in the text; that is, as the degree of contextual support increases, activated inferential information becomes increasingly more specific and, therefore, could be detected by activation of a single lexical item. In the case of instrumental inferences, the context seems to influence the extent to which activated features converge on one specific lexical item. Indeed, the results suggest that in the high-context implicit condition, the number of features consistent with the targeted instrumental inference that has been activated is greater than in the low-context implicit condition. As a result, in the high-context implicit condition, the set of features that became activated was detectable with a word-naming task. The results from Experiments 2 and 3 indicate that instrumental inferences become available to readers to varying degrees as a function of contextual support, either from an explicit mention of the instrumental inference or contextual constraint. Experiment 4 was designed to examine whether instrumental inferences were instantiated into long-term memory and how contextual support might influence instantiation. EXPERIMENT 4 The passages were similar to those from Experiment 2 with two modifications (see Table 6 for a sample passage). First, the high-context version from Experiment 3 was included. Second, a backgrounding section was added after the explicit, implicit inference-evoking, and control sentences to shift attention away from the target instrument. As in Experiment 2, reading times were recorded on the critical sentence. If the inference is instantiated into long-term memory in both low-context and high-context conditions, we expect to see the same pattern of results as in Experiment 2; that is, reading times for the critical sentence should be slower when either the explicit sentence or implicit inference-evoking sentence is presented in the passage than when the control sentence is presented. If the inference is not instantiated, a slowdown in reading should appear only when the explicit sentence is presented. Method Participants. Participants were 90 University of New Hampshire undergraduates, who had not participated in the previous experiments. They received partial course credit for their involvement in the experiment. Forty-five participants read the passages in the high-context version, and 45 participants read the passages in the low-context version.

15 INSTRUMENTAL INFERENCES 481 TABLE 6 Sample Passage From Experiment 4 Low-Context Introduction Carol had been working on a quilt for some time. Her daughter had requested that she make one for her new baby. She did all of her work by hand, which of course took longer. High-Context Introduction Carol had been working on a quilt for some time. She was careful to use a thimble because she was always pricking herself. The thimble kept the sharp point from puncturing her in her thumb. Implicit Inference-Evoking Sentence Carol focused on sewing each stitch very carefully. Explicit Sentence Carol focused on sewing each stitch very carefully with a needle. Control Sentence Carol focused on attaching the seams together carefully with a glue gun. Backgrounding Section She wanted this to be perfect for her new little grandchild. This was Carol s first grandchild and she was thrilled to be a grandmother. Suddenly she noticed she had made a mistake on the quilt. She had to retrace her steps and redo a whole section to fix the seam. Critical Sentence It would be easier if Carol had a needle. Closing section She tried hard to keep working patiently. She thought about how exciting it would be to have a grandchild. It was her first grandchild and she couldn t wait to have a new baby around. Comprehension Question Was Carol making a sweater? Materials. The materials were the passages from Experiment 2 with the following modifications (see Table 6 for a sample passage and the Appendix for additional examples). First, the high-context introduction from Experiment 3 was included to investigate the influence of context. Thus, each passage began with either the high-context or low-context introduction followed by either the implicit inference-evoking, explicit sentence, or the control sentence. The second modification was the addition of four backgrounding sentences, which shifted the focus of the passage away from instrument information but continued the storyline developed in the introductory sentences. The backgrounding section had a mean length of words, with a range of 47 to 51 words. Finally, in addition to the comprehension question, the critical sentence and closing sections from Experiment 2 were included.

16 482 HARMON-VUKIĆ, GUÉRAUD, LASSONDE, O BRIEN In this experiment, context was treated as a between-subjects factor, whereas instrument mention was treated as a within-subjects factor. Six material sets were created, with three material sets in each of the two context conditions. Within each context version, each material set contained eight passages in each of the three instrument-mention conditions. Across the three material sets within each context version, each passage appeared once in either the implicit inferenceevoking, explicit, or control condition. An additional eight filler passages were added to balance the number of consistent and inconsistent passages. Procedure. The procedure was the same as in Experiment 2. Results and Discussion The mean reading times for the critical sentence are presented in Table 7. Separate analyses of variance were conducted on the critical sentence in the high-context and low-context conditions. There was an effect of explicitness of instrument mention in both the high-context condition, F 1 (2, 84) D 4.17, MSE D 75, and F 2 (2, 42) D 4.46, MSE D 66,274.79; and the low-context condition, F 1 (2, 84) D 18.63, MSE D 64, and F 2 (2, 42) D 8.12, MSE D 64, In the high-context condition, planned comparisons revealed shorter reading times on the critical sentence when it followed the control sentence than when it followed the implicit inference-evoking sentence, F 1 (1, 42) D 9.42, MSE D 105, and F 2 (1, 21) D 5.09, MSE D 182,705.24; or the explicit sentence, F 1 (1, 42) D 6.73, MSE D 133, and F 2 (1, 21) D 6.81, MSE D 123, Reading times on the critical sentence did not differ reliably when it followed either the implicit inference-evoking sentence or the explicit sentence (p s >.88). In the low-context condition, planned comparisons revealed shorter reading times on the critical sentence when it followed the control sentence than when it followed the implicit inference-evoking sentence, F 1 (1, 42) D 14.95, MSE D 101, and F 2 (1, 21) D 5.75, MSE D 97,716.71; or the explicit TABLE 7 Mean Reading Times (in Milliseconds) and Standard Deviations for the Critical Sentence as a Function of Explicitness of Instrument Mention and Context Condition in Experiment 4 Instrument Mention Control Implicit Explicit Context Condition M SD M SD M SD Low context 2, , , High context 2, , ,

17 INSTRUMENTAL INFERENCES 483 sentence, F 1 (1, 42) D 35.12, MSE D 135, and F 2 (1, 21) D MSE D 190, However, the critical sentence was read more slowly following the explicit sentence than the implicit inference-evoking sentence: F 1 (1, 42) D 6.11, MSE D 149,441.36; F 2 (1, 21) D 4.92, MSE D 99, Overall, the results of Experiment 4 demonstrated that participants slowed down when they encountered the critical sentence, indicating that information about the instrument had been encoded into long-term memory in both the highcontext and low-context conditions. An increase in reading time was observed when the instrument was either explicitly or implicitly stated compared to the control condition. More interesting, however, was that in the low-context condition, this increase in reading time was larger when the explicit sentence was included in the passage than when the implicit inference-evoking sentence was included; in contrast, this difference was not reliable in the high-context condition. That explicitness of mentioning the instrument has an effect in the low-context condition but does not in the high-context condition provides further evidence that more features consistent with the target instrument were available when the inference-supporting context was high than when it was low. In the high-context implicit condition, the greater number of features consistent with the target instrument resulted in the same level of comprehension difficulty as in the high-context explicit condition. These results demonstrate that either an explicit mention of the instrumental inference or sufficient contextual support can provide the conditions necessary to detect instrumental-inference activation. GENERAL DISCUSSION This set of experiments was designed to further explore the conditions under which instrumental inferences become available to readers and to assess how contextual information influences the type of inferential information that becomes activated. Using a word-naming task, Experiment 1 replicated previous results, demonstrating that the lexical item representing the implied instrument did not become activated if the instrument was not explicitly stated in the text (Dosher & Corbett, 1982; Lucas et al., 1990). This was even true when the inference-evoking sentences contained verbs that were highly supportive of the target instrument. The results of Experiment 2 showed that when passages contained a sentence that implied the use of an instrument, participants exhibited a slowdown in reading on a sentence that contradicted the use of that instrument. This finding indicates that even when the context did not provide sufficient support to detect activation of the lexical item representing an implied instrument, a set of features consistent with the implied instrument had become available and, in turn, disrupted comprehension.

18 484 HARMON-VUKIĆ, GUÉRAUD, LASSONDE, O BRIEN In Experiment 3, the amount of context supporting an instrumental inference was increased without actually mentioning the target instrument. In this case, naming times for the target instrument were facilitated. Thus, it is likely that increasing the contextual support has the same effect as explicitly mentioning the target instrument: they both serve to constrain activation sufficiently to produce detectable activation of an instrumental inference with a specific lexical item. Therefore, just as with previous studies of elaborative inferences (Cook et al., 2001; Garrod & Terras, 2000; McKoon & Ratcliff, 1986; O Brien et al., 1988), activation of an instrumental inference is dependent on the degree of contextual support in the text. Admittedly, we investigated situation model contextual support at two ends of the spectrum: low and high. However, such support can occur at various points on the continuum. In any case, the degree of contextual support would likely influence memory activation and the ability to detect that activation; as contextual support increases, from both the situation model and the sentence level, it becomes more likely that certain features will become activated and that activation is more likely to be detected. Consistent with research on predictive inference (Cook et al., 2001; Peracchi & O Brien, 2004), the findings from Experiment 4 demonstrated that instrumental inferences were instantiated into long-term memory. More important, they further illustrated the influence of context on inferential processing. Recall that participants read a sentence that contradicted the target inference after the inferential information had been backgrounded. When the context was less supportive of the target instrument, participants slowed down on the critical sentence. However, that slowdown was less dramatic than when the target instrument had been explicitly stated in the text. In contrast, when contextual support was high, reading times were slow regardless of whether the instrument was explicitly mentioned. This pattern of results extended the findings from the first three experiments in two ways. First, it provided further evidence that instrument information became available to readers when the supporting context was low. Second, these results offered additional support for the findings from Experiment 3, showing that the contextual information influenced the extent to which features associated with the instrument inference were constrained toward a more specific lexical item. In Experiment 3, the greater contextual support resulted in activation of the target instrument that was detectable with a naming time measure. In Experiment 4, the additional contextual support resulted in the same level of comprehension difficulty regardless of whether the instrument was explicitly stated. These findings add to a growing body of literature that has emphasized that inferences may be represented in memory as a set of features rather than a single lexical item (e.g., Cook et al., 2001; McKoon & Ratcliff, 1986; McRae et al., 2005). For example, Cook et al. investigated the conditions under which predictive inferences become activated and whether they were instantiated into

19 INSTRUMENTAL INFERENCES 485 long-term memory. Their results demonstrated that facilitation for a specific predictive inference may occur online but that, after a delay, this inference is not represented in long-term memory as a specific item. Instead, the information is encoded as a set of features that represents a change in state a view originally proposed by McKoon and Ratcliff (1986). Our results extend this view by showing that this is true for instrumental inferences as well. These findings also raise issues involving the methods used to study inference activation during the reading process. An assumption common to many studies of inference activation is that detection is determined by the availability of a specific lexical item (e.g., facilitation in naming time). Given the finding that inferences often involve the activation of a set of features that may or may not be measurable with methods such as word naming, lexical decision, or word recognition, it would be inaccurate to interpret null results from such methods as evidence that an inference was not activated (see Gerrig & O Brien, 2005). Thus, in some instances, using a reading task in which a target sentence contradicts an inference may actually be a more accurate method for detecting the more general type of inferential information that becomes available to readers. ACKNOWLEDGMENTS Portions of this research were conducted by Mary Harmon-Vukic in partial fulfillment of the requirements for the master s degree at the University of New Hampshire under the direction of Edward J. O Brien. We thank John Limber and Elizabeth Stine-Morrow, who also served as members of the committee. In addition, we thank Kelly Peracchi for helpful comments on improving this manuscript. Finally, we thank four anonymous reviewers and Art Graesser for their insightful comments. REFERENCES Blanc, N. (2006). Emotion et cognition: Quand l émotion parle à la cognition [Emotion and cognition: When emotion speaks to cognition]. Paris: Éditions in Press. Clark, H. H., & Sengul, C. J. (1979). In search of referents for nouns and pronouns. Memory & Cognition, 7, Cook, A. E., Limber, J. E., & O Brien, E. J. (2001). Situation-based context and the availability of predictive inferences. Journal of Memory and Language, 44, Corbett, A. T., & Dosher, B. A. (1978). Instrument inferences in sentence encoding. Journal of Verbal Learning and Verbal Behavior, 17, Dosher, B. A., & Corbett, A. T. (1982). Instrument inferences and verb schemata. Memory & Cognition, 10,

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