This work was supported by the National Natural Science Foundation of China [61433015], National Social Science Major Fund of China[14ZDB154; 15ZDB017], and the MOE (Ministry of Education in China) Project of Humanities and Social Sciences [14YJC740104]. We express great gratitude to the two anonymous reviewers for their valuable suggestions.

The present protocol was approved by the Institutional Review Board of Tsinghua University.
1. Stimuli construction
<ol>
	<li>Construct critical anomalous sentences for the repetition and non-repetition groups
	<ol>
		<li>Prepare an adequate number of correct sentences for the construction of anomalous sentences (no less than 40). For example, &#8220;These two components were separated by a centrifugal device.&#8221; Try to use only emotion-free sentences as...

<ol>
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T., Curran, T., Menn, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comprehending+conventional+and+novel+metaphors:+An+ERP+study.">Comprehending conventional and novel metaphors: An ERP study.</a> Brain Research. 1284, 145-155 (2009).</li><li>Oldfield, R. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+assessment+and+analysis+of+handedness:+The+Edinburgh+inventory.">The assessment and analysis of handedness: The Edinburgh inventory.</a> Neuropsychologia. 9, 97-113 (1971).</li><li>Huang, Y., Jiang, M., Guo, Q., Yang, F. -. P. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=N400+amplitude+does+not+recover+from+disappearance+after+repetitions+despite+reinitiated+semantic+integration+difficulty.">N400 amplitude does not recover from disappearance after repetitions despite reinitiated semantic integration difficulty.</a> Neuroreport. 29, 1341-1348 (2018).</li><li>Brouwer, H., Crocker, M. W., Venhuizen, N. J., Hoeks, J. C. 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L., Li, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Context+modulates+neural+activity+of+N400+and+P600+to+visual+words.">Context modulates neural activity of N400 and P600 to visual words.</a> Journal of Neurolinguistics. 26, 490-509 (2013).</li><li>Hagoort, P., Brown, C. 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There are no competing financial interests.

Experimental results and significance 
In the repetition part, the results demonstrated that the N400 effect became smaller and smaller until almost non-existent. The greatly attenuated N400 effect proved that multiple repetitions did significantly modulate the amplitude of N400. However, the results in this part cannot show whether N400 was actually affected by the change of expectancy or semantic integration. The attenuated N400 effect can still be explained differently. One explanation is that ex...

Anomalous sentences are widely used by linguists to study online cognitive processing of normal languages. For example, in event-related potentials (ERP) studies, sentences with semantic anomalies (e.g., &#34;He spread the warm bread with socks.&#34;) were reported to elicit an N400 effect1 (but also see some other studies reporting a semantic P600 effect2,3), while sentences with syntactic difficulties or anomalies (e.g., &#34;The woman persuaded to answer the door&#8230;&#34;) were reported to elicit a P600 effect4,5. These electrophysiological components are widely used as reliable indicators for investigating the normal temporal courses of processing information from different aspects of language, such as syntax and semantics.
Anomalous sentences cause great difficulties for semantic integration processing during comprehension. However, confounding factors such as unexpectedness (i.e., any anomalous expression is naturally an unexpected expression) make it difficult to determine the true cognitive process underlying the observed effect elicited by anomalous sentences. For example, if an N400 effect is elicited by an anomalous sentence, it is unclear whether it is caused by unexpectedness6,7,8 or integrative difficulty1,9,10.
To ascertain whether it is expectancy or semantic integration difficulty that contributes to the elicited electrophysiological effect, we need to dissociate these two factors. Traditionally, expectancy is often measured by corpus frequency (in word studies) or cloze probability (in sentence studies). The widely applied method to manipulate expectancy in traditional experiments is by choosing stimuli with high and low scores in expectancy to form expected and unexpected groups. This method is effective in manipulating expectancy and has produced abundant insightful results.
However, as a static approach to manipulating expectancy, it has one limitation: it is hard for the expected and unexpected groups to have the same semantic integration difficulty. With this manipulation, the stimuli selected for the expected and unexpected groups have to be different; thus the semantic integration difficulty is altered when we manipulate expectancy by using different stimuli with different expectancy values or cloze probabilities). While we may find unexpected but reasonable expressions (i.e., unexpected expressions made up of words that can be successfully integrated into a reasonable message), it is possible that the integrative efforts required by these unexpected but reasonable expressions are different from those required by normal expressions. If the differences are not controlled, significant differences in brain responses might ensue, as clear evidence demonstrates that the integrative processing of unexpected but reasonable new metaphorical expressions triggers brain responses quite different from those triggered by conventional metaphors11,12.
To address this issue, we propose a new method to dynamically enhance participants&#39; expectancy for anomalous sentences while trying to maintain the semantic integration difficulty. Specifically, we quickly familiarize participants with unfamiliar anomalous sentences and thus enhance their expectancy through multiple repetitions. Importantly, multiple repetitions do not change the stimulus itself; therefore, the semantically anomalous information itself remains unchanged (i.e., the critical word still cannot be successfully integrated into the context).
However, the brain might give up integration after learning that the anomalous information cannot be successfully integrated into the previous context at all (i.e., the integration processing might be absent so that there is no integration difficulty). Therefore, this protocol proposes to repeat only the core anomalous information extracted from the anomalous sentence first, and then use the complete anomalous sentence which contains the identical anomalous information as a semantically enriched version of this core anomalous information, to initiate new semantic integration processing in the repetition condition. With the identical anomalous information in the semantically enriched complete anomalous sentence and the initiated new semantic integration processing, we assume that the semantic integration difficulty triggered by the anomalous information in the complete anomalous sentence after multiple repetitions should remain almost the same as that triggered by the anomalous information before repetitions (regardless of the status of semantic integration processing during repetitions). Hence, we assume the factor of semantic integration difficulty in the semantically enriched complete anomalous sentences remains the same after repetitions as in the correspondingly simplified core structures, but the expectancy is greatly enhanced.
Based on these assumptions, we compare the N400 effect elicited by semantically enriched complete anomalous sentences containing the repeated core anomalous information with that elicited by newly-met complete anomalous sentences, to investigate the major contributor of this elicited ERP effect. The working hypotheses are as follows: according to previous studies, the N400 effect would be significantly attenuated by repetitions. On the basis of the attenuated N400, if the newly initiated semantic integration of the same anomalous information causes recovery of the attenuated N400 effect to a level similar to that elicited by the same type of anomalous information contained in newly-met anomalous sentences with no repetitions, then it suggests that the semantic integration difficulty is the dominant contributor of the elicited N400 effect; otherwise it suggests that unexpectedness is the major contributor.

<table>
	<tbody>
		<tr>
			<td>BrainAmp DC amplifier system (Brain Products GmbH)</td>
			<td>Brain Products, Gilching, Germany</td>
			<td></td>
			<td>BrainAmp S/N AMP13061964DC Input 5.6DC=150mA Operation 7mA Standby</td>
		</tr>
		<tr>
			<td>Easycap (Brain Products GmbH)</td>
			<td>Brain Products, Gilching, Germany</td>
			<td></td>
			<td>62 
			Ag/AgCl electrodes with a configuration 
			of the international 10&#8211;20 system of electrode</td>
		</tr>
	</tbody>
</table>

dissociation of the confounding influences of expectancy and integrative difficulty residing in anomalous sentences in event-related potential studies

The confounding factors of unexpectedness and semantic integration difficulty naturally residing in anomalous sentences in language studies make it difficult to determine the underlying processing mechanism of ERP components. Unlike the traditional static approach of manipulating expectancy through corpus frequency or cloze probability, this protocol proposes a dynamic method to enhance participants&#39; expectancy for rarely-met anomalous sentences by multiple repetitions while maintaining their semantic integration difficulties. To address the time cost increase resulting from multiple repetitions, this protocol proposes to repeat only the strictly simplified core structure extracted from the anomalous sentence before presenting the semantically enriched, much more informative complete anomalous sentence containing the anomalous core structure to reinitiate the semantic integration processing. The complete anomalous sentence elicited a P600 effect. It suggests that the participants did not give up processing the anomalous information after repetitions and the same semantic integration difficulty was successfully reinitiated. Importantly, the representative experimental results reveal that the greatly attenuated N400 effect caused by multiple repetitions was not recovered by the follow-up reinitiated semantic integration difficulty. It suggests that the attenuated N400 effect should be mainly attributed to the enhancement of expectancy for anomalous information by multiple repetitions. The experimental results show that this method can effectively enhance participants&#39; expectancy for anomalous sentences while retaining the semantic integration difficulty.

The present protocol was used in one of our recent studies to investigate whether the N400 effect reflects semantic integration processing14. The stimuli used in that study were in Chinese, as shown in Table 2.
<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td colspan="3">(a) Example of the simplified core structures in the repetition part</td>
		</tr>
		<tr>
			<td></td>
			<td>Im...

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Dissociation of the Confounding Influences of Expectancy and Integrative Difficulty Residing in Anomalous Sentences in Event-related Potential Studies

We present a protocol to dissociate the intertwining factors of integrative difficulty and unexpectedness in semantically anomalous sentences by applying multiple repetitions to enhance participant&#39;s expectancy for anomalous sentences. The dissociation helps to investigate the major contributor of elicited event-related potentials (ERP) effects such as N400 in language studies.

The confounding factors of unexpectedness and semantic integration difficulty naturally residing in anomalous sentences in language studies make it ...

This protocol provides an effective way to dissociate the confounding factors of unexpectedness in intuitive difficulty in anomalous sentences to determine the real contributor of N400 effect in language studies. Unlike the traditional static approach of manipulating expectancy through corpus frequency or cloze probability. This protocol proposed a dynamic mission to achieve this goal by multiple repetitions.With this protocol, we can also examine how other ERP components, such as P600, may respond to multiple repetitions. It may help to reveal the underlying mechanism of P600 as well. Begin by escorting the patient to the testing room and have them sit comfortably in a chair.Then prep the participant's skin with facial scrub and a cotton-swab on the forehead, under the left eye, near the outer canthus of the right eye, and around the left and right mastoid bone. Place the elastic cap with electrodes on the participant's head. Ensure that the CZ electrode on the cap is located at the vertex of the head and the cap has a left-right symmetry with midline electrodes placed over the midline of the head.Next, stick the adhesive tape to the electrodes that record eye movements and fill them with conductive gel. Fix the one electrode at the outer canthus of the right eye and the other below the left eye. Then fasten the strap under the chin to prevent the adjacent electrodes from moving during the experiment and connect the cap electrodes to the recording system.Finally, to reduce the impedance of all electrodes below five kilohms or 10 kilohms, switch the recording software to the impedance monitoring interface. Then starting with the ground and reference electrodes, past the blunt tip needle of the syringe containing conductive gel through the eyelets of the electrodes and hairs until it reaches the skin of the scalp. Push the syringe plunger to inject a small dose of the conducting gel onto to the skin until the gel connects the metal circle on the electrode and the skin.Finally, check the real time impedance level displayed in different colors on the monitor until the impedance decreases to below the threshold value. Check all electrodes. Begin by asking the participant to relax and try to avoid excessive eye blinks and body movements during the experiment.Inform the participant about the tasks and the repetition part in the tasks in the main sentence part. Ensure the participant understands that an incorrect sentence will be followed by a repetition part and a correct sentence by another complete sentence, which may be correct or incorrect. Then start the stimuli presentation program, and let the participant practice with the practicing section.For the repetition part, present the extracted core structure and its correct filler expression together seven times in a random order. For the semantic re-initiating complete sentence, present the complete anomalous sentence right after its corresponding repetition part. After the practice session is complete, begin the formal experimental session and record the electric physiological signals.Finally, after the experiment is complete, save the recorded electric physiological data and help the participant take off the cap. Instruct the participant to wash away the conductive gel on the skin and hair and provide them with a reward for their participation. The 11 related potentials were ERPs in the first time, the fourth time, and the seventh time presentation of the anomalous core structures revealed that the N400 effect in the 300-500 millisecond time window disappeared gradually.ERPs in the unrepeated anomalous sentence group were more negative than those in the control group. ERPs in the repeated group were more positive than those in the unrepeated group. Remember to place all electrodes at the right location impedance of all electrodes below five kilohm or 10 kilohm before the experiment.This protocol effectively limits the time of repeating sentences for multiple trials. Multiple repetitions of sentences may help to reveal the real memory in sentence comprehension.

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5.3K visualizações.  Tsinghua University. Este protocolo fornece uma maneira eficaz de dissociar os fatores confusos de inesperado em dificuldade intuitiva em sentenças anômalas para determinar o real contribuinte do efeito N400 em estudos linguísticos. Ao contrário da abordagem estática tradicional de manipular a expectativa através da frequência de corpus ou probabilidade de cloze. Este protocolo propôs uma missão dinâmica para alcançar esse objetivo por múltiplas repetições.Com este protocolo, também podemos ...

Vídeo: Dissociation of the Confounding Influences of Expectancy and Integrative Difficulty Residing in Anomalous Sentences in Event-related Potential Studies