Tell me sweet little lies: An event-related potentials study on the processing of social lies

Tell me sweet little lies: An event-related potentials study on the processing of social lies Tell me sweet little lies: An event-related potentials study on the processing of social lies Tell me sweet little lies: An event-related potentials study on the processing of social lies

Abstract In reading tasks, words that convey a false statement elicit an enhanced N four hundred brainwave response, relative to words that convey a true statement. N four hundred amplitude reductions are generally linked to the online expectancy of upcoming words in discourse. White lies, contrary to false statements, may not be unexpected in social scenarios. We used the event-related potential technique to determine whether there is an impact of social context on sentence processing. We measured ERP responses to target words that either conveyed a social "white" lie or a socially impolite blunt truth, relative to semantic violations. Word expectancy was controlled for by equating the cloze probabilities of white lying and blunt true targets, as measured in previous paper-and-pencil tests. We obtained a classic semantic violation effect (a larger N four hundred for semantic incongruities relative to sense making statements). White lies, in contrast to false statements, did not enhance the amplitude of the N four hundred component. Interestingly, blunt true statements yielded both a late frontal positivity and an N four hundred response in those scenarios particularly biased to white lying. Thus, white lies do not interfere with online semantic processing, and they do not engage further reanalysis processes, which are typically indexed by subsequent late positivity ERP effects. Instead, an N four hundred and a late frontal positivity obtained in response to blunt true statements indicate that they were treated as unexpected events. In conclusion, unwritten rules of social communicative behavior influence the electrical brain response to locally coherent but socially inappropriate statements.

People lie, on average, once or twice per day. Lying is generally considered an antisocial behavior, and most human cultures have some prohibition against lying. However, it sometimes serves a prosocial function depending on the context in which communication takes place as well as on the speaker's motivation to lie. In human social interactions, a particular type of lies commonly named "white" lies are often uttered. They consist of trivial, diplomatic, or well-intentioned untruths told in order to be polite or to stop someone from being upset by the truth. In fact, quite early in our social development, we are able to make moral judgments about lie telling, taking into account its expected social consequences. In a public situation where telling a truth is likely to have a negative social consequence (e.g., hurt feelings), children as young as seven to eleven years of age rate lie telling more positively than truth telling.

The high temporal resolution of event-related potentials make them ideally suited to study how social lying is processed. ERPs allow a direct measure of neural responses without the need of any additional task or behavioral response such as making a grammatical, semantic, or moral judgment. Thus far, ERP and functional magnetic resonance imaging studies have explored lying from the "liar" perspective. Only a few ERP studies have explored lying from the receiver of the lie perspective. In this regard, and resembling the classical N four hundred effect elicited by semantic incongruities embedded in a sentence, violations of true facts from our world knowledge (e.g., fact-related lies) elicit an N four hundred effect, that is, a larger negative-going voltage post target word onset, in the four hundred milliseconds range, relative to target words conveying the truth. For example, Dutch native speakers reading the sentence "The Dutch trains are white and very crowded" generate a large N four hundred at the critical word white, since it is a well-known fact among Dutch people that their trains are yellow instead. This result indicates that the processing of false statements incurs in a difficulty of semantic processing. Thus, statements that clash with world knowledge stored in long-term memory elicit an N four hundred response. However, the most recent views on what the N four hundred indexes highlight its role as a sign that online predictions are being made about upcoming words in discourse. Thereafter, the N four hundred is not as sensitive to truth-value computations as it is an online predictor for upcoming information based on world knowledge.

ERP measures also reveal that a wider discourse context (e.g., a fictitious one) can overrule the consequences of processing a priori unexpected statements. For example, reading that a peanut was "in love" becomes paradoxically easier to process than reading that it was "salted" when embedded in a supportive discourse context about an animated peanut. Thus, the N four hundred effect is sometimes neutralized based on a broader discourse context. Intuitively, a part of our world knowledge includes rules of social communicative behavior. Some statements are socially sanctioned despite being inaccurate based on prior context (white lies). Others can be true based on prior discourse context but are socially inappropriate statements and perhaps unexpected to be told. Online expectancy might go beyond the lexical level (a word that is expected to be told) to the social level (what kinds of words are expected or unexpected to be told in a social scenario).

In the ERP literature on language processing, two types of late positivities (frontal versus parietally distributed) have been linked to different kinds of unexpected events. Frontal late positivities arise for plausible but unexpected words in highly constraining contexts. This frontal effect is linked to the cost of a disconfirmed prediction. Its brain topography, maximal over frontal sites, suggests that it arises from different brain regions and thus reflects different functional processes than those attributed to parietal P six hundred effects.

Parietal positivities, instead, have been linked to the processing of anomalies that prompt sentence reanalysis processes. For example, the comprehension of ironic versus literal meanings has revealed an increase in this P six hundred ERP component. To date, the P six hundred functional interpretation remains controversial. Originally obtained for syntactic violations and ambiguities, it is also observed following semantic abnormalities. A recent study distinguishes between a widespread P six hundred reflecting reanalysis or repair processes that follow syntactic anomalies and a more constrained centro-parietal P six hundred to pragmatic anomalies, such as the processing of ironic messages. However, a P six hundred effect most prominent over frontal electrode sites has also been reported for the processing of ironic versus literal statements. Finally, when extralinguistic information (i.e., prosody) is available, brain responses show a distinction between white lies and true compliments. Specifically, listeners generate greater P six hundred amplitudes over right frontal areas of the scalp in response to sincere versus insincere compliments.

In the current study, we aimed to determine whether there is an impact of social knowledge on sentence comprehension, beyond the online expectancy for a particular word item. We specifically examined how the brain responds to visually presented target words that either conveyed a "white" lie or a socially impolite blunt truth. To that end, we presented an initial paragraph depicting a social situation (e.g., having guests for dinner) in which the truth was unpleasant (e.g., the host is not a good cook and dinner got burned). In that social scenario, the host requests an opinion (e.g., she asks her guests how much they liked dinner) and then a word-by-word sentence is presented to the reader in which one of the guests tells a white lie (e.g., the meat sauce was tasty) or a socially impolite truth (e.g., the meat sauce was overcooked). Based on prior paper-and-pencil tests, these alternative endings (i.e., those marked in italics in previous examples) were matched in their low likelihood of being used to complete the sentence. They are thus expected to elicit an equally large N four hundred response. Nonetheless, by using these contrasting words as experimental targets, the local semantic and the social contexts became at odds. Whereas the local semantic context favors the processing of a word such as overcooked (i.e., a word closer to reality according to the information provided earlier in the discourse, such as burned), our social knowledge favors the encountering of a word such as tasty or a similar complimenting adjective, given the context of a social interaction where compliments are rather appropriate. An overt semantic violation was also included in our experimental design (e.g., the meat sauce was romantic) in order to obtain a robust N four hundred effect, against which any potential N four hundred enhancements could be contrasted.

As outlined earlier, in contrast to fact-related lies, prosocial lies are morally acceptable and might not be unexpected in social scenarios. Our study thus uses ERP measures to examine how processing unfolds for verbal information that is factually inaccurate but socially sanctioned (white lies) compared to factually true but impolite information. If white lies are processed as the factual lies in the Dutch white trains study they would raise the N four hundred ERP component. However, if our social knowledge anticipates a white-lying communicative behavior, they would fail to increase the amplitude of the N four hundred component. Alternatively, they could be processed as ironic messages mismatching reality, thus giving rise to late latency ERP effects. On the other hand, factually true but impolite statements might clash with anticipated verbal outcomes and thus elicit a larger N four hundred relative to white-lying statements, a frontal late positivity, or both.

Based on the finding that men and women tend to differ in semantic processes indexed by the N four hundred component and particularly on the social or pragmatic aspects of language processing (i.e., empathy), for this initial study we limited the sample to female participants.

Method

Participants

Twenty-seven female native Spanish speakers (mean age equals twenty-two point six years, range equals eighteen to thirty years) volunteered to participate in the study. All participants gave written informed consent. Twenty-five participants reported being right-handed and two being left-handed. The average handedness score for the right-handed participants was positive seventy-eight point three (range, forty-three to positive one hundred). All participants reported normal or corrected-to-normal vision and none had a history of neurological or psychiatric disorders. The study was approved by the local ethics committee.