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

Cogn Affect Behav Neurosci (2016) 16:616–625 DOI 10.3758/s13415-016-0418-3 Tell me sweet little lies: An event-related potentials study on the processing of social lies Eva M. Moreno 1 & Pilar Casado 2 & Manuel Martín-Loeches 2 Published online: 23 March 2016 # Psychonomic Society, Inc. 2016 Abstract In reading tasks, words that convey a false statement elicit an enhanced N400 brainwave response, relative to words that convey a true statement. N400 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 (ERP) 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 paperand-pencil tests. We obtained a classic semantic violation effect (a larger N400 for semantic incongruities relative to sense making statements). White lies, in contrast to false statements, did not enhance the amplitude of the N400 component. Interestingly, blunt true statements yielded both a late frontal positivity and an N400 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 N400 and a late frontal positivity obtained in response to blunt true statements indicate that they were treated as unexpected events. In * Eva M. Moreno 1 Human Brain Mapping Unit at Instituto Pluridisciplinar & Psychology Department, Universidad Complutense de Madrid, Paseo Juan XXIII 1, 28040 Madrid, Spain 2 Center for Human Evolution and Behavior, UCM-ISCIII, Madrid, Spain conclusion, unwritten rules of social communicative behavior influence the electrical brain response to locally coherent but socially inappropriate statements. Keywords Event-related potentials . Language . Social lies . N400 . Frontal late positivity People lie, on average, once or twice per day (DePaulo, Kirkendol, Kashy, Wyer, & Epstein, 1996; but see Serota, Levine, & Boster, 2010). 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 7 to 11 years of age rate lie telling more positively than truth telling (Ma, Xu, Heyman, & Lee, 2011). The high temporal resolution of event-related potentials (ERPs), 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 (fMRI) studies have explored lying from the “liar” perspective (Proverbio, Vanutelli, & Adorni, 2013). Only a few ERP studies have explored lying from the receiver of the lie Cogn Affect Behav Neurosci (2016) 16:616–625 perspective. In this regard, and resembling the classical N400 effect elicited by semantic incongruities embedded in a sentence (Kutas & Hillyard, 1980), violations of true facts from our world knowledge (e.g., fact-related lies) elicit an N400 effect, that is, a larger negative-going voltage post target word onset, in the 400 ms 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 N400 at the critical word white, since it is a wellknown fact among Dutch people that their trains are yellow instead (Hagoort, Hald, Bastiaansen, & Petersson, 2004; Hald, Steenbeek-Planting, & Hagoort, 2007). 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 N400 response. However, the most recent views on what the N400 indexes highlight its role as a sign that online predictions are being made about upcoming words in discourse (Boudewyn, Long, & Swaab, 2015; Otten, Nieuwland, & Van Berkum, 2007; Van Berkum, Brown, Zwitserlood, Kooijman, & Hagoort, 2005; Wicha, Moreno, & Kutas, 2004). Thereafter, the N400 is not as sensitive to truthvalue computations as it is an online predictor for upcoming information based on world knowledge (Nieuwland, 2015; Nieuwland & Kuperberg, 2008). 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 (Nieuwland & Van Berkum, 2006). Thus, the N400 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 (Van Petten & Luka, 2012). Frontal late positivities arise for plausible but unexpected words in highly constraining contexts (Federmeier, Wlotko, De Ochoa-Dewald, & Kutas, 2007). 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 P600 effects (Thornhill & Van Pe (...truncated)