General Discussion
During communication, speakers produce visual cues signaling their confidence level in the content of their speech, which can reflect their word retrieval (Goodwin and Goodwin, 1986; Rimé and Schiaratura, 1991; Krauss et al., 1996) and/or their (un)conscious desire to communicate their mental state to others (Goodwin and Goodwin, 1986; Visser et al., 2014). However, it is unknown if observers use the visual cues from these cognitive and social processes when perceiving a speaker's confidence level. There is a lack of research investigating whether there is a difference between the types of visual cues speakers produce because of their transient confidence level and the types of visual cues observers use to assess this mental state. This study tested this issue in relation to a speaker's confidence for general knowledge facts by observers indicating the visual cues they used after evaluating a speaker's confidence level.


Effect of Situational Factors on Visual Cue Production and Evaluation
Compared to previous studies that report the occurrence of visual cues in relation to a speaker's confidence level, our results shed light on the frequency of these visual cues that speakers produce, and consequently their effect on observers' confidence evaluations. Overall, we found that speakers do not often produce changes in eye gaze, facial expressions and postural shifts, but when salient changes in these cues are produced, they can impact observers' evaluations. We postulate that one reason for this low frequency production of visual cues is due to the stakes level of social evaluation created by our experiment. A situation involving high-stakes social evaluation occurs when an individual (or group) has significant power to impact another's future (Gifford et al., 1985; Cuddy et al., 2012) such as in a job interview. Here, a speaker's speech content and their confidence level in this content, through vocal and visual cues, can greatly impact the outcome of their social interaction. In contrast, a situation of low-stakes social evaluation does not pose a risk to a speaker's social status. For example, a speaker may mundanely report inaccurate information due to inaccurately recalling (highly or less accessible) information and they will not face major social consequences for this (Depaulo et al., 1996; Gozna et al., 2001; Azizli et al., 2016). Our trivia question task may have simulated a situation of low-stakes social evaluation, in that if speakers answered a question incorrectly it did not have negative social consequences for them or their interaction with the examiner. The speakers did not know the examiner, the accuracy of their responses was not important for their social status, pausing due to word retrieval difficulties could occur because there was low social demand to respond quickly, and the questions were not used to elicit an emotional state in the speakers. This low-stakes context may explain why the speakers did not often produce postural shifts or happy, amused or embarrassed facial expressions based on their confidence level, as these cues are more often associated with situations involving social judgments and affect (Costa et al., 2001; Coleman and Wu, 2006; Hareli and Parkinson, 2008). Alternatively, the low frequency of embarrassed or amused facial expressions may have been related to the few instances where speakers answered questions about well-known general knowledge incorrectly (Table 1). Future research may explore the effect of shared knowledge that is known by the audience/observer on the visual cues that speakers produce and the visual cues that observers subsequently attend to. For example, if an observer knows the information that a speaker is trying to recall, or a speaker has difficulty recalling information that is well-known knowledge to an observer or audience; how do these situations affect a speaker's perceived confidence and the cues that observers attend to. This question may be addressed by examining the interaction between a speaker's visual and vocal cues on their perceived confidence.


This low-stakes context may also explain the small difference in speakers' perceived confidence ratings for high vs. low confidence. Since speakers were in a situation of low social stress, the quantity and types of visual cues they produced to indicate high vs. low confidence in their speech content, may have been less differentiated to observers. Future research may explore how the level of social evaluation in a given context can impact speaker's memory retrieval and visual cues as well as observers' evaluations. Nonetheless, we do not know if observers detected that speakers produced speech in a low-stakes context, and if detecting this context may have affected the types of visual cues used in their social evaluations.


Research on a speaker's transient confidence level based on their speech content has largely tested speakers' level of certainty for general knowledge facts (Smith and Clark, 1993; Brennan and Williams, 1995; Swerts and Krahmer, 2005). More research is needed to understand the impact of speakers' transient confidence level for other information, such as their opinions. This is particularly relevant when speakers are trying to persuade an audience of their stance, as the speech content may also elicit a greater emotional valence compared to responding to general knowledge questions. Here, speakers' responses, including their visual cues, are more likely to be socially evaluated by others such as an employer conducting a job interview (DeGroot and Motowidlo, 1999), a person on a date (Muehlenhard et al., 1986; Fichten et al., 1992; Ambady and Skowronski, 2008), a judge in court (Cramer et al., 2009), a customer interacting with a salesperson (Leigh and Summers, 2002), or a border security officer. Future research should explore this branch of a speaker's confidence in their speech content with greater consideration for situational factors. In these contexts, speakers may (un)consciously produce visual cues to save face (Goffman, 1967, 1971; Visser et al., 2014) or reinforce their level of certainty (Moons et al., 2013), and observers' evaluations of a speaker's confidence level via their non-verbal cues can have real social implications.


Limitations and Conclusions
One limitation of our study was our inter-rater reliability for the subcategories of visual cues speakers produced. Though the inter-rater agreement between the coders was significantly greater than chance, the coefficients did not indicate strong agreement. Thus, the detection of a speaker's visual cues may require more training as individuals can vary in their conceptualization of and identification for visual cues. Also, a speaker's production of eye movements to signal their confidence level may be influenced by their cultural background, in accordance with cultural display rules in the eyes and facial expressions (McCarthy et al., 2006, 2008). Our results were based on native speakers of Canadian English with various cultural backgrounds; controlling for this factor could help explain some of the variability between the speakers in the quantity and types of visual cues produced. Moreover, examining the effect of observers' cultural attitudes based on a speaker's physical appearance would also allow us to examine other types of social factors that may have influenced observers' confidence evaluations of speakers and whether the types of visual cues that observers used in their evaluations differed based on a speaker's physical appearance. Also, having a larger sample of speakers would allow us to increase the generalizability of our findings. Lastly, our study operated under the assumption that when observers only have access to the visual communication channel, they can accurately recall what visual cues they used in their evaluation of a speaker's confidence. It may be argued that this manipulation created an unnatural context to evaluate a speaker's confidence level, since in everyday communication observers have access to many communication channels and can assess a speaker's mental state in real time. On the other hand, there are also real-life contexts where observers have heightened attention for/use of the visual communication channel, such as interacting with speakers of a foreign or second language (Sueyoshi and Hardison, 2005) or listening to speech in a noisy environment (Neely, 1956). Use of an eye-tracking paradigm could provide an objective, real-time measure of the visual cues that observers used in their confidence evaluations. Nonetheless, observers rarely reported they did not know which visual cues they used in their evaluations. This result may indicate that when observers only have access to the visual communication channel, they are to some extent, aware of the visual cues they perceive.


In conclusion, this study showed that observers can accurately perceive a speaker's confidence level in the content of their speech in a low-stakes context based on their visual cues, by primarily using the speaker's facial expressions and eye movements. Observers may be socially attuned to salient, yet infrequent cues in the facial regions so they can efficiently infer a speaker's confidence level in the speech content. This social attention may be important as the stakes of the situation increase for speakers. Future research should explore using more video recordings of speakers' spontaneous speech and examining variability across speakers, to improve descriptions of the visual cues that speakers produce signaling their confidence level in the speech content. These methodological changes will better reflect the cues that aid in observers' assessments of a speaker's confidence level and their communicative interactions with others.




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