Introduction
Social exclusion threatens the fundamental human need to belong (Williams,
2007), lowers mood (Gerber & Wheeler,
2009) and elicits social pain (MacDonald & Leary,
2005). Excluded individuals have an acute need to regain other people’s acceptance (Smart Richman & Leary,
2009; Williams,
2007), and thus they may exhibit affiliative behavior, such as increased conformity (Williams, Cheung, & Choi,
2000) and nonverbal mimicry (Lakin, Chartrand, & Arkin,
2008). Interestingly, when people are socially excluded, they become more efficient in processing of social information, leading to, for instance, increased acuity in identification of facial expressions (Bernstein, Young, Brown, Sacco, & Claypool,
2008), and enhanced memory for social information (Gardner, Pickett, & Brewer,
2000). These findings suggest that excluded individuals allocate a large amount of attentional resources toward socially salient information.
Attentional deployment consists of several different processes such as shifting, engagement, and disengagement of attention (Posner & Petersen,
1990). When an unattended stimulus attracts attention, an individual may shift attention towards it. Some categories of stimuli, such as faces, attract attention more than others so that when several stimuli compete for attention, it is more likely that attention is shifted to these stimuli (Langton, Law, Burton, & Schweinberger,
2008). Biases in the initial shifts of attention toward stimuli belonging to specific categories have been suggested to help in rapid detection of important stimuli (e.g., Cisler & Koster,
2010). After a shift of attention, attention can be engaged by the stimulus, allowing deeper processing of relevant stimulus features. When a novel stimulus suddenly demands attention, attention has to be disengaged from the attended stimulus. Research has revealed that attentional biases can also occur at the stage of attentional disengagement so that disengagement from specific categories of stimuli is delayed. For instance, disengagement is slower from faces than from non-social control pictures (Bindemann, Burton, Hooge, Jenkins, & Haan,
2005), and individuals suffering from anxiety have difficulties in disengaging attention from threatening stimuli (Bar-Haim, Lamy, Pergamin, Bakermans-Kranenburg, & Van IJzendoorn,
2007).
To cope with exclusion, people often allocate attention toward affiliative cues containing information that is particularly important for individuals whose social status is threatened. For instance, in studies where participants have been presented with two faces with different facial expressions, exclusion has been shown to increase the tendency to shift attention toward a smiling face (DeWall, Maner, & Rouby,
2009, Experiment 4; Tanaka & Ikegami,
2015; Xu et al.,
2015). It has also been reported that excluded participants are faster than controls in locating smiling faces, but not other emotional faces, from a crowd of faces (DeWall et al.,
2009, Experiment 1; but see Tuscherer et al.,
2015). Other studies have presented participants simultaneously with several different emotional faces over a period of time, and found that excluded participants, compared to control groups, fixate more on smiling faces, but not other emotional faces (Buckner, DeWall, Maner, & Schmidt,
2010; DeWall et al.,
2009, Experiments 2–3; but see Kraines, Kelberer, & Wells,
2018). These findings suggest that excluded individuals tend to shift their attention toward smiling faces, and engage their attention with these faces, possibly because attending to affiliative cues helps them cope with the adverse experience.
Not only facial expressions, but also eye gaze is an important social cue to signal affiliation or exclusion. Direct gaze (gaze directed at the observer’s eye region) indicates that the observer is in the center of the looker’s attention (Conty, George, & Hietanen,
2016). Seeing another’s direct gaze evokes positive affective responses in the perceiver (e.g., Chen, Helminen, & Hietanen,
2017; Chen, Peltola, Ranta, & Hietanen,
2016; Hietanen et al.,
2018), and activates brain mechanisms related to approach motivation (Hietanen, Leppänen, Peltola, Linna-aho, & Ruuhiala,
2008). Gaze aversion, on the other hand, is a common way to indicate social exclusion (Williams, Shore, & Grahe,
1998), and it can indeed evoke feelings of exclusion and relational devaluation in the observer (Leng, Zhu, Ge, Qian, & Zhang,
2018; Wirth, Sacco, Hugenberg, & Williams,
2010).
Exclusion has been found to modulate responses to others’ gaze directions. In a recent study, participants were excluded or included in a virtual ball-tossing game Cyberball (see Williams & Jarvis,
2006), which was played ostensibly with other participants present in the laboratory (Lyyra, Wirth, & Hietanen,
2017). After the manipulation, participants judged whether faces with varying gaze directions were looking at them or not. It was discovered that excluded participants, compared to included participants, were biased to view others as portraying direct gaze, suggesting that they viewed others as signaling affiliation with their gaze. However, another study showed that when this game was played ostensibly online with players located in other laboratories, excluded participants tended to judge others as portraying averted gaze instead (Syrjämäki, Lyyra, & Hietanen,
2018). It was suggested that this was because the online setting offered no opportunity for reaffiliation. Exclusion has also been shown to amplify attentional shifts triggered by other people’s gaze. Wilkowski, Robinson, and Friesen (
2009) showed that the gaze-cuing effect (the tendency to shift attention toward others’ gaze directions) was larger among individuals with low self-esteem, compared to high self-esteem (Experiment 1), and among participants who had reflected on social exclusion, as compared to those having reflected on inclusion (Experiment 2).
As well as averted gaze, also direct gaze influences perceivers’ attention. Faces portraying direct gaze attract attention more than faces showing other gaze directions (e.g., Böckler, van der Wel, & Welsh,
2014; Conty, Tijus, Hugueville, Coelho, & George,
2006; Lyyra, Astikainen, & Hietanen,
2018; von Grünau & Anston,
1995). Importantly, it has also been suggested that direct gaze holds the perceiver’s visuospatial attention so that attentional disengagement from the face is delayed. This was proposed based on a result that manual response times in detection of peripheral stimuli were longer when participants were shown, in the fixation, a face portraying direct gaze compared to downward gaze or closed eyes (Senju & Hasegawa,
2005). Similarly, a later study reported that delays in saccades to peripheral stimuli were longer from schematic faces suddenly shifting eyes into direct gaze, compared to faces shifting gaze upward or downward (Ueda, Takahashi, & Watanabe,
2014). In another study measuring saccadic latencies and saccadic peak velocities to peripheral targets after pictures of faces with static direct gaze and closed eyes, there was no effect of gaze direction on saccadic latencies, but compatible with the previous studies suggesting delayed attentional disengagement, the peak velocity of the saccades was lower after faces with direct gaze (Dalmaso, Castelli, & Galfano,
2017). Interestingly, however, a recent study found that manual response times in the identification of peripheral stimuli were shorter, not longer, when participants viewed live faces portraying direct gaze, compared to downward gaze (Hietanen, Myllyneva, Helminen, & Lyyra,
2016). The authors suggested that eye contact with the live person increased physiological arousal, and this led to shortened response times after direct gaze stimuli. Thus, the current evidence suggests that only pictures of faces with direct gaze, but not real faces portraying direct gaze, slow down disengagement of attention from the stimulus.
If pictures portraying faces with direct gaze hold perceivers’ visuospatial attention, this effect might be amplified by social exclusion. As exclusion increases allocation of attention to affiliative cues (e.g., DeWall et al.,
2009), and amplifies attentional shifts triggered by averted gaze (Wilkowski et al.,
2009), it could be expected that the attention holding effect of direct gaze might be particularly strong among excluded individuals. This should lead to further slowing of response times to peripheral target stimuli in the context of direct gaze, as compared to downward gaze.
In the current study, we manipulated participants’ feelings of social exclusion and social inclusion using Cyberball (Williams & Jarvis,
2006), followed by a similar attentional disengagement task as that used by Senju and Hasegawa (
2005). In the widely used Cyberball manipulation, participants engage in a virtual ball-tossing game ostensibly with other individuals. Unbeknownst to the participants, the other characters in the game are actually controlled by the computer and are preprogrammed to either include the participants in the game or exclude them from it. Exclusion from this game, compared to inclusion, consistently evokes affective responses associated with social exclusion, such as lowered satisfaction of basic social needs (Hartgerink, van Beest, Wicherts, & Williams,
2015).
A limitation of most studies using the Cyberball manipulation is that they cannot disentangle the effects of social exclusion from the effects of social inclusion. In a typical experiment, excluded participants are compared to included participants, and any differences between the two groups are inferred to reflect effects of social exclusion. However, without a control group it is impossible to determine whether exclusion, inclusion or both caused the observed differences. In the current study, we included a non-social control group, in which participants played a similar ball-tossing game as in the other groups, but the game contained no social interaction (the manipulation has been previously used in Syrjämäki et al.,
2018).
The non-social control group also allowed us to investigate the possibility that social inclusion could also slow down attentional disengagement from direct gaze. It has been shown that social inclusion, but not social exclusion, increases interest in mating (Brown, Young, Sacco, Bernstein, & Claypool,
2009; Sacco, Brown, Young, Bernstein, & Hugenberg,
2011). If inclusion can alter social behavior, then it might influence the allocation of attention to social cues as well. Recent evidence shows that the effect of direct gaze, compared to downward gaze, on self-reported arousal is stronger when participants have been primed with affective sentences related to positive social interactions, or social interactions involving the self, compared to negative interactions, or interactions involving other individuals, respectively (McCrackin & Itier,
2018). This suggests that activation of affiliation-related cognitive processes can cause an observer to experience another’s direct gaze as a particularly potent and salient cue. Furthermore, one study found that participants induced with positive mood made more eye contact than participants induced with negative or neutral mood (Natale,
1977). Based on these findings, it seems possible that a positive social experience such as an inclusive social interaction could also modulate responses to others’ gaze, and thus possibly slow down disengagement of attention from faces with direct gaze. On the other hand, only one study has found inclusion in Cyberball causing effects compared to a condition with no manipulation (increased interest in mating; Brown et al.,
2009), whereas several studies have found no differences on various measurements when comparing inclusion to non-social control manipulations (Dvir, Kelly, & Williams,
2018; Riva, Williams, Torstrick, & Montali,
2014; Syrjämäki et al.
2018). Thus, exclusion would be more likely to exert an effect on attentional disengagement from direct gaze than social inclusion.
After the social exclusion, social inclusion, or control manipulation, participants completed a task, in which we examined attentional disengagement from faces. We used realistic, computer-generated face stimuli. These kinds of face stimuli have proved useful substitutions for photographs in studies on attention to faces because they provide precise control over many important properties of the stimuli, such as their gaze direction, head orientation, and facial expression (e.g., Becker, Anderson, Mortensen, Neufeld, & Neel,
2011). Similar to earlier research on attentional disengagement from direct gaze, the faces were rotated laterally (Hietanen et al.,
2016; Senju & Hasegawa,
2005). In the attentional disengagement task, participants were first shown a face portraying direct or downward gaze in the middle of the computer screen, and after a brief delay (200 ms or 500 ms), a target stimulus appeared on either the left or the right side of the face. Participants were instructed to identify the target stimulus as quickly as possible using one of two keys on a keyboard. We hypothesized that participants in all groups would be slower to identify the target stimuli when presented with a picture of a face portraying direct gaze as compared to downward gaze. Most importantly, we investigated whether social exclusion, and possibly social inclusion, would enhance this effect. We hypothesized that the difference in response times between direct and downward gaze trials would be larger in the social exclusion group, compared to the non-social control group, which would indicate that excluded participants’ attention is particularly strongly held by direct gaze. As described above, there was some basis to expect that the attention holding effect by direct gaze could be enhanced also in the included individuals relative to the control group.