Human beings are shaped by their social relationships that create their environment and influence mental health (Yoshioka and Noguchi, 2009). These influences are impacted by the nature of the environment and can have different outcomes, such as social inclusion, acceptance, or support, that have been widely observed to be associated with pleasant feelings, healthy physiological functions, and good physical health (Eisenberger, 2013; Eisenberger et al., 2003; Kiecolt-Glaser et al., 2010; Pressman et al., 2019). Social exclusion or rejection induces negative or painful emotions (Jones et al., 2011; Wesselmann et al., 2022), which make individuals more inclined toward self-interest when faced with decisions or choices (Li et al., 2010). For example, individuals who have experienced rejection may exhibit heightened fear of negative social evaluation (Twenge et al., 2007) and are too sensitive to monetary reward cues (Xu and Wang, 2021; Xu et al., 2022). In summary, social exclusion has an effect on reward sensitivity in college students (Groschwitz et al., 2016; Olié et al., 2017). Due to their hearing impairments, deaf college students might isolate themselves in a passively exclusionary environment, akin to other excluded groups in many communication processes, owing to a mismatch of modalities and information (Spisak and Indurkhya, 2023). Students who are accustomed to using spoken language can receive and convey more information of higher quality, whereas deaf students who have grown up using sign language education often have difficulty communicating with hearing college students (Stinson et al., 1996). Therefore, it is important to examine the characteristics of reward processing in deaf college students in different social contexts.

The reward process is an effective method for influencing behavior and reflecting individuals’ motivations, expectations, and other mental processes. It includes two components: expectations and feedback on results (Maunsell, 2004; Wesselmann et al., 2022). The monetary incentive delay (MID) task represents a classic paradigm commonly used in reward processing research (Balodis and Potenza, 2015; Gu et al., 2019; Wilson et al., 2018) that measures reward-related expectancy, attention, and motivational mental processes (Zhang et al., 2020). The social incentive delay (SID) task was developed based on the monetary incentive delay task by using emotional faces instead of money as reward feedback materials (Smoski et al., 2011). Previous studies have indicated that hearing college students prioritize money over social rewards (Altikulaç et al., 2019; Rademacher et al., 2010). It is well established that both monetary incentives (Cristofori et al., 2015) and social rewards (such as social support) (Morese et al., 2019) can mitigate the negative consequences of social exclusion. Studies have explored the regulatory effect of social exclusion on reward sensitivity and found that social exclusion can increase an individual’s sensitivity to rewards (Chen et al., 2017). For instance, social exclusion has been demonstrated to increase an individual’s desire for monetary rewards (Zhou and Gao, 2008). Conversely, acute stress has been shown to reduce the degree of striatal activation in response to monetary rewards, suggesting that social exclusion may result in a blunted brain response to these rewards (Ossewaarde et al., 2011). In addition, individuals who have experienced rejection showed higher sensitivity to social rewards compared to monetary rewards (Mead et al., 2011). Considering these differing perspectives, the present study investigated the neurophysiological characteristics of reward processing mechanisms in deaf college students across diverse social contexts by using the MID and SID tasks.

The current study depended on the event-related potential (ERP) technique since its high temporal resolution enables recognizing substages within both anticipatory and consummatory reward processing mechanisms (Ait Oumeziane et al., 2019), enabling a direct comparison of social and monetary reward processing (Greimel et al., 2018). This study focused on two ERP components to investigate anticipatory and consummatory reward processing, the significance of which has been confirmed by previous studies using both the MID and SID tasks (Ait Oumeziane et al., 2017; Flores et al., 2015).

The P3 and feedback-related negativity (FRN) are components of the electroencephalogram (EEG) that are often associated with the anticipation and feedback phases of reward (Zhang et al., 2020). In previous studies, P3 has been found to be a positive deflection and is considered one of the reward-related electrophysiological markers (Broyd et al., 2012; Pfabigan et al., 2014; Vignapiano et al., 2016). The amplitude of P3 is related to the individual’s attention allocation and motivation for the task and the value of the stimulus (Groom et al., 2009; Polich and Kok, 1995; Vignapiano et al., 2016). Additionally, it has been shown that P3 associated with the expectation of monetary rewards, the Cue P3 response has greater amplitude for anticipatory tasks that represent the ability to obtain monetary cues (Pfabigan et al., 2014). Furthermore, P3 amplitude is greater for monetary reward cues than for neutral cues. Studies examining other types of rewards, including monetary rewards, have shown that P3 has a greater amplitude for larger rewards (Goldstein et al., 2006). Combined with the above-mentionedand the behavioural performance of individuals inthe context of social exclusion (Feng et al., 2021), we estimatedthat deaf college students may be more inclined toward monetary reward cues than neutral cues.

FRN is a negative component associated with feedback results (Li et al., 2018), mainly induced when results are evaluated (Yuan et al., 2012). The FRN reaches its maximum approximately 200–300 ms after the onset of the outcome feedback, exhibiting a more negative deflection for unfavorable outcomes (e.g., monetary losses) compared to favorable feedback (Gehring and Willoughby, 2002; Glazer et al., 2018; Holroyd and Coles, 2002; Miltner et al., 1997). This reflects an initial binary evaluation of outcomes as better or worse than expected (Foti et al., 2011; Holroyd et al., 2008). Source localization suggests that the intracerebral source of FRN occurrence is in the vicinity of the anterior cingulate cortex (ACC), which is associated with behavioral decision-making and cognitive control. Consequently, the FRN component reflects an individual’s learning and decision-making processes in the context of outcome evaluation (Holroyd and Coles, 2002; Holroyd and Yeung, 2012; Li et al., 2018; Xiang et al., 2008). This study, therefore, explored whether the deaf college students exhibit comparable reactions to rewarded feedback during this stage and the distinctions in feedback across different reward categories.

This study aimed to explore the behavioral responses and the corresponding ERP responses of deaf college students’ reward processing in the context of social exclusion and inclusion. This may facilitate a further understanding of the characteristics of deaf college students from the perspective of reward and provide preliminary suggestions for their future life and studies.

The present study explored the neurophysiological characteristics of reward processing in deaf college students under different social contexts with the MID and SID tasks by using ERP. At the behavioral level, there was a significant main effect of social context, such that the deaf college students showed a higher hit rate in the social inclusion context on the reward task. ERP results showed that reward cues evoked greater Cue P3 amplitude in the social exclusion context, and small-magnitude reward feedback evoked greater Feedback-evoked P3 amplitude than large-magnitude reward feedback. In addition, large-magnitude reward feedback elicited a larger FRN amplitude in the monetary reward cues than in the social reward cues.

Deaf college students exhibited a higher hit rate on the white square reward task in social inclusion. Furthermore, participants demonstrated a greater expectation of rewards and a higher hit rate when presented with social inclusion contextual pictures. One potential explanation is that people are born with an instinctive tendency and desire for social affiliation and interpersonal interaction (Ait Oumeziane et al., 2017; Baumeister and Leary, 1995). However, previous research has indicated that social exclusion may increase the expectation of monetary rewards and that negative experiences from exclusion may increase individuals’ pursuit of money (Feng et al., 2021; Lea and Webley, 2006). A review of the theory of pecuniary analgesia revealed that the experience of unpleasant pain caused by social exclusion motivates the pursuit of external relief, whereas the pleasurable sensations brought about by social inclusion may encourage the individual to a certain extent (Li et al., 2010). Consequently, the individual performed better in social inclusion, which is inconsistent with the ERP results possibly because behavioral outcomes can be affected by external factors that differ from EEG in time course. ERP technology has excellent temporal resolution, allowing comparison of the time course of social and monetary incentive processing (Ait Oumeziane et al., 2019; Greimel et al., 2018).

In the ERP results, the cue-evoked Cue P3 amplitude was greater in the social exclusion context than in the social inclusion context (Pfabigan et al., 2014). This indicated that social exclusion brought unpleasant experiences that strengthened individuals’ expectation and attention to rewards (Löw et al., 2008). Cue P3 is related to the allocation of attentional resources for decision-making or outcome evaluation, as well as motivation, reflecting the allocation of attention to reward-predicting cues (Ait Oumeziane et al., 2019; Ait Oumeziane et al., 2017), especially those stimuli that are task-relevant, infrequent, or unexpected (Courchesne et al., 1975; Donchin and Coles, 1988). Deaf college students may be too sensitive to specific information because of their hearing deficits and thus devote further attention resources (Bavelier et al., 2006; Marschark et al., 2013; Marschark et al., 2017). Previous studies have shown that social exclusion can lead to the development of unpleasant feelings such as internal isolation and self-doubt (Riva et al., 2016). To alleviate these feelings, individuals may attempt to mitigate the negative experience of social exclusion by monetarily enhancing their individual social charisma (Baumeister et al., 2008; Cristofori et al., 2015; Hess and Pickett, 2010; Li et al., 2010). Thus, deaf college students may have expectations and desires of monetary rewards following a series of situational pictures of social exclusion (Feng et al., 2021; Zhou et al., 2009). The greater Cue P3 amplitude elicited by the monetary reward cue in the social exclusion of the interaction also validated this idea (Lea and Webley, 2006). Moreover, the Cue P3 amplitude induced by the social exclusion context was greater in the small-magnitude reward cue condition than in the large-magnitude reward cue condition, which also suggested a greater effect of the social exclusion context (Xu et al., 2022). The results seemed to diverge from the prevailing view that reward expectation is proportional to reward magnitude (Dhingra et al., 2020) The greater the magnitude of the reward, the greater the activity in the brain regions activated by the reward expectation (Knutson et al., 2001), which suggested that a higher degree of expectation was associated with reward (Boukezzi et al., 2020). However, for the challenge of a new task, individuals may have minimal expectations, guaranteeing that they will be able to obtain the minimum gain before paying greater attention to and expecting larger expected rewards.

The P3 component is also related to the outcome of reward feedback (Gray et al., 2004; Leng and Zhou, 2010). The small magnitude of reward feedback induced a greater amplitude of Fb-P3, suggesting that deaf college students do pay attention to the small-rewarded task during the task and have a minimum expectation of reward acquisition (Ulrich et al., 2023; Wang et al., 2023). This indicated that deaf college students have conservative attitudes when facing task challenges (Batten et al., 2014; Fellinger et al., 2012). The minimum expectation mindset and the preference for monetary reward feedback respond to the complexity of expectations and feedback characteristics of deaf college students during the processing of rewards in different conditions, which reveals that for deaf college students there is a need for more practical and physical encouragement than hearing college students. Additionally, it is noteworthy that deaf college students in the monetary reward condition showed greater amplitude of the FRN in response to substantial reward feedback. This indicated that deaf college students are more concerned about obtaining greater monetary gains (Feng et al., 2021; Jia et al., 2011), exhibiting a heightened sense of favoritism toward monetary rewards (Altikulaç et al., 2019; Rademacher et al., 2014) and a more pronounced emotional involvement (Yuan et al., 2012). Despite a greater concern for smaller reward cues, this did not conflict with the desire to gain more, suggesting that deaf college students are pragmatic in their approach to tasks and benefits.

There are some limitations to this study, and potential future directions should be noted. First, the sample size of this study was small and the study group was single with only deaf college students; therefore, the findings may not be generalizable to other deaf groups. Future research could investigate the causes of developmental delays in deaf individuals by increasing the number of subjects and subject groups, as well as considering variables that may be associated with reward processing. These variables could include the degree of hearing loss, academic environment, socialization, and cognitive experiences. Second, the study did not adequately take into account that the deaf participants may have different interpretations, emotional experiences, and neural responses to context-based social images when selecting stimuli and can be further explored in future studies for the emotional attributes of facial expressions and social context to balance experimental control with ecological validity. Furthermore, the current study lacked a hearing control group, and a multifactorial mixed design could be used in the future to include a control group for comparative studies. Finally, the category of rewards in this study only examined money and social context. A subsequent study should investigate the rewards that deaf college students value or dislike to develop a deeper understanding of their reward characteristics.

In conclusion, deaf college students were more concerned with monetary rewards in the context of social exclusion. Additionally, their concern for small reward cues and feedback suggests that they approached the tasks in this study with a minimum expectation mentality.