Adult-like neuroelectrical response to inequity in children: Evidence from the ultimatum game

Dynamic modulation of inequality aversion in human interpersonal negotiations

Negotiating with others about how finite resources should be distributed is an important aspect of human social life. However, little is known about mechanisms underlying human social-interactive decision-making in gradually evolving environments. Here, we report results from an iterative Ultimatum Game (UG), in which the proposer’s facial emotions and offer amounts were sampled probabilistically based on the participant’s decisions. Our model-free results confirm the prediction that both the proposer’s facial emotions and the offer amount should influence acceptance rates. Model-based analyses extend these findings, indicating that participants’ decisions in the UG are guided by aversion to inequality. We highlight that the proposer’s facial affective reactions to participant decisions dynamically modulate how human decision-makers perceive self–other inequality, relaxing its otherwise negative influence on decision values. This cognitive model underlies how offers initially rejected can gradually become more acceptable under increasing affective load (predictive accuracy ~86%). Furthermore, modelling human choice behaviour isolated the role of the central arousal systems, assessed by measuring pupil size. We demonstrate that pupil-linked central arousal systems selectively encode a key component of subjective decision values: the magnitude of self–other inequality. Taken together, our results demonstrate that, under affective influence, aversion to inequality is a malleable cognitive process.

The effect of a proposer’s facial emotions on a receiver’s likelihood to accept offers in an iterative Ultimatum Game is unknown. Here, modelling participant behaviour demonstrates that facial emotions dynamically tune participants’ inequality aversion.

Ranking status differentially affects rejection sensitivity in adolescence: An event-related potential study

Adolescents are sensitive to peer rejection but this may be dependent on their status. This study examined the role of ranking status on rejection sensitivity in adolescence using an experimental bargaining design. To manipulate ranking status, participants between ages 9-22-years (final sample n = 102) performed a reaction time task with two peers to induce high and low status. Next, participants played an iterative Ultimatum Game as high or low status proposer with an opposite status responder. Rejection of fair offers was associated with larger Medial Frontal Negativity (MFN) compared to acceptance of fair offers. An interaction between age and status group revealed that after rejection of fair offers, mid-adolescents showed a larger MFN when having a low status and smaller MFN when having a high status, relative to children and adults. These findings suggest that the MFN reacts as a neural alarm system to social prediction errors, signaling a need for vigilance to deviations from the norm, which is influenced by ranking status especially during mid-adolescence.

Neural processing of equitable and inequitable distributions in 5-year-old children

This study aimed at investigating the neurocognitive correlates of the perception and evaluation of equitable and inequitable distributions in five-year-old children. Children observed one character distributing toys or candies between two recipients. One of the recipients already possessed many resources, and the other possessed just a few. We used event-related potentials to compare brain activity elicited by equitable (the poor receives more) and inequitable (the rich receives more) distribution. On a behavioral level, children evaluated inequitable distribution as worse than equitable and considered the distributor as mean and worthy of punishment when she distributed inequitably as compared to equitably. On the neural level, we expected to find a MFN effect between 250 and 350 ms after picture onset. Instead, we found a frontal positivity (P2), which was greater for inequitable vs. equitable distributions, indicating greater saliency and attentional capture. This was followed by marginally significant greater positivity for equitable distributions between 600 and 1000 ms after picture onset (LPP), which indicates greater allocation of processing resources. Furthermore, a greater LPP was associated with more extreme evaluations for both conditions. This suggests that the more resources children invest in processing the distribution, the more they endorse equity and condemn inequity.

Parental presence with encouragement alters feedback processing in preschoolers: An ERP study

External feedback plays an important role in adapting to the environment; however, feedback processing in preschoolers has not been fully understood. The present event-related brain potential (ERP) study sought to understand the influence of parental presence with encouragement on feedback processing by focusing on reward positivity (RewP: mean amplitude between 200-350 ms). Five-year-old children (N = 21) completed an animal search task both alone (the alone condition) and with a parent who offered words of encouragement (the with a parent condition). ERPs were recorded while they received negative and positive feedback. We found a larger RewP amplitude in response to positive feedback in the with a parent condition relative to in the alone condition. In addition, differences in RewP between positive and negative feedback were only observed in the with a parent condition. These findings suggest that everyday parental encouragement has the potential to promote differential positive and negative feedback processing possibly by enhancing the reward value of positive feedback.