关键词: 公正, FRN, P300, 主成分分析

Abstract:

Opportunity equity is highly desired in human society. Previous studies have shown that opportunity (in)equity influences the evaluation of subsequent outcomes. However, it is unclear whether this influence occurs only at an early cognitive stage or extends to a late cognitive stage as well. Based on the notion that “people seem to be more committed to outcome equity than opportunity equity,” we hypothesized that opportunity (in)equity would affect outcome evaluation at an early stage in the cognitive process, but not at a late stage. Additionally, we indicate how limitations in the experimental design and data analysis of previous studies may have affected their conclusions.

To examine the cognitive stage at which opportunity (in)equity influences outcome evaluations in a competitive social context, we recruited 31 college students (19 females, 19.52 ± 1.46 years) to participate in a competitive two-person choice game with their opponents. To account for the difference between subjective and objective predictions and the effect of varied choice numbers, we designed the game so that the participants had four cards in all trials. In contrast, their opponents randomly received two, four, or six cards in each trial, creating three opportunity conditions: advantageous opportunity inequity (AI), opportunity equity (OE), and disadvantageous opportunity inequity (DI). Both players selected only one card from the available options to compare their outcomes, which could result in a win, draw, or loss. Similar to previous studies, we recorded and analyzed event-related potential responses to actual outcomes, focusing on feedback-related negativity (FRN) and P300. We performed principal component analysis (PCA) to disentangle the overlap of FRN and P300.

The analysis of behavioral results of our study demonstrated a significant interaction between opportunities and outcomes in relation to subjective pleasantness rating scores, indicating that opportunity (in)equity indeed influenced outcome evaluation. Furthermore, we found a significant interaction between opportunities and outcomes for both the original and PCA-FRN amplitudes, indicating that opportunity (in)equity affected outcome evaluation at an early cognitive stage. Specifically, when participants experienced a win, there was no significant difference in the original and PCA-FRN amplitudes among the three opportunity conditions. In contrast, when participants lost, AI and DI elicited more negative original and PCA-FRN amplitudes than OE, suggesting that participants were sensitive to opportunity equity in the context of loss. Moreover, we did not find a significant interaction between opportunities and outcomes, nor a main effect of opportunities, for either the original or PCA-P300 amplitudes. These results suggest that opportunity (in)equity did not have a significant influence on outcome evaluation at a late cognitive stage. Notably, draws elicited larger PCA-P300 amplitudes compared to wins and losses, indicating that participants were sensitive to outcome equity.

In conclusion, our study demonstrates that opportunity (in)equity influences outcome evaluation at an early cognitive stage but not at a late stage. These findings provide valuable insights into the intricate temporal dynamics of the interaction between opportunity equity and actual outcomes, and contribute to fostering a more equitable society.

Key words: equality, FRN, P300, principal component analysis