Schuck Katharina, Niedeggen Michael, Kerschreiter Rudolf
Division of Experimental Psychology and Neuropsychology, Department of Education and Psychology, Free University of Berlin, Berlin, Germany.
Division of Social, Organizational, and Economic Psychology, Department of Education and Psychology, Free University of Berlin, Berlin, Germany.
Front Psychol. 2018 Sep 25;9:1762. doi: 10.3389/fpsyg.2018.01762. eCollection 2018.
Previous social exclusion experiments identified two factors affecting the participants' evaluation of participation in a virtual ball tossing game (cyberball): ball reception probability and vertical position of the participant's avatar on the screen. The P3 component in the event-related brain potentials (ERPs) indicated that both factors moderate subjective expectancies on social participation. The present research builds on an expectancy model explaining these effects and tests whether its predictions - established in a within-participant design - also hold in a between-participant design more common in behavioral cyberball studies. Participants were randomly assigned to four conditions which differed in ball reception probability (16% vs. 26%) and the avatar's vertical position (inferior vs. superior). To track the state of expectancy of involvement online, we recorded the ERP response evoked by ball receptions of the participant. Retrospectively, social involvement and social need threat were rated in a questionnaire. As hypothesized, low ball reception probability elicited enlarged P3 amplitudes in the ERPs, increased negative mood, and threatened social needs. For participants at inferior position, ERP and questionnaire effects were less expressed. This effect of verticality can be traced back to an adjustment in the expected involvement as signaled by a differential adaptation of the P3 amplitude within an experimental run. These results confirm that the predictions of an expectancy model also apply to cyberball studies using a between-participant design. However, the comparison with the results of previous within-participant design studies suggests that the sensitivity of the adjustment processes critically depends on the choice of the experimental design.
先前的社会排斥实验确定了影响参与者对参与虚拟抛球游戏（网络球）评价的两个因素：接球概率和参与者在屏幕上的虚拟形象的垂直位置。事件相关脑电位（ERP）中的P3成分表明，这两个因素都调节了对社会参与的主观预期。本研究基于一个解释这些效应的预期模型，并测试其预测——在参与者内设计中确立的——在行为网络球研究中更常见的参与者间设计中是否也成立。参与者被随机分配到四个条件，这些条件在接球概率（16%对26%）和虚拟形象的垂直位置（下方对上方）上有所不同。为了在线追踪参与预期的状态，我们记录了参与者接球所诱发的ERP反应。回顾性地，在一份问卷中对社会参与和社会需求威胁进行了评分。正如所假设的，低接球概率在ERP中引发了更大的P3波幅，增加了负面情绪，并威胁到了社会需求。对于处于下方位置的参与者，ERP和问卷效应表现得较弱。这种垂直性效应可以追溯到预期参与的调整，这在实验过程中通过P3波幅的差异适应得到了体现。这些结果证实，预期模型的预测也适用于使用参与者间设计的网络球研究。然而，与先前参与者内设计研究的结果比较表明，调整过程的敏感性关键取决于实验设计的选择。
