Department of Psychology, McGill University, Montréal, Québec, Canada.
Centre de Recherche de l'Institut Universitaire de Gériatrie de Montréal, Université de Montréal, Montréal, Québec, Canada.
Eur J Pain. 2022 Mar;26(3):668-679. doi: 10.1002/ejp.1895. Epub 2021 Dec 20.
In order to decide between avoiding pain or pursuing competing rewards, pain must be assigned an abstract value that can be traded against that of competing goods. To assess the relationship between subjectively perceived pain and its value, we conducted an experiment where participants had to accept or decline different intensities of painful electric shocks in exchange of monetary rewards.
Participants (n = 90) were divided into three groups that were exposed to different distributions of monetary rewards. Monetary offers ranged linearly from $0 to $5 or $10 in groups 1 and 2, respectively, and exponentially from $0 to $5 in group 3. Pain offers ranged from pain detection to pain tolerance thresholds. The value of pain was assessed by identifying the indifference points corresponding to a 50% chance of accepting a certain level of pain for a given monetary reward.
The value of pain increased quadratically as a function of the anticipated pain intensity and was found to be relative to the mean and standard deviation of monetary offers. Moreover, decision times increased as a function of the intensity of accepted painful stimulations. Finally, inter-individual differences in psychological traits related to harm avoidance and persistence influenced the value of pain.
This is the first demonstration that the value of pain follows a curvilinear function and is relative to the mean and standard deviation of competing monetary rewards. These new observations significantly contribute to our understanding of how pain is assigned value when making decisions between avoiding pain and obtaining rewards.
This work provides a description of the pain value function indicating how much people are willing to pay to avoid different intensities of pain. We found that the function was curvilinear, suggesting that the same unit of subjective pain has more value in the high vs. low pain range. Moreover, the pain value was influenced by the experimental manipulation of the rewards distribution and of the inter-individual differences in harm avoidance and persistence. Altogether, the present study provides a detailed account of how subjectively experienced pain is assigned value.
为了在避免疼痛和追求竞争奖励之间做出选择，必须为疼痛赋予一个可以与竞争商品进行交易的抽象价值。为了评估主观感知疼痛与其价值之间的关系，我们进行了一项实验，让参与者在不同强度的电击疼痛和金钱奖励之间做出接受或拒绝的选择。
参与者（n=90）被分为三组，分别暴露在不同的金钱奖励分布中。第一组和第二组的金钱奖励分别呈线性分布，从 0 美元到 5 美元或 10 美元，第三组呈指数分布，从 0 美元到 5 美元。疼痛刺激的强度从疼痛感知到疼痛耐受阈值不等。通过确定对应于接受给定金钱奖励的某个疼痛水平的 50%概率的无差异点来评估疼痛的价值。
疼痛的价值随预期疼痛强度的二次函数增加，并且与金钱奖励的均值和标准差相关。此外，决策时间随着接受的疼痛刺激强度的增加而增加。最后，与回避和坚持有关的心理特质的个体差异影响了疼痛的价值。
这是首次证明疼痛的价值遵循曲线函数，并且与竞争金钱奖励的均值和标准差相关。这些新的观察结果显著有助于我们理解在避免疼痛和获得奖励之间做出决策时，疼痛是如何被赋予价值的。
这项工作提供了疼痛价值函数的描述，表明人们愿意支付多少来避免不同强度的疼痛。我们发现该函数是曲线的，这表明相同的主观疼痛单位在高疼痛和低疼痛范围内具有更高的价值。此外，疼痛价值受到奖励分布的实验操作以及回避和坚持的个体差异的影响。总的来说，本研究提供了一个详细的描述，说明主观体验的疼痛是如何被赋予价值的。
