Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3DY, United Kingdom.
Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3DY, United Kingdom
J Neurosci. 2022 Feb 23;42(8):1510-1528. doi: 10.1523/JNEUROSCI.1275-21.2021. Epub 2021 Dec 22.
Economic choice is thought to involve the elicitation of the subjective values of the choice options. Thus far, value estimation in animals has relied on stochastic choices between multiple options presented in repeated trials and expressed from averages of dozens of trials. However, subjective reward valuations are made moment-to-moment and do not always require alternative options; their consequences are usually felt immediately. Here, we describe a Becker-DeGroot-Marschak (BDM) auction-like mechanism that provides more direct and simple valuations with immediate consequences. The BDM encourages agents to truthfully reveal their true subjective value in individual choices ("incentive compatibility"). Male monkeys reliably placed well-ranked BDM bids for up to five juice volumes while paying from a water budget. The bids closely approximated the average subjective values estimated with conventional binary choices (BCs), thus demonstrating procedural invariance and aligning with the wealth of knowledge acquired with these less direct estimation methods. The feasibility of BDM bidding in monkeys paves the way for an analysis of subjective neuronal value signals in single trials rather than from averages; the feasibility also bridges the gap to the increasingly used BDM method in human neuroeconomics. The subjective economic value of rewards cannot be measured directly but must be inferred from observable behavior. Until now, the estimation method in animals was rather complex and required comparison between several choice options during repeated choices; thus, such methods did not respect the imminence of the outcome from individual choices. However, human economic research has developed a simple auction-like procedure that can reveal in a direct and immediate manner the true subjective value in individual choices [Becker-DeGroot-Marschak (BDM) mechanism]. The current study implemented this mechanism in rhesus monkeys and demonstrates its usefulness for eliciting meaningful value estimates of liquid rewards. The mechanism allows future neurophysiological assessment of subjective reward value signals in single trials of controlled animal tasks.
经济选择被认为涉及对选择选项的主观价值的推断。到目前为止，动物的价值估计依赖于在多次试验中呈现的多个选项之间的随机选择，并从数十次试验的平均值中得出。然而，主观奖励值是实时做出的，并不总是需要替代选项；它们的后果通常是立即感受到的。在这里，我们描述了一种类似于 Becker-DeGroot-Marschak（BDM）拍卖的机制，该机制提供了更直接和简单的评估，具有即时的后果。BDM 鼓励代理人在个人选择中如实揭示他们的真实主观价值（“激励相容性”）。雄性猴子在使用水预算的情况下，可靠地对排名前五的 BDM 出价进行出价。这些出价与使用传统二进制选择（BC）估计的平均主观值非常接近，因此证明了程序不变性，并与这些不那么直接的估计方法所获得的丰富知识相一致。猴子进行 BDM 出价的可行性为在单次试验中而不是从平均值中分析主观神经元价值信号铺平了道路；这种可行性也弥合了与人类神经经济学中越来越多使用的 BDM 方法之间的差距。奖励的主观经济价值不能直接测量，只能从可观察的行为中推断出来。到目前为止，动物的估计方法相当复杂，需要在重复选择中比较几种选择选项；因此，这些方法不符合个人选择结果的紧迫性。然而，人类经济研究已经开发出一种简单的拍卖式程序，可以直接而即时地揭示个人选择中的真实主观价值[Becker-DeGroot-Marschak（BDM）机制]。本研究在恒河猴中实施了这一机制，并证明了它在引出有意义的液体奖励价值估计方面的有用性。该机制允许未来在受控动物任务的单次试验中对主观奖励价值信号进行神经生理学评估。
