Book excerpt: I explore fundamental behavioral aspects of several market design environments in a variety of projects using both theoretical models and laboratory experiments. I show that human tendencies can drastically shift potential outcomes away from those which would result if individuals were fully 'rational' and unbiased in decision problems similar to those found frequently in the field. I explore two common classes of centralized matching mechanisms--Deferred Acceptance and Priority--which have wildly different success rates in practice despite both being open to manipulation by agents who have incomplete information about the other participants in the match. For this reason, theory predicts both mechanisms in equilibrium will yield match outcomes which are unstable, meaning some agents will desire to renegotiate with one another after receiving their match assignments, and thus reduce participants' confidence in using the match. I provide laboratory evidence that out-of-equilibrium truth telling by agents is substantially more frequent in the Deferred Acceptance environment and thus Deferred Acceptance matches will generally be more stable in practice than matches using a Priority mechanism. This may explain why Deferred Acceptance mechanisms appear to be more viable in the field. I also explore two different models of decentralized two-sided matching environments where establishing scarce signaling methods can improve market outcomes. In a laboratory experiment, I show that allowing potential receiving job offers to send a single signal to their favorite potential employer before job offers are made increases overall match rates in the market, but is potentially damaging to the firms making offers when compared to the market without such a signal. Then, in a theoretical model where pre-offer communication takes the form of an interview process where workers have natural limits on the number of interviews in which they can participate, I show that in many cases firms can benefit themselves and the market as a whole by voluntarily restricting the number of interviews they offer to participate in. While not traditionally thought of as market design problems, voting mechanisms are fundamentally goods allocation problems as well and have many of the same issues as traditional markets do. I explore the effects of voter bias on outcomes in an otherwise standard voting model and find that even slight external pressure on individuals in a committee tasked with coming to a collective decision can destroy the ability of that committee to arrive at the correct result, even when individuals have good information about the best decision to make. Furthermore, the quality of the decision made by such a committee can actually degrade as the committee size increases, in contrast with the canonical Condorcet Jury Theorem which predicts that a committee's ability to choose the right outcome increases quickly as more members are added.