Self-Admitted Technical Debt, or SATD, is a self-admission of technical debt present in a software system. To effectively manage SATD, developers need to estimate its priority and assess the effort required to fix the described technical debt. About a quarter of descriptions of SATD in software systems express some form of negativity or negative emotions when describing technical debt. In this paper, we report on an experiment conducted with 59 respondents to study whether negativity expressed in the description of SATD \textbf{actually} affects the prioritization of SATD. The respondents are a mix of professional developers and students, and in the experiment, we asked participants to prioritize four vignettes: two expressing negativity and two expressing neutral sentiment. To ensure realism, vignettes were based on existing SATD. We find that negativity causes between one-third and half of developers to prioritize SATD, in which negativity is expressed as having more priority. Developers affected by negativity when prioritizing SATD are twice as likely to increase their estimation of urgency and 1.5 times as likely to increase their estimation of importance and effort for SATD compared to the likelihood of decreasing these prioritization scores. Our findings show how developers actively use negativity in SATD to determine how urgently a particular instance of TD should be addressed. However, our study also describes a gap in the actions and belief of developers. Even if 33% to 50% use negativity to prioritize SATD, 67% of developers believe that using negativity as a proxy for priority is unacceptable. Therefore, we would not recommend using negativity as a proxy for priority. However, we also recognize that developers might unavoidably express negativity when describing technical debt.