Experimental Design Details
Participants first complete a baseline survey including screening questionnaires for mental health, several days before the rest of the experiment. In the main experiment, they do four rounds of the navigation task divided into two batches of two rounds. In between these rounds, they answer a survey on their beliefs about other participants in the task and their willingness to pay to be the guide versus the tourist in subsequent rounds.
In each round of the task, participants are matched in pairs and assigned to be guides or tourists. The guide then sees a profile of the tourist, which may or may not include a mental health signal, and reports their willingness to pay to work with the tourist they're matched to. They then complete the task. Afterwards, if both players have another round to play in this batch, the guide is again asked their willingness to pay to continue with this tourist. Willingness to pay is elicited via a Becker-deGroot-Marschak (BDM) mechanism which is implemented with 20% probability.
In the task itself, adapted from de Vries et al. (2018), the tourist is (virtually) dropped at an unknown New York intersection and can talk to the guide via a chat window. The guide has a simplified map of the tourist’s immediate area, with a destination marked, but does not know where the tourist is on the map. To earn a payoff, the tourist must get to the destination and the guide must confirm their arrival. The challenge of the task is finding where the tourist is on the map to start with as well as keeping track of the tourist's orientation relative to the map; the task thus requires careful, clear communication. Both participants also have an opportunity to give up.
I measure mental health in the baseline survey using two standard short-form survey instruments, the PHQ-8 for depression (specifically, major depressive disorder) and the GAD-7 for anxiety (specifically, generalized anxiety disorder). These instruments contain the PHQ-2 and GAD-2, very short questionnaires that are also used as screening tools in their own right and which I use as my signals of mental health that are shown to the guide.
In this design, I test the following hypotheses:
1. Do people discriminate against those with depression/anxiety symptoms when choosing who to work with? To answer this question, I estimate how the inclusion of these symptoms in a tourist's profile affects the guide's willingness to pay for the tourist before starting the task.
2. Is this discrimination statistical? To answer this, I compare the willingness to pay effect above with the average effect on actual earnings in the task of being assigned a tourist with vs. without symptoms in their profile. To estimate the earnings effect I use the 80% subsample for which the BDM mechanism is not implemented and tourists are thus exogenously assigned.
3. Do guides effectively discriminate in their in-task behavior, in ways that affect earnings? The earnings penalty from working with someone with revealed depression or anxiety symptoms may reflect both the direct correlation of depression or anxiety with ability at the task, and the effect of seeing these symptoms on the guide's behavior in the task. For instance, a belief that such people are more likely to give up may mean guides choose to give up sooner themselves. I therefore estimate how the appearance of depression/anxiety symptoms in the tourist profile affects earnings in the task, conditional on whether the tourist actually does have these symptoms. Additionally, I can look into how these earnings effects might come about by looking at the same effect on guide behavior, such as number and frequency of messages, and whether they click 'give up'.
4. What are the dynamics of discrimination -- do guides discriminate against those with depression/anxiety symptoms conditional on past performance in the task? To investigate this, I look at the willingness to pay to keep working with a given tourist after a round of the task. I ask whether guides are willing to pay less for tourists with a symptom of depression/anxiety conditional on having just failed at the task with that tourist. As performance is endogenous, I leverage randomized features of the task which affect its difficulty (in ways that could be misattributed to the tourist) such as the number of easily recognizable landmarks. I use these to create instrumental variables for success or failure.
5. What is the willingness to reveal mental health information in this task? A major goal of many awareness campaigns is to increase openness around mental health at work, but fear of discrimination could be a major barrier to 'coming out' as feeling depressed/anxious. I therefore investigate in my setting the willingness to pay to reveal mental illness symptoms. To measure this, I ask participants halfway through to choose via a BDM mechanism what information they would like or not like to be in their 'profile' that their guide will see if they are in fact the tourist in later rounds. This BDM mechanism is also only implemented for 20% of the sample.
I use additional features of the experiment to investigate mechanisms behind any discrimination result I might find. In particular, if discrimination is not wholly statistical, is this because people have on average inaccurate beliefs about depression/anxiety and performance at this task? To investigate this I elicit participants' beliefs about the performance of other participants in a separate survey mid-way through the experiment. I show profiles of actual participants, use a log-scoring rule to elicit subjective probabilities that these participants succeeded, and estimate how including depression/anxiety symptoms in the profile changes these beliefs.
Another potential mechanism is that guides feel less (or more) altruistic towards tourists showing symptoms of depression or anxiety. As the task is collaborative, altruism towards one's partner should motivate higher effort in the task. I measure the effect of revealing symptoms on altruism using a simple dictator game: at the end of the experiment, the guide is asked if they would like to send any of the bonus payment they have earned to the tourist, 'as a thank you'. The guide is told truthfully that the tourist will not find out if they send nothing.