Modeling effects of risk and social distance on vaccination choice

Jarmolowicz et al. (2018) asked adults to imagine choosing a flu shot. The team varied how well the shot worked, how bad the side effects felt, and who got protected.

People made yes-or-no choices on a computer. The researchers drew curves to see how much each factor shrank willingness to get the shot.

Acceptance dropped fast when the vaccine helped less, side effects hurt more, or the protected person was a stranger. The pattern matched the same hyperbolic curves used for delayed money.

Social distance acted like a delay: saving a stranger felt almost as distant as waiting two years for cash.

Odum et al. (2020) reviewed 30 years of discounting papers and placed vaccination inside the bigger family of non-money goods. Their map shows health choices are discounted even more steeply than cash.

Harman et al. (2020) found that wording alone changes discounting: saying 'how long' instead of 'how much' steepened money curves. Jarmolowicz adds a new frame—social closeness—that moves the curve without touching reward size or time.

Howard et al. (2023) surveyed real DSPs who delayed COVID shots. Younger, lower-income staff waited longer. The survey data line up with the lab model: when the beneficiary feels distant, uptake falls.

You can now treat vaccine refusal as a discounting problem. Bring the beneficiary closer in time and space: use photos of the client, tell stories of their favorite activity, or have them give the shot consent themselves. Even a short video call with the family before clinic day can flatten the social-distance curve and raise acceptance.