Unconscious death thoughts Do they play a role in time trade-off and visual analogue scale scores for health?

Background  Several factors influence the Time Trade-off (TTO) and Visual Analogue Scale (VAS) health measures. In qualitative TTO studies, respondents often report thoughts of death which may induce mortality awareness. According to Terror Management Theory (TMT), mortality awareness gives rise to anxiety and increases unconscious death thought accessibility (DTA), potentially mitigated by secure attachment. Therefore a relation between DTA and attachment versus TTO and VAS is expected.
Research questions  (1) Does DTA occur in TTO and VAS methods, (2) How are DTA and attachment related to TTO and VAS scores. We hypothesize: (1) DTA increases when respondents complete TTO or VAS tasks, and (2) TTO scores increase in those with a secure attachment.
Methods  In an online experiment, 4572 members of the general public were randomised to one of four conditions: TTO, VAS, Mortality Salient (MS), and control. TTO and VAS scores were obtained for a hypothetical wheelchair health state, and for self-experienced health. MS and control conditions served as manipulation checks. DTA was measured with a validated word completion task. ANOVAs and Pearson’s correlations examined differences between conditions and associations among variables.
Results  Mean (SD) DTA scores were: TTO = 2.86, (1.75); VAS = 2.94, (1.72); MS = 3.24, (1.89); control = 2.98, (1.70). The MS condition showed elevated DTA. Unexpectedly, DTA in the TTO condition tended to be lower than in the control condition, 95% CI [− .27, .03]. DTA was not associated with the TTO. DTA was negatively correlated with the VAS, both for the wheelchair and self-experienced states (both r = − 0.13, p < .01). Attachment showed negative correlations with the TTO and VAS self-experienced health scores (− 0.17 to − 0.13, p < 0.001), but was not associated with hypothetical wheelchair scores.
Conclusion  DTA and attachment are novel factors influencing TTO and VAS scores. Our data suggest that VAS may reflect broader psychological health concepts than the TTO, despite that both methods quantify health. The rational nature of the TTO may suppress DTA. In this online context, DTA was unrelated to hypothetical wheelchair state scores, suggesting that DTA might have little impact on national health valuation studies.