Fig 1.
Number of respondents by age and sex.
Table 1.
Basic attributes of the three datasets.
Table 2.
Characteristics of respondents’ children and parents.
Fig 2.
Experimental procedure for investigating nudging messages for recycling disposable plastics.
The black dashed boxes show the interventions. The targets of the interventions are highlighted with red dashed boxes.
Fig 3.
Message presented to the control group.
Fig 4.
Message presented to treatment group 1.
The intervention is highlighted with red rectangles.
Fig 5.
Message presented to those under 50 years of age in treatment group 2.
The intervention is highlighted with red rectangles.
Fig 6.
Message presented to those 50 years of age and older in treatment group 2.
The intervention is highlighted with red rectangles.
Table 3.
Summary of interventions.
Fig 7.
Risk perception on disposable plastics by group before receiving the designed messages.
Higher values on the vertical axis indicate higher perceived risks. Error bars show 95% confidence intervals. CG, control group; T1, treatment group 1; T2, treatment group 2; Fut, Future Generations; You, Yourself.
Fig 8.
Daily COVID-19 cases per million people by country from February 10 to March 5, 2021.
Retrieved from [38], the dataset of which is based on the COVID-19 Data Repository of the Center for Systems Science and Engineering at Johns Hopkins University.
Fig 9.
Higher values on the vertical axis indicate higher perceived danger of COVID-19. Error bars show 95% confidence intervals. CG, control group; T1, treatment group 1; T2, treatment group 2.
Fig 10.
Perception by group that COVID-19 threatens the respondents’ family and relatives.
Higher values on the vertical axis indicate higher perceived danger. Error bars show 95% confidence intervals. CG, control group; T1, treatment group 1; T2, treatment group 2.
Fig 11.
Post-intervention effect in attitude change toward disposable plastics (D).
Higher values on the vertical axis indicate lower perceived danger of disposable plastics. Error bars show 95% confidence intervals. CG, control group; T1, treatment group 1; T2, treatment group 2; Fut, Future Generations; You, Yourself.
Fig 12.
Perception that the respondent has benefited from the actions of relatives belonging to older generations after receiving one of the nudge message interventions.
Error bars show 95% confidence intervals. CG, control group; T1, treatment group 1; T2, treatment group 2.
Fig 13.
Perception that the respondents’ younger relatives have benefited from disposable plastics after receiving one of the nudge message interventions.
Error bars show 95% confidence intervals. CG, control group; T1, treatment group 1; T2, treatment group 2.
Table 4.
Correlation coefficients between post-intervention effect in attitude change (D) and perceptions of benefiting from the older generations.
Table 5.
Correlation coefficients between post-intervention effect in attitude change (D) and perceptions that younger relatives are benefiting rom disposable plastics.
Fig 14.
Post-intervention effect in attitude change toward disposable plastics (D) by sex.
Error bars show 95% confidence intervals. Higher values on the vertical axis indicate lower perceived danger of plastic recycling. CG, control group; T1, treatment group 1; T2, treatment group 2; Fut, Future Generations; You, Yourself; M, men; W, women.
Fig 15.
Post-intervention effect in attitude change toward disposable plastics (D) by age.
Error bars show 95% confidence intervals. Higher values on the vertical axis indicate lower perceived danger of plastic recycling. CG, control group; T1, treatment group 1; T2, treatment group 2; Fut, Future Generations; You, Yourself; Y, respondents under the age of 50 years; O, respondents 50 years of age and older.
Table 6.
Coefficients from linear regression analysis.
Table 7.
Characteristic responses for CG.
Table 8.
Characteristic responses for T1.
Table 9.
Characteristic responses for T2.
Table 10.
Characteristic responses from respondents whose Cfamily was high.
Table 11.
Responses suggesting long-term intervention effects.