Below are data from: 1) A **questionnaire** concerning demographic information, changes in health behaviours as a result of lockdown, and pandemic-/lockdown-related experiences, completed by residents of Scotland and Japan (Sample file) 2) **Negative mood scale** (Mood file) 3) **Perceived social isolation scale** (Isolation file) 4) **Five cognitive tasks** (Iowa gambling, flanker Acc & RT, symbol learning, time production, and DSST Acc & RT files) The **Variables file** provides more information about questions and coding schemes for categorical variables. The **Performance notes file** lists participants with suboptimal performance on the DSST and flanker tasks. The **Materials folder** contains stimuli/materials used in the study. For more information on the **data from the change in health behaviours questions and mood and isolation scales**, see "Exploring the effects of COVID-19 restrictions on wellbeing across different styles of lockdown" by Ingram, Hand, Hijikata, & Maciejewski (under revision). For more information on the **data from the cognitive tasks**, see "Physical, mental, and cognitive wellbeing during the COVID-19 pandemic: Data from Scotland and Japan" by Ingram, Hand, Hijikata, & Maciejewski (submitted).