Impact of Positive Mental Vs. Physical Health Messaging on Motivation to Stop Smoking

Motivation to stop smoking was measured using the Motivation to Stop Scale (MTSS). The MTSS asks participants "Which of the following best describes you?" with the following ordinal scale: 1) "I don't want to stop smoking"; 2) "I think I should stop smoking but don't really want to"; 3) "I want to stop smoking but haven't thought about when"; 4) "I REALLY want to stop smoking but I don't know when I will"; 5) "I want to stop smoking and hope to soon"; 6) "I REALLY want to stop smoking and intend to in the next 3 months"; 7) "I REALLY want to stop smoking and intend to in the next month".

Participants were asked their intention to quit smoking "Are you planning to quit smoking within the next month?" using a 10-point visual analogue scale, where 1 indicates low intention to quit and 10 indicates higher intention to quit smoking

To measure participants' self-efficacy to quit smoking, participants responded to the questions "Overall, how confident are you that you can stop smoking within the next month?" on a 5-point scale 1 ('not at all') to 5 ('completely confident') and "For me cutting down on the number of cigarettes that I smoke in the next month would be…." On a scale off 1 ('very difficult') to 5 ('very easy'). The mean score across the two items was calculated, with a higher score indicating higher self-efficacy

Participants rated their agreement to the statements "smoking helps people relax", "smoking helps to reduce stress", "smoking helps to keep weight down" "smoking increases social comfort" "those who smoke are more popular" and "second hand smoke is not harmful" using a 5-point scale from 1 ('not at all') to 5 ('a lot'). The mean score across the five items was calculated, with a higher score indicating more favourable beliefs towards smoking

Participants rated two statements 'these labels are worth remembering' and 'these labels grabbed my attention' on a 5-point scale from 1 ('not at all') to 5 ('a lot'), mean score across the two items was calculated, with a higher score indicating greater attention

To measure affective reactions to the health labels we used the Self-Assessment Manakin (SAM, (Bradley & Lang, 1994)). Participants rated their affective reactions: valence, arousal, and dominance on a 9-point visual analogue scale. Scales for valence range from 1 'unpleasant' to 9 'pleasant', arousal ranged from 1 'calm' to 9 'excited', and dominance ranged from 1 'controlled' to 9 'in control' with 5 as neutral for all items

Perceptions of believability of the health label were measured using the question "How believable are these health labels?", participants rated this on a 5-point scale from 1 ('not at all') to 5 ('a lot')