Table 1.
Overview of acceptance studies included in the meta-analysis
| Studies | N | Design | Stimuli | Acceptance instruction | Control condition instruction | N foci A > C | N foci C > A |
|---|---|---|---|---|---|---|---|
| 1. Kross et al. (2009) | 24 healthy (15 F) | Blocks within subjects | Negative autobiographical memories (cue phrases) | ‘… to recognize that the feelings they experienced during recollection were passing mental events that were psychologically distant from the self and did not control them.’ | ‘… to focus on the specific feelings that naturally flowed through their mind as they thought about their recalled experiences.’ (CFE) | 0 | 3 |
| 2. Lutz et al. (2014) | 46 healthy (15 F) | Between-group design | Negative pictures | ‘Try to consciously be aware of yourself, of what happens to you at this moment. Do this while expecting the picture and while looking at it. Do not judge; remain conscious and attentive to your present state. You may focus on thoughts, on emotions or on bodily sensations.’ | ‘… to expect and perceive the emotional stimuli.’ (CNR) | 3 | 2 |
| 3. Smoski et al. (2015a) | 19 healthy (12 F) | Event-related within subjects | Sad pictures | ‘To accept, your task is to notice what you are thinking and feeling, and to allow those thoughts and feelings to be there. So rather than try to push the feeling or thought away or try to feel differently, you just acknowledge it, perhaps saying, “That’s just how it is right now,” “This feeling will come and go,” or “I can accept this thought.” Note that acceptance doesn’t mean that you have to like the feeling, or that you are resigning yourself to the feeling. It is reminding yourself that it’s ok to feel what you feel without having to change it’ | ‘… not to regulate their emotion response.’ (CNR) | 8 | – |
| 4. Smoski et al. (2015b) | 18 Remitted MDD (14 F) | 5 | – | ||||
| 5. Murakami et al. (2015) | 21 healthy (11 F) | Event-related within subjects | Negative IAPS | ‘… to observe objectively and describe their subjective feelings or thoughts in their minds, and physiological changes in bodies, not with voice but just mentally, and to not suppress the emotions that are evoked by viewing the negative pictures.’ | ‘Simply look at the neutral or negative pictures and respond naturally.’ (CNR) | 22 | – |
| 6. Lebois et al. (2015) | 30 healthy (15 F) | Blocks within subjects | One-sentence stressful scenarios | ‘… to remain aware of their current physical location while thinking about the scenarios. They were further asked to notice the kinds of reactions that they normally have during immersion, but rather than “living” the event, they were instructed to simply observe their thoughts and reactions to it in the present moment. Participants were asked to perceive their thoughts about the stimuli as transitory mental states, not as parts of the scenarios, but as their psychological responses to them.’ | ‘Become completely absorbed in the experience of the scenarios, as if they were happening in the moment. They were to mentally time travel and experience the sensory details, physical sensations, feelings, emotions, and bodily states associated with engaging in the scenario vividly.’ (CFE) | 14 | 18 |
| 7. Westbrook et al. (2013) | 47 smokers (31 F) | Event-related within subjects | Craving stimuli | ‘… to actively focus on their responses to the picture, including thoughts, feelings, memories and bodily sensations, while maintaining a nonjudgmental attitude toward those responses’ | ‘… simply to relax and view the picture as naturally as possible’ (CNR) | 0 | 1 |
| 8. Ellard et al. (2017) | 21 GAD (21 F) | Blocks within subjects | Worry statements | ‘Observe and accept. “Observing” means instead of trying to do something about the distress you feel when you read statements about things you are worried about, try to observe your reaction in an objective way[…] “Accept” means allowing yourself to feel distress, knowing that this distress will peak and fade, and that it is ok to have this initial reaction.’ | ‘… just let yourself respond in whatever way you might naturally respond when you think about these topics. Don’t try and stop yourself from worrying, just let yourself worry as you might usually do.’ (CFE) | 2 | 10 |
| 9. Kober et al. (2019a) | 17 healthy (5 F) | Blocks within subjects | Negative IAPS | ‘… to attend to and accept their experience as it is. This instruction was modeled after the two-component […] (i) attention to present moment sensation, coupled with (ii) non-judgmental acceptance of the sensation as it is, allowing it to exist without trying to avoid it or react to it.’ | ‘React naturally, whatever your response might be’ (CNR) | 0 | 3 |
| 10. Kober et al. (2019b) | Pain | 0 | 9 | ||||
| 11. Goldin et al. (2019) | 35 healthy (15 F) | Event-related within subjects | Negative self-belief statements | ‘… simply observing and accepting without judgment from moment to moment (and not attempting to modify or change) any responses, including thoughts, emotions, memories, images, and physical sensations.’ | ‘… reacting to negative self-beliefs by considering how it reflected something true about themselves’ (CFE) | 11 | 4 |
| 12. Dixon et al. (2020a) | 113 SAD (61 F) | Blocks within subjects | Negative self-belief statements | ‘to regulate their reaction by ccepting their reactions, which involved a nonjudgmental monitoring of thoughts, memories, emotions, and sensations as they appeared and dissolved, without modifying or avoiding them.’ | ‘to react to the negatives statements by reflecting on how the NSB may describe something true about themselves and to let themselves feel the sting of the statement’ (CFE) | 2 | 9 |
| 13. Dixon et al. (2020b) | 35 healthy (22 F) | 0 | 6 |
N foci A > C = Number of foci for acceptance versus control condition.
N foci C > A = Number of foci for control condition versus acceptance.
IAPS = International Affective Pictures System.
GAD = Generalized Anxiety Disorder.
F = female.