The aim of this study is to explore whether a brief mental exercise (developed and widely advocated in the field of positive psychology) can change the processing of emotion-related information in a similar way as previously observed for antidepressant drugs. Healthy volunteers are randomly allocated to a 7-day practice of the "Three Good Things" (TGT) exercise or a previously used placebo exercise (unspecified childhood memory recall) with study participants as well as investigators being blind as to which practice is conducted. After a 7-day practice period, all study participants undergo testing with the Oxford Emotional Test Battery, an established battery of cognitive tasks that allow to assess how emotional information is processed. The working hypothesis of the study is that the TGT exercise, as compared to the placebo exercise, can push the processing of emotional information towards a prioritisation of positive (relative to negative) input.

Background and objective:

Previous research indicates that various physiological treatments for depression (especially antidepressant drugs) can induce positive biases in emotional information processing and it has been suggested that this might be a crucial common mechanism through which they exert their clinical effects. This study aims to investigate whether similar positive biases can also be induced by a brief mental exercise (developed and widely used within the field of positive psychology) that has previously been shown to have antidepressant and/or happiness-enhancing effects.

Methods:

Using a double-blind, parallel-group design, 100 healthy volunteers (male and female) are randomly allocated to a 7-day mental exercise practice conducting either the widely reported Three Good Things (TGT) exercise or a previously established placebo condition (unspecific childhood memory recall). After 7 days of practice, all participants undergo testing with the Oxford Emotional Test Battery in order to assess emotional information processing in different cognitive domains. This battery consists of a facial expression recognition task, an emotional categorization task, an emotional dot probe task, an emotional recall task and an emotional recognition task. In addition, prior to and immediately after the 7-day practice period salivary cortisol awakening response and subjective state (using various questionnaires) is assessed.

Hypotheses:

The working hypothesis of the study is that, similar to physiological antidepressant interventions, the TGT exercise (as compared to the placebo exercise) might induce biases towards positive stimuli in multiple cognitive domains.

Implications of the study:

This study will show whether engaging in a simple mental exercise can alter emotional information processing in a similar way as previously observed for antidepressant drugs and other physiological interventions.

Inclusion Criteria:

1. Female or male
2. Age: 18 to 65 years
3. Good general health
4. Competency to give informed consent

Exclusion Criteria:

1. Any current or past psychiatric disorder
2. Any first-degree relative with a diagnosis of schizophrenia-spectrum or other psychotic disorder, bipolar disorder, or depressive disorder
3. Regular engagement in mental exercises specifically aimed at improving cognitive abilities (concentration, attention, memory etc.), mood, or general well-being, such as (online) cognitive training, positive psychology exercises, regular meditation or mindfulness practices, yoga practices, or psychotherapeutic exercises.
4. Regular engagement in any of the exercises outlined above within the last 6 months.
5. Any severe medical condition not stabilized at the time of the study (e.g. asthma, heart disease, epilepsy)
6. Any current or past physical illness that has the potential to significantly affect mental functioning (e.g. stroke, Parkinson's disease, multiple sclerosis)
7. Current intake of medication that has a significant potential to affect mental functioning, or intake of such medication in the previous 3 months (e.g. antidepressants, neuroleptics, tranquilizers)
8. Any intake of recreational drugs in the last 3 months before the experiment
9. Regular consumption of higher doses of alcohol (more than 2 pints of beer or equivalent on more than 3 days a week within the last month)
10. Any other reasons that preclude participants from full participation in the experiment (e.g. insufficient knowledge of English language)
11. Any other condition which can make participation in the study harmful for a participant, or which can severely compromise the quality of the data (e.g. low intellectual functioning)