Can transcranial direct current stimulation enhance positive emotional processing bias?

INTERVENTION: Intervention 1: 1 mA transcranial direct current stimulation (tDCS). Anodal stimulation will be applied to the left dorsolateral prefrontal cortex and the cathode will be placed over the right orbit. Stimulation will be delivered for for 20‐minutes using a Starstim/Neuroelectrics stimulator and will be administered with concurrent attentional bias modification training. Attentional bias modification is a computerised dot‐probe task. It involves simultaneous presentation of positive and negative stimuli and repeated orientation of attention towards the positive stimuli via dot probe. All participants will complete two experimental sessions, one each of the following: ‐ active tDCS + attentional bias modification training ‐ sham tDCS + attentional bias modification training Sessions will be conducted a minimum of 72‐hours apart and interventions will be administered by a single trained researcher. Session order will follow a pre‐determined randomisation schedule. CONDITION: Affective processing bias in healthy adults PRIMARY OUTCOME: Pre versus post performance on attentional bias assessment task. ; ; Attentional bias assessment task: the attentional bias assessment task is a computerised dot‐probe task. It follows the same format as the attentional bias modification in that it involves simultaneous presentation of positive and negative stimuli. It differs in that the dot probes are are presented in a 50:50 positive: negative contingency and differences in reaction time to positive and negative stimuli are used to infer attentional bias. SECONDARY OUTCOME: Pre versus post intervention EEG activity during completion of an emotive sternberg working memory task. ; ; Emotive Sternberg Task: comprises blocks of positive, neutral and negative stimuli. Differences in accuracy and reaction times by valence and stimulation condition will be examined. INCLUSION CRITERIA: 1. Are voluntary and competent to consent 2. Are right handed 3. Have no history of traumatic brain injury, cognitive impairment (learning difficulty, ADHD), neurological or mental illness