I submitted my PhD thesis in February 2019. My research broadly focused on the factors that influence our memory for negative or traumatic material, compared to neutral and positive material. In particular my thesis focused on how these factors vary for voluntary (e.g., recognition, free recall) vs. involuntary (e.g., traumatic intrusions) memories. I used a range of methods in behavioural experiments to understand these factors; testing recognition memory for emotional and non-emotional images encoded in the left or the right hemisphere, inducing earworms (i.e., having a song stuck in your head) using instrumental film music, and measuring intrusions that arise from reading traumatic scenarios. I was particularly interested in demonstrating that the same mechanisms underlie our memory for traumatic, as for non-traumatic, material. This research holds important applications for our understanding of situations where emotional processing can become problematic to psychological wellbeing, e.g., in Post-Traumatic Stress Disorder (PTSD).