Emotional similarity between personally-relevant photographs of negative world events

The meaning of our experiences is informed by their emotional tone, but to what extent judging that events evoke similar emotions (“emotional similarity”) determines our perception that these events are similar to each other overall? To investigate this question, in two experiments, we solicited judgments of the similarity between pairs of photographs of major real-world events on several dimensions, including their emotional and overall similarity. Ratings of the emotionality of single photographs were also collected. Participants in Experiment 2 completed questionnaires that quantified trait anxiety and depression. Explicit judgements of emotional similarity predicted judgements of overall similarity better than single-stimulus judgments, an important methodological point which should inform future studies of this construct. Our findings suggest that perceived emotional similarity is highly predictive of how similar stimuli are perceived to be overall. Despite the high correlation among the facets of similarity between stimuli, emotional similarity had a unique explanatory power. Depression severity decreased the perceived similarity. Because this relationship was unexpected we analysed two existing datasets where participants with a diagnosis of depression were compared to non-depressed controls. Our findings suggest that depression may sharpen the representation of negative experiences, exaggerating, rather than diminishing, the differences between them.