A novel direction of radiology research is better understanding the links between cognitive and personality factors and radiologists' accuracy and performance. This study examines relationships between Emotional Intelligence (EI) scores and observer performance by radiologists in breast cancer detection. Three separate samples were collected with Australian and US breast imaging radiologists. The radiologists were asked to undertake a mammographic interpretation task to identify malignant breast lesions and localise them, in addition to use a confidence rating scale to report confidence in the decision. Following this activity, the radiologists were administered the EI Trait (TEIQue-SF) questionnaire. The Trait EI test gives a Global EI score and 4 sub-scores in Well-being, Self-Control, Emotionality and Sociability. Sample 1 (Sydney 2012) radiologists were divided into 2 experience bands; radiologists practicing <13 years as “less” experience and <13 years as “more”. There was a significant correlation (r = 0.849, p =0.012) between Self-Control and Location Sensitivity in the “less” experience group; however there was little correlation between this EI trait in “more” experience, although more experienced radiologists had significantly higher EI scores for sociability than their less experienced counterparts (z = -1.981, P = 0.047). In the second sample (Darwin 2013) radiologists were divided into 2 groups: high and low experience, however there were no statistically significant correlation between EI and performance in any band. For sample 3 (Louisville 2013) radiologists were divided into 3 groups of experience, with the “medium “experience radiologists having correlations between EI factors “emotionality” and “sociability” to Location Sensitivity and JAFROC. Our preliminary results indicate EI is correlated to observer performance in lesser experienced radiologists. It is suggested that tasks perceived as more difficult by less experienced radiologists may evoke more emotion (uncertainty, frustration, pressure). As experience increases, radiologists may develop an ability to control their emotions or emotional intelligence becomes less important in decision making.