This paper aims to examine the role emotion plays in advertising and brand building and the implications this has for measurement. Viewing brands as a complex compound of functional, symbolic and emotional values and benefits is now widely accepted. Brands are built using a variety of tools and techniques but the informational and transformational abilities of advertising are central to the development of many brands. However, the ability of advertising effectiveness and brand tracking measurement techniques used by practitioners to adequately capture the role and impact of affect is increasingly being questioned. Traditional evaluation methods may be adequate for the functional components of brand image, but the emotional elements are more covert. They may play a subversive role, influencing the measurement of perception, experience and memory. This paper seeks to examine the ability of existing methods to unlock recollections, feelings and beliefs in the process of building and sustaining brands. It is argued that whilst recall-based metrics have improved in recent years evidence from recent research from the neurosciences suggests that fundamental flaws remain. In particular, measurement of emotion, using essentially cognitive interpretation reporting should be treated with caution. New methods are currently being developed but there are significant obstacles to progress due in part to the inherently conservative nature of research agencies and clients.