As primates evolved from roaming the world on four legs to exploiting their environment on two, it is clear that vision slowly came to replace olfaction as the primary sense. Implications of this hence include a rapidly evolving visual system indicated by the amount of human brain now dedicated to vision (Cozolino, 2006). Throughout this essay, an evolutionary approach will be primarily used to examine the evidence that some emotions expressed in the face can be detected faster than others. For the purpose of this essay, emotions will be defined as a conscious experience consisting of behavioural, subjective and physiological elements, (Frijda, 1986). .
Face recognition in general is proven to be a completely different task from object recognition, as holistic processing tends to be used. In 1986, Bruce and Young designed a model of face recognition comprised of 8 component parts. They suggested that, "structural encoding," which includes description of facial expressions, occurs initially. It is visible from the model that expression descriptions and analysis are processed faster than recognition units and name generation. This again implies that the detection of emotions before other associations with facial recognition must be evolutionarily advantageous. Cozolino (2006) has described that quick and efficient understanding of the state of mind in which others are in, has aided our survival throughout history.
Human precedence of detecting fearful faces must therefore be an evolutionary survival strategy, as there is evidence of visual orientation of attention towards fearful stimuli. Pourtois et al. (2004) investigated the bias of attention towards fearful faces whilst participants completed a task regarding spatial orienting. A pair of faces (fearful and neutral) was shown to each participant for only 100ms, followed by small vertical bar that appeared in the place of either the fearful or neutral face (for 150ms).