Taste: Beyond Sensation, the Role of Papillae, Categorical Perception and Levels of Processing in the Psychology of Eating.

Our understanding of the psychology of food choice and eating has gaps when it comes to the understanding at the basic cognitive level. This thesis aimed to address this gap, applying theories and methods not previously used with the sense of taste. This would include investigating taste perception and taste buds. Additionally the nature of tastant categories and the mnemophysics of flavour will also be investigated. Research has shown that papillae numbers affect perception ability; i.e., whether someone is a non-taster, taster or super-taster. This thesis has shown that this effect does not extend to effecting memory performance. The number of papillae does not relate to memory performance. Levels of processing, which was the most influential theory and methodological framework of memory during the last century was applied to taste for the first time in this PhD. The theory states that memory is dependent on the depth of processing. The first study used liking (deep) and pulpiness (shallow) as orientating tasks. The second study used liking by a significant other (deepest), liking (deep) and sip size as orientating tasks. Despite best efforts no LOP effect could be found for flavour using orange juice as the stimuli the issue of power was identified as a substantial caveat to this conclusion. The second half of the thesis investigated whether there was a CP effect for flavour and whether the traditional CP account, or Shift Toward Prototype (STP) or Perceptual Magnet theory could account for the effect. A categorical perception effect for flavour was identified in all three binary tastant mixtures, comprising mixtures of orange, lemon or blackcurrant. The effect was replicated three times for the orange-lemon tastant mixtures. A 'prototype effect' was also identified at the orange, lemon and blackcurrant 100% concentrations. The pattern of results at the prototype resembled the pattern at the category boundary. This does not support perceptual magnet theory. It may support novel tastant detection as demonstrated by Mojet and Koste (2005). While there was evidence for a CP effect this seemed to diminish with time. This contradicted the STP account. The role of memory is given consideration and the idea of prototypes in the studies is evaluated. A critical evaluation of the research and possible future directions are included