This thesis throws new light on issues debated in the experimental literature on neutralisation. They concern the extent of phonetic merger (the completeness question) and the empirical validity of the phonetic effect (the genuineness question). Regarding the completeness question, I present acoustic and perceptual analyses of vowel/zero alternations in Bedouin Hijazi Arabic (BHA) that appear to result in neutralisation. The phonology of these alternations exemplifies two neutralisation scenarios bearing on the completeness question. Until now, these scenarios have been investigated separately within small-scale studies. Here I look more closely at both, testing hypotheses involving the acoustics-perception relation and the phonetics-phonology relation. I then discuss the genuineness question from an experimental and statistical perspective. Experimentally, I devise a paradigm that manipulates important variables claimed to influence the phonetics of neutralisation. Statistically, I reanalyse neutralisation data reported in the literature from Turkish and Polish. I apply different pre-analysis procedures which, I argue, can partly explain the mixed results in the literature. My inquiry into these issues leads me to challenge some of the discipline’s accepted standards for characterising the phonetics of neutralisation. My assessment draws on insights from different research fields including statistics, cognition, neurology, and psychophysics. I suggest alternative measures that are both cognitively and phonetically more plausible. I implement these within a new model of lexical representation and phonetic processing, the Variability Field Model (VFM). According to VFM, phonetic data are examined as jnd-based intervals rather than as single data points. This allows for a deeper understanding of phonetic variability. The model combines prototypical and episodic schemes and integrates linguistic, paralinguistic, and extra-linguistic effects. The thesis also offers a VFM-based analysis of a set of neutralisation data from BHA. In striving for a better understanding of the phonetics of neutralisation, the thesis raises important issues pertaining to the way we approach phonetic questions, generate and analyse data, and interpret and evaluate findings.