# Categorical Perception of Emotion in Vocal Expression Laukka **Keywords:** emotion, vocal expression, categorical perception, speech synthesis **Opening (not a real abstract):** Categorical perception (CP) occurs when continuous sensory stimulation is sorted out by the brain into discrete categories. One effect of this is that equal-sized physical differences between stimuli are perceived as smaller or larger depending on whether the stimuli are perceived as belonging to the same category or to different categories.1 Several studies have investigated CP of facial emotion expressions by creating continua of interpolated (morphed) pictures of facial affect, from one expression to another, that differ by equal physical amounts.2–5 Evidence of CP is generally assessed in two stages. First, subjects should identify the morphed expressions as belonging to two distinct sections separated by a category boundary even though the expression information is linearly manipulated. Second, it should be easier for **Authors:** [[PETRI LAUKKA]]