Figure 2.

The TASTE apparatus, showing its workings (hidden from the subjects). For a detailed description, see Ashkenazi et al. (2004). The hidden workings include a sliding nozzle array that allows for rapid switching between stimuli. Because each line and each nozzle was dedicated to a specific flavorant, cross-contamination and sniffing of the stimuli before stimulus onset was precluded. The subjects readied themselves for stimulus presentation by extending the tongue to the Teflon guide under the outflow point of the preselected nozzle. After stimulus presentation, the subject indicated, as quickly as possible, if a target stimulus was present (sucrose, citral or, sucrose–citral mixture) by pressing the response button. Between trials, subjects rinsed with deionized water and expectorated into the sink. This figure appears in color in the online version of Chemical Senses.