Twelve young adults in a good general health were observed during habitual posture of tongue and jaw in different emotional conditions induced by watching three video sequences. The position of the mandible was tracked by the displacements of an electromagnetic sensor glued to the chin. The tongue-to-palate distance was obtained by 2-D location of three electromagnetic sensors placed on the tongue upper midline surface. Head displacements were evaluated with a sensor fixed to an upper central incisor and were subtracted from corresponding displacements of tongue and chin sensors to obtain the real tongue and mandible positions during continuous recording sequences. Emotional conditioning by a fear movie influenced the vertical position of the mandible: the mean interarch distances during the fear movie (2 center dot 34 +/- 0 center dot 24mm) were significantly different from those measured during the tender (3 center dot 13 +/- 0 center dot 35) and neutral (3 center dot 42 +/- 0 center dot 80) movies, respectively (anova repeated measure, SNK; P<0 center dot 05). anova repeated measure indicated that the tongue-to-palate distance differed significantly when the subjects were watching the conditioning movies (P=0 center dot 003), the tip of the tongue taking a lower position during the fear movie than during the tender and neutral movies.