Monocular without stereopsis with and head movement

Random dots moving with various velocity gradients were presented to observers; the motion was yoked to head movement in one condition and to no head movement in another. In Experiment 1, 12 observers were shown motion gradients with sine, triangle, sawtooth, and square waveforms with amplitudes (equivalent disparities) of 12′ and 1° 53′. In Experiment 2, 48 observers were shown only the sinewave or square-wave gradient of 1° 53′ disparity either with or without head movement so that the observers’ expectation to see depth in one condition did not transfer to another. The main findings were: (1) with 12′ disparity, the head-movement condition produced perceived depth but almost no perceived motion, whereas the no-head-movement condition produced both perceived depth and perceived motion; (2) with 1° 53′ disparity, both conditions produced perceived depth and perceived motion; and (3) when the expectation to see depth was removed, the no-head-movement condition with the square-wave gradient produced no perceived depth, only motion. We suggest that monocular stereopsis with head movement can be achieved without perception of motion but monocular stereopsis without head movement requires perception of motion.     

Visual information for categorizing facial expression of emotions

Two experiments were conducted to reveal the visual information from the face utilized for the categorization of its expression of emotions. In Experiment 1 the subjects produced six schematic faces expressing six basic emotions by using a computer graphics system. By a series of factor analyses on the variables of displacements of feature points for deforming a neutral schematic face to produce the six expressional ones, two factors of ‘curvedness/openness’ and ‘slantedness’ of facial elements were obtained. In Experiment 2 another group of subjects made category judgements of emotions for 72 of the total 216 schematic faces produced in Experiment 1. The relationship between the displacements of feature points in Experiment 1 and subjects' categorical responses in Experiment 2 were examined by canonical discriminant analysis. It was found that the categorical judgements were well explained by two canonical variables whose structures were quite similar to those of factors obtained in Experiment 1. These results indicated that we extract the information of changes in curvedness/openness and slantedness of facial elements among other information on the face for categorizing its expressions of emotions. Lastly, the relationship between the dimensions of visual information obtained here and those of semantic affective meanings found in earlier research was discussed.