Despite the complexity and diversity of natural scenes, humans are very fast and accurate at identifying basic-level scene categories, In this paper we develop a new technique (based on Bubbles. Gosselin & Schyns. 2001 as Schyns, Bonnar, & Gosselin, 2002) to determine some of the information requirements of basic-level scene categorizations, Using 2400 scenes from an established scene database the Fourier coefficients (Oliva & Torralba, 2001). the algorithm randomly samples the Fourier coefficients of the phase spectrum. Sampled Fourier coefficients retain their original phase while the phase of nonsampled coefficients is replaced with that of white noise. Observers categorized the stimuli into 8 basic-level categories. The location of the sampled Fourier coefficients leading to correct categorizations was recorded per trial. Statistical analyses revealed the major scales and orientations of the phase spectrum that observers used to distinguish scene categories

Research has shown that auditory speech recognition is influenced by the appearance of a talker's face, but the actual nature of this visual information has yet to be established, Here, we report three experiments that investigated visual and audiovisual speech recognition using color, gray-scale, and point-light talking faces (which allowed comparison with the influence of isolated kinematic information). Auditory and visual forms of the syllables Ibal, Ibil, Igal, Igil, Ivai, and Ivil were used to produce auditory, visual, congruent, and incongruent audiovisual speech stimuli. Visual speech identification and visual influences on identifyingthe auditory components of congruent and incongruent audiovisual speech were identical for color and gray-scale faces and were much greater than for point-light faces, These results indicate that luminance, rather than color, underlies visual and audiovisual speech perception and that this information is more than the kinematic information provided by point-light faces. Implications for processing visual and audiovisual speech are discussed.

We conducted four experiments to investigate the role of colour and luminance information in visual and audiovisual speech perception. In experiments 1a (stimuli presented in quiet conditions) and 1b (stimuli presented in auditory noise), face display types comprised naturalistic colour (NC), grey-scale (GS), and luminance inverted (LI) faces. In experiments 2a (quiet) and 2b (noise), face display types comprised NC, colour inverted (CI), LI, and colour and luminance inverted (CLI) faces. Six syllables and twenty-two words were used to produce auditory and visual speech stimuli. Auditory and visual signals were combined to produce congruent and incongruent audiovisual speech stimuli. Experiments 1a and 1b showed that perception of visual speech, and its influence on identifying the auditory components of congruent and incongruent audiovisual speech, was less for LI than for either NC or GS faces, which produced identical results. Experiments 2a and 2b showed that perception of visual speech, and influences on perception of incongruent auditory speech, was less for LI and CLI faces than for NC and CI faces (which produced identical patterns of performance). Our findings for NC and CI faces suggest that colour is not critical for perception of visual and audiovisual speech. The effect of luminance inversion on performance accuracy was relatively small (5%), which suggests that the luminance information preserved in LI faces is important for the processing of visual and audiovisual speech.

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