Abstract
HYPOTHESIS: Basic visual functions develop rapidly during the first year of life. Since infants' endogenous attention system is not yet quite matured, salience has an almost exclusive role in controlling their visual attention. However, there has been little research on the relationship between detectability and salience in infants, or on the relative salience of different visual features.
METHODS: We first measured detection thresholds and then the relative salience of iso-detectable stimuli, using a forced-choice preferential looking technique. Detection: Stimuli consisted of a dense 20×20 array of Gabor patches, where a 3×4 region either differed from the background elements in ‘color’ (red saturation: 6–31%, background: 0%) or in ‘motion’, with Gabors in the region phase-shifted with a constant velocity (0.3–1.2 Hz, background: static). This region appeared either on the left or the right side of the array. Salience: Iso-detectable (at the 70% and 80% level) stimuli were pitted against each other (on the same background as in the detection task). Gaze directions were coded in both experiments.
RESULTS: Our results are based on data collected from six 6-month-old infants. Detection thresholds were successfully determined with our paradigm. In terms of relative salience (of iso-detectable stimuli), preliminary results indicate that color stimuli were more salient than motion stimuli.
CONCLUSION: Consistent with the results of our earlier study on color vs. spatial frequency (Kaldy, Blaser, Kibbe & Pomplun, VSS 2005), detectability again did not fully predict salience. The inputs of different features into the computation of salience values are weighted differently.