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- Creators: School of Life Sciences
- Member of: Barrett, The Honors College Thesis/Creative Project Collection
- Resource Type: Text
This study investigates the effects of familiarity and the size of a novel object on perception of depth. Familiar size is a visual depth cue that provides information about the distance of an object. This project explores if the familiar size illusion is a result of an automatic perceptual process or an intellectual thought process. This data was collected in two phases, a familiarization phase and a testing phase. The experimental participants were familiarized for 30 seconds with a novel object, while the control group was not shown any objects prior to presentation of test objects. The novel test stimuli were constructed in 5 sizes and participants in the familiar group were familiarized with the medium size object. Participants were then asked to indicate the perceived distance of different sized objects by moving a rod with a pointer at the end to match the distance. The smaller comparison objects subtended visual angles that participants had not previously experienced, while larger comparison objects produced a larger visual angle than the participants had seen during the familiarization phase. The testing phase was identical for both familiar and unfamiliar control groups. Apparent distance was influenced by the size of the objects. Larger objects were judged to be closer than the smaller objects. Participants not familiarized showed smaller effects of stimulus size than the familiarized group. The effect of familiarity was not significant for the smaller stimuli but was very significant for the larger stimuli. The results were not consistent with the cognitive theory which argues that familiar size is a result of a conscious thought process. These outcomes are predicted under the model of familiar size being an automatic perceptual process.
performance is limited by poor spectral resolution. Acoustic CI simulation has been widely used
in normal-hearing (NH) listeners to study the effect of spectral resolution on speech perception,
while avoiding patient-related confounds. It is unclear how speech production may change with
the degree of spectral degradation of auditory feedback as experience by CI users. In this study,
a real-time sinewave CI simulation was developed to provide NH subjects with auditory
feedback of different spectral resolution (1, 2, 4, and 8 channels). NH subjects were asked to
produce and identify vowels, as well as recognize sentences while listening to the real-time CI
simulation. The results showed that sentence recognition scores with the real-time CI simulation
improved with more channels, similar to those with the traditional off-line CI simulation.
Perception of a vowel continuum “HEAD”- “HAD” was near chance with 1, 2, and 4 channels,
and greatly improved with 8 channels and full spectrum. The spectral resolution of auditory
feedback did not significantly affect any acoustic feature of vowel production (e.g., vowel space
area, mean amplitude, mean and variability of fundamental and formant frequencies). There
was no correlation between vowel production and perception. The lack of effect of auditory
feedback spectral resolution on vowel production was likely due to the limited exposure of NH
subjects to CI simulation and the limited frequency ranges covered by the sinewave carriers of
CI simulation. Future studies should investigate the effects of various CI processing parameters
on speech production using a noise-band CI simulation.