Biomedical subjects

Erica J Williams

Publications and source records attributed to Erica J Williams.

2 recordsLinked to original sources

PubMed2005

Compression estimates using behavioral and otoacoustic emission measures.

Cochlear compression in normal-hearing listeners was estimated at octave frequencies from 250 to 4000 Hz using a forward-masking paradigm. Temporal masking curves (TMCs) for a 10-dB SL signal were obtained with two maskers -- one equal in frequency to the signal and another an octave below the signal. The ratio of the slope of the off-frequency function to that of the mid-level portion of the on-frequency function was computed as an estimate of the amount of compression at each frequency. Compression was less frequency selective at low frequencies, so an average of the off-frequency slopes at high frequencies (1000, 2000, and 4000 Hz) was used in computing the ratio for each signal frequency. Results indicated strong compression (approximately 0.15-0.30) at all frequencies using the averaged off-frequency slopes, indicating little difference in compression across frequencies. Distortion product otoacoustic emission (DPOAE) input-output (I-O) functions were obtained for each subject at 1000, 2000, and 4000 Hz. The slopes of the DPOAE I-O functions and the psychophysical growth rates were similar to one another, reinforcing the assumption that the forward-masking procedure is providing an estimate of cochlear compression, at least at frequencies from 1000 to 4000 Hz.

Acoustic Impedance Tests↗

PubMed2004

Paws + cause = pause? Memory load and memory blends in homophone recognition.

Previous research has shown that separate information sources, activated closely together in time, can induce errors suggestive of memory blends. In Experiment 1, homophones were used to induce such memory errors. In a study task, participants made relatedness judgments to word pairs that included homophones (e.g., PAWS-BEAR). During this task, one group (study-similar) maintained memory loads with words that were orthographically similar to the presented homophones (e.g., JAWS). Another group (test-similar) maintained memory loads similar to those obtained for the study homophone's alternate spelling (e.g., CAUSE). A third group maintained no memory load during the task. In a surprise recognition test, participants were presented both previously viewed homophones (PAWS) and non-presented alternate spellings (PAUSE). We hypothesized that partially activated alternate spellings, in conjunction with the orthographically similar memory words, would result in the creation of blended memories. The results followed suit: The test-similar condition produced significantly elevated false alarms, relative to both the study-similar and the no-load conditions. Experiment 2 replicated these results while including memory loads to control for potential orthographic confusions. The findings are discussed in terms of multiple, episodic memories later activated as single, blended memories.

Humans↗