Generalization of Frequency Discrimination Learning Across Frequencies and Ears: Implications for Underlying Neural Mechanisms in Humans

Abstract

Frequency discrimination thresholds (FDTs) at 750, 1500, 3000, and 6000 Hz were measured in 32 normal-hearing listeners before and after each listener practiced the task for 12 h at one of the above frequencies using a single ear. Marked improvements in thresholds taking place over several hours were observed during the frequency-and ear-specific training period. Comparisons between pre-and posttraining thresholds showed large improvements at the trained frequency, but also at other frequencies. The improvements were initially slightlyVbut significantlyV larger at the trained frequency than at untrained frequencies. However, this trained-frequency advantage disappeared rapidly during the course of the twohour multifrequency posttraining session, suggesting rapid relearning or learning generalization across frequencies. In contrast, no significant ear specificity was found, not even at early stages of the posttraining session. These findings add to earlier results suggesting that, in humans, frequency discrimination learning is only weakly frequency-specific, and they reveal that a complete generalization across frequencies can occur rapidly with little retraining at the initially untrained frequencies. Implications regarding underlying mechanisms are discussed.

A review of the generalization of auditory learning

“…In a number of experiments, listeners who were trained at one frequency also improved at untrained frequencies. Such generalization has been observed among 0.75, 1.5, 3 and 6 kHz (nZ8 per group; Delhommeau et al 2005), between 5 (nZ8) and 8 kHz (nZ8) (Irvine et al 2000), from 1 to 1.1 and 2 kHz (nZ5, 350 trials per session; Roth et al 2003), from 1 to 0.5, 2 and 4 kHz (nZ12; Amitay et al 2005), and from 3 to 1.2 and 6.5 kHz (nZ8; Demany & Semal 2002). However, in nearly every case, there was some indication that this generalization was not complete.…”

Perceptual learning of time-compressed and natural fast speech

“…Transfer of learning involves the application of skills or knowledge learned in one context to another context ͑Cormier and Hagman, 1987;Haskell, 2001;Thorndike and Woodforth, 1901͒. Transfer of learning has been found in the auditory domain for nonspeech stimuli ͑Delhommeau et al, 2005;Delhommeau et al, 2002͒ andspeech stimuli ͑Bradlow andBent, 2008;McClaskey et al, 1983;Tremblay et al, 1997͒. Transfer of learning was, for instance, reported for auditory frequency discrimination tasks: Delhommeau et al ͑2002͒ measured listeners' frequency discrimination thresholds ͑FDTs͒ ͑the smallest audible difference frequency, ⌬f, around a center frequency͒ for four center frequencies ͑750, 1500 3000, and 6000 Hz͒ before and after training. Listeners were then trained for a specific center frequency ͑e.g., 750 Hz͒ and then subsequently tested again at all four center frequencies.…”

Psychoacoustic abilities as predictors of vocal emotion recognition

“…The practical reason for employing log transformation considerations is that the logarithmic transformation helps to avoid a violation of the homoscedasticity assumption of the parametric statistical tests, which is a result of extensive variability of frequency discrimination thresholds, which increases with their magnitude. It is important to note that the use of a logarithmic or square-root transformation of frequency discrimination thresholds is common practice in the psychoacoustic literature (Delhommeau, Micheyl, & Jouvent, 2005;Demany & Semal, 2002;Irvine, Martin, Klimkeit, & Smith, 2000;Micheyl, Delhommeau, Perrot, & Oxenham, 2006). 3.242, p < .01.…”