Pitch priming in sequences of two sounds

Individual differences in temporal order judgment

Large individual differences can be observed in studies reporting spectral TOJ. In the present study, we aimed to explore these individual differences and explain them by employing Warren and Ackroff (1976) framework of direct identification of components and their order (direct ICO) and holistic pattern recognition (HPR). In Experiment 1, results from 177 participants replicated the large variance in participants' performance and suggested three response patterns, validated using the K-Means clustering algorithm. In Experiment 2, the introduction of three tone-pairs to 90 participants, as opposed to a single pair, markedly decreased the propensity of participants to utilize HPR. Experiment 3 assessed 85 participants and demonstrated that diotic presentations significantly reduced the prevalence of HPR utilization. These results confirmed that direct ICO is used mainly when stimuli are difficult to group, and when grouping is possible, HPR is used. The results also show that these strategies are flexible and change according to the experimental manipulation. Spectral TOJ provides an opportunity to observe individual differences in auditory perception and facilitates the investigation of the diverse psychoacoustic cues underlying its performance.

Effect of Context on the Contribution of Individual Harmonics to Residue Pitch

There is evidence that the contribution of a given harmonic in a complex tone to residue pitch is influenced by the accuracy with which the frequency of that harmonic is encoded. The present study investigated whether listeners adjust the weights assigned to individual harmonics based on acquired knowledge of the reliability of the frequency estimates of those harmonics. In a two-interval forced-choice task, seven listeners indicated which of two 12-harmonic complex tones had the higher overall pitch. In context trials (60 % of all trials), the fundamental frequency (F0) was 200 Hz in one interval and 200 + ΔF0 Hz in the other. In different (blocked) conditions, either the 3rd or the 4th harmonic (plus the 7th, 9th, and 12th harmonics), were replaced by narrowband noises that were identical in the two intervals. Feedback was provided. In randomly interspersed test trials (40 % of all trials), the fundamental frequency was 200 + ΔF0/2 Hz in both intervals; in the second interval, either the third or the fourth harmonic was shifted slightly up or down in frequency with equal probability. There were no narrowband noises. Feedback was not provided. The results showed that substitution of a harmonic by noise in context trials reduced the contribution of that harmonic to pitch judgements in the test trials by a small but significant amount. This is consistent with the notion that listeners give smaller weight to a harmonic or frequency region when they have learned that this frequency region does not provide reliable information for a given task.