The perception of octave pitch affinity and harmonic fusion have a common origin.

Musicians say that the pitches of tones with a frequency ratio of 2:1 (one octave) have a distinctive affinity, even if the tones do not have common spectral components. It has been suggested, however, that this affinity judgment has no biological basis and originates instead from an acculturation process ‒ the learning of musical rules unrelated to auditory physiology. We measured, in young amateur musicians, the perceptual detectability of octave mistunings for tones presented alternately (melodic condition) or simultaneously (harmonic condition).

Automatic Frequency-Shift Detection in the Auditory System: A Review of Psychophysical Findings.

The human brain has the task of binding successive sounds produced by the same acoustic source into a coherent perceptual stream, and binding must be selective when several sources are concurrently active. Binding appears to obey a principle of spectral proximity: pure tones close in frequency are more likely to be bound than pure tones with remote frequencies. It has been hypothesized that the binding process is realized by automatic "frequency-shift detectors" (FSDs), comparable to the detectors of spatial motion in the visual system.

Detecting temporal changes in acoustic scenes: The variable benefit of selective attention.

Four experiments investigated change detection in acoustic scenes consisting of a sum of five amplitude-modulated pure tones. As the tones were about 0.7 octave apart and were amplitude-modulated with different frequencies (in the range 2-32 Hz), they were perceived as separate streams.

The Effect of Cochlear Damage on the Sensitivity to Harmonicity.

Objectives: A sum of simultaneous pure tones with harmonic relationships (i.e., simple frequency ratios) is normally heard as a single sound, with a single pitch, even when its components are fully resolved in the auditory periphery.

Pitch priming in sequences of two sounds.

Frequency discrimination limens (FDLs) were measured for pairs of stimuli differing from each other with respect to pitch salience. One of the two stimuli to be compared within a trial was a pure tone of at least 100 ms, evoking a salient pitch, while the other stimulus consisted of only eight sinusoidal cycles (experiment 1), or was a noise band with a Gaussian spectral envelope, evoking a weak pitch corresponding to the peak frequency (experiment 2). From trial to trial, frequency was varied randomly and widely.

Harmonic fusion and pitch affinity: Is there a direct link?

Simultaneous pure tones approximately one octave apart tend to be fused perceptually and to evoke a single pitch sensation. Besides, sequentially presented pure tones show a subjective "affinity" or similarity in pitch when their frequency ratio is close to one octave. The aim of the study reported here was to determine if these two perceptual phenomena are directly related.

Auditory attention is divisible: segregated tone streams can be tracked simultaneously.

Can auditory attention be split? We addressed this question using rapid sequences of tones alternating in frequency between 2 remote registers. In these rapid sequences, consecutive tones could not be perceptually linked; the tones were instead inevitably segregated into 2 concurrent melodic streams. Listeners had to determine if the 2 melodies interleaved in a sequence were exact transpositions of each other or not.

A late-emerging auditory deficit in autism.

Objective: Individuals with autism spectrum disorders (ASD) show enhanced perceptual and memory abilities in the domain of pitch, but also perceptual deficits in other auditory domains. The present study investigated their skills with respect to "echoic memory," a form of short-term sensory memory intimately tied to auditory perception, using a developmental perspective.

Method: We tested 23 high-functioning participants with ASD and 26 typically developing (TD) participants, distributed in two age groups (children vs.

The auditory enhancement effect is not reflected in the 80-Hz auditory steady-state response.

The perceptual salience of a target tone presented in a multitone background is increased by the presentation of a precursor sound consisting of the multitone background alone. It has been proposed that this "enhancement" phenomenon results from an effective amplification of the neural response to the target tone. In this study, we tested this hypothesis in humans, by comparing the auditory steady-state response (ASSR) to a target tone that was enhanced by a precursor sound with the ASSR to a target tone that was not enhanced.

No Need for Templates in the Auditory Enhancement Effect.

The audibility of a target tone in a multitone background masker is enhanced by the presentation of a precursor sound consisting of the masker alone. There is evidence that precursor-induced neural adaptation plays a role in this perceptual enhancement. However, the precursor may also be strategically used by listeners as a spectral template of the following masker to better segregate it from the target.

Enhancement of increments in spectral amplitude: further evidence for a mechanism based on central adaptation.

The threshold for detecting a tone in a multitone masker is lower when the masker-plus-signal stimulus is preceded by a copy of the masker. One potential explanation of this "enhancement" phenomenon is that the -precursor stimulus acts as a "template" of the subsequent masker, thus helping listeners to segregate the signal from the masker. To assess this idea, we measured enhancement for precursors that were perceptually similar to the masker and for precursors that were made dissimilar to the masker by gating their components asynchronously.

The perceptual enhancement of tones by frequency shifts.

In a chord of pure tones with a flat spectral profile, one tone can be perceptually enhanced relative to the other tones by the previous presentation of a slightly different chord. "Intensity enhancement" (IE) is obtained when the component tones of the two chords have the same frequencies, but in the first chord the target of enhancement is attenuated relative to the other tones. "Frequency enhancement" (FE) is obtained when both chords have a flat spectral profile, but the target of enhancement shifts in frequency from the first to the second chord.

Auditory discrimination of frequency ratios: the octave singularity.

Sensitivity to frequency ratios is essential for the perceptual processing of complex sounds and the appreciation of music. This study assessed the effect of ratio simplicity on ratio discrimination for pure tones presented either simultaneously or sequentially. Each stimulus consisted of four 100-ms pure tones, equally spaced in terms of frequency ratio and presented at a low intensity to limit interactions in the auditory periphery.

Auditory enhancement of increments in spectral amplitude stems from more than one source.

A component of a test sound consisting of simultaneous pure tones perceptually "pops out" if the test sound is preceded by a copy of itself with that component attenuated. Although this "enhancement" effect was initially thought to be purely monaural, it is also observable when the test sound and the precursor sound are presented contralaterally (i.e.

A note about insensitivity to pitch-change direction.

Some listeners are insensitive to the direction of pure-tone frequency changes when the standard frequency is roved widely over trials, but less so when the standard frequency is fixed and trial-by-trial feedback is provided. The present experiment tested the hypothesis that fixing the standard frequency and providing feedback is advantageous for direction-impaired listeners because under these conditions the listeners can learn to respond correctly without genuinely perceiving frequency-change direction. This hypothesis was ruled out by the experiment.

Frequency-shift detectors bind binaural as well as monaural frequency representations.

Previous psychophysical work provided evidence for the existence of automatic frequency-shift detectors (FSDs) that establish perceptual links between successive sounds. In this study, we investigated the characteristics of the FSDs with respect to the binaural system. Listeners were presented with sound sequences consisting of a chord of pure tones followed by a single test tone.

Enhancing a tone by shifting its frequency or intensity.

When a test sound consisting of pure tones with equal intensities is preceded by a precursor sound identical to the test sound except for a reduction in the intensity of one tone, an auditory "enhancement" phenomenon occurs: In the test sound, the tone which was previously softer stands out perceptually. Here, enhancement was investigated using inharmonic sounds made up of five pure tones well resolved in the auditory periphery. It was found that enhancement can be elicited not only by increases in intensity but also by shifts in frequency.

Implicit versus explicit frequency comparisons: two mechanisms of auditory change detection.

Listeners had to compare, with respect to pitch (frequency), a pure tone (T) to a combination of pure tones presented subsequently (C). The elements of C were either synchronous, and therefore difficult to hear out individually, or asynchronous and therefore easier to hear out individually. In the "present/absent" condition, listeners had to judge if T reappeared in C or not.

Fundamental differences in change detection between vision and audition.

We compared auditory change detection to visual change detection using closely matched stimuli and tasks in the two modalities. On each trial, participants were presented with a test stimulus consisting of ten elements: pure tones with various frequencies for audition, or dots with various spatial positions for vision. The test stimulus was preceded or followed by a probe stimulus consisting of a single element, and two change-detection tasks were performed.

Tuning properties of the auditory frequency-shift detectors.

Demany and Ramos [(2005). J. Acoust.

Continuous versus discrete frequency changes: different detection mechanisms?

Sek and Moore [J. Acoust. Soc.

Enhancement, adaptation, and the binaural system.

In a test sound consisting of a burst of pink noise, an arbitrarily selected target frequency band can be "enhanced" by the previous presentation of a similar noise with a spectral notch in the target frequency region. As a result of the enhancement, the test sound evokes a pitch sensation corresponding to the pitch of the target band. Here, a pitch comparison task was used to assess enhancement.

Auditory temporal processing in Parkinson's disease.

Previous research has suggested that Parkinson's disease (PD) impairs perceptual acuity in the temporal domain. In the present study, psychophysical tests assessing several aspects of auditory temporal processing were administered to a group of PD patients treated with bilateral subthalamic nucleus (STN) stimulation and to a normal control group. Each patient was tested in three clinical conditions: without treatment, with levodopa therapy, and during STN stimulation.

Auditory change detection: simple sounds are not memorized better than complex sounds.

Previous research has shown that the detectability of a local change in a visual image is essentially independent of the complexity of the image when the interstimulus interval (ISI) is very short, but is limited by a low-capacity memory system when the ISI exceeds 100 ms. In the study reported here, listeners made same/different judgments on pairs of successive "chords" (sums of pure tones with random frequencies). The change to be detected was always a frequency shift in one of the tones, and which tone would change was unpredictable.

Individual differences in the sensitivity to pitch direction.

It is commonly assumed that one can always assign a direction-upward or downward-to a percept of pitch change. The present study shows that this is true for some, but not all, listeners. Frequency difference limens (FDLs, in cents) for pure tones roved in frequency were measured in two conditions.