Single-trial visually evoked potentials predict both individual choice and market outcomes.

A central assumption in the behavioral sciences is that choice behavior generalizes enough across individuals that measurements from a sampled group can predict the behavior of the population. Following from this assumption, the unit of behavioral sampling or measurement for most neuroimaging studies is the individual; however, cognitive neuroscience is increasingly acknowledging a dissociation between neural activity that predicts individual behavior and that which predicts the average or aggregate behavior of the population suggesting a greater importance of individual differences than is typically acknowledged. For instance, past work has demonstrated that some, but not all, of the neural activity observed during value-based decision-making is able to predict not just individual subjects' choices but also the success of products on large, online marketplaces-even when those two behavioral outcomes deviate from one another-suggesting that some neural component processes of decision-making generalize to aggregate market responses more readily across individuals than others do. While the bulk of such research has highlighted affect-related neural responses (i.e. in the nucleus accumbens) as a better predictor of group-level behavior than frontal cortical activity associated with the integration of more idiosyncratic choice components, more recent evidence has implicated responses in visual cortical regions as strong predictors of group preference. Taken together, these findings suggest a role of neural responses during early perception in reinforcing choice consistency across individuals and raise fundamental scientific questions about the role sensory systems in value-based decision-making processes. We use a multivariate pattern analysis approach to show that single-trial visually evoked electroencephalographic (EEG) activity can predict individual choice throughout the post-stimulus epoch; however, a nominally sparser set of activity predicts the aggregate behavior of the population. These findings support an account in which a subset of the neural activity underlying individual choice processes can scale to predict behavioral consistency across people, even when the choice behavior of the sample does not match the aggregate behavior of the population.

Absolute pitch judgments of familiar melodies generalize across timbre and octave.

Most listeners can determine when a familiar recording of music has been shifted in musical key by as little as one semitone (e.g., from B to C major). These findings appear to suggest that absolute pitch memory is widespread in the general population. However, the use of familiar recordings makes it unclear whether these findings genuinely reflect absolute melody-key associations for at least two reasons. First, listeners may be able to use spectral cues from the familiar instrumentation of the recordings to determine when a familiar recording has been shifted in pitch. Second, listeners may be able to rely solely on pitch height cues (e.g., relying on a feeling that an incorrect recording sounds "too high" or "too low"). Neither of these strategies would require an understanding of pitch chroma or musical key. The present experiments thus assessed whether listeners could make accurate absolute melody-key judgments when listening to novel versions of these melodies, differing from the iconic recording in timbre (Experiment 1) or timbre and octave (Experiment 2). Listeners in both experiments were able to select the correct-key version of the familiar melody at rates that were well above chance. These results fit within a growing body of research supporting the idea that most listeners, regardless of formal musical training, have robust representations of absolute pitch - based on pitch chroma - that generalize to novel listening situations. Implications for theories of auditory pitch memory are discussed.

Generalizing across tonal context, timbre, and octave in rapid absolute pitch training.

Absolute pitch (AP) is the rare ability to name any musical note without the use of a reference note. Given that genuine AP representations are based on the identification of isolated notes by their tone chroma, they are considered to be invariant to (1) surrounding tonal context, (2) changes in instrumental timbre, and (3) changes in octave register. However, there is considerable variability in the literature in terms of how AP is trained and tested along these dimensions, making recent claims about AP learning difficult to assess. Here, we examined the effect of tonal context on participant success with a single-note identification training paradigm, including how learning generalized to an untested instrument and octave. We found that participants were able to rapidly learn to distinguish C from other notes, with and without feedback and regardless of the tonal context in which C was presented. Participants were also able to partly generalize this skill to an untrained instrument. However, participants displayed the weakest generalization in recognizing C in a higher octave. The results indicate that participants were likely attending to pitch height in addition to pitch chroma - a conjecture that was supported by analyzing the pattern of response errors. These findings highlight the complex nature of note representation in AP, which requires note identification across contexts, going beyond the simple storage of a note fundamental. The importance of standardizing testing that spans both timbre and octave in assessing AP and further implications on past literature and future work are discussed.

Going Beyond Rote Auditory Learning: Neural Patterns of Generalized Auditory Learning.

The ability to generalize across specific experiences is vital for the recognition of new patterns, especially in speech perception considering acoustic-phonetic pattern variability. Indeed, behavioral research has demonstrated that listeners are able via a process of generalized learning to leverage their experiences of past words said by difficult-to-understand talker to improve their understanding for new words said by that talker. Here, we examine differences in neural responses to generalized versus rote learning in auditory cortical processing by training listeners to understand a novel synthetic talker. Using a pretest-posttest design with EEG, participants were trained using either (1) a large inventory of words where no words were repeated across the experiment (generalized learning) or (2) a small inventory of words where words were repeated (rote learning). Analysis of long-latency auditory evoked potentials at pretest and posttest revealed that rote and generalized learning both produced rapid changes in auditory processing, yet the nature of these changes differed. Generalized learning was marked by an amplitude reduction in the N1-P2 complex and by the presence of a late negativity wave in the auditory evoked potential following training; rote learning was marked only by temporally later scalp topography differences. The early N1-P2 change, found only for generalized learning, is consistent with an active processing account of speech perception, which proposes that the ability to rapidly adjust to the specific vocal characteristics of a new talker (for which rote learning is rare) relies on attentional mechanisms to selectively modify early auditory processing sensitivity.

Individual differences in human frequency-following response predict pitch labeling ability.

The frequency-following response (FFR) provides a measure of phase-locked auditory encoding in humans and has been used to study subcortical processing in the auditory system. While effects of experience on the FFR have been reported, few studies have examined whether individual differences in early sensory encoding have measurable effects on human performance. Absolute pitch (AP), the rare ability to label musical notes without reference notes, provides an excellent model system for testing how early neural encoding supports specialized auditory skills. Results show that the FFR predicts pitch labelling performance better than traditional measures related to AP (age of music onset, tonal language experience, pitch adjustment and just-noticeable-difference scores). Moreover, the stimulus type used to elicit the FFR (tones or speech) impacts predictive performance in a manner that is consistent with prior research. Additionally, the FFR predicts labelling performance for piano tones better than unfamiliar sine tones. Taken together, the FFR reliably distinguishes individuals based on their explicit pitch labeling abilities, which highlights the complex dynamics between sensory processing and cognition.

Revisiting discrete versus continuous models of human behavior: The case of absolute pitch.

Many human behaviors are discussed in terms of discrete categories. Quantizing behavior in this fashion may provide important traction for understanding the complexities of human experience, but it also may bias understanding of phenomena and associated mechanisms. One example of this is absolute pitch (AP), which is often treated as a discrete trait that is either present or absent (i.e., with easily identifiable near-perfect "genuine" AP possessors and at-chance non-AP possessors) despite emerging evidence that pitch-labeling ability is not all-or-nothing. We used a large-scale online assessment to test the discrete model of AP, specifically by measuring how intermediate performers related to the typically defined "non-AP" and "genuine AP" populations. Consistent with prior research, individuals who performed at-chance (non-AP) reported beginning musical instruction much later than the near-perfect AP participants, and the highest performers were more likely to speak a tonal language than were the lowest performers (though this effect was not as statistically robust as one would expect from prior research). Critically, however, these developmental factors did not differentiate the near-perfect AP performers from the intermediate AP performers. Gaussian mixture modeling supported the existence of two performance distributions-the first distribution encompassed both the intermediate and near-perfect AP possessors, whereas the second distribution encompassed only the at-chance participants. Overall, these results provide support for conceptualizing intermediate levels of pitch-labeling ability along the same continuum as genuine AP-level pitch labeling ability-in other words, a continuous distribution of AP skill among all above-chance performers rather than discrete categories of ability. Expanding the inclusion criteria for AP makes it possible to test hypotheses about the mechanisms that underlie this ability and relate this ability to more general cognitive mechanisms involved in other abilities.

Cortical mechanisms of talker normalization in fluent sentences.

Adjusting to the vocal characteristics of a new talker is important for speech recognition. Previous research has indicated that adjusting to talker differences is an active cognitive process that depends on attention and working memory (WM). These studies have not examined how talker variability affects perception and neural responses in fluent speech. Here we use source analysis from high-density EEG to show that perceiving fluent speech in which the talker changes recruits early involvement of parietal and temporal cortical areas, suggesting functional involvement of WM and attention in talker normalization. We extend these findings to acoustic source change in general by examining understanding environmental sounds in spoken sentence context. Though there may be differences in cortical recruitment to processing demands for non-speech sounds versus a changing talker, the underlying mechanisms are similar, supporting the view that shared cognitive-general mechanisms assist both talker normalization and speech-to-nonspeech transitions.

Absolute pitch can be learned by some adults.

Absolute pitch (AP), the rare ability to name any musical note without the aid of a reference note, is thought to depend on an early critical period of development. Although recent research has shown that adults can improve AP performance in a single training session, the best learners still did not achieve note classification levels comparable to performance of a typical, "genuine" AP possessor. Here, we demonstrate that these "genuine" levels of AP performance can be achieved within eight weeks of training for at least some adults, with the best learner passing all measures of AP ability after training and retaining this knowledge for at least four months after training. Alternative explanations of these positive results, such as improving accuracy through adopting a slower, relative pitch strategy, are not supported based on joint analyses of response time and accuracy. The results also did not appear to be driven by extreme familiarity with a single instrument or octave range, as the post-training AP assessments used eight different timbres and spanned over seven octaves. Yet, it is also important to note that a majority of the participants only exhibited modest improvements in performance, suggesting that adult AP learning is difficult and that near-perfect levels of AP may only be achievable by subset of adults. Overall, these results demonstrate that explicit perceptual training in some adults can lead to AP performance that is behaviorally indistinguishable from AP that manifests within a critical period of development. Implications for theories of AP acquisition are discussed.

The Aesthetic Preference for Nature Sounds Depends on Sound Object Recognition.

People across the world seek out beautiful sounds in nature, such as a babbling brook or a nightingale song, for positive human experiences. However, it is unclear whether this positive aesthetic response is driven by a preference for the perceptual features typical of nature sounds versus a higher-order association of nature with beauty. To test these hypotheses, participants provided aesthetic judgments for nature and urban soundscapes that varied on ease of recognition. Results demonstrated that the aesthetic preference for nature soundscapes was eliminated for the sounds hardest to recognize, and moreover the relationship between aesthetic ratings and several measured acoustic features significantly changed as a function of recognition. In a follow-up experiment, requiring participants to classify these difficult-to-identify sounds into nature or urban categories resulted in a robust preference for nature sounds and a relationship between aesthetic ratings and our measured acoustic features that was more typical of easy-to-identify sounds. This pattern of results was replicated with computer-generated artificial noises, which acoustically shared properties with the nature and urban soundscapes but by definition did not come from these environments. Taken together, these results support the conclusion that the recognition of a sound as either natural or urban dynamically organizes the relationship between aesthetic preference and perceptual features and that these preferences are not inherent to the acoustic features. Implications for nature's role in cognitive and affective restoration are discussed.

Manual directional gestures facilitate cross-modal perceptual learning.

Action and perception interact in complex ways to shape how we learn. In the context of language acquisition, for example, hand gestures can facilitate learning novel sound-to-meaning mappings that are critical to successfully understanding a second language. However, the mechanisms by which motor and visual information influence auditory learning are still unclear. We hypothesize that the extent to which cross-modal learning occurs is directly related to the common representational format of perceptual features across motor, visual, and auditory domains (i.e., the extent to which changes in one domain trigger similar changes in another). Furthermore, to the extent that information across modalities can be mapped onto a common representation, training in one domain may lead to learning in another domain. To test this hypothesis, we taught native English speakers Mandarin tones using directional pitch gestures. Watching or performing gestures that were congruent with pitch direction (e.g., an up gesture moving up, and a down gesture moving down, in the vertical plane) significantly enhanced tone category learning, compared to auditory-only training. Moreover, when gestures were rotated (e.g., an up gesture moving away from the body, and a down gesture moving toward the body, in the horizontal plane), performing the gestures resulted in significantly better learning, compared to watching the rotated gestures. Our results suggest that when a common representational mapping can be established between motor and sensory modalities, auditory perceptual learning is likely to be enhanced.

A note by any other name: Intonation context rapidly changes absolute note judgments.

Absolute pitch (AP) judgments, by definition, do not require a reference note, and thus might be viewed as context independent. Here, we specifically test whether short-term exposure to particular intonation contexts influences AP categorization on a rapid time scale and whether such context effects can change from moment to moment. In Experiment 1, participants heard duets in which a "lead" instrument always began before a "secondary" instrument. Both instruments independently varied on intonation (flat, in-tune, or sharp). Despite participants being instructed to judge only the intonation of the secondary instrument, we found that participants treated the lead instrument's intonation as "in-tune" and intonation judgments of the secondary instrument were relativized against this standard. In Experiment 2, participants heard a short antecedent context melody (flat, in-tune, or sharp) followed by an isolated target note (flat, in-tune, or sharp). Target note intonation judgments were once again relativized against the context melody's intonation, though only for notes that were experienced in the context or implied by the context key signature. Moreover, maximally contrastive intonation combinations of context and target engendered systematic note misclassifications. For example, a flat melody resulted in a greater likelihood of misclassifying a "sharp F-sharp" as a "G." These results highlight that both intonation and note category judgments among AP possessors are rapidly modified by the listening environment on the order of seconds, arguing against an invariant mental representation of the absolute pitches of notes. Implications for general auditory theories of perception are discussed. (PsycINFO Database Record

Hearing sounds as words: Neural responses to environmental sounds in the context of fluent speech.

Environmental sounds (ES) can be understood easily when substituted for words in sentences, suggesting that linguistic context benefits may be mediated by processes more general than some language-specific theories assert. However, the underlying neural processing is not understood. EEG was recorded for spoken sentences ending in either a spoken word or a corresponding ES. Endings were either congruent or incongruent with the sentence frame, and thus were expected to produce N400 activity. However, if ES and word meanings are combined with language context by different mechanisms, different N400 responses would be expected. Incongruent endings (both words and ES) elicited frontocentral negativities corresponding to the N400 typically observed to incongruent spoken words. Moreover, sentential constraint had similar effects on N400 topographies to ES and words. Comparison of speech and ES responses suggests that understanding meaning in speech context may be mediated by similar neural mechanisms for these two types of stimuli.

Long-term pitch memory for music recordings is related to auditory working memory precision.

Most individuals have reliable long-term memories for the pitch of familiar music recordings. This pitch memory (1) appears to be normally distributed in the population, (2) does not depend on explicit musical training and (3) only seems to be weakly related to differences in listening frequency estimates. The present experiment was designed to assess whether individual differences in auditory working memory could explain variance in long-term pitch memory for music recordings. In Experiment 1, participants first completed a musical note adjustment task that has been previously used to assess working memory of musical pitch. Afterward, participants were asked to judge the pitch of well-known music recordings, which either had or had not been shifted in pitch. We found that performance on the pitch working memory task was significantly related to performance in the pitch memory task using well-known recordings, even when controlling for overall musical experience and familiarity with each recording. In Experiment 2, we replicated these findings in a separate group of participants while additionally controlling for fluid intelligence and non-pitch-based components of auditory working memory. In Experiment 3, we demonstrated that participants could not accurately judge the pitch of unfamiliar recordings, suggesting that our method of pitch shifting did not result in unwanted acoustic cues that could have aided participants in Experiments 1 and 2. These results, taken together, suggest that the ability to maintain pitch information in working memory might lead to more accurate long-term pitch memory.

Understanding environmental sounds in sentence context.

There is debate about how individuals use context to successfully predict and recognize words. One view argues that context supports neural predictions that make use of the speech motor system, whereas other views argue for a sensory or conceptual level of prediction. While environmental sounds can convey clear referential meaning, they are not linguistic signals, and are thus neither produced with the vocal tract nor typically encountered in sentence context. We compared the effect of spoken sentence context on recognition and comprehension of spoken words versus nonspeech, environmental sounds. In Experiment 1, sentence context decreased the amount of signal needed for recognition of spoken words and environmental sounds in similar fashion. In Experiment 2, listeners judged sentence meaning in both high and low contextually constraining sentence frames, when the final word was present or replaced with a matching environmental sound. Results showed that sentence constraint affected decision time similarly for speech and nonspeech, such that high constraint sentences (i.e., frame plus completion) were processed faster than low constraint sentences for speech and nonspeech. Linguistic context facilitates the recognition and understanding of nonspeech sounds in much the same way as for spoken words. This argues against a simple form of a speech-motor explanation of predictive coding in spoken language understanding, and suggests support for conceptual-level predictions.

Perceptual Plasticity for Auditory Object Recognition.

In our auditory environment, we rarely experience the exact acoustic waveform twice. This is especially true for communicative signals that have meaning for listeners. In speech and music, the acoustic signal changes as a function of the talker (or instrument), speaking (or playing) rate, and room acoustics, to name a few factors. Yet, despite this acoustic variability, we are able to recognize a sentence or melody as the same across various kinds of acoustic inputs and determine meaning based on listening goals, expectations, context, and experience. The recognition process relates acoustic signals to prior experience despite variability in signal-relevant and signal-irrelevant acoustic properties, some of which could be considered as "noise" in service of a recognition goal. However, some acoustic variability, if systematic, is lawful and can be exploited by listeners to aid in recognition. Perceivable changes in systematic variability can herald a need for listeners to reorganize perception and reorient their attention to more immediately signal-relevant cues. This view is not incorporated currently in many extant theories of auditory perception, which traditionally reduce psychological or neural representations of perceptual objects and the processes that act on them to static entities. While this reduction is likely done for the sake of empirical tractability, such a reduction may seriously distort the perceptual process to be modeled. We argue that perceptual representations, as well as the processes underlying perception, are dynamically determined by an interaction between the uncertainty of the auditory signal and constraints of context. This suggests that the process of auditory recognition is highly context-dependent in that the identity of a given auditory object may be intrinsically tied to its preceding context. To argue for the flexible neural and psychological updating of sound-to-meaning mappings across speech and music, we draw upon examples of perceptual categories that are thought to be highly stable. This framework suggests that the process of auditory recognition cannot be divorced from the short-term context in which an auditory object is presented. Implications for auditory category acquisition and extant models of auditory perception, both cognitive and neural, are discussed.

Telling in-tune from out-of-tune: widespread evidence for implicit absolute intonation.

Absolute pitch (AP) is the rare ability to name or produce an isolated musical note without the aid of a reference note. One skill thought to be unique to AP possessors is the ability to provide absolute intonation judgments (e.g., classifying an isolated note as "in-tune" or "out-of-tune"). Recent work has suggested that absolute intonation perception among AP possessors is not crystallized in a critical period of development, but is dynamically maintained by the listening environment, in which the vast majority of Western music is tuned to a specific cultural standard. Given that all listeners of Western music are constantly exposed to this specific cultural tuning standard, our experiments address whether absolute intonation perception extends beyond AP possessors. We demonstrate that non-AP listeners are able to accurately judge the intonation of completely isolated notes. Both musicians and nonmusicians showed evidence for absolute intonation recognition when listening to familiar timbres (piano and violin). When testing unfamiliar timbres (triangle and inverted sine waves), only musicians showed weak evidence of absolute intonation recognition (Experiment 2). Overall, these results highlight a previously unknown similarity between AP and non-AP possessors' long-term musical note representations, including evidence of sensitivity to frequency.

What the [bleep]? Enhanced absolute pitch memory for a 1000Hz sine tone.

Many individuals are able to perceive when the tuning of familiar stimuli, such as popular music recordings, has been altered. This suggests a kind of ubiquitous pitch memory, though it is unclear how this ability differs across individuals with and without absolute pitch (AP) and whether it plays any role in AP. In the present study, we take advantage of a salient single frequency - the 1000Hz sine tone used to censor taboo words in broadcast media - to assess the nature of this kind of pitch memory across individuals with and without AP. We show that non-AP participants are accurate at selecting the correct version of the censor tone among incorrect versions shifted by either one or two semitones, though their accuracy was still below that of an AP population (Experiment 1). This suggests a benefit for AP listeners that could be due to the use of explicit note categories or greater amounts of musical training. However, AP possessors still outperformed all non-AP participants when incorrect versions of the censor tone were shifted within a note category, even when controlling for musical experience (Experiment 2). Experiment 3 demonstrated that AP listeners did not appear to possess a category label for the censor tone that could have helped them differentiate the censor tones used in Experiment 2. Overall, these results suggest that AP possessors may have better pitch memory, even when divorced from pitch labeling (note categories). As such, these results have implications for how AP may develop and be maintained.

Variability in Vowel Production within and between Days.

Although the acoustic variability of speech is often described as a problem for phonetic recognition, there is little research examining acoustic-phonetic variability over time. We measured naturally occurring acoustic variability in speech production at nine specific time points (three per day over three days) to examine daily change in production as well as change across days for citation-form vowels. Productions of seven different vowels (/EE/, /IH/, /AH/, /UH/, /AE/, /OO/, /EH/) were recorded at 9AM, 3PM and 9PM over the course of each testing day on three different days, every other day, over a span of five days. Results indicate significant systematic change in F1 and F0 values over the course of a day for each of the seven vowels recorded, whereas F2 and F3 remained stable. Despite this systematic change within a day, however, talkers did not show significant changes in F0, F1, F2, and F3 between days, demonstrating that speakers are capable of producing vowels with great reliability over days without any extrinsic feedback besides their own auditory monitoring. The data show that in spite of substantial day-to-day variability in the specific listening and speaking experiences of these participants and thus exposure to different acoustic tokens of speech, there is a high degree of internal precision and consistency for the production of citation form vowels.

The effects of acoustic variability on absolute pitch categorization: Evidence of contextual tuning.

Absolute pitch (AP) is defined as the ability to label a musical note without the aid of a reference note. Despite the large amounts of acoustic variability encountered in music, AP listeners generally experience perceptual constancy for different exemplars within note categories (e.g., recognizing that a C played on a tuba belongs to the same category as a C played on a piccolo). The present studies investigate whether AP possessors are sensitive to context variability along acoustic dimensions that are not inherently linked to the typical definition of a note category. In a speeded target recognition task, AP participants heard a sequence of notes and pressed a button whenever they heard a designated target note. Within a trial the sequence of notes was either blocked according to note-irrelevant variation or contained a mix of different instruments (Experiment 1), amplitude levels (Experiment 2), or octaves (Experiment 3). Compared to the blocked trials, participants were significantly slower to respond in the mixed-instrument and mixed-octave trials, but not the mixed-amplitude trials. Importantly, this performance difference could not be solely attributed to initial performance differences between instruments, amplitudes, or octaves. These results suggest that AP note identification is contextually sensitive.