Selective Adaptation Paradigm Research Articles

Psycholinguists should resist the allure of linguistic units as perceptual units

Abstract The current study has empirical, methodological, and theoretical components. It draws heavily on two recent papers: Bowers et al. (2016) (JML, 87, 71–83) used results from selective adaptation experiments to argue that phonemes play a critical role in speech perception. Mitterer et al. (2018) (JML, 98, 77–92) responded with their own adaptation experiments to advocate instead for allophones. These studies are part of a renewed use of the selective adaptation paradigm. Empirically, the current study reports results that demonstrate that the Bowers et al. findings were artifactual. Methodologically, the renewed use of adaptation in the field is a positive development, but many recent studies suffer from a lack of knowledge of prior adaptation findings. As the use of selective adaptation grows, it will be important to draw on the considerable existing knowledge base (this literature is also relevant to the currently popular research on phonetic recalibration). Theoretically, for a half century there has been a recurring effort to demonstrate the psychological reality of various linguistic units, such as the phoneme or the allophone. The evidence is that listeners will use essentially any pattern that has been experienced often enough, not just the units that are well-suited to linguistic descriptions of language. Thus, rather than trying to identify any special perceptual status for linguistic units, psycholinguists should focus their efforts on more productive issues.

Acoustic cues, not phonological features, drive vowel perception: Evidence from height, position and tenseness contrasts in German vowels

Phonological features have frequently been singled out as the units of perception, especially for vowels. Evidence of the use of features has been provided for vowel height and vowel position, which have one acoustic correlate only. However, findings on acoustically complex features such as tenseness are less clear. The present study assessed the role of phonological features in perception using the selective adaptation paradigm. Selective adaptation effects on German vowel contrasts differing in vowel height (Experiment 1), position (Experiment 2) and tenseness (Experiment 3) were examined. We tested how the categorization of each vowel contrast was affected by adaptation to words containing vowels that differently resembled or diverged from the vowels in the critical contrast acoustically and in terms of their phonological feature specifications. Results showed that selective adaptation patterns could be predicted by the vowels’ phonological features for the height and position contrasts, but not for the tenseness contrast. However, adaptation patterns for the latter can be explained by the relationship between adaptors and continuum endpoints in each of the relevant acoustic cues to the contrast. This suggests that vowel perception may be dependent on these acoustic cues rather than phonological features.

Allophones, not phonemes in spoken-word recognition

Abstract What are the phonological representations that listeners use to map information about the segmental content of speech onto the mental lexicon during spoken-word recognition? Recent evidence from perceptual-learning paradigms seems to support (context-dependent) allophones as the basic representational units in spoken-word recognition. But recent evidence from a selective-adaptation paradigm seems to suggest that context-independent phonemes also play a role. We present three experiments using selective adaptation that constitute strong tests of these representational hypotheses. In Experiment 1, we tested generalization of selective adaptation using different allophones of Dutch /r/ and /l/ – a case where generalization has not been found with perceptual learning. In Experiments 2 and 3, we tested generalization of selective adaptation using German back fricatives in which allophonic and phonemic identity were varied orthogonally. In all three experiments, selective adaptation was observed only if adaptors and test stimuli shared allophones. Phonemic identity, in contrast, was neither necessary nor sufficient for generalization of selective adaptation to occur. These findings and other recent data using the perceptual-learning paradigm suggest that pre-lexical processing during spoken-word recognition is based on allophones, and not on context-independent phonemes.

Does seeing an Asian face make speech sound more accented?

Prior studies have reported that seeing an Asian face makes American English sound more accented. The current study investigates whether this effect is perceptual, or if it instead occurs at a later decision stage. We first replicated the finding that showing static Asian and Caucasian faces can shift people's reports about the accentedness of speech accompanying the pictures. When we changed the static pictures to dubbed videos, reducing the demand characteristics, the shift in reported accentedness largely disappeared. By including unambiguous items along with the original ambiguous items, we introduced a contrast bias and actually reversed the shift, with the Asian-face videos yielding lower judgments of accentedness than the Caucasian-face videos. By changing to a mixed rather than blocked design, so that the ethnicity of the videos varied from trial to trial, we eliminated the difference in accentedness rating. Finally, we tested participants' perception of accented speech using the selective adaptation paradigm. After establishing that an auditory-only accented adaptor shifted the perception of how accented test words are, we found that no such adaptation effect occurred when the adapting sounds relied on visual information (Asian vs. Caucasian videos) to influence the accentedness of an ambiguous auditory adaptor. Collectively, the results demonstrate that visual information can affect the interpretation, but not the perception, of accented speech.

Determinants of board size in an emerging market

AbstractDrawing largely upon the selective adaptation paradigm, the resource dependence literature, and the capture argument, we examine determinants of board size using panel data set of Korean‐listed companies that have experienced dramatic changes in their governance system following the 1997 Asian crisis and regulatory reforms. Observing that the firm's compliance with statutory requirements reflects a strategic choice, our results also investigate the idea that the determinants of board size differ between firms actively and passively adapting to regulatory reforms. For actively adaptive firms, board size increases along with firm complexity but it varies inversely with the power of controlling shareholders (CSHs). In contrast, the roles of complexity and CSHs are not significant but seniority‐based promotion is an important factor to increase the size for the passive firms. Our results suggest that determinants of board size differ depending on corporate strategies to comply with statutory requirements in an emerging market where family business is dominant and corporate governance system has substantially changed.

Role of timbre and fundamental frequency in voice gender adaptation.

Prior adaptation to male (or female) voices causes androgynous voices to be perceived as more female (or male). Using a selective adaptation paradigm the authors investigate the relative impact of the vocal fold vibration rate (F0) and timbre (operationally in this paper as characteristics that differentiate two voices of the same F0 and loudness) on this basic voice gender aftereffect. TANDEM-STRAIGHT was used to morph between 10 pairs of male and female speakers uttering 2 different vowel-consonant-vowel sequences (20 continua). Adaptor stimuli had one parameter (either F0 or timbre) set at a clearly male or female level, while the other parameter was set at an androgynous level, as determined by an independent set of listeners. Compared to a control adaptation condition (in which both F0 and timbre were clearly male or female), aftereffects were clearly reduced in both F0 and timbre adaptation conditions. Critically, larger aftereffects were found after timbre adaptation (comprising androgynous F0) compared to F0 adaptation (comprising an androgynous timbre). Together these results suggest that timbre plays a larger role than F0 in voice gender adaptation. Finally, the authors found some evidence that individual differences among listeners reflect in part pre-experimental contact to male and female voices.

Perceptual adaptation to structure-from-motion depends on the size of adaptor and probe objects, but not on the similarity of their shapes

Perceptual adaptation destabilizes the phenomenal appearance of multistable visual displays. Prolonged dominance of a perceptual state fatigues the associated neural population, lowering the likelihood of renewed perception of the same appearance (Nawrot & Blake in Perception & Psychophysics, 49, 230-44, 1991). Here, we used a selective adaptation paradigm to investigate perceptual adaptation for the illusory rotation of ambiguous structure-from-motion (SFM) displays. Specifically, we generated SFM objects with different three-dimensional shapes and presented them in random order, separating successive objects by brief blank periods, which included a mask. To assess the specificity of perceptual adaptation to the shape of SFM objects, we established the probability that a perceived direction of rotation persisted between successive objects of similar or dissimilar shape. We found that the strength of negative aftereffects depended on the volume, but not the shape, of adaptor and probe objects. More voluminous objects were both more effective as adaptor objects and more sensitive as probe objects. Surprisingly, we found these volume effects to be completely independent, since any relationship between two shapes (such as overlap between volumes, similarity of shape, or similarity of velocity profiles) failed to modulate the negative aftereffect. This pattern of results was the opposite of that observed for sensory memory of SFM objects, which reflects similarity between objects, but not volume of individual objects (Pastukhov et al. in Attention, Perception & Psychophysics, 75, 1215-1229, 2013). The disparate specificities of perceptual adaptation and sensory memory for identical SFM objects suggest that the two aftereffects engage distinct neural representations, consistent with recent brain imaging results (Schwiedrzik et al. in Cerebral Cortex, 2012).

The three-channel model of sound localization mechanisms: Interaural time differences

Previous psychophysical work on sound localization in humans has proposed that a midline channel be added to the current two-channel model of mammalian sound localization mechanisms. Evidence for this third channel has been found in interaural time difference (ITD) studies with low-frequency tones, and interaural level difference (ILD) studies with both high- and low-frequency tones. The latter is interesting because it suggests that, despite the fact that low frequencies do not generate significant ILDs for humans in natural settings, there is a constancy of ILD coding mechanisms across the frequency domain. To complement this finding, the present study sought to determine whether the three-channel model holds for ITDs at high frequencies. In three experiments, a selective adaptation paradigm was used in combination with transposed tones to probe for the existence of three (left, right, and midline) perceptual channels for sound source azimuth. The experiments provided evidence for lateral hemifield ITD channels but little evidence for a midline ITD channel at high frequencies.

The three-channel model of sound localization mechanisms: Interaural level differences

The current understanding of mammalian sound localization is that azimuthal (horizontal) position assignments are dependent upon the relative activation of two populations of broadly-tuned hemifield neurons with overlapping medial borders. Recent psychophysical work has provided evidence for a third channel of low-frequency interaural time difference (ITD)-sensitive neurons tuned to the azimuthal midline. However, the neurophysiological data on free-field azimuth receptive fields, especially of cortical neurons, has primarily studied high-frequency cells whose receptive fields are more likely to have been shaped by interaural level differences (ILDs) than ITDs. In four experiments, a selective adaptation paradigm was used to probe for the existence of a midline channel in the domain of ILDs. If no midline channel exists, symmetrical adaptation of the lateral channels should not result in a shift in the perceived intracranial location of subsequent test tones away from the adaptors because the relative activation of the two channels will remain unchanged. Instead, results indicate a shift in perceived test tone location away from the adaptors, which supports the existence of a midline channel in the domain of ILDs. Interestingly, this shift occurs not only at high frequencies, traditionally associated with ILDs in natural settings, but at low frequencies as well.

Selective Adaptation of WTO Transparency Norms and Local Practices in China and Japan

This article focuses on the importance of Chinese and Japanese local practices, their regulatory infrastructure and local cultural norms related to transparency as factors in the selective adaptation of the World Trade Organization norms. International laws can acquire a variety of local meanings that require an understanding of the local history and culture in addition to knowledge of the local economy and laws. This article analyzes the selective adaptation paradigm, which allows for a determination of the extent to which noncompliance or less than full compliance can be attributed to the cultural particularities of states political factors such as the relationship between the central and local authorities. This article argues that a shift in perception of regulatory transparency norms in China and Japan has occurred, and that this shift has had important economic and political consequences internally and externally, which has brought about significant administrative law reforms and improved compliance with international norms.

The conjunction of feature and depth information

By inducing feature-contingent depth aftereffects, we show that the human visual system combines feature information with depth information. These contingent aftereffects were revealed through the use of a novel selective adaptation paradigm whose stimuli required the combination of feature and depth information in order to segment two interleaved, transparent surfaces. We argue that this combined processing exemplifies the remarkable resourcefulness of a visual system that has adapted to exploit conjunctions of cues that can aid in the segmentation of visual surfaces.

Direction-selective Coding of Stereoscopic (Cyclopean) Motion

This study employed a selective adaptation paradigm and investigated thresholds for direction discrimination of translational stereoscopic motion (moving binocular disparity information). The stimuli were moving arrays of randomly positioned stereoscopic discs created from disparity embedded in dynamic random-element stereograms. When discrimination thresholds were measured across a range of base directions following adaptation in a fixed direction, discrimination thresholds were maximally elevated 20–30 deg away from adaptation and reduced in the same direction as adaptation. These results are consistent with a distributed-channel model of direction coding and indicate that the direction of stereoscopic motion is encoded by adaptable direction-selective mechanisms similar to those proposed for luminance-defined motion. © 1997 Elsevier Science Ltd. All rights reserved.

Perceiving and encoding timbre.

Interactions with the auditory environment often require accurate recognition of sound objects and events (e.g., voices and instruments, and the utterances that emanate from them). Two lines of research in the lab have been exploring how listeners process the auditory dimension of timbre as one step toward understanding object recognition. In one, commonalties in processing different classes of timbres (human voices, musical instruments) using the selective adaptation paradigm are explored. In the second, the characteristics of timbre memory using the interpolated tone paradigm are examined [Deutsch, Science 168, 1604–1605]. Findings will be discussed in the context of similar results in the literature.

A new twist on the rotating-trapezoid illusion: evidence for neural-adaptation effects.

In a series of experiments, the selective-adaptation paradigm was applied to the rotating-trapezoid illusion in an effort to demonstrate neural-adaptation effects in the figural reversal of this classic illusion. Prior to viewing the standard trapezoid, the observer adapted to a rectangle rotating unambiguously in the same direction as the trapezoid or in the opposite direction. In accordance with the neural hypothesis, illusion strength was greatest when the two figures rotated in the same direction and weakest when the two figures rotated in opposite directions. Results were confirmed with two separate dependent variables: the observer's 'first look' at the illusion after adaptation and the observer's reversal rate during a test period. These findings were discussed in terms of (a) the basic similarity of results for the rotating trapezoid and reversible figures such as the Necker cube and (b) the need for a multiprocess model of both classes of illusions which emphasizes bottom-up and top-down processes.

Perceptual normalization of speech and nonspeech

Within the information processing approach to speech perception, the problem of acoustic-phonetic variability is solved by positing multiple stages of processing that transform the acoustic input into a stable phonetic percept. If this problem is viewed as part of the broader problem of perceptual normalization, a question that arises is whether the mechanisms that normalize speech stimuli also normalize nonspeech stimuli. Five experiments addressed this question by investigating the normalization of musical timbre using a selective adaptation paradigm. The results parallel some of those found with speech, suggesting that a single mechanism normalizes both types of stimuli.

Effects of natural and synthetic adaptors on a synthetic voice continuum

The perception of a synthetic male-female voice continuum was examined using the selective adaptation paradigm. In a series of experiments, voice categorization performance was assessed before and after adaptation with various adaptors. In the first experiment, the results showed that synthetic male and female endpoint adaptors and naturally produced male and female adaptors had similar effects on voice categorization, with voice boundary shifts toward the endpoints. In a second experiment, synthetic adaptors that overlapped with the male endpoint only in F0 or only in formant values were used. Neither of these adaptors had significant perceptual effects. Overall, the results indicate that auditory overlap of the adaptor with the voice continuum endpoint is not necessary or (in the case of isolated acoustic cues related to voice) is not sufficient to produce adaptation. These findings are discussed in terms of the levels of processing and representation used for voice encoding during speech perception.

Selective adaptation vs. transfer of decrement: the conjoint effects of neural fatigue and perceptual learning.

Statement of Problem In the last few years, my colleagues and I have been interested in the processes underlying the perceived reversals of reversible figures (Long & Toppino, 1981; Long, Toppino, & Kostenbauder, 1983; Toppino & Long, 1987). One ofthe approaches we have used in our work is the popular selective-adaptation paradigm as a means by which to identify the potential role in this type of illusion of localized neural mechanisms that are subject to fatigue. In this method, an inspection figure is viewed during an adaptation period of perhaps 2-3 min, and a test figure is then shown which shares certain hypothesized features with the adaptation figure. To the extent that the prior adaptation alters the perception of the test figure, one can conclude that similar localized mechanisms are involved in the perception of both figures. This selectiveadaptation paradigm has proven extremely powerful in the investigation of numerous illusions, such as the tilt aftereffect, the motion aftereffect, and the size aftereffect. Reflecting its current popularity, the selective-adaptation paradigm has been referred to as the psychologist's electrode (Frisby, 1980) with which to probe the tuning and response characteristics of hypothesized neural channels in the visual system (e.g., Regan, 1982). In our work, we have attempted to demonstrate the role of localized fatigue effects on the reported reversals of the rotating Necker cube. In this illusion, a threedimensional Necker cube frame is rotated about one of its vertices at a constant speed. An observer viewing either the cube itself or its shadow reports a striking change in the perceived direction of rotation when the cube changes its perspective. As with other reversible figures, the number of reported reversals increases and then levels off at a high rate during a 2-3-min viewing period. For several reasons, we (and others) have proposed that this changing reversal rate reflects fatigue effects in particular visual channels; in our work, we have attempted to demonstrate the limited (i. e., local) character of this fatigue by means of the selective-adaptation paradigm. In one recent experiment (Toppino & Long, 1987, Experiment 1), a rotating cube in the left (or right) visual field was viewed for a 2-min adaptation period, which was followed immediately by a 2-min test period with a cube in the same or

Red herring detectors and speech perception: In defense of selective adaptation

The selective adaptation paradigm was used extensively for about 5 years following its introduction to speech research in 1973. During the next few years, its use dropped dramatically; it is now little used. Several reasons for the abandonment of the paradigm are discussed, and theoretical and empirical justification is provided for rejecting these reasons. Experiment 1 demonstrates that “acoustic similarity” of an adapting sound and test items cannot account for the observed results. Experiments 2–4 demonstrate that adaptation effects are not equivalent to simple contrast effects. These experiments indicate that selective adaptation produces robust reaction time effects—items in the adapted category are identified more slowly than unadapted items. The effects found in a simple paired-contrast procedure differ from those found with selective adaptation. Most strikingly, contrast effects are extremely ear dependent—much larger effects occur if testing is conducted in the right ear than in the left; adaptation effects are relatively symmetrical with respect to ear. The empirical and theoretical analyses suggest that the selective adaptation paradigm can be a powerful tool for investigating the perception of complex acoustic stimuli like speech.

Evidence for a reappraisal of the psychophysical selective adaptation paradigm.

The human psychophysical adaptation literature infers the existence of channels in the auditory system sensitive to frequency modulation (FM) from selective increases in FM detection thresholds following adaptation with FM stimuli. Using this psychophysical paradigm to characterize the attributes of feature-sensitive channels requires knowledge of the phenomenon's stability over repeated testing. In this study FM detection thresholds were measured in human subjects with continued testing over numerous sessions. During adapting intervals within the sessions either FM upsweeps or silence was presented. Exposure to FM upsweeps initially resulted in an increase in FM detection thresholds by a factor of 2 to 3 relative to those measured following silence. These initial threshold elevations decreased markedly with repeated testing (more than five 30-min experimental sessions). Final threshold differences between adapted and nonadapted conditions approached zero. In one subject, such asymptotic threshold values were regained in a single session, after a 4-month hiatus. The findings suggest multiple determinants of the selective adaptation function, as well as a reevaluation of inferred mechanisms.

Adaptation of voicing: effects of ear presentation and acoustic energy variables

Although empirical evidence from the selective adaptation paradigm supports peripheral and central processes of phonetic variables, little research exists on levels of perceptual processing of acoustic energy variables. The purpose of this investigation was to determine the effects of ear presentation, intensity, and number of repetitions of adaptors varying in voice onset time (VOT) on changes in stimulus rating of boundary and non-boundary stimuli. Subjects rated stimuli varying in VOT between 15–45 ms before and after periods of stimulus repetition. The number of stimulus repetitions during each of 28 trials was either 4, 16, or 85, and the intensity of the stimulus was either 50 or 70 dB SPL. The major findings were as follows: (1) evidence of a strong monaural component for intensity and ear effect was obtained for only the voiced stimulus; (2) monaural effects of the voiced stimulus appeared for both boundary and non-boundary stimuli; and (3) the repetition effect supported a higher level process in adaptation to voicing. The monaural effects of the voiced stimulus support a fatigue model; whereas the effects of number of stimulus repetitions and the asymmetries of acoustic energy variables for the voiced and voiceless adaptors suggest a more complicated process in adaptation to speech than that accounted for in models of feature detection and response contrast.