Psychology

In a sensorimotor synchronization task requiring subjects to tap in synchrony with an auditory stimulus, occasional perturbations (i.e., interval changes) in an otherwise isochronous sequence of auditory metronome stimuli are known to be compensated remarkably swift and with surprising precision, even when they are too small to be consciously perceived. To investigate the neural substrate and the informational basis of error correction in sensorimotor synchronization, we recorded movement-related, auditory-evoked, and error-related EEG potentials. Experiment 1 confirmed rapid adjustment to stimulus phase shifts, with faster correction of large (50 ms) compared to small (15 ms) shifts. In addition to being corrected faster, there was overcorrection of the 50 ms shifts, attributed to engagement of period correction mechanisms. For ϩ50 ms shifts, a neural correlate of period correction was identified in the form of medial frontal cortex activation, preceded by an error-related brain potential (ERN). Auditory-evoked potential (AEP) amplitudes were sensitive to stimulus phase shifts of both large and small magnitude. Further experiments with a smaller magnitude 10 ms phase shift (Experiment 2) and passive auditory stimulation (Experiment 3) provided evidence that the modulation of AEP amplitudes is not due to metronome interval changes, but may represent auditory-somatosensory activation. Together, behavioral and neurophysiological data support the hypothesis that phase correction is a largely automatic process, not dependent on conscious perception of changes in timing. By contrast, perceivable phase shifts may invoke timekeeper adjustments accompanied by medial frontal cortex activity.

The contribution of temporal asynchrony, spatial separation, and frequency separation to the cross-spectral fusion of temporally contiguous brief narrow-band noise bursts was studied using the Rhythmic Masking Release paradigm ͑RMR͒. RMR involves the discrimination of one of two possible rhythms, despite perceptual masking of the rhythm by an irregular sequence of sounds identical to the rhythmic bursts, interleaved among them. The release of the rhythm from masking can be induced by causing the fusion of the irregular interfering sounds with concurrent ''flanking'' sounds situated in different frequency regions. The accuracy and the rated clarity of the identified rhythm in a 2-AFC procedure were employed to estimate the degree of fusion of the interferring sounds with flanking sounds. The results suggest that while synchrony fully fuses short-duration noise bursts across frequency and across space ͑i.e., across ears and loudspeakers͒, an asynchrony of 20-40 ms produces no fusion. Intermediate asynchronies of 10-20 ms produce partial fusion, where the presence of other cues is critical for unambiguous grouping. Though frequency and spatial separation reduced fusion, neither of these manipulations was sufficient to abolish it. For the parameters varied in this study, stimulus onset asynchrony was the dominant cue determining fusion, but there were additive effects of the other cues. Temporal synchrony appears to be critical in determining whether brief sounds with abrupt onsets and offsets are heard as one event or more than one.

The rhythm created by spacing a series of brief tones in a regular pattern can be disguised by interleaving identical distractors at irregular intervals. The disguised rhythm can be unmasked if the distractors are allocated to a separate stream from the rhythm by integration with temporally overlapping captors. Listeners identified which of 2 rhythms was presented, and the accuracy and rated clarity of their judgment was used to estimate the fusion of the distractors and captors. The extent of fusion depended primarily on onset asynchrony and degree of temporal overlap. Harmonic relations had some influence, but only an extreme difference in spatial location was effective (dichotic presentation). Both preattentive and attentionally driven processes governed performance.

By characterizing the function of the ventral and dorsal visual streams as, respectively, vision-for-perception and vision-for-action, have brought some action onto the perceptual scene. However, with the distinction of the ventral "what" system and the dorsal "how" system, comes a dilemma: How is the operation of the two systems united toward common goals? This is an example of a binding problem. We propose that for binding these two systems, no mechanism needs to exist in the brain to bring ventral and dorsal representations together. Coherent behavior may be accomplished by focusing the two streams upon the same external object through a strategy of spatial selection, using either the fovea or selective attention. This strategy exploits the simple fact that two objects cannot occupy the same place at the same time. Other kinds of binding, like that involving the perceptual binding of the elements of a scene into coherent perceptual units, may be accomplished by exploiting other regularities of the environment, such as the likelihood that two simultaneous sounds were caused by a common event. From an evolutionary perspective, the most effective way to cope with the distant environment is to use different but complementary sensors, both contributing to aspects of identification and action guidance. For example, audition plays a role both in perceptual analysis and in action guidance, suggesting the possibility of segregated processing of auditory information. Thus, the functional distinction between a "what" system and a "how" system may not be limited to the visual modality, but may be a fundamental distinction for behavioral control in general.

We demonstrate that observation of everyday rhythmical actions biases subsequent motor execution of the same and of different actions, using a paradigm where the observed actions were irrelevant for action execution. The cycle time of the distractor actions was subtly manipulated across trials, and the cycle time of motor responses served as the main dependent measure. Although distractor frequencies reliably biased response cycle times, this imitation bias was only a small fraction of the modulations in distractor speed, as well as of the modulations produced when participants intentionally imitated the observed rhythms. Importantly, this bias was not only present for compatible actions, but was also found, though numerically reduced, when distractor and executed actions were different (e.g., tooth brushing vs. window wiping), or when the dominant plane of movement was different (horizontal vs. vertical). In addition, these effects were equally pronounced for execution at 0, 4, and 8 s after action observation, a finding that contrasts with the more short-lived effects reported in earlier studies. The imitation bias was also unaffected when vision of the hand was occluded during execution, indicating that this effect most likely resulted from visuomotor interactions during distractor observation, rather than from visual monitoring and guidance during execution. Finally, when the distractor was incompatible in both dimensions (action type and plane) the imitation bias was not reduced further, in an additive way, relative to the single-incompatible conditions. This points to a mechanism whereby the observed action's impact on motor processing is generally reduced whenever this is not useful for motor planning. We interpret these findings in the framework of biased competition, where intended and distractor actions can be represented as competing and quasi-encapsulated sensorimotor streams.

We demonstrate that observation of everyday rhythmical actions biases subsequent motor execution of the same and of different actions, using a paradigm where the observed actions were irrelevant for action execution. The cycle time of the distractor actions was subtly manipulated across trials, and the cycle time of motor responses served as the main dependent measure. Although distractor frequencies reliably biased response cycle times, this imitation bias was only a small fraction of the modulations in distractor speed, as well as of the modulations produced when participants intentionally imitated the observed rhythms. Importantly, this bias was not only present for compatible actions, but was also found, though numerically reduced, when distractor and executed actions were different (e.g., tooth brushing vs. window wiping), or when the dominant plane of movement was different (horizontal vs. vertical). In addition, these effects were equally pronounced for execution at 0, 4, and 8 s after action observation, a finding that contrasts with the more short-lived effects reported in earlier studies. The imitation bias was also unaffected when vision of the hand was occluded during execution, indicating that this effect most likely resulted from visuomotor interactions during distractor observation, rather than from visual monitoring and guidance during execution. Finally, when the distractor was incompatible in both dimensions (action type and plane) the imitation bias was not reduced further, in an additive way, relative to the single-incompatible conditions. This points to a mechanism whereby the observed action's impact on motor processing is generally reduced whenever this is not useful for motor planning. We interpret these findings in the framework of biased competition, where intended and distractor actions can be represented as competing and quasi-encapsulated sensorimotor streams.

We demonstrate that observation of everyday rhythmical actions biases subsequent motor execution of the same and of different actions, using a paradigm where the observed actions were irrelevant for action execution. The cycle time of the distractor actions was subtly manipulated across trials, and the cycle time of motor responses served as the main dependent measure. Although distractor frequencies reliably biased response cycle times, this imitation bias was only a small fraction of the modulations in distractor speed, as well as of the modulations produced when participants intentionally imitated the observed rhythms. Importantly, this bias was not only present for compatible actions, but was also found, though numerically reduced, when distractor and executed actions were different (e.g., tooth brushing vs. window wiping), or when the dominant plane of movement was different (horizontal vs. vertical). In addition, these effects were equally pronounced for execution at 0, 4, and 8 s after action observation, a finding that contrasts with the more short-lived effects reported in earlier studies. The imitation bias was also unaffected when vision of the hand was occluded during execution, indicating that this effect most likely resulted from visuomotor interactions during distractor observation, rather than from visual monitoring and guidance during execution. Finally, when the distractor was incompatible in both dimensions (action type and plane) the imitation bias was not reduced further, in an additive way, relative to the single-incompatible conditions. This points to a mechanism whereby the observed action's impact on motor processing is generally reduced whenever this is not useful for motor planning. We interpret these findings in the framework of biased competition, where intended and distractor actions can be represented as competing and quasi-encapsulated sensorimotor streams.

An age-related difference in accuracy and variability of unpaced timing tasks suggests that the internal clock for the processing of intervals of hundreds of milliseconds slows down with age. However, we recently found that sensorimotor synchronization (SMS) error detection and correction abilities are preserved into the ninth and tenth decades, although fastest tapping rate decreases (Turgeon, Wing, & Taylor, 2011). Further testing with the same sample of participants in the present study provides evidence for slowing of the internal clock with age. We report an age-related decrease in spontaneous motor tempo (SMT), an age-related increase in produced period when estimating target durations of 500 ms and 1000 ms, and an age-related increase in “clock variance” in continuing tapping intervals ranging from 300 ms to 900 ms. The profile of age-related difference across the 2 studies suggests a late onset, starting in the ninth decade, of clock slowing without age-related difference in timing error monitoring. The finding that unpaced timing is affected by age, whereas paced timing involved in SMS is not, suggests separate underlying mechanisms for internally generated intervals and monitoring of external timing errors.

This study assessed motor limits of regular tapping, timing error detection, and correction in 60 participants aged from 19 to 98 years. Rate limitations on motor production were estimated from the average inter-tap interval when tapping as fast as possible for 30 s. Timing error detection required participants to judge whether a sound sequence presented at a slow, intermediate, or fast speed contained an irregularity because of phase shift. This was performed with or without synchronizing to the sounds. On the basis of the just-detectable positive phase shift (JND), participants synchronized with sequences containing phase shifts that were subliminal, just detectable or supraliminal. On average, JNDs were 9% of the inter-onset interval and by and large were not affected by synchronization tapping. Speed of error correction was estimated from the number of tones to return within 20% of the preshift synchronization error. Consistent with previous findings of motor slowing with aging, the fastest inter-tap interval increased with age. However, there was no age-related decline in JNDs or speed of error correction, both of which reflect predictive abilities for intervals within the motor repertoire of human adults. These results point towards intact timing error processing up to an advanced age. In assessing timing abilities in the brain of older adults, it is important to differentiate between motor slowing and its impact on rhythmic behavior (e.g., walking pace) from anticipatory mechanisms ('what to expect when') and how these are used to adjust the timing of actions ('what to do when').

Frequency difference limens (FDLs) were measured for Huggins pitch (HP) stimuli, consisting of a 30-Hz wide band of interaurally decorrelated noise in a diotic low-pass noise and for 30-Hz wide bands of diotic narrowband noise presented in a diotic low-pass noise background. FDLs at a 400ms duration for the two stimulus types were equated by adjusting the level of the narrowband noise relative to the background. The effects of duration on the FDLs were then measured for center frequencies of 300, 600, and 900 Hz. Although the results were compromised by floor effects at 900 Hz, at 300 and 600 Hz, the duration effects were very similar for the HP and narrowband noise stimuli, with a large improvement in performance between 100 and 400 ms. In contrast to previous results for pure tones, the effect of duration was independent of frequency. The results suggest that: (1) Binaural and monaural pitches may be processed using a common mechanism; (2) discrimination performance for HP and low-sensation-level narrowband noise stimuli is not determined by the number of waveform periods.

The rhythm created by spacing a series of brief tones in a regular pattern can be disguised by interleaving identical distractors at irregular intervals. The disguised rhythm can be unmasked if the distractors are allocated to a separate stream from the rhythm by integration with temporally overlapping captors. Listeners identified which of 2 rhythms was presented, and the accuracy and rated clarity of their judgment was used to estimate the fusion of the distractors and captors. The extent of fusion depended primarily on onset asynchrony and degree of temporal overlap. Harmonic relations had some influence, but only an extreme difference in spatial location was effective (dichotic presentation). Both preattentive and attentionally driven processes governed performance.

Three studies examined how people maintain their self-images when they face threat to interpersonal aspects of the self. In Studies 1 and 2, we found evidence that low self-esteem people lower their estimates of their performance when they expect immediate feedback in order to protect themselves from the interpersonal threat inherent in such feedback, and that self-affirmation reduces this tendency among low self-esteem people. In Study 3, we found that when people are selfaffirmed they are more likely to engage in upward social comparisons and less likely to engage in downward social comparisons. Together these findings suggest that people can cope with threats to interpersonal aspects of the self by affirming other important aspects of the self.

This study examined the normative temporal sequence of the coping process and whether stressor severity or adult attachment styles moderated that sequence. Participants (N = 75) described a minor or a major stressor. They were given a stack of index cards, representing coping strategies from five different domains. They selected strategies they had employed and sorted them into the order used. Overall, support from partner was one of the first coping techniques used. Adult attachment styles moderated the coping sequence. For major stressors, dismissing attachment predicted later use of support seeking from partner and earlier use of distancing coping, while preoccupied attachment predicted earlier use of emotion-focused coping.

The Illness Attitudes Scale (IAS) is a self-rated measure that consists of nine subscales designed to assess fears, attitudes and beliefs associated with hypochondriacal concerns and abnormal illness behavior [Kellner, R. (1986). Somatization and hypochondriasis. New York: Praeger; Kellner, R. (1987). Abridged manual of the Illness Attitudes Scale. Department of Psychiatry, School of Medicine, University of New Mexico]. The purposes of the present study were to explore the hierarchical factor structure of the IAS in a nonclinical sample of young adult volunteers and to examine the relations of each illness attitudes dimension to a set of anxiety-related measures. One-hundred and ninety-seven undergraduate university students (156 F, 41 M; mean age=21.9 years) completed the IAS as well as measures of anxiety sensitivity, trait anxiety and panic attack history. The results of principal components analyses with oblique (Oblimin) rotation suggested that the IAS is best conceptualized as a four-factor measure at the lower order level (with lower-order dimensions tapping illness-related Fears, Behavior, Beliefs and Effects, respectively), and a unifactorial measure at the higher-order level (i.e. higher-order dimension tapping General Hypochondriacal Concerns). The factor structure overlapped to some degree with the scoring of the IAS proposed by Kellner (1986, 1987), as well as with the factor structures identified in previously-tested clinical and nonclinical samples [Ferguson, E. & Daniel, E. (1995). The Illness Attitudes Scale (IAS): a psychometric evaluation on a nonclinical population. Personality and Individual Differences, 18, 463–469; Hadjistavropoulos, H. D. & Asmundson, G. J. G. (1998). Factor analytic investigation of the Illness Attitudes Scale in a chronic pain sample. Behaviour Research and Therapy, 36, 1185–1195; Hadjistavropoulos, H. D., Frombach, I. & Asmundson, G. J. G. (in press). Exploratory and confirmatory factor analytic investigations of the Illness Attitudes Scale in a nonclinical sample. Behaviour Research and Therapy; Speckens, A. E., Spinhoven, P., Sloekers, P. P. A., Bolk, J. H. & van Hemert, A. M. (1996). A validation study of the Whitley Index, the Illness Attitude Scales and the Somatosensory Amplification Scale in general medical and general practice patients. Journal of Psychosomatic Research, 40, 95–104]. The Fears, Beliefs and Effects lower-order factors and the General Hypochondriacal Concerns higher-order factor, were shown to be strongly associated with anxiety sensitivity, even after accounting for trait anxiety and panic history. Implications for understanding the high degree of comorbidity between the diagnoses of panic disorder and hypochondriasis, as well as future research directions for exploring the utility of various IAS dimensions in predicting responses to lab-based bodily symptom-induction procedures, are discussed.

Objective: the present study investigated childhood learning experiences potentially associated with the development of elevated hypochondriacal concerns in a non-clinical young adult sample, and examined the possible mediating roles of anxiety sensitivity (i.e., fear of anxiety-related symptoms) and trait anxiety (i.e., frequency of anxiety symptoms) in explaining these relationships.Method: 197 university students participated in a retrospective assessment of their childhood instrumental (i.e., parental reinforcement) and vicarious (i.e., parental modeling) learning experiences with respect to arousal–reactive (e.g., dizziness) and arousal–non-reactive (e.g., lumps) bodily symptoms, respectively. Childhood learning experiences were assessed using a revised version of the Learning History Questionnaire (LHQ), anxiety sensitivity levels with the Anxiety Sensitivity Index (ASI), trait anxiety levels with the State-Trait Anxiety Inventory-Trait (STAI-T) scale, and degree of hypochondriacal concerns with the Illness Attitudes Scale (IAS)-Total score.Results: consistent with earlier findings [Watt MC, Stewart SH, Cox BJ. A retrospective study of the learning history origins of anxiety sensitivity. Behav Res Ther 1998; 36: 505–525.], elevated anxiety sensitivity levels were associated with increased instrumental and vicarious learning experiences related to both arousal–reactive and arousal–non-reactive bodily symptoms. Similarly, individuals with elevated hypochondriacal concerns also reported both more instrumental and vicarious learning experiences around bodily symptoms than did students with lower levels of such concerns. However, contrary to the hypothesis, the childhood learning experiences related to hypochondriacal concerns were not specific to arousal–non-reactive symptoms, but instead involved parental reinforcement and modeling of bodily symptoms in general (arousal–reactive and –non-reactive symptoms alike). Anxiety sensitivity, but not trait anxiety, partially mediated the relationships between childhood learning experiences and elevated hypochondriacal concerns in young adulthood.Conclusions: elevated anxiety sensitivity appears to be a risk factor for the development of hypochondriasis when learning experiences have involved both arousal–reactive and arousal–non-reactive bodily symptoms.