Exposure effects on music preference and recognition

In three experiments, the effects of exposure to melodies on their subsequent liking and recognition were explored. In each experiment, the subjects first listened to a set of familiar and unfamiliar melodies in a study phase. In the subsequent test phase, the melodies were repeated, along with a set of distractors matched in familiarity. Half the subjects were required to rate their liking of each melody, and half had to identify the melodies they had heard earlier in the study phase. Repetition of the studied melodies was found to increase liking of the unfamiliar melodies in the affect task and to be best for detection of familiar melodies in the recognition task (Experiments 1, 2, and 3). These memory effects were found to fade at different time delays between study and test in the affect and recognition tasks, with the latter leading to the most persistent effects (Experiment 2). Both study-to-test changes in melody timbre and manipulation of study tasks had a marked impact on recognition and little influence on liking judgments (Experiment 3). Thus, all manipulated variables were found to dissociate the memory effects in the two tasks. The results are consistent with the view that memory effects in the affect and recognition tasks pertain to the implicit and explicit forms of memory, respectively. Part of the results are, however, at variance with the literature on implicit and explicit memory in the auditory domain. Attribution of these differences to the use of musical material is discussed.     

Anarchic-hand syndrome: ERP reflections of lost control over the right hemisphere

In patients with the callosal type of anarchic-hand syndrome, the left hand often does not act as intended and counteracts the right hand. Reports are scarce about the underlying neurophysiological mechanisms. We report the case G.H. who developed the syndrome after infarction of the left arteria pericallosa. It has been suggested that the syndrome arises out of lacking inhibition from the dominant left hemisphere on the right hemisphere. Yet, in tests of spatial intelligence G.H. performed much better with his “anarchic” left hand than with his dominant right hand, similar to observations commonly reported in split-brain patients. Left-right manual choice responses and event-related EEG potentials to laterally presented stimuli were measured. Asymmetries were evident in G.H.’s behavior and EEG potentials, different from age-matched healthy participants (n = 11). His right-hand responses were fast and unaffected by incompatibility with stimulus location, whereas his left-hand responses were variable and accompanied by a large negative central-midline EEG potential, probably reflecting efforts in initiating the response. G.H.’s visual N1 component peaked earlier and was larger at the right than the left side of the scalp, and the P3 component was distinctly reduced at the right side. Both features occurred independent of side of stimulus presentation and side of responding hand. The effort indicated by the midline negativity and the asymmetrically reduced P3 might directly reflect G.H.’s lack of control on his right hemisphere’s processing. The faster visual processing of the right hemisphere suggested by the N1 asymmetry might contribute to “anarchic” processing, making the right hemisphere process stimuli before control impulses exert their effect. These neurophysiological results tend to support the split-brain account which assumes that the syndrome arises by the lack of communication between hemispheres that act according to their respective competences.     

Recognizing melodies: A dynamic interpretation

Two experiments explore hypotheses about rhythm and contour in recognition of simple pitch strings (melodies). Target melodies that differed with respect to pitch relationships (interval and contour pitch differences) and rhythm, were presented to ordinary listeners who were told to learn the melodies (Phase I). In a subsequent recognition test (Phase II), listeners had to recognize these same target melodies although they were transposed to a different musical key. In recognition, target melodies appeared in the original rhythm or in new rhythms that simulated some pause properties of the original rhythm. Target melodies were interspersed with decoy melodies that either preserved the pitch contour of targets or did not; all appeared in the original rhythm and in new rhythms. Results indicated that a new rhythmic context lowered recognizability of target melodies, and that decoys were most confusing when they possessed the same “dynamic shape” (contour-plus-rhythm) as targets (Experiment 1). Also, target recognition improved with Phase I familiarity (Experiment 2), although rhythmic shifts remained detrimental across levels of target familiarity. Confusions based on “dynamic shape” accounted for a relatively high proportion of errors where familiarity with targets is low. Findings were interpreted in terms of a theory of context-sensitive dynamic attending in which remembering is assumed to involve recapitulation of the original rhythmical activities involved in attending to melodies.     

Implicit achievement motive limits the impact of task difficulty on effort-related cardiovascular response

In contrast to the motive literature, motivational intensity theory predicts that the implicit achievement motive (nAch) should only exert an indirect impact on effort by limiting the impact of task difficulty. To contrast these two views, sixty-eight participants with a low or high nAch performed an easy or difficult arithmetic task. Effort was assessed using cardiac pre-ejection period (PEP). Supporting motivational intensity theory’s view, PEP response was low in both easy-task conditions but stronger in the high-nAch group than in the low-nAch group in the difficult task. These findings suggest that nAch exerts an indirect effect on effort investment by setting the maximally justified effort instead of directly determining the amount of effort that is invested to satisfy the motive.     

The contingent negative variation laterality and dynamics in antisaccade task in normal and unmedicated schizophrenic subjects

Contingent negative variation (CNV) topography, hemispheric asymmetry and time-course were investigated in healthy subjects and non-medicated paranoid schizophrenic patients in two antisaccade paradigms with the short (800-1000 ms) and long (1200-1400 ms) durations of the fixation period. EEG and electrooculogram (EOG) were recorded. Saccade characteristics and mean amplitudes of slow cortical potentials time-locked to peripheral target were analyzed in 23 healthy volunteers and 19 schizophrenic patients. Compared to healthy control subjects, schizophrenic patients had significantly slower antisaccades and committed significantly more erroneous saccades in the both antisaccade tasks. The prolongation of the fixation period resulted in noticeable decrease of error percent in patients group. The analysis of CNV time-course has revealed two distinct stages in both groups. The early CNV stage was represented by a negative wave with the maximal amplitude over midline fronto-central area, and the late stage was characterized by increased CNV amplitude at the midline and left parietal electrode sites. In healthy subjects the simultaneous activation of frontal and parietal areas was observed in the paradigm with the shorter fixation interval; the increase of the fixation period produced consecutive activation of these areas. Schizophrenic patients' CNV amplitude was generally smaller than that of healthy subjects. The most pronounced between-group differences of the negative shift amplitude were revealed at frontal electrode sites during the early CNV stage in both modifications of the antisaccade task. The deficit of frontal activation revealed in patients at the early stage of antisaccade preparatory set in both antisaccadic paradigms may be related to pathogenesis of paranoid schizophrenia.     

时间分配的执行功能:双重效价联合任务的证据

采用内隐联想测验的修订版本双重效价联合任务范式,利用ERP技术探究不同时间分配倾向个体在执行冲突和转换任务时的执行功能,以揭示不同时间分配倾向个体在相容和不相容任务过程中脑内时程的动态变化。研究结果发现,多重组个体显示出更快的反应时;ERP结果表明,相比于多重组,单一组在不相容任务中比在相容任务中诱发了更大的N170,说明多重组个体可能更善于同时执行多项任务,而单一组执行冲突任务可能需要投入更多的注意资源。同时在认知加工的晚期阶段单一组比多重组诱发了更大的LPP,提示单一组需要更强的认知控制加工。     

Stimulus-dependent flexibility in non-human auditory pitch processing

Songbirds and humans share many parallels in vocal learning and auditory sequence processing. However, the two groups differ notably in their abilities to recognize acoustic sequences shifted in absolute pitch (pitch height). Whereas humans maintain accurate recognition of words or melodies over large pitch height changes, songbirds are comparatively much poorer at recognizing pitch-shifted tone sequences. This apparent disparity may reflect fundamental differences in the neural mechanisms underlying the representation of sound in songbirds. Alternatively, because non-human studies have used sine-tone stimuli almost exclusively, tolerance to pitch height changes in the context of natural signals may be underestimated. Here, we show that European starlings, a species of songbird, can maintain accurate recognition of the songs of other starlings when the pitch of those songs is shifted by as much as ±40%. We observed accurate recognition even for songs pitch-shifted well outside the range of frequencies used during training, and even though much smaller pitch shifts in conspecific songs are easily detected. With similar training using human piano melodies, recognition of the pitch-shifted melodies is very limited. These results demonstrate that non-human pitch processing is more flexible than previously thought and that the flexibility in pitch processing strategy is stimulus dependent.     

Emotion perception and recognition: An exploration of cultural differences and similarities

The electroencephalogram (EEG) is a powerful method for investigation of different cognitive processes. Recently, EEG analysis became very popular and important, with classification of these signals standing out as one of the mostly used methodologies. Emotion recognition is one of the most challenging tasks in EEG analysis since not much is known about the representation of different emotions in EEG signals. In addition, inducing of desired emotion is by itself difficult, since various individuals react differently to external stimuli (audio, video, etc.). In this article, we explore the task of emotion recognition from EEG signals using distance-based time-series classification techniques, involving different individuals exposed to audio stimuli. Furthermore, since some of the participants in the experiment do not understand the language of the stimuli, we also investigate the impact of language understanding on emotion perception. Using time-series distances as features for the construction of new data representations, applied here for the first time to emotion recognition and related tasks, lead to excellent classification performance, indicating that differences between EEG signals can be used to build successful models for recognition of emotions, individuals, and other related tasks. In the process, we observed that cultural differences between the subjects did not have a significant impact on the recognition tasks and models.     

Neurophysiological evidence of how quiet eye supports motor performance

Prolonged quiet eye (QE) duration is associated with greater performance in various types of targeting and interceptive tasks. However, the mechanism by which QE affects performance remains debatable. This study aimed to test the validity of the pre-programming and online control hypotheses using electromyography (EMG), electrooculography (EOG) and electroencephalography (EEG) during a golf putting task. Twenty-one college students were recruited for this study. Each participant performed 100 golf putting trials during which the putting performance, EMG, EOG, and EEG signals were recorded. The QE duration including the pre- and post-movement initiation components, and movement-related cortical potentials (MRCPs) were analyzed off-line. We found that successful putts were associated with longer QEtotal (the total QE duration from QE onset to QE offset), QEpre (QE occurring before movement initiation), and QEpost (QE occurring after movement initiation) durations than failed putts. Greater cortical activation in the MRCPs was observed within the prefrontal, premotor, and parietal cortices during successful putts compared with failed putts. These findings suggest that QE serves both pre-programming and online control roles in supporting golf putting performance.

     

Dealing with artifacts: The EOG contamination of the event-related brain potential

Eye movements and blinks represent a major source of artifacts in the electroencephalogram (EEG) and event-related brain potentials (ERPs). The origin of this artifact is the large difference in potential that exists between the cornea and the retina. Eye movements and blinks produce shifts of the electric fields that propagate across the whole head and that can be several times larger than the activity generated by the brain. Ocular activity can be monitored by electrodes located near the eyes (electrooculogram, or EOG). The electric fields associated with eye movements and blinks are somewhat different. The simplest procedure for dealing with ocular artifacts is to eliminate trials on which EOG activity is detected (rejection). However, this technique may result in data loss and biased data samples, especially when one is comparing clinical populations or tasks involving large amounts of eye movements. Another approach involves estimation and correction of the ocular artifact on the EEG and ERP traces. Several techniques have been proposed. Some of them are reviewed in the present paper. Issues related to the accuracy of the various techniques, as well as other advantages and limitations, are also discussed. Finally, general guidelines for how to deal with ocular artifacts are proposed.     

视觉空间工作记忆组间差异的神经机制

为考察视觉空间工作记忆（working memory, WM）维持和操作的组间差异及其神经机制,本研究记录了高、低WM组完成延迟再认（维持）任务和心理旋转（操作）任务时的行为和事件相关电位数据。结果发现,在操作任务中,高WM组比低WM组的反应时显著更短;高WM组的中前额叶慢波显著更正、双侧后顶区慢波显著更负,并且两者的波幅显著负相关。在维持任务中,两组被试的反应时无显著差异;高WM组的中前额叶慢波显著更正。结果表明,高WM组的执行注意能力可能更强,能通过有效调节和分配加工资源来表征视觉信息。     

Neural Processing to Visual Stimuli in a Three-Choice Reaction-Time Task

Some authors have suggested that certain components of the event-related potentials (ERPs) reflect underlying stages in the discrimination process. Previous studies have shown that in an auditive three-choice reaction-time task the discrimination is accomplished as a two-stage process, with the more frequently occurring stimulus discriminated at an earlier point than the rarer stimulus and the subjects could be classified as fast and slow responders in function of their response to the most frequent of the three tones. We continuously recorded the electrocerebral activity (EEG) from the scalp and the electromyographic activity (EMG) from the responding muscles in a visual three-choice reaction-time task in 10 strictly right-handed subjects. EEG and EMG responses were subsequently analyzed off-line by aligning them by the onset of either the stimulus (stimulus-synchronized) or the response (response-synchronized). The results suggest that processes of visual stimuli evaluation and response execution are continuously integrated. The discrimination and response systems to visual stimuli is accomplished as a three-stage process, one to frequent tone, another for rare 1, and the last for rare 2. The subjects were classified as fast and slow responders in function of their response to the most frequent of the three tones.     

Effects and aftereffects of continuous noise and computation work on risk and effort choices

Choices between risk and effort, in a format (COPE) previously shown to reflect fatigue, were obtained from subjects in noise or quiet. Both sexes were used in the experiment, half the subjects working at the Norinder arithmetic task while half rested. The COPE test took a computational form, offering choices between digit lists of differing lengths in which target sums were imbedded. The baseline choice levels were established in quiet, but half the subjects were exposed to noise during the posttest. As previously found in comparable conditions, the Norinder task showed no effect of noise. Pretest-posttest comparisons on the COPE test showed that exposure to noise, like computation work, had the predicted effect of decreasing the choice of high-probability, high-effort alternatives. The presence of noise during posttest had no overall effect on risk effort choices, although there were indications that changes of any kind in the test conditions might be a factor. The data seem difficult to explain in an arousal framework, but may be simply interpreted as showing that exposure to noise produces real fatigue.     

Driver performance, rewards and motivation: A simulator study

It has been suggested that effort invested in a task may be moderated by the perception of the nature of reward offered, e.g., whether social or financial in nature. If levels of payment for empirical work meaningfully influence the effort invested in tasks by participants, the implications may be serious and wide-ranging for the reliability and validity of published data. The study reported in this paper, examines this thesis in a driving context. Thirty-six participants were allocated to either a No payment, Low payment or Medium payment condition in a driving simulator. They undertook both easy and difficult driving scenarios in which performance was measured. Subjective workload and performance results indicated that task difficulty was successfully manipulated with the study. However, in contrast to the previous research in non-driving contexts, participants not receiving rewards were found to perform more poorly and experience increased time pressure.     

Changes in the EEG frequency spectrum in various phases of mental stress

To obtain evidence about the relationship between spontaneous EEG activity and mental activity, an experiment was designed and executed with EEG recordings during a concept-learning task. We varied task performance (self-paced vs. machine-paced) and distinguished different stages of information processing during task performance. Using factor analysis calculated on all spectral coefficients, we found two orthogonal variables in the clinical alpha band. Alpha 2 power (10.5-12 Hz) seems to reflect the overall processing demands imposed on the individuals. Furthermore, there are different EEG frequency patterns during perceptual-central- compared with response-related processing as well as during processing of positive vs. negative feedback. The results suggest using (1) conservative procedures in hypothesis testing and (2) procedures to reduce between subject variability (a posteriori defined frequency variables, relative power values, scaling of reaction values) in further studies relating EEG activity to mental activity during task performance.     

Changes in spontaneous slow potentials and visually (flash) evoked potentials in response to stimuli with no performance implication]

The influence of spontaneous slow potential shifts (SPSs) on visual (flash-)evoked potentials (VEPs) was studied. Eighteen subjects received 100 flashes. The sequence of interstimulus-intervals (ISIs) was pseudo-randomized. ISI-durations were 3, 5, 7, 9 or 11 seconds. EEG was recorded from Fz, Cz, Pz and Oz with linked-mastoids as reference. EEG was EOG-corrected and VEPs were calculated for preceding positive SPSs. Averaging was done for local SPSs; VEP pairings as well as VEPs were calculated over occipital SPS-polarities. Results showed an influence of SPSs on VEP-amplitudes. Differences in amplitudes were interpreted with the 'activation-correction'-hypothesis and with the 'ceiling'-hypothesis. Negative SPSs were followed by smaller negative peaks, and positive SPSs were followed by smaller positive peak-amplitudes. Differences in latencies of N145-P300 peak-to-peak amplitudes after SPSs of different polarity were explained with the threshold-regulation hypothesis. Spectral-analysis were done for SPS-data. There were only poor effects, showing increased parietal alpha 2-power after negative SPSs.     

Evidence for holistic processing of faces viewed as photographic negatives

Inversion and photographic negation both impair face recognition. Inversion seems to disrupt processing of the spatial relationship between facial features ('relational' processing) which normally occurs with upright faces and which facilitates their recognition. It remains unclear why negation affects recognition. To find out if negation impairs relational processing, we investigated whether negative faces are subject to the 'chimeric-face effect'. Recognition of the top half of a composite face (constructed from top and bottom halves of different faces) is difficult when the face is upright, but not when it is inverted. To perform this task successfully, the bottom half of the face has to be disregarded, but the relational processing which normally occurs with upright faces makes this difficult. Inversion reduces relational processing and thus facilitates performance on this particular task. In our experiments, subjects saw pairs of chimeric faces and had to decide whether or not the top halves were identical. On half the trials the two chimeras had identical tops; on the remaining trials the top halves were different. (The bottom halves were always different.) All permutations of orientation (upright or inverted) and luminance (normal or negative) were used. In experiment 1, each pair of 'identical' top halves were the same in all respects. Experiment 2 used differently oriented views of the same person, to preclude matches being based on incidental features of the images rather than the faces displayed within them. In both experiments, similar chimeric-face effects were obtained with both positive and negative faces, implying that negative faces evoke some form of relational processing. It is argued that there may be more than one kind of relational processing involved in face recognition: the 'chimeric-face effect' may reflect an initial 'holistic' processing which binds facial features into a 'Gestalt', rather than being a demonstration of the configurational processing involved in individual recognition.     

Task determinants of ear differences in melody processing

In Experiment 1 nonmusicians were presented with dichotic melodies, which differed either on all pitches or by a single note, followed by a set of four binaural melodies. They were asked to recognize among the alternatives only one member of the dichotic pair in the “single-focus” task, and both dichotic melodies in the “double-focus” task. These different attention requirements led to a LEA in the first task which contrasted with the REA observed in the other task when melodies differed by all pitches. A possible confounding (fusion of the common pitches) prevents comparison of the tasks for melodies differing by a single pitch. The role of the extent of melody differences was further investigated in a second experiment by changing melodies on one, two, or three notes. No effect of material was observed on ear asymmetries. Task demands appeared as the most critical determinant of ear differences and are discussed in terms of their particular influence on the adoption of an analytic or holistic processing mode. Male subjects were found to be more responsive than females to analytic processing suggestions.     

Laterality effects in processing tonal and atonal melodies with affective and nonaffective task instructions

Right-handed university subjects were presented with monaural melodies that either conformed to the rules of the Western tonal system (tonal melodies) or that systematically deviated from it (atonal melodies) while containing similar contours and pitch skips. Subjects were tested under two different task instructions. One group was requested to judge whether each melody sounded correct or not (the nonaffective task); the other group had to judge whether each melody sounded pleasant or not (the affective task). The nonaffective task was found to elicit essentially no ear difference. In contrast, the affective instruction induced opposite and reliable laterality effects, depending on the valence of the response. The pleasant responses were indicative of a left hemisphere predominance and the unpleasant responses of a right hemisphere predominance. The results are consistent with the claim that the left hemisphere is biased toward positive emotions and the right to negative emotions. Moreover, the results suggest that affective appreciation of melodies is dissociable from their nonaffective judgment.     

Comparison of magneto-and electroencephalographic techniques in event-related response research—a brief survey

Event-related brain potentials are widely used in psychophysiological and neurophysiological research. Recently it has become possible to record weak magnetic fields associated with the electric events of the human brain. In this short survey the magnetoencephalo-graphic (MEG) techniques are compared with the conventional electric measures. MEG and EEG are sensitive to current sources of different orientation. Extracerebral tissues smear and damp the electric potentials but they do not have any significant effect on the magnetic fields. EEG measures potential differences whereas the actual current paths determine the magnetic fields measured outside the skull. In general MEG provides better spatial resolution than the electric recordings, as far as the cortical sources are concerned. It is concluded that EEG and MEG are complementary noninvasive techniques in brain research. As an example slow EEG and MEG shifts preceding voluntary foot movements are compared.