The face is a rich source of information about human behavior. Available methods for coding facial displays, however, are human-observer dependent, labor intensive, and difficult to standardize. To enable rigorous and efficient quantitative measurement of facial displays, we have developed an automated method of facial display analysis. In this report, we compare the results with this automated system with those of manual FACS (Facial Action Coding System, Ekman & Friesen, 1978a) coding. One hundred university students were videotaped while performing a series of facial displays. The image sequences were coded from videotape by certified FACS coders. Fifteen action units and action unit combinations that occurred a minimum of 25 times were selected for automated analysis. Facial features were automatically tracked in digitized image sequences using a hierarchical algorithm for estimating optical flow. The measurements were normalized for variation in position, orientation, and scale. The image sequences were randomly divided into a training set and a cross-validation set, and discriminant function analyses were conducted on the feature point measurements. In the training set, average agreement with manual FACS coding was 92% or higher for action units in the brow, eye, and mouth regions. In the cross-validation set, average agreement was 91%, 88%, and 81% for action units in the brow, eye, and mouth regions, respectively. Automated face analysis by feature point tracking demonstrated high concurrent validity with manual FACS coding.

Two experiments examined the effects of visually presented threat and nonthreat word lead stimuli on blink modification among unselected young adults (Experiment 1, N = 35) and participants selected for low and high trait anxiety (Experiment 2, N = 60). The blink reflex was elicited by a white noise probe of 105 dB. Lead stimulus intervals of 60, 120, 240, and 2000 ms were used in both experiments. Prepulse inhibition was observed at the 240-ms interval and prepulse facilitation was observed at the 60-ms interval in both experiments. Also, greater facilitation was found in both experiments during threat words at the 60-ms interval and greater inhibition during threat words at the 240-ms interval. Experiment 2 provided some evidence that the greater facilitation during threat words than during nonthreat words at the 60-ms probe interval may be found in high trait anxious participants, but not in low trait anxious participants. The results are discussed in relation to contemporary information processing theories of anxiety.

Event-related brain potentials (ERPs) were used to investigate how and when a semantic factor (animacy) affects the early analysis of a difficult syntactic structure, namely, object relative sentences. We contrasted electrophysiological and behavioral responses to two object relative types that were syntactically and lexically identical and varied only in the order of the component animate and inanimate nouns [Inanimate (Animate) vs. Animate (Inanimate)]. ERPs were recorded from 40 subjects to each word of 30 I(A) and 30 A(I) sentences that occurred randomly among a set of various other sentence types read for comprehension. ERP effects to the early noun animacy manipulation were observed beginning with the initial noun and extending past the main clause verbs. We interpret the timing and multitude of electrophysiological effects, including the N400, P600, and left-anterior negativity, as evidence that both semantic and syntactic, and perhaps other types of information, are used early during structural analysis and message-level computations as needed for comprehension.

Event-related potentials (ERPs) were recorded in male and female participants in response to 32 male and 32 female faces. Participants were instructed to simply look carefully at each face; after ERP collection they were asked to rate each face on a 5-point attractiveness scale. A positive correlation between average rating and average P300 scores to opposite sex faces was observed in male (r = .40) and in preovulatory (r = .41) and postovulatory (r = .44) female subjects. Correlations to same sex faces were only found in postovulatory females (r = .61). Male participants showed a much larger average P300 than did female participants, and the P300 evoked in female participants was unexpectedly larger to female than to male faces. Neither task relevance nor stimulus probability is a plausible explanations for these findings because they were experimentally controlled. These results support the emotional value hypothesis, according to which classical P300 processes reflect an affective evaluation of the stimulus, which in turn produces context updating.

Facial flushing was studied in 38 young women who scored high or low on trait anger. To induce anger in the subjects, their task was to solve a difficult puzzle, with or without harassment from a female research assistant. Facial blood flow increased in response to provocation, together with increases in cardiovascular and electrodermal activity. Flushing was associated with large increases in electrodermal activity and small increases in diastolic blood pressure. Subjects high in trait anger reported most anger and embarrassment, but physiological activity did not differ from subjects with low trait anger. The findings suggest that sympathetically mediated vasodilatation in facial blood vessels competes with cutaneous vasoconstriction during anger. Unpleasant sensations of facial warmth might heighten aversive emotional experiences, but dilatation of facial blood vessels could also act as a type of “safety valve” by opposing increases in blood pressure. An angry predisposition may influence the subjective experience of anger in women, but does not seem to have a major influence on physiological reactivity to mild provocation.

Pupillary response to noxious stimulation was investigated in men (n = 11) and women (n = 9). Subjects experienced repeated trials of noxious electrical fingertip stimulation at four intensities, ranging from faint to barely tolerable pain. Measures included pupil dilation response (PDR), pain report (PR), and brain evoked potentials (EPs). The PDR began at 0.33 s and peaked at 1.25 s after the stimulus. Multivariate mixed-effects analyses revealed that (a) the PDR increased significantly in peak amplitude as stimulus intensity increased, (b) EP peaks at 150 and 250 ms differed significantly in both amplitude and latency across stimulus intensity, and (c) PR increased significantly with increasing stimulus intensity. Men demonstrated a significantly greater EP peak amplitude and peak latency at 150 ms than did women. With sex and stimulus intensity effects partialled out, the EP peak latency at 150 ms significantly predicted PR, and EP peak amplitude at 150 ms significantly predicted the PDR peak amplitude.

A wordstem priming task (nondeclarative memory), and a mental spatial rotation task (declarative memory) were presented to subjects of an experimental “sleep” group (n = 11) and of a “wake” control group (n = 10). Repetition priming effects and recall of spatial memory were tested after 3-hr retention intervals, which followed learning and were placed either in the early or in the late half of the night. Sleep group subjects slept during the retention intervals while subjects of the wake group stayed awake. As expected, early retention sleep was dominated by slow wave sleep (SWS), whereas rapid eye movement (REM) sleep prevailed during late retention sleep. After early retention sleep, recall of spatial memory was superior to that after late retention sleep (p < .01), and also to that after retention intervals of wakefulness (p < .05). In contrast, priming was more effective after late than early retention sleep (p < .05). It appears that early sleep dominated by SWS facilitates consolidation of declarative memory whereas late sleep dominated by REM sleep facilitates consolidation of nondeclarative memory.

Rhythmic properties of spoken language such as metrical stress, that is, the alternation of strong and weak syllables, are important in speech recognition of stress-timed languages such as Dutch and English. Nineteen subjects listened passively to or discriminated actively between sequences of bisyllabic Dutch words, which started with either a weak or a strong syllable. Weak-initial words, which constitute 12% of the Dutch lexicon, evoked more negativity than strong-initial words in the interval between P2 and N400 components of the auditory event-related potential. This negativity was denoted as N325. The N325 was larger during stress discrimination than during passive listening. N325 was also larger when a weak-initial word followed a sequence of strong-initial words than when it followed words with the same stress pattern. The latter difference was larger for listeners who performed well on stress discrimination. It was concluded that the N325 is probably a manifestation of the extraction of metrical stress from the acoustic signal and its transformation into task requirements.

Increased frequency of anticipatory saccades during smooth pursuit eye movements is a potential marker of genetic risk for schizophrenia even in the absence of clinical symptomology. The operational definition of anticipatory saccades has often included an amplitude criterion; however, these amplitude criteria have often differed across studies. This study reports on the effect of varying amplitude criteria on the effect size in a comparison of 29 schizophrenic adults and 29 normal subjects during a 16.7°/s constant velocity task. The inclusion of small amplitude anticipatory saccades, with amplitudes of 1–4°, consistently increased effect size (largest effect size = 1.61). The inclusion of large anticipatory saccades, with amplitudes of 4° or greater, had an inconsistent impact on effect size. The separation of anticipatory saccades into leading saccades (anticipatory saccades with amplitude 1–4°) and large anticipatory saccades (amplitude >4°) deserves further exploration.

Facial reactions in schizophrenic patients were assessed via electromyography (EMG) in response to pictures of facial expressions. Male patients and nonpatient controls viewed photographs of positive and negative facial expressions while EMG activity from the corrugator and zygomatic muscle regions was recorded. Both schizophrenic patients and controls exhibited greater zygomatic reactivity in response to positive pictures than in response to negative pictures and greater corrugator reactivity in response to negative pictures than in response to positive pictures. Schizophrenic patients exhibited greater corrugator reactivity than did nonpatient controls. Implications for understanding emotion expression and perception in schizophrenic patients are discussed.

The temporal and hierarchical relationships between the dorsal and the ventral streams in selective attention are known only in relation to the use of spatial location as the attentional cue mediated by the dorsal stream. To improve this state of affairs, event-related brain potentials were recorded while subjects attended simultaneously to motion direction (mediated by the dorsal stream) and to a property mediated by the ventral stream (color or shape). At about the same time, a selection positivity (SP) started for attention mediated by both streams. However, the SP for color and shape peaked about 60 ms later than motion SP. Subsequently, a selection negativity (SN) followed by a late positive component (LPC) were found simultaneously for attention mediated by both streams. A hierarchical relationship between the two streams was not observed, but neither SN nor LPC for one property was completely insensitive to the values of the other property.

To determine if the inability to take advantage of the predictability of an aversive stimulus to diminish its psychological impact reflects a deficit in inhibitory control related to the development of substance dependence, we recorded skin conductance responses (SCRs), heart rate (HR), and anticipatory electrodermal nonspecific fluctuations (NSFs) from 175 16–18-year-old boys when a white noise blast was either unpredictable or temporally predictable. Compared with boys who had moderately reduced or augmented SCRs to predictable blasts (moderate and poor modulators, respectively), boys whose SCRs were greatly reduced (good modulators) had fewer symptoms of alcohol and nicotine dependence and more anticipatory NSFs. HR appeared to index an active coping response for good and moderate modulators. The autonomic response pattern evident for good modulators may index an inhibitory control mechanism protecting them from developing substance dependence.

Event-related potentials were recorded using color pictures of real objects. Participants made relatedness judgments for pictures that were highly, moderately, or unrelated to a picture of a preceding prime object (Experiment 1) or object identification decisions for related/easily identified, unrelated/easily identified, and unrelated/unidentifiable objects preceded by prime objects (Experiment 2). Unrelated pictures elicited larger event-related potential negativities between 225 and 500 ms than did related pictures, although the first portion of this epoch had a more frontal distribution than did the later portion. The later epoch differentiated the unrelated from the moderately related and the moderately related from the highly related pictures (Experiment 1), but the early epoch produced differences only between the unrelated and related pictures (Experiments 1 and 2). This pattern supports the existence of two separate components, an anterior, image-specific N300 and a later, central/parietal amodal N400.

Thoracic impedance is modulated by events within the respiratory cycle, which represents a source of “noise” in impedance cardiography. Respiration itself, however, is a physiological rhythm of interest to psychophysiologists. We report here methods and validation for deriving impedance pneumographic measures of respiration from impedance cardiography signals, based on standard tetrapolar band electrodes. We recorded the change in impedance (ΔZ), the first derivative of the change in impedance (dZ/dt), output from a strain-gauge respirometer, and criterion spirometry from eight healthy adults during rest, paced breathing, abdominal breathing, thoracic breathing, and a mental arithmetic task. Transfer function analyses revealed that a ΔZd signal (derived by integration of the dZ/dt signal) provided the best estimate of the criterion spirometric measure for all parameters (coherence, phase, and gain), accounting for almost 90% of the variance in respiratory waveform morphology. The results document the potential utility of impedance pneumography, as derived from standard impedance cardiography signals.

We investigated emotional disturbances in 36 schizophrenia patients, 48 of their first-degree relatives, and 56 controls to determine if abnormal affective startle modulation could be associated with genetic risk for schizophrenia. Both patients and relatives had a pattern of startle modulation indistinguishable from controls, with potentiated startle amplitude while viewing negative valence slides and attenuation while viewing positive slides. Patients with flat affect did not differ from those without in startle modulation or slide ratings. The patients and their relatives had lower pleasantness ratings of positive slides and the patients had higher pleasantness ratings of the negative slides than controls. The startle paradigm may not be useful for identifying individuals with a genetic liability for schizophrenia. The results suggest that low-level defensive and appetitive behaviors are unaffected in schizophrenia.

To determine if the P300 component of the event-related potential indexes risk for substance use and related disorders, we presented a community sample of 377 16–18-year-old males a visual oddball task and selected 31 subjects with the smallest and 31 subjects with the largest P300 amplitudes. An additional 31 subjects whose amplitudes fell in the middle of the amplitude distribution were assigned to the average group. The small and average amplitude groups were more likely to have alcohol dependence and more symptoms of alcohol dependence than the large amplitude subjects. The small amplitude group had more symptoms of illicit drug dependence than the other groups. There was also a significantly larger proportion of subjects with externalizing disorders in the small amplitude group than in the large P300 group. These findings suggest that P300 amplitude may index a spectrum of risk for disinhibited psychopathology.

The temporal course of startle reflex modulation and autonomic response patterns to fear-relevant and fear-irrelevant pictures in subjects with high and low levels of animal fear was investigated. Thirty-eight high-fear and 48 low-fear volunteers viewed photos of snakes and spiders and pictures of neutral and pleasant content. The slides were presented for 6 s or for only 150 ms, depending on the group. Acoustic startle probes were presented at five different times after slide onset. Relative potentiation of the startle responses started 300 ms after onset of snake/spider pictures in fearful subjects. This fear-potentiated startle effect was maintained for the later probe times and was identical in the 150-ms condition. Fear-relevant pictures also prompted a sympathetically dominated autonomic response profile in fearful persons. These data support the idea that fear can be activated very rapidly, requiring only minimal stimulus input.

Detecting deviant, and potentially meaningful, auditory events depends on transient representations of preceding stimuli. Here, we examined whether the neural circuitry underlying deviance detection system varied as a function of deviance type. In different blocks of trials, participants were presented with a sequence that included standard and deviant tones differing in frequency or a sequence of tones that alternated regularly in frequency with occasional deviant repetitions. Both frequency- and pattern-deviant stimuli elicited a mismatch negativity (MMN) peaking between 120 and 175 ms poststimulus. The MMN amplitude distribution was more frontal for frequency-deviant than for pattern-deviant stimuli. There are two possible explanations for these results. Both frequency- and pattern-deviation MMNs might arise in the same set of generators whose relative strength of activation varies. Alternatively, frequency- and pattern-deviation MMNs could originate in different generators. These alternatives were investigated using principal component analysis and signal identification methods. These methods revealed that no common signal space could account for both of the MMNs, indicating different generator sources for the analysis of frequency and pattern deviance. The results suggest separate memory-related processing for auditory frequency and patterns and indicate that the neural circuit of deviance detection varies as a function of the perceptual context.

Performance on heartbeat counting tasks is usually interpreted in terms of cardiac sensitivity. We tested the hypothesis that heartbeat counting is influenced by beliefs about heart rates by dissociating beliefs about heart rates and actual heart rates. In a within-subjects design, heart rates of 50 patients with cardiac pacemakers were set to a low (50 bpm), medium (75 bpm), or high (110 bpm) pacing rate unknown to the patients via remote control while they performed a heartbeat tracking task. Results showed that patients' heartbeat counting did not follow the shifts in their actual heart rates adequately, although their overall performance was comparable to that of young and healthy control participants. As a result, tracking scores decreased significantly in the high pacing rate condition where beliefs about heart rates and actual heart rates were most extremely dissociated. The findings suggest that tracking scores reflect beliefs about heart rates rather than cardiac sensitivity.

Transcranial cortical magnetic stimulation (CMS) is a noninvasive, non-noxious procedure to induce perceptual attenuation when applied concomitant to sensory stimuli. To investigate the perceptual timing of simple stimulus features in the somatosensory modality, we applied right hemisphere CMS at different intervals following a stimulus delivered to the left hand. Different intervals between peripheral stimuli and CMS were defined according to the components of the somatosensory-evoked potentials (SEP), previously obtained in response to the same stimulus. Perceptual attenuation was maximal when CMS coincided with the primary cortical response (parietal N20 potential); conversely, perception of stimulus intensity was not modified when CMS was concomitant with the N200 and P300 potentials. Using small CMS intensities, a “perceptual dip” was observed when CMS arrived in coincidence with the N120 potential, a SEP response thought to be originated in part in the second somatic area. Our results support the view that both N200 and P300 are post-perceptual responses. The results also suggest that the cortical processes active during the N20 and N120 potentials may be essential for the conscious perception of somatosensory stimuli delivered to the hand.