Extraversion and neuroticism in orienting reflex dishabituation

The present study examined the effects of extraversion (E) and neuroticism (N) as individual difference dimensions and of stimulus intensity on electrodermal orienting response habituation, test response, and dishabituation. Subjects were 162 college students selected from a screening sample of 860 as representing extreme groups of high, medium, and low E crossing with high, medium, and low N. Subjects in all nine resulting groups were habituated to criterion on auditory stimuli of 60, 80, and 100 db. A novel (test) stimulus and a dishabituating standard stimulus followed criteron habituation at each intensity. Results indicated that response amplitude for initial, test, and dishabituation responses was a direct function and that habituation rate (trials-to-criterion) was an inverse function of stimulus intensity. Extraverts habituated more rapidly than introverts at high intensity and gave smaller test and dishabituation responses. Some results differed when regression coefficients defined habituation rate and when first stimulus intensities alone were examined. Correlations among initial, test, and dishabituation responses and between each of these and the two measures of habituation rate are also reported. Results were interpreted as partially supportive of Eysenck's theory.     

Heart rate deceleration is not an orienting reflex; Heart rate acceleration is not a defensive reflex

Graham and Clifton (1966) proposed an integration of Sokolov’s theory of orienting and defensive reflexes with the stimulus intake/rejection dichotomy of the Laceys. This integration consisted of hypothesizing that heart rate deceleration is a measure of the orienting reflex, and that cardiac acceleration is a measure of the defensive reflex. This article demonstrates that Graham and Clifton failed to establish a valid integration of these two theories. This failure is a consequence of 1) their misconstruing Sokolov’s theory, and 2) an inaccurate and selective review of the research literature then available. Consideration of more recent research would seem to rule out the possibility that their thesis was correct in spite of these flaws in its derivation. Cardiac responding in the OR context thus remains open to further investigation and interpretation.     

Auditory awareness negativity is an electrophysiological correlate of awareness in an auditory threshold task

One theory of visual awareness proposes that electrophysiological activity related to awareness occurs in primary visual areas approximately 200 ms after stimulus onset (visual awareness negativity: VAN) and in fronto-parietal areas about 300 ms after stimulus onset (late positivity: LP). Although similar processes might be involved in auditory awareness, only sparse evidence exists for this idea. In the present study, we recorded electrophysiological activity while subjects listened to tones that were presented at their own awareness threshold. The difference in electrophysiological activity elicited by tones that subjects reported being aware of versus unaware of showed an early negativity about 200 ms and a late positivity about 300 ms after stimulus onset. These results closely match those found in vision and provide convincing evidence for an early negativity (auditory awareness negativity: AAN), as well as an LP. These findings suggest that theories of visual awareness are also applicable to auditory awareness.     

Stimulus significance effects in habituation of the phasic and tonic orienting reflex

Phasic and tonic measures of electrodermal activity were examined in a simple habituation paradigm, using innocuous visual stimuli. Separate groups were used to investigate the effects of stimulus significance, as manipulated by instructions. One group had no stimulus-related task (indifferent group), while the other was asked to silently count the stimuli to report to the experimenter later (significant group). Prestimulus skin conductance levels were considered as measures of the arousal level at each stimulus presentation, and the subsequent electrodermal responses were taken as the phasic orienting reflex (OR) elicited by each stimulus. Changes in prestimulus arousal were taken as measures of the tonic OR to the experimental series. Marked group differences were found in both phasic and tonic components of the OR. Some, but not all, of the significance effects in the phasic OR were attributable to differences in arousal. The results are discussed in the context of theoretical accounts of the OR.     

Temporal pattern and spectral complexity as stimulus parameters for eliciting a cardiac orienting reflex in human fetuses

The purpose of this study was to determine whether temporal pattern and/or spectral complexity were important stimulus parameters for eliciting a cardiac orienting reflex (OR) in low-risk human fetuses. Each of 28 term fetuses was exposed to four sounds formed from the four different combinations of temporal pattern (pulsed, continuous) and spectral complexity (sine wave, /a/). The fetal cardiac electrical signal was captured transabdominally at a rate of 1024 Hz, and fetal R-waves were extracted by using adaptive signal-processing techniques. We found that pulsed sounds elicited a significantly greater decrease in heart rate (HR) than did continuous sounds. However, the HR response was relatively unaffected by spectral complexity. For the pure tone and the phoneme used in this study, our results indicate that temporal characteristics were more effective at eliciting a cardiac OR in human fetuses than was spectral complexity.     

Habituation and dishabituation of the electrodermal orienting reflex in relation to extraversion and neuroticism

Orienting reflex (OR) habituation and dishabituation may be influenced by individual difference variables, including Eysenck's Extraversion (E) and Neuroticism (N) dimensions. Ninety subjects formed nine groups based on the crossover of high, medium, and low E and N. Each subject received, at each of two auditory stimulus intensities, two blocks of tone presentations. The last standard stimulus trial was followed by a novel stimulus and four repetitions of the standard stimulus. Using square root SCR, extraverts showed smaller initial response amplitudes than introverts at the low intensity of stimulation, while the reverse was true at high intensity. E and N were unrelated to SCR habituation rate. However, extraverts showed no dishabituation, while introverts did dishabituate.     

Enhanced orienting effects: Evidence for an interaction principle

Predictive arrow cues, as used in the classic “Posner paradigm”, that were long thought to engage and isolate voluntary attention, may in fact trigger a strong interaction between voluntary and involuntary attention (Ristic & Kingstone, 2006). This interaction produces an orienting effect that exceeds both the effects of involuntary and voluntary attention alone, and the additive combination of involuntary and voluntary orienting. The present study shows that nonpredictive peripheral cues—understood to engage and isolate involuntary attention—if made predictive, result in enhanced orienting effects similar to predictive arrows. The important contribution of these data is that they suggest an “interaction principle”: If attention cues can elicit reliable involuntary orienting, then when they are made spatially predictive, the resulting attention effect will be greater than the sum of involuntary and voluntary orienting alone.     

Behavioural reactions to an emotion evoking task in infants at increased likelihood for autism spectrum disorder

Infants at increased likelihood for autism spectrum disorder (ASD) exhibit more negative affect and avoidance behaviour than typically developing infants, and children with ASD express fear differently than typically developing peers. We examined behavioural reactions to emotion-evoking stimuli in infants at increased familial likelihood for ASD. Participants included 55 increased likelihood (IL) infants (i.e., siblings of children diagnosed with ASD) and 27 typical likelihood (TL) infants (i.e., no family history of ASD). At 18 months, we showed infants two masks that commonly elicit fearful responses in older children and examined potential behavioural differences in approach, avoidance, ‘freezing’, crying, gaze aversion, and smiling. At 24 months, infants were assessed with the Toddler Module of the Autism Diagnostic Observation Schedule, 2nd edition (ADOS-2). Results of video-based coding showed that (1) IL infants exhibited more intense avoidance behaviour than TL infants in response to masks, and (2) intensity of avoidance and duration of freezing were positively correlated with ADOS-2 symptom severity scores. Findings suggest that differences in response to emotion-eliciting stimuli may predict later ASD symptoms. Such behavioural differences may inform early detection and intervention in ASD.     

Retention of orienting reaction habituation in patients with postmeningoencephalitic epilepsy

A polygraphic study on habituation of the somatic, autonomic, and EEG components of the orienting reaction elicited by a repetitive auditory stimulus during successive (weekly) sessions was performed in 29 patients with postmeningoencephalic epilepsy (PME) and in 116 control subjects. The study evidenced significant retention disturbances of orienting reaction habituation (i.e., of learning), the “saving” of stimulation, achieved from one session to another to obtain the habituation criterion, being lesser in PME patients than in control subjects. The severity of habituation retention disturbances depended on seizure frequency, electroclinical form, and history, as well as on features of EEG tracings.     

Perceptual dependence: Evidence for an internal threshold

Ss were asked to make two forced-choice discriminations on each trial: in Experiment I, they had to tell on which side of the display a latter pair appeared and whether or not its members were identical; in Experiment II, to say where the pair appeared and whether it consisted of Xs or Os; in Experiment III, to say where a letter appeared and whether it rhymed with E; and in Experiment IV, to say whether a letter pair was presented and whether it was a word. In Experiment III, and for some Ss in Experiment I, the second discrimination was dependent on the first; that is, when the S was wrong on the first, he performed at chance level on the second. In Experiment IV, when Ss indicated that nothing was presented (with confidence), they performed at chance level on the recognition task; thus, recognition was dependent upon some information about the detection task. It is argued that perceptual dependence implies that a threshold state, a state in which the S has no information, exists for the dependent discrimination. One explanation of dependence assumes mediation of the dependent discrimination by a processing stage which succeeds stages mediating the other task.     

Retention of orienting reaction habituation in patients with epileptogenic cerebral tumors

An electrographic study on habituation of the somatic (EMG), autonomic (finger plethysmogram, galvanic skin reaction, respiration, pulse) and EEG (acoustic evoked potential and EEG-blocking reaction) components of the orienting reaction elicited by a repetitive auditory stimulus during successive (weekly) sessions was performed in 41 patients with epileptogenic cerebral tumors (ECT) and in 128 control subjects. The study evidenced significant retention disturbances of orienting reaction habituation (i.e., of learning), the “saving” of stimulations, achieved from one session to the other to obtain the habituation criterion, being lesser in ECT patients than in control subjects. The severity of habituation retention disturbances depended on the tumor site and size, as well as on the electro-clinical form and frequency of seizures. Thus, the most marked habituation retention disturbances were found in patients with temporal or predominantly temporal epileptogenic tumors, in cases with large hemispheric epileptogenic tumors (over 6 cm), in patients with generalized or generalized plus partial seizures, as well as in those with frequent (daily) seizures.     

Auditory repetition priming is impaired in pure alexic patients

Alexia without agraphia, or "pure" alexia, is an acquired impairment in reading that leaves writing skills intact. Repetition priming for visually presented words is diminished in pure alexia. However, it is not possible to verify whether this priming deficit is modality-specific or modality independent because reading abilities are compromised. Hence, auditory repetition priming was assessed with lexical decision and word stem completion tasks in pure alexic patients with lesions in left inferior temporal-occipital cortex and the splenium. Perceptually based, modality-specific priming models predict intact auditory priming, since auditory association cortex is spared in the patients. Alternatively, modality-independent models, which suggest that priming reflects the temporary modification of an amodal system, might predict impairments. Baseline performance was matched in the patients and controls, although lexical decision priming measures showed an interaction between group and repetition lag. The patients showed intact immediate priming but significantly less priming than controls at longer delays. Furthermore, word stem completion priming was abolished in the patients. One explanation for the deficit is that left inferior temporal-occipital cortex supports amodal aspects of priming, as suggested by recent neuroimaging results. Another possibility is that long-term auditory priming relies on covert orthographic representations which were unavailable in the patients. The results provide support for interactive models of word identification.