Effect of intensity of visual stimulation on auditory sensitivity in relation to personality

Auditory thresholds were determined by a modified method of limits under 10 intensities of light (patterned or homogeneous). An analysis of variance of the data showed significant results for intensity conditions, personality type and the interaction of these parameters. Auditory sensitivity increased under weak, and decreased under strong, intensities of light in introverts. It increased under all intensities in extraverts, with greater increase at greater intensities, and increased under weak and medium intensities in ambiverts. The EPI E, but not N, scale scores and sensitivity increases correlated positively, at medium and strong intensities of light.     

Reactivity and response to pain

Male and female volunteers (N = 144) answered the Reactivity Scale (RS) and underwent testing for their perceived intensity and tolerance for finger-pressure pain. Half the Ss were randomly assigned to a low-intensity treatment (1150 g) and half to a high-intensity treatment (2300 g). Pain was rated at 30 and 60 sec., and Ss were asked to endure it as long as possible up to 5 min. The major findings were as follows: (1) women outscored men on reactivity; (2) the three pain measures intercorrelated highly; (3) high-intensity stimulation produced higher pain ratings and shorter tolerance than did low-intensity stimulation; (4) men gave lower intensity ratings than women and tolerated the pain longer; (5) reactivity related positively to judged pain at 30 and 60 sec, and negatively to pain tolerance; (6) there were no significant interaction effects among stimulus intensity, sex and reactivity for any pain measure; (7) the variance in the pain measures accounted for by stimulus intensity, sex and reactivity ranged from 26 to 32%. The implications were briefly discussed for the validity of the RS and factors explaining responses to experimentally-induced pain.     

Extraversion, attention, and habituation of the auditory evoked response

Short-term changes in the auditory evoked response to low-frequency tones (0.5 kHz, 80 dB) were examined for independent groups of introverts and extraverts under attend and ignore conditions. Introverts displayed greater N1-P2 amplitude than extraverts to the first stimulus in a four-stimulus train. The N1-P2 amplitude differences between introverts and extraverts could not be attributed to differences between the groups in either habituation or attention processes. Overall, the effect is indicative of the introverts' enhanced sensitivity to physical stimulation.     

Reliability of auditory responses under increasing intensity of visual stimulation in relation to personality

Auditory thresholds were determined in each subject on two different occasions, by a modified method of limits under 10 intensities of light. Coefficients of reliability and analyses of variance of the data showed significant reliability of responses to tones in introverts (I) and extraverts (E), under increasing intensities of light. The auditory responses were most reliable in I and least in ambiverts (A). The same visual stimuli produced the same effects on auditory sensitivity, in the same subjects, on different days. These effects included facilitation and inhibition of sensitivity in I, facilitation in E and A, and interaction of intensity conditions and personality type.     

Brainstem auditory electrical response characteristics of stutterers and nonstutterers: A preliminary report

In the present study, eight adult male stutterers and nonstutterers showed no significant latency or amplitude differences in BSERs recorded in response to monaural and binaural clicks. However, significantly greater variance was found in the stutterers' group under the monaural stimulation condition at click rates of 12/sec and 5/sec. Left and right monaural waveforms were subtracted individually from the binaural waveform. The resultant binaural interaction difference traces were examined to determine auditory tract preference for binaural stimulation. While some subjects from both groups showed no auditory tract preference, it was found that the significant variance between groups for wave V latency was attributable to the subset of stutterers without auditory tract preference. This finding is interpreted as evidence of neurological differences in stutterers' auditory processing at the brainstem level.     

Force control under auditory feedback: effector differences and audiomotor memory

Audiomotor integration is a basic form of sensorimotor control for regulating vocal pitch and vocal loudness, but its contribution to general motor control has only been studied minimally. In this paper, auditory feedback for prolonged force control was investigated by comparing manual and oral force generation and testing short-term audiomotor memory for these effectors. Ten healthy volunteers between the ages of 20 and 30 years old were recruited. The participants produced continuous force for 30 sec. with the lip or finger to match auditory targets. In the feedback condition, when auditory feedback was provided for 30 sec., lip force was more variable than finger force. In the memory condition, the force output of both effectors remained stable for approximately 4 sec. after feedback removal, followed by significant decay. A longer short-term memory capacity could facilitate encoding of motor memories for tasks having acoustic goals. The results demonstrate that "audiomotor" integration was effective for sustaining forces, and that audiomotor force memory is comparable to reports of visuomotor force memory.     

Primacy effect in orienting responses to auditory stimuli of tones and music.

This 25 factorial experiment investigated the primacy effect in the orienting response. The type of stimuli (tone or "music"), stimulus intensities (loud or soft), length of adaptation period (same, 5 or 30 sec; or different, 5 min.), interstimulus intervals (5 or 30 sec.), and sex were studied. College students, 32 males and 32 females were randomly assigned to each group. In the same condition, the tone (or music) was soft (or loud) for 5 sec. (or 30 sec.) in adaptation and was then changed alternately without interruption to loud, soft, etc. (or soft, loud, etc.) for 5 sec. (or 30 sec.). The different condition was identical except for the length of adaptation period in which the stimuli sounded continously for 5 min. Analyses of the GSR manifestation of the orienting responses indicated: (a) an over-all primacy effect with the auditory stimuli and (b) the primacy effect occurred in the 5-sec.-same but not in the 30-sec.-same condition as predicted.     

Determinants of serial discrimination learning by squirrel monkeys

Squirrel monkeys were presented multiple serial discriminations 1, 2, 4, and 8 problems long. They were then presented problems designed to separate the effects of within-list associative interference from the effects of within-problem intertrial interval as list length was increased. The Ss committed consistently fewer errors after Trial 1 reward than after Trial 1 nonreward and showed strong stimulus perseveration. An increase in within-problem intertrial interval from 30 sec to 4 min had no effect whereas the associative interference resulting from increased problem length caused a small but significant performance decrement. Old and new problems had about equal effects on serial discrimination. The findings indicated that squirrel monkeys are relatively insensitive to within-problem associative interference.     

Simple visual reaction time,personality and strength of the nervous system: A signal-detection theory approach

Eysenck (1967) has reviewed evidence which suggests that introverts have a higher level of arousal than extraverts. Moreover, Gray (1967) has proposed that introverts have weak nervous systems, in the Russian terminology. Studies of simple reaction time such as that of Mangan and Farmer (1967) have posed problems for these views, but it is suggested that this may have been due to criterion differences between introverts and extraverts. In the present study a simple visual reaction-time task and a signal-detection task were conducted side by side. No significant differences between introverts and extraverts were found in measures of strength derived from the former, or measures of criterion derived from the latter. However, high N Ss were found to have a significantly lower value for Nebylitsyn's index of the slope of the reaction time/stimulus intensity function, thus supporting the view that high N Ss have relatively weak nervous systems.     

Extraversion and sleep: A psychophysiological study of the arousal hypothesis

In order to examine Eysenck's (1967) hypothesis concerning the relationship between extraversion and arousal, autonomic measures were taken from introverts and extraverts immediately before sleep and during 6 hr of sleep. Introverts and extraverts did not differ in heart rate (HR) or skin-potential response rate (SPR) during the pre-sleep period. A variety of sleep-related measures of arousal provided no strong support for the hypothesis that introverts are more aroused than extraverts. The only consistent autonomic difference between introverts and extraverts during sleep was a tendency for introverts to have higher SPRs in the second 3 hr of the night. The results are discussed in terms of the level of environmental stimulation present in the experimental conditions, and suggestions are made for future sleep studies of the relationship between extraversion and arousal.     

Rapid acquisition of a sidman avoidance response

Rats were trained on a Sidman avoidance task with a 22-sec R-S and a 6-sec S-S interval for six daily 30-min training sessions. Disabling the response lever during and 0.5 sec after shock termination represented one factor in the 2 by 2 factorial design and the presentation of a feedback light cue accompanying an effective response was the other. Rats in the lever-disable condition with feedback light made significantly more avoidance responses than the other treatment groups. In a second experiment, daily 60-min sessions were observed. Using a lever-disable plus feedback light treatment, rats made more avoidance responses and received fewer shocks during the second 30-min as opposed to the first 30 min period.     

A portable solid-state stimulus programmer

This paper describes a miniature solid-state timing device particularly useful for presenting repetitive signal sequences in classical conditioning experiments. The device uses transistors, silicon-controlled rectifiers, and four-layer diodes, and is powered by 20-hour rechargeable nickel-cadmium batteries. Visual monitoring is provided for the unelapsed ITI and battery charge. Ranges are; ITI, 15 sec. to 5 min., ISI, 0–50 secs., CS duration, 0.5 to 30 sec., US duration, 0.5 to 30 sec. The CS and US durations are adjustable and the onset of the latter may be at any time after the CS onset. Cycling is continuous and automatic; the outputs are in the form of relay closures.     

The effect of temporal distribution in relation to constant frequency of stimuli on habituation of the orienting reaction

The lack of empirical evidence for faster habituation with the regular presentation of stimuli suggests that it is not the constancy of presentation of stimuli, but rather the rate of stimulation--defined as the reciprocal of the harmonic mean of the interstimulus intervals--that determines the speed of habituation. Using alternation of 10-70 and 30-50 sec and a constant sequence of 40 sec, three different rates of stimulation were realized. The hypothesis of faster habituation of skin conductance reactions with higher rates of stimulation was not confirmed. However, a consistent pattern of skin conductance reactions, with an increase in reaction after long intervals and a decrease after short intervals, was found, especially in the group with alternating intervals of 10 and 70 sec. The analysis of an additional group with a random sequence of intervals showed that the response pattern did not result simply from the expired time since last stimulus, i.e., a simple mechanical effect. The possibility of anticipating the stimuli and differing information content of the stimuli are discussed as possible determining factors.     

Extraversion and arousal: Effects of attentional conditions on electrodermal activity

Recent work has demonstrated that introverts show arousal decrements with increasing caffeine dosages under nonsignal conditions, but reverse this pattern under signal conditions. Other work, particularly in the areas of vigilance and memory, has pointed to greater attentiveness in introverts than extraverts. It was therefore hypothesized that the two groups would respond differentially under signal and nonsignal conditions as a function of attentional variations. The present study tested introverts and extraverts in a habituation paradigm involving systematic manipulation of signal and attentional conditions. Half of each personality group was randomly assigned to a distraction condition, the other half to an attending condition. Each S received two blocks of 19 habituation trials, a test stimulus and a dishabituation stimulus. In one of the two trial blocks, each stimulus was preceded by an auditory preparatory signal. Results showed that introverts gave larger SCRs, had higher SCLs, and showed greater dishabituation than extraverts. The signal reduced responding significantly more in introverts than in extraverts, and introverts were less affected by the distraction condition than were extraverts. Finally, extraverts showed more rapid habituation under nonsignal conditions and the signal produced a greater increase in habituation rate for introverts than for extraverts. Results were basically supportive of hypotheses derived from the Eysenck theory.     

Explaining the extraversion/positive affect relation: sociability cannot account for extraverts' greater happiness

The association between Extraversion and positive affect is one of the most robust findings in the study of personality and emotion. Temperament models posit that the association is direct; instrumental models posit that the association is mediated by additional processes. Two experience sampling studies were conducted to test instrumental mechanisms that might underlie the effect. According to a mediation model, extraverts' greater social activity can account for their increased positive affect when compared to introverts. According to a person-by-situation interaction model, extraverts react more positively to social situations than do introverts, and this interaction can account for the association. Only weak support for the instrumental models was found; consistent with temperament models, a moderate direct association remained even after controlling for these effects.     

What Eye Movements Reveal About Later Comprehension of Long Connected Texts

We know that reading involves coordination between textual characteristics and visual attention, but research linking eye movements during reading and comprehension assessed after reading is surprisingly limited, especially for reading long connected texts. We tested two competing possibilities: (a) the weak association hypothesis: Links between eye movements and comprehension are weak and short-lived, versus (b) the strong association hypothesis: The two are robustly linked, even after a delay. Using a predictive modeling approach, we trained regression models to predict comprehension scores from global eye movement features, using participant-level cross-validation to ensure that the models generalize across participants. We used data from three studies in which readers (Ns = 104, 130, 147) answered multiple-choice comprehension questions ~30 min after reading a 6,500-word text, or after reading up to eight 1,000-word texts. The models generated accurate predictions of participants' text comprehension scores (correlations between observed and predicted comprehension: 0.384, 0.362, 0.372, ps < .001), in line with the strong association hypothesis. We found that making more, but shorter fixations, consistently predicted comprehension across all studies. Furthermore, models trained on one study's data could successfully predict comprehension on the others, suggesting generalizability across studies. Collectively, these findings suggest that there is a robust link between eye movements and subsequent comprehension of a long connected text, thereby connecting theories of low-level eye movements with those of higher order text processing during reading.     

Alcohol and vigilance performance: effect of small doses of alcohol on simple visual reaction time

The effects of small doses of alcohol were tested in a vigilance setting. Subjects were repeatedly tested during three 30-min. sessions. The stimulus event was a visual light located in front of subjects. The average intersignal interval was 3.75 sec., and the dependent measure was simple reaction time. Analysis indicates that alcohol produced a skewness in the RT-distribution with time on task; the longer reactions increased more than the shorter ones. Especially the extremely long reactions (blockings) increased markedly with time on task under alcohol. Results were discussed in relation to other studies reporting divergent results in similar test situations.     

Increased analgesia to thermal stimuli in rats after brief exposures to complex pulsed 1 microTesla magnetic fields

Nociceptive thresholds to a 55 degrees C hot surface were measured for female Wistar rats before treatments and 30 min. and 60 min. after the treatments. After injection with either naloxone or saline following baseline measurements, the rats were exposed for 30 min. to either sham fields or to weak (about 1 microTesla) burst-firing magnetic fields composed of 230 points (4 msec. per point) presented once every 3 sec. The rats that had received the burst-firing magnetic fields exhibited elevated nociceptive thresholds that explained about 50% of the variance. A second pattern, designed after the behaviour of individual thalamic neurons during nociceptive input and called the "activity rhythm magnetic field" produced only a transient analgesic effect. These results replicated previous studies and suggest that weak, extremely low frequency, pulsed magnetic fields with biorelevant temporal structures may have utility as adjuncts for treatment of pain.     

Counting strategies and assimilation effects in short-term retention of temporal information

The purpose of the present research was to examine proactive interference in general and assimilation effects (i.e., shifts in constant error caused by prior responses) in particular, when subjects used covert counting to aid their retention of the temporal information. Visually presented durations of 1, 4, and 8 sec. were estimated by 18 subjects under the method of reproduction. Three retention intervals (i.e., immediate, 15, and 30 sec.) and three intertrial intervals (i.e., immediate, 15, and 30 sec.) were employed. Analysis of constant error provided no indication that proactive interference was operating in the retention of temporal information as there was no increase in error across trials, no increase in error for longer retention intervals, and no interaction between trials and retention intervals. Also, there was no change in variable error as the retention intervals lengthened for any temporal duration except for the 4-sec. criterion. Finally, the rate of counting (counting units/sec.) was different across the durations to be remembered. The major conclusion of the present research was that counting greatly facilitates retention of temporal information as compared to retention without such a time-aiding strategy.     

Preference and discrimination between response-dependent and response-independent schedules of reinforcement

Four Asian quail (Coturnix coturnix japonica) were exposed to concurrent-chain schedules, the terminal links of which were either variable-interval 30 sec and variable-time 30 sec, or fixed-interval 30 sec and fixed-time 30 sec. Except for one bird that exhibited a preference for the variable-interval schedule over the variable-time schedule, no consistent preferences were demonstrated for response-dependent or response-independent schedules. However, response rates were three times greater on response-dependent than on response-independent schedules. The discrimination between terminal-link schedules was rapidly recovered after the schedule positions were reversed. Casual observations revealed that the birds engaged in stereotypic circling and pecking while the response-independent schedules were operative.