Evidence for acute effects of alcohol and marijuana on color discrimination

Significant dose-related impairments in hue discrimination on the Farnsworth-Munsell 100 hue test were produced by acute doses of alcohol and marijuana. The impairment of color discrimination was predominantly located in the blue region of the color circle and resembles that seen in acquired color vision defects associated with retinal pathology. The transient nature of the reduced color discrimination raises practical problems in tasks which require stable color perception.     

Spatial-frequency discrimination, brain lateralisation, and acute intake of alcohol

The effect of alcohol (breath-alcohol level of 0.1%) on perceptual discrimination of low (1.5 cycles deg-1) and high (8 cycles deg-1) spatial frequencies in the left and right visual field was measured in eighteen right-handed males, in a double-blind, balanced placebo design. Discrimination thresholds for briefly (180 ms) presented sinusoidal gratings were determined by two-alternative forced-choice judgments with four interleaving psychophysical staircases providing random trial-to-trial variation of reference spatial frequency and visual field, in addition to a random (+/- 10%) jitter of reference spatial frequency. Alcohol produced overall higher discrimination thresholds but did not alter the visual-field balance: no main effect of visual field was observed, but in both placebo and alcohol conditions spatial frequency interacted with visual field in the direction predicted by the spatial-frequency hypothesis of hemispheric asymmetry in visual-information processing, with left-visual-field/right-hemisphere superiority in discrimination of low spatial frequencies and right-visual-field/left-hemisphere superiority in discrimination of high spatial frequencies.     

Controlling anger in self-reported sober and alcohol intoxicated states: moderating effects of trait anger and alcohol consumption

Controlling anger in self-reported sober and alcohol intoxicated states: Moderating effects of trait anger and alcohol consumption. Scandinavian Journal of Psychology 52, 382-388. Retrospective self-reports about prior sober and alcohol intoxicated states were explored to reveal moderating effects of trait anger and alcohol consumption on anger control. The analyses were based on self-reports of trait anger and alcohol consumption as well as self-reports of the participants' typical levels of anger control in sober and alcohol intoxicated states in a population based sample of Finnish twins and their siblings (N = 4,852). The reported levels of anger control were lower regarding prior alcohol intoxicated states than sober states. A three-way interaction between alcohol consumption, trait anger and anger control was found. Whereas no interaction between alcohol consumption and trait anger was found in the self-reported sober state, there was an interactive effect of trait anger and alcohol consumption on anger control in the intoxicated state, indicating that the difference in anger control between those with high levels of alcohol consumption and those with low levels, was greater at higher levels of trait anger. Women had lower levels of anger control than men, but the relationship between trait anger, alcohol consumption and anger control was similar for both genders. In conclusion, the results showed that those with high levels of trait anger and alcohol consumption showed the lowest levels of anger control in self-reported alcohol intoxicated states, and indicate the importance of separating between anger control when sober and intoxicated since anger control seems to be differently related to at least trait anger and alcohol consumption in these states.     

Visual discrimination between rectangular and nonrectangular parallelopipeds

Twenty-seven university students judged whether each of 128 drawings of parallelopipeds appeared to represent three-dimensional rectangular boxes. Half the pictures could not geometrically have been projections of rectangular boxes. The null hypothesis that Ss’ judgments were unrelated to geometry was rejected at the .001 level of significance, and the correlation between Ss’ judgments and perfect discrimination averaged .86 over three variations of the experiment. The results support a general hypothesis about the perception of simple space forms according to which viewers impose geometric constraints, such as rectangularity and symmetry, but only when the constraints are projectively possible.     

Experiences of HIV-related discrimination and consequences for internalised stigma,depression and alcohol use

Objective: HIV stigma undermines health and well-being of people living with HIV (PLWH). Conceptual work on stigma mechanisms suggests that experiences of stigma or discrimination increase internalised stigma. However, not all PLWH may internalise the HIV discrimination they experience. We aimed to investigate the role of stress associated with events of HIV-related discrimination on internalised HIV stigma, as well as the downstream effects on depressive symptoms and alcohol use severity.

Design: 199 participants were recruited from an HIV clinic in the southeastern United States.

Main study measures: HIV-related discrimination was assessed using items adapted from measures of enacted HIV stigma and discrimination. Participants rated perceived stress associated with each discrimination item. Internalised HIV stigma was assessed using the internalised stigma subscale of the HIV Stigma Mechanisms Scale. Depressive symptoms were assessed with the Centre for Epidemiological Studies-Depression Index. Alcohol use severity was assessed with the Alcohol Use Disorders Identification Test.

Results: In serial mediation models, HIV-related discrimination was indirectly associated with both depressive symptoms and alcohol use severity through its associations with stress and internalised HIV stigma.

Conclusions: Understanding the mechanisms through which PLWH internalise HIV stigma and lead to poor health outcomes can yield clinical foci for intervention.     

今、帛、竹书《周易》疑难卦爻辞及其今、古文辨析(三)

(竹)革,攺日(?)孚,元羕貞,利貞,呣亡。 (帛)[勒,巳日乃]復,元亨,利貞,(?)亡。 (今)革,巳日乃孚,元亨,利貞,悔亡。 本卦今本与竹书作"革",帛本作"勒",古从"革"之字亦可与"革"通假。如《诗·小雅 ·斯干》:"如鸟斯革。"《释文》:"革,《韓诗》作(革羽)。"是其证。另,《玉篇》言部释"諽"曰:"一 日更也,或作惮。"《玉篇》解"諽"为"更也",显然以义通"革"。 今本"巳日"之"巳",帛本缺,竹书作"攺"。作"巳"与"攺",其义一也。案《说文》释 "攺":"攺讀若巳。"是其证。     

今、帛、竹书《周易》疑难卦爻辞及其今、古文辨析(二)

(竹)豚卿,少利貞. (帛)椽亨,小利貞. (今)遯亨,小利貞. 今本[1]遯卦之"遯",帛本[2]作"椽",阜阳简本[3]亦作"椽".     

The effects of induced affective states on letter discrimination in disadvantaged preschool children

The relationship between affective state and academic performance was examined using 30 4- to 6- year old economically disadvantaged black children. Children were assigned to one of three affective induction groups: positive, negative, or neutral affect. Changes from pre- to posttest administrations of a letter discrimination task suggest that negative and positive affect inductions produce different changes in both errors and response latency. These findings suggest that further research on the possibility that negative affect may be responsible in part for the academic difficulties of disadvantaged children and other children under stress is warranted.     

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.     

Similarities between retrospective and actual anxiety states

The purpose of the study was to examine the fit and calibration of the items in Spielberger, Gorsuch, and Lushene's (1970) State-Trait Anxiety Inventory during measurement of actual and retrospective anxiety. Subjects in the actual anxiety situation (n = 113) and in the retrospective anxiety situation (n = 55) were administered the inventory, and 20 scale items were analyzed individually by the probabilistic Rasch Model (Wright & Masters, 1982). Comparisons between the items' values in both situations revealed that 17 of the 20 items were rated similarly. In the retrospective anxiety state, 9 items (misfits) failed to discriminate between high- and low-anxious subjects, but only 6 failed to do so in the actual anxiety state. Despite the similarities, we recommend that the scales be modified to yield a more reliable measure of anxiety and to discriminate more accurately among subjects with varying levels of anxiety.     

The relation between gap discrimination and auditory stream segregation

Gap discrimination and stream segregation were examined using sequences of 2, 4, 8, or 16 tones. The frequency differences between tones ranged from 1/24 to 2 1/2 octaves. Judgments of stream segregation show large intersubject variability, whereas gap thresholds are comparatively stable. Gap thresholds and streaming judgments are both affected by the frequency separation between tones. However, only streaming judgments are affected by presentation rate. Gap-threshold functions show no discontinuities or plateaus with increasing frequency differences and faster presentation rates. These results suggest that stream segregation is not a primary factor limiting gap-discrimination performance in tonal sequences.     

Generalization of skills between operant control and discrimination of EEG alpha

While biofeedback is often said to increase self-control of physiological states by increasing awareness of their subjective correlates, relatively few studies have analyzed the relationship between control (standard biofeedback) and awareness (a discrimination paradigm). We hypothesized that the two skills would generalize and facilitate each other for 8–12 Hz EEG amplitude (alpha). Participants were given 7 sessions of training to either control or discriminate Pz alpha followed by 3 sessions of the other paradigm. Another group was given 7 sessions with time divided equally between the two types of training. The control-training first group showed significant generalization of skills to the discrimination task. However, the reverse was not true, and the combined task group did no better in either task than the other two groups. These results provide ambivalent support for the role of awareness in biofeedback, and suggest possible improvements in the discrimination paradigm.     

Effects of alcohol and marijuana on dynamic visual acuity: I. Threshold measurements

Alcohol and marijuana produce significant dose-related reductions in dynamic visual acuity. Ten subjects participated in a double-blind experiment involving three dose levels of each drug (including placebo). The reduction of DVA produced by alcohol (1.0 ml 95% ethanol/kg body weight) was greater than for marijuana (15 mg Δ-9-tetrahydrocannabinol), and we suggest that this difference was produced by differential oculomotor effects of the two drugs. We have speculated that reduction in DVA under alcohol may be a contributing factor in alcohol-related traffic accidents.     

Purchase task sensitivity to drug and nondrug reinforcers in opioid-agonist treatment patients

The behavioral economics of substance abuse has been increasingly recognized as a method of determining the value of abused substances for individuals who use those substances. It has been hypothesized that such analyses could serve as a clinical tool and that demand functions can be targeted predictors for the level of intervention necessary. This study evaluated the sensitivity of a demand task in 2 patient groups in a medication assisted treatment program (methadone maintenance), those who had used opioids in the last 2 months and those who had not used opioids in at least 18 months. Demand for 7 drugs and a control was assessed using hypothetical purchase tasks. Participants maintaining long-term abstinence had significantly higher α (sensitivity to price) and lower Q₀ (intensity of demand) for heroin than participants who had recently used opioids. Further research is necessary to illustrate if treatment is responsible for this reduction in demand. If so, demand analyses may provide clinical utility as an aid for treatment planning or as a target for treatment.     

Frequency discrimination between and within line gratings by dynamic touch

Line gratings were used to investigate the tactual discrimination thresholds for line frequency. In Experiment 1, participants were asked to discriminate between two gratings, each with a different line frequency. We used four standard frequencies in the eightfold range from 0.5 to 4 lines/cm. Thresholds were found to be constant at about 10.6%. In this experiment, we also measured hand speed and contact force. Hand speed was roughly in the range between 0.12 and 0.44 m/sec; contact force ranged from 0.62 to 2.76 N. In Experiment 2, we determined discrimination thresholds for line frequency transitions within a single grating. We used two frequencies and three transition lengths. The transition length had no effect on the threshold. In a third experiment, line frequency was modulated periodically. Varying the standard frequency and the size of the modulation period was found to have no effect on the discrimination thresholds. We conclude three things. First, Weber fractions for line frequency discrimination decrease as a function of line frequency within the experimental range. Second, discrimination thresholds are not altered by the length of the transition between two adjacent gratings with different line frequencies. And finally, the size of a modulation period in periodically modulated gratings is of no influence on the modulation detection threshold.