Perceiver bias in the processing of human faces: neuropsychological mechanisms.

Previous research has suggested that in face-to-face contexts perceivers are biased to judge the side of the poser's face to their left as more similar to the full face than the side to their right. Traditional explanations of the perceiver bias have presumed that it is a visual field effect, with the side of the poser's face falling within the perceiver's left visual field dominating impressions of the full face. In this study, five experiments are reported. In the first experiment, the validity of the perceiver bias phenomenon was supported. The remaining experiments examined three alternative accounts of the neuropsychological processes that underlie the perceiver bias. No support was obtained for the visual field explanation, nor for an account of the bias as due to asymmetry in gaze patterns. Support was obtained for an account emphasizing a hemispatial bias in central processing. Despite equivalent intake of information from both sides of space, the brain may differentially weight information as a function of hemispatial origin. Practical and theoretical implications are discussed.

Perceiver bias in the processing of deliberately asymmetric emotional expressions.

Posers were requested to produce happy and sad emotional expressions, deliberately accentuated on the left and right sides of the face. Raters judged the emotional intensity of expressions when presented in original and mirror-reverse orientation. Left-side-accentuated sad expressions were rated as more intense than right-side-accentuated sad expressions. Raters were biased to judge expressions as more intense when the accentuated side was to their left. The findings indicated that the perceiver bias in weighting information from the side of the face in left hemispace extends to judgments of emotional intensity.

Haloperidol in the treatment of infantile autism: effects on learning and behavioral symptoms.

In this double-blind, placebo-controlled study the administration of haloperidol resulted in significant decreases in behavioral symptoms and in general clinical improvement in 40 autistic children ages 2.33 to 6.92 years. Haloperidol also produced greater facilitation and retention of discrimination learning in the laboratory. No adverse effects were observed at therapeutic doses, which ranged from 0.5 to 3.0 mg/day or 0.019 to 0.217 mg/kg per day.

Saliva lithium levels in children: their use in monitoring serum lithium levels and lithium side effects.

The reliability of saliva lithium levels in monitoring serum lithium levels in children taking lithium has rarely been studied, despite the potential usefulness of such a study and despite a number of adult studies focusing on the technique. In a study of 61 aggressive school-age children diagnosed as undersocialized, aggressive conduct disorder, a subsample of 21 children received lithium. Saliva lithium levels aided in monitoring side effects, and in 15 of the 21 children simultaneous saliva and serum lithium levels were done. These were highly correlated (r = 0.83) and the saliva to serum ratio was 2.53 across subjects. The results indicate that future work with larger numbers of children should study the ratio of saliva to serum lithium levels. Adult studies have shown that there is too great a variability in saliva to serum lithium level ratios to support the use of a fixed saliva to serum lithium ratio. This may not be the case in children. Seventeen children from the lithium subsample experienced 41 lithium-related side effects. Most children suffered side effects on relatively high doses of lithium, and those few who experienced side effects on low dosage had saliva lithium levels that were proportionately high. However, it remains unclear whether saliva lithium can be used to monitor side effects.

Cognitive effects of lithium carbonate and haloperidol in treatment-resistant aggressive children.

The effects of lithium carbonate and haloperidol on cognition were examined in a placebo-controlled, double-blind study of 61 treatment-resistant, hospitalized school-aged children. They all had a DSM-III diagnosis of conduct disorder-- undersocialized , aggressive, with a profile of highly explosive and aggressive behavior. Children were assessed at the end of a two-week placebo-baseline period and again after four weeks of treatment. Drug effects on cognition were mild. Haloperidol (mean dose, 2.95 mg/day) caused significant decreases in Porteus Maze test quotient scores and a slowing of reaction time (RT) on a simple RT task. Lithium carbonate (mean dose, 1,166 mg/day) adversely affected qualitative scores on the Porteus Maze test. No significant treatment effects were found for the Matching Familiar Figures Test, short-term recognition memory and concept attainment tasks, or the Stroop Test.

Effects of predictors of hemispheric specialization on individual differences in hemispheric activation.

In two studies predictors of variation in hemispheric specialization--handedness, sex, familial history of sinistrality, writing posture and sighting dominance--were found not to be independent of individual differences in characteristic activation asymmetry. Predominant direction of conjugate lateral eye movements was used to assess activation asymmetry. The lack of independence between these two dimensions of individual difference, predictors of variation in hemispheric specialization and in activation asymmetry, suggests caution in interpreting the results of studies in which one dimension is examined and the other is uncontrolled.

Electroencephalogram and treatment of hospitalized aggressive children with haloperidol or lithium.

Electroencephalograms (EEGs) of 48 children ages 5.2 to 12.9 years were examined on baseline placebo and on optimal dosages of haloperidol, lithium, or placebo. These children represent a subgroup of 61 hospitalized aggressive and explosive patients diagnosed as Conduct Disorder, undersocialized, aggressive who completed a double-blind study comparing the efficacy of haloperidol, lithium, and placebo. EEGs were correlated across treatment groups with behavioral ratings, ratings of untoward effects, and optimal dosages of medication. During the baseline placebo period 58.3% of the children had abnormal EEGs. Children receiving haloperidol or lithium had a significant probability that their EEGs on optimal dose would worsen, and would be more likely to show paroxysmal or focal abnormalities than those children treated with placebo. It was possible to identify children treated with haloperidol, lithium, or placebo on the basis of EEG alone. Thus, despite limitations, visual evaluation of EEGs is of value. No statements can be made with confidence regarding associations between baseline EEGs and behavioral changes, side effects, or optimal dosages of haloperidol or lithium.