Richard H. Haude

Breastfeeding and cognitive development in the first 2 years of life

The relationship between breastfeeding and cognitive development in the first 2 years of life was examined in a cohort of children being followed in a study of risk factors in development. A significant difference between bottlefed children, children breastfed less than or equal to 4 months and those breastfed greater than 4 months was found on the Mental Development Index of the Bayley Scales at ages 1 and 2 years, favoring the breastfed children. At age 6 months, the direction of the relationship was the same but did not reach significance. Supplementary regression analyses examining the strength of the relationship between duration of breastfeeding and cognitive development similarly showed a small but significant relationship between duration of breastfeeding and scores on the Bayley at 1 and 2 years. Alternative explanations for the results are discussed.

Visual observing by rhesus monkeys: Some relationships with social dominance rank

Five rhesus monkeys were tested in a visual exploration situation to determine whether the mean frequency or mean duration of visual observing were systematically related to the dominance status of the observing animal. A dominance hierarchy among the five subjects was first determined by means of a competitive food-getting task. Following dominance testing, visual exploration testing was begun. All subjects were permitted to observe all other subjects in a round-robin pairing system involving two animals at a time. In each pairing, one animal served as the experimental subject (observer); the other as the stimulus (visual incentive). A highly significant linear effect of dominance was found in regard to duration of observing. Subjects high in the dominance hierarchy observed for significantly shorter durations than low-dominant subjects. Significant effects of dominance on the frequency of observing were also found, with animals intermediate in the hierarchy viewing more frequently than animals at either extreme. The data were interpreted in terms of the arousal and reduction of fear as a function of dominance and also through the notion of dominance distance.

The Relation between Sign Language Skill and Spatial Visualization Ability: Mental Rotation of Three-Dimensional Objects

The present study was designed to ascertain whether a relationship exists between the experience of an individual in American Sign Language (ASL) and performance on the Mental Rotations Test. 51 women were divided into three groups on the basis of self-reported ASL skill (years of experience). All subjects then completed the Mental Rotations Test, a paper-and-pencil test of spatial ability. The State-Trait Anxiety Inventory was also administered to examine possible apprehension about evaluation. Significant differences in scores on mental rotations were found, with 18 experienced signers scoring significantly higher than either mean of the two less experienced groups (ns = 16 and 17). It appears that people experienced in ASL perform better on the Mental Rotations Test. No evidence for a difference in anxiety related to the amount of experience a person had in ASL was found.

DOMINANCE TESTING IN RHESUS MONKEYS: COMPARISON OF COMPETITIVE FOOD-GETTING, COMPETITIVE AVOIDANCE, AND COMPETITIVE DRINKING PROCEDURES

Three general laboratory methods of dominance testing in rhesus monkeys (competitive food-getting, competitive avoidance, and competitive drinking) were compared to determine their respective reliabilities and their equivalence in terms of measuring the same attribute. The basic competitive food-getting procedure was modified into three additional procedures: (1) experimenter out of view; (2) experimenter out of view and 48-hr. deprivation; and (3) experimenter out of view, 48-hr. deprivation, and automated delivery of food items. All procedures, with the exception of the competitive shock avoidance, were reliable as reflected by significant intratest rank correlations and intratest mean variance measures. All procedures, with the exception of the competitive shock avoidance, were essentially equivalent in measuring the same attribute as reflected by interrank correlations. The competitive water drinking method, a group testing procedure, offered a practical advantage in reduced testing time, and the dominance hierarchies obtained were highly correlated with those obtained by the other methods in which all possible pairs of animals were tested in a round-robin fashion.

Sensitivity to sucrose in smokers and nonsmokers: A comparison of TSD and percent correct measures

Ten smokers and 10 nonsmokers were compared for taste sensitivity to sucrose on two discrimination tasks, one at near-threshold (NT) concentration level and one at suprathreshold (ST) concentration level. The data were analyzed using the ds and area under ROC curve measures based on the theory of signal detection (TSD). and by using the percentage correct responses. Analysis of both TSD measures showed smokers to be significantly more sensitive than nonsmokers on the NT .task and more sensitive on the ST task, but not significantly so. Comparison of mean percent correct responses showed no significant differences. A reflexive enhancement phenomenon was suggested as a possible interpretation. A decreased sensitivity to the bitter taste in smokers apparently results in an increased sensitivity to the sweet taste.

Visual observing behavior in the squirrel monkey

Ten squirrel monkeys were tested to determine whether visual observing behavior could be measured using a technique developed for rhesus monkeys. The Ss engaged in visual observation of a set of projected color slides of other squirrel monkeys to an extent comparable with visual observation by rhesus monkeys. Significant differences in both mean cumulative viewing time and mean frequency of visual observing were found for the different visual incentive conditions used. Previous reports of a low level of visual attention by squirrel monkeys were not confirmed.

Evaluation of Feminine Professional Competence as a Function of Level of Accomplishment

This study extended prior work. 57 female and 39 male college students were given booklets containing articles from fields of traditional male, female, and neutral sexual association for evaluation. Authors of the articles were portrayed as either males or females, and as either students (attempting to accomplish) or holders of advanced degrees (accomplished). The main effect of traditional sexual association of the field and interaction between level of accomplishment and association of the field were significant. Female authors were evaluated more positively in female fields than in male fields, while male authors in female fields were evaluated more positively than males in male fields, by subjects of both sexes. In addition, contrary to the findings of Pheterson, et al. (1971), the work of females attempting to accomplish was evaluated more favorably than that of females who had accomplished.

Sense of humor and longevity: older adults' self-ratings compared with ratings for deceased siblings.

33 older adults (mean age = 72.3 yr.) rated themselves and a deceased sibling on the Multidimensional Sense of Humor Scale. A significant mean difference between the two groups on the subscale of Humor appreciation suggested the possibility of a positive relationship between humor appreciation and longevity.

Color-Naming and Color-Matching by Preschool Children as a Function of Visual Field and Sex

The accuracy for both a color-naming and a color-matching task as a function of visual field and sex was investigated in preschool children. Subjects were 17 boys and 17 girls ranging in age from 4.4 to 5.6 yr. Each subject was tested on both tasks, for which the target stimuli were presented tachistoscopically. Accuracy measures for each task were obtained separately for both left and right visual fields. A two-factor (sex x visual field) analysis of variance with repeated measures on the visual-field factor showed a significant difference between the sexes on the color-naming task only. No significant difference between visual fields was found for either task. However, significant interactions between sex and visual field for both the color-naming and color-matching tasks were obtained, t tests for simple main effects showed a significant right visual-field advantage for girls in naming colors. Conversely, a significant left visual-field advantage for color-matching was found for boys. Also, on the color-matching task, significant sex differences were found for both visual fields when compared separately. Boys were more accurate for left and girls more accurate for right visual field. Boys performed in a more strongly lateralized fashion on the color-matching task than did the girls, supporting the notion of greater lateralization among males.

DIFFERENTIAL VISUAL FIELD-INTERHEMISPHERIC TRANSFER: CAN IT EXPLAIN SEX AND HANDEDNESS DIFFERENCES IN LATERALIZATION?

104 men and women were tested for visual field-hemispheric transfer of spatial information on a dot-localization task. Right-handed subjects showed significant improvement when stimuli were presented to the left visual field of the right hemisphere (LVF-RH) after practice on the same task presented to the right visual field of the left hemisphere (RVF-LH) first. No improvement was found when the task was presented in the reverse order (LVF-RH first followed by RVF-LH). It was concluded that, for right-handers, transfer of spatial information to the right hemisphere is facilitated while transfer to the left hemisphere is inhibited. Left-handed subjects demonstrated no significant improvement in either condition, suggesting inhibition or lack of transfer of spatial information in either direction. No sex differences were found in either right-handed or left-handed subjects. The findings suggest that there may be different mechanisms underlying the similarities in functional lateralization of women and left-handers.