Toward solving the inferential problem in laterality research: effects of increased reliability on the validity of the dichotic listening right-ear advantage.

As noted by Satz, the prevalence of lateralized language in the general population is underestimated substantially by the proportion of people who show the typical asymmetry on a laterality task. In a series of two dichotic listening experiments with a total of 171 right-handers and 170 left-handers, we tested the hypothesis that increased reliability of measurement will lead to increased classification accuracy. Experiment 1 showed that neither the frequency nor magnitude of the right-ear advantage (REA) for fused rhyming words increased as the number of trials increased from 120 to 480. Ear-difference scores were highly reliable (r = .85), even when based on 120 trials. Experiment 2, which involved lists of dichotic word pairs, yielded similar results. Even though retest reliability of the ear-difference score for 132 word pairs was only .45, neither the incidence nor strength of the REA increased significantly when the number of pairs was increased to 528. The results indicate that the poor classification accuracy of dichotic listening tasks cannot be attributed to unreliability.

Mothers' estimates of hearing family members' competence in sign language and the deaf child's loneliness.

This study examined the associations between mothers' estimates of both hearing family members' competence in sign language and their deaf child's loneliness. 32 mothers of children who functioned as deaf were asked to assess their hearing family members' competence in sign language and to complete the UCLA Loneliness Scale for an estimate of their deaf child's loneliness. Significant positive correlations were found among hearing family members' estimated competence in sign language; however, no significant correlations were found between hearing family members' estimated competence in sign language and their deaf child's estimated loneliness. These findings suggest that hearing members may contribute to each other's competence in sign language and may communicate with their deaf child through alternative methods rather than formal sign language.

Enumeration of total coliforms, fecal coliforms, and Escherichia coli in foods by hydrophobic grid membrane filter: collaborative study.

A collaborative study was conducted in 18 laboratories to assess the performance of the hydrophobic grid membrane filter method against that of the AOAC official first action method 46.013-46.016 for enumerating total and fecal coliforms and Escherichia coli. The study was carried out on frozen breaded fish, raw comminuted poultry, unroasted walnut pieces, ground black pepper, and cheddar cheese. The hydrophobic grid membrane filter method recovered significantly larger numbers of target bacteria in 7 of the food/analysis combinations: fecal coliforms in fish; E. coli in poultry; fecal coliforms and E. coli in walnuts; and total coliforms, fecal coliforms and E. coli in black pepper. Random error (Sr2) associated with the hydrophobic grid membrane filter method was significantly lower than that of the reference method in over 30% of the paired sample series. The hydrophobic grid membrane filter method for total coliform, fecal coliform, and E. coli enumeration in foods has been adopted official first action.