Seymour Axelrod

Numbers are better than words: Verbal specifications of frequency have no place in medicine

We were concerned about the precision (i.e., consensus as to meaning) of adjectives and adverbs used to express frequency in the medical literature. We asked 103 physicians and 106 nonphysicians to assign to each of 22 such modifiers a percentage representing their understanding of the term. As indexed by the standard deviations, the degree of imprecision for 17 terms was so great for both physicians and for laymen as to make their use unacceptable. Consensus was significantly less among laymen than among physicians for 10 of the terms. Greater consensus was shown by native English-speaking physicians than by those with other native languages. Our data suggest further that American graduates of American medical schools show more consensus than American graduates of foreign medical schools. Board-certified physicians did not show greater consensus than physicians who were not board-certified. Verbal expressions of frequency should be eliminated from medical communications; failing that, the author should specify numerically the frequency he intends when he uses any such expression.

On the laterality of psychogenic somatic symptoms.

Tabulation of cases reported in the literature of unilateral psychogenic somatic symptoms revealed that more symptoms were on the left side of the body than on the right; this result, although falling short of statistical significance, is consistent with recent reviews of hospital records by Stern and by Galin et al. A review of organic diseases and traumata for which lateral preferences have been reported, and a retrospective study of hospital emergency room records, provided no evidence for the hypothesis that the left-sided predominance of psychogenic symptoms is underlain by a generalized greater vulnerability of the left side to organic pathologies. The status of three other explanations for the asymmetrical incidence of psychogenic symptoms is discussed

Intra-familial learning is only a minor factor in manifest handedness.

Abstract From the information provided by 2257 university students and faculty members, both the incidence of handedness types (right, left, non-right) and the degree of handedness (strength and consistency) were analyzed as a function of five familial sinistrality variables. In addition, the handedness characteristics of a separate group of subjects (N=80) who had switched handedness were compared with those of the major sample. The frequency data showed that the incidence of nondextrality in respondents was significantly higher when there were nondextral siblings in the family than when all relatives were dextral, and higher still when a parent, rather a sibling, was the nondextral relative. The strength and consistency data showed that the presence of familial sinistrality was associated with miniscule reductions in degree of handedness not only in dextrals but, contrary to prediction, in sinistrals as well. The data from the hand-change subgroup showed that the incidence of ambilaterality was strikingly higher than among no-change subjects and that the degree of right- and left-handedness was lower than among their like-handed no-change counterparts. The finding that familial sinistrality was associated with large increases in the incidence of nondextrality but with very small changes in the degree of handedness suggests that incidental intra-familial learning is a negligible factor in human handedness.

Not All Sinistrality is Pathological

Information regarding age, sex, birth stress, and handedness was obtained form 762 university faculty members and 1869 undergraduate and medical students, who also provided age, sex, and handedness information for their first-degree relatives. In addition, students reported the occupations and educational levels of their parents. Analyses of the effects of birth order, reported birth stress, and maternal, paternal, and joint parental age showed that an increased incidence of sinistrality was only rarely associated with high birth risk; in all cases, the effects were confined to male subjects, most frequently male faculty members. Sinistrality was not associated with low socioeconomic status; on the contrary, there were significantly more sinistrals among parents of high than of low educational and occupational levels. The pathogenic hypothesis has other implications which fail to find support in the current literature, thus casting further doubt on the proposition that all sinistrality is pathological in origin.

The stability and intertest consonance of lateral postural—motor biases in rats: results and implications

Each of six different tests of lateral postural—motor asymmetries was repeatedly administered to 126 rats. Directional reliability was found for rotatory swimming, open-field exploration, and stepping down from a beam. Neonatal posture, turn in an unbaited T maze, and orientation to tail pinch proved not to be reliable across days. The behavioral asymmetries in the open-field and step-down tests were directionally consonant with each other, but neither was related to the asymmetry exhibited in rotatory swimming, implying the existence of at least two independent asymmetrical neural substrates underlying the behaviors. Neither sample-wide directional biases nor major sex differences in bias were found. The sexes were, however, differentially influenced in direction on some tests by the number of males in their natal litters, implying a role for intrauterine exposure to androgens in predisposing rats toward some left- or right-biased behaviors.

Underestimation of dichotic click rates: Results using methods of absolute estimation and constant stimuli.

In Experiment 1, Ss made absolute estimates of monotic and dichotically-alternating click rates. In Experiment 2, Ss compared monotic and dichotic rates in a constant-stimuli procedure. Results of both experiments were similar to those obtained with a different method, and reported earlier: relative underestimation of dichotic rates was small at 1/sec, increased rapidly as dichotic rate was increased to 5–10/sec, and then levelled off.

Oral report of words and word approximations presented to the left or right visual field

Abstract Subjects reported letter strings forming words, pronounceable high approximations to words, and unpronounceable low approximations to words presented tachistoscopically to the left or right visual field (LVF, RVF). (a) For number of strings totally correct, the same RVF superiority was obtained with high approximations as with words, the field difference with low approximations being negligible. (b) In contrast, for letter scores from partially correct strings, RVF superiority did not vary with string type. Finding (a) is interpreted to indicate that the left hemisphere is differentially specialized for processing words as units and that requiring oral report makes pronounceable strings processable as word-like units. Finding (b) suggests that the left hemisphere is not specialized for processing subword fragments.

Septal lesions impair rats' Morris test performance but facilitate left-right response differentiation

Lesions in the septum impaired performance on the Morris test, a task in which the rat locates a hidden escape platform by use of fixed landmarks, but facilitated a water maze-based left-right response differentiation, a task in which the rat finds a hidden escape ramp by means of its internal sense of direction. These results are interpreted as supporting an allocentric/egocentric dichotomy with respect to navigation, and support the notion that rats approach spatial problems with a hierarchy of potential solutions in which allocentric solutions take precedence over egocentric ones. The septal lesions are inferred to disrupt the allocentric mapping system.

Behavioral bias and left–right response differentiation in the rat

To examine the proposition that lateral asymmetry facilitates left-right response differentiation in rats, we examined the relationships between the strengths of several behavioral biases and the scores on a learning task requiring left-right response differentiation. No support was found for a simple model positing a monotonic relationship between any behavioral bias and the learning scores. However, performance showed a U-shaped relationship to one behavioral bias. This finding conforms to a curvilinear model in which rats at either extreme of asymmetry are disadvantaged, at low degrees of asymmetry by a lack of navigational reference, and at high degrees by resultant strong position habits; moderately asymmetrical rats have neither disadvantage and are best able to use the asymmetry as a reference in processing left-right information.

Learning in escape/avoidance tasks in female rats does not vary with reproductive condition ☆

To determine whether the development of novel stimulus-response associations by the mother during the periparturient period is attributable to a general facilitation of learning produced by the hormonal milieu during that period, learning ability under various reproductive conditions was assessed in two tasks unrelated to the periparturitional situation. The two tasks, selected because they equalized the various groups for motivation and performance variables, were acquisition of a water-maze escape (including two reversals), and acquisition and retention of an unsignalled shuttlebox shock avoidance. The groups tested in the water maze were a midpregnant group, an immediately prepartum group, and an immediately postpartum group. In the shuttlebox, the same conditions (different rats) were compared, together with a nonpregnant estrus condition, and a nonpregnant diestrus condition. The results of both experiments indicate that although learning occurred, the characteristics of acquisition and retention were not influenced by reproductive condition.