Gregory V. Jones

Sex Differences in Left-Handedness : A Meta-Analysis of 144 Studies

Human handedness, a marker for language lateralization in the brain, continues to attract great research interest. A widely reported but not universal finding is a greater male tendency toward left-handedness. Here the authors present a meta-analysis of k = 144 studies, totaling N = 1,787,629 participants, the results of which demonstrate that the sex difference is both significant and robust. The overall best estimate for the male to female odds ratio was 1.23 (95% confidence interval = 1.19, 1.27). The widespread observation of this sex difference is consistent with it being related to innate characteristics of sexual differentiation, and its observed magnitude places an important constraint on current theories of handedness. In addition, the size of the sex difference was significantly moderated by the way in which handedness was assessed (by writing hand or by other means), the location of testing, and the year of publication of the study, implicating additional influences on its development.

Back to Woodworth: Role of interlopers in the tip-of-the-tongue phenomenon

When a person reports that a word is on the tip of his or her tongue, that person often recalls instead another word that is similar in sound to the target word. Two opposite roles have been suggested for these interlopers. An older view (Woodworth, 1929) holds that they are instrumental in the development of tip-of-the-tongue (TOT) states because they obstruct successful retrieval of intended targets. A more recent view (R. Brown & McNeill, 1966) holds, on the other hand, that interlopers tend to nullify TOT states by facilitating complete retrieval of the intended targets. A study is reported in which participants were explicitly presented with interloper words. The results provide two planks of support for Woodworths hypothesis. First, more TOT states occurred when the interloper was similar in sound to the target than when it was not. Second, more TOT states occurred when the interloper was presented at the actual time of retrieval than when it was presented earlier. It appears that interlopers tend to induce TOT states by obstructing retrieval, rather than to nullify them by facilitating retrieval.

INTEGRAL BIAS IN NAMING OF PHOBIA-RELATED WORDS

Abstract There is now considerable evidence that a persons cognitive processing is influenced by emotional factors. It is less clear, however, how this bias arises. Two hypotheses are distinguished and compared in the present study. The Inferred Bias hypothesis asserts that the cognitive effects of an emotion are not, in general, inherent consequences of that emotion, but instead arise from earlier experiences in which the particular patterns of emotional and Cognitive activity have tended to be associated. The Integral Bias hypothesis asserts, in contrast, that the cognitive effects of an emotion are in general a fundamental characteristic of that emotion. In order to compare these two hypotheses, the cognitive effects of a phobia in children were studied. An effect on the Stroop naming of spider-related words was detected in spider-phobic children as young as 6 or 7 years old. Furthermore, the magnitude of this effect did not differ significantly over the age range to 12 or 13 years old. These results ...

Handedness and season of birth: a gender-invariant relation.

In an earlier study, Dellatolas, Curt and Lellouch (1991) concluded that handedness is not related to season of birth. However, post-hoc exploration of their and other sets of data has shown that there is an apparent tendency for left-handedness to be more prevalent in the period March-July than in the period August-February. The present work tested this seasonal hypothesis prospectively among university students. It was found that the proportion of all left-handed participants who were born in the period March-July was indeed significantly greater than the proportion of all right-handed participants who were born in the same period. Furthermore, the pattern of seasonal influence upon handedness did not vary significantly between females and males. The relation between handedness and season of birth may be linked to seasonal variation in other factors such as the incidence of infectious agents.

Reasoning with three types of conditional: Biases and mental models

Two experiments are reported which compare conditional reasoning with three types of rule. These consist of two types of rule that have been widely studied previously, if p then q and p only if q, together with a third type, q if p. In both experiments, the p only if q type of rule yields a different pattern of performance from the two other types of rule. Experiment 1 is an abstract rule-evaluation task and demonstrates differential effects of temporal order and of suppositional bias. Experiment 2 investigates rule generation, rephrasing, and comparison, and demonstrates differential effects of temporal order and of thematic content. An analysis of the results is offered in terms of biases and mental models. Effects of rule form and context can be explained as reflecting the different sequences in which mental models are created for each rule form. However, it is necessary to consider the internal structure of individual mental models to account for effects arising from temporal ordering of rules.

Misremembering a common object: When left is not right

Three experiments were carried out to investigate peoples memory for British coins. Two principal issues were studied. First, it has previously been shown that memory for U.S. pennies and other coins is surprisingly imperfect. How do other countries compare? It turned out that recall of the design of British pennies was, if anything, worse even than that of U.S. pennies. The situation was no better for a larger coin with an unusual shape. It is suggested that individual features are poorly remembered if they have low levels of meaningfulness, redundancy, identifiability, and discriminativeness. Second, in addition to this generally weak level of remembering, an instance of systematic misremembering was consistently observed. The Queens portrait always faces to the right on British coins. Yet in all three experiments, the proportion of participants who recalled that the portrait faces to the right was so low (overall, 19%) that it was significantly less than even the 50% baseline to be expected from people in a state of complete ignorance. It follows that the participants were not in a state of complete ignorance. Rather, they relied-upon extraneous knowledge of either a general or a specific nature (bias and schemahypotheses, respectively), whose importation into this domain was in fact invalid. The resulting belief that coin portraits face left was not right.

Motor imagery theory of a contralateral handedness effect in recognition memory: Toward a chiral psychology of cognition

The assumption that cognitive processes are independent of handedness was questioned. Five experiments with left-handed and right-handed participants centered on investigating recognition memory for the orientation of heads. Their results provided consistent evidence of a general contralateral handedness effect: Left-facing heads are more likely to be remembered correctly by right-handed participants, whereas right-facing heads are more likely to be remembered correctly by left-handed participants. Motor imagery and hemispheric differences explanations were compared. The results supported the hypothesis that the effect is a consequence of differences between handedness groups in terms of specific patterns of underlying motor activation rather than in terms of more general differences in function between cerebral hemispheres. The possibility of a chiral psychology of cognition that takes note of a persons handedness is considered.

Seasonal anisotropy in handedness

The preference for using either the left or the right hand has been linked to important human characteristics such as language lateralisation within the cerebral hemispheres, and evidence has been reported that the proportions of different types of handedness may be influenced by factors such as levels of maternal hormones and anxiety. Under such influences, it is possible in principle that distributions of handedness provide evidence of seasonal anisotropy, that is, variation in the direction of handedness for births in different parts of the year. The results of a number of studies are compared here, and shown to provide evidence of a significant tendency for the incidence of left-handed people to be higher among those born in the spring and ensuing months (March-July in the northern hemisphere) than among those born in the remainder of the year, at least among the male population.

Language dominance, handedness and sex : recessive X-linkage theory and test

The possibility is investigated that cerebral dominance for language and handedness share a common X-linkage and that the relation between the two is therefore a function of sex. In particular, an X-linked recessive account is shown to predict an overall configuration of language dominance, handedness and sex within which there is a sex effect in the pattern of language dominance among right-handed but not left-handed people. The recent accurate determination of cerebral dominance among relatively large samples of the general population by means of functional transcranial Doppler ultrasonography makes it possible to test this new theory rigorously, and its parameter-free pattern of predictions is found to be supported.

Encouraging the perceptual underdog: Positive affective priming of nonpreferred local–global processes.

Two experiments examined affective priming of global and local perception. Participants attempted to detect a target that might be present as either a global or a local shape. Verbal primes were used in 1 experiment, and pictorial primes were used in the other. In both experiments, positive primes led to improved performance on the nonpreferred dimension. For participants exhibiting global precedence, detection of local targets was significantly improved, whereas for participants exhibiting local precedence, detection of global targets was significantly improved. The results provide support for an interpretation of the effects of positive affective priming in terms of increased perceptual flexibility.