Revisiting the self-generation effect in proofreading.

The self-generation effect refers to the finding that people's memory for information tends to be better when they generate it themselves. Counterintuitively, when proofreading, this effect may make it more difficult to detect mistakes in one's own writing than in others' writing. We investigated the self-generation effect and sources of individual differences in proofreading performance in two eye-tracking experiments. Experiment 1 failed to reveal a self-generation effect. Experiment 2 used a studying manipulation to induce overfamiliarity for self-generated text, revealing a weak but non-significant self-generation effect. Overall, word errors (i.e., wrong words) were detected less often than non-word errors (i.e., misspellings), and function word errors were detected less often than content word errors. Fluid intelligence predicted proofreading performance, whereas reading comprehension, working memory capacity, processing speed, and indicators of miserly cognitive processing did not. Students who made more text fixations and spent more time proofreading detected more errors.

Laterality indices consensus initiative (LICI): A Delphi expert survey report on recommendations to record, assess, and report asymmetry in human behavioural and brain research.

Laterality indices (LIs) quantify the left-right asymmetry of brain and behavioural variables and provide a measure that is statistically convenient and seemingly easy to interpret. Substantial variability in how structural and functional asymmetries are recorded, calculated, and reported, however, suggest little agreement on the conditions required for its valid assessment. The present study aimed for consensus on general aspects in this context of laterality research, and more specifically within a particular method or technique (i.e., dichotic listening, visual half-field technique, performance asymmetries, preference bias reports, electrophysiological recording, functional MRI, structural MRI, and functional transcranial Doppler sonography). Experts in laterality research were invited to participate in an online Delphi survey to evaluate consensus and stimulate discussion. In Round 0, 106 experts generated 453 statements on what they considered good practice in their field of expertise. Statements were organised into a 295-statement survey that the experts then were asked, in Round 1, to independently assess for importance and support, which further reduced the survey to 241 statements that were presented again to the experts in Round 2. Based on the Round 2 input, we present a set of critically reviewed key recommendations to record, assess, and report laterality research for various methods.

Are only infants held more often on the left? If so, why? Testing the attention-emotion hypothesis with an infant, a vase, and two chimeric tests, one "emotional," one not.

Most adults, especially women, hold infants and dolls but not books or packages on the left side. One reason may be that attention is more often leftward in response to infants, unlike emotionally neutral objects like books and packages. Women's stronger bias may reflect greater responsiveness to infants. Previously, we tested the attention hypothesis by comparing women's side-of-hold of a doll, book, and package with direction-of-attention on the Chimeric Faces Test (CFT) [Harris, L. J., Cárdenas, R. A., Spradlin, Jr., M. P., & Almerigi, J. B. (2010). Why are infants held on the left? A test of the attention hypothesis with a doll, a book, and a bag. Laterality: Asymmetries of Body, Brain and Cognition, 15(5), 548-571. doi:10.1080/13576500903064018]. Only the doll was held more often to the left, and only for the doll were side-of-hold and CFT scores related, with left-holders showing a stronger left-attention bias than right-holders. In the current study, we tested men and women with a doll and the CFT along with a vase as a neutral object and a "non-emotional" chimeric test. Again, only the doll was held more often to the left, but now, although both chimeric tests showed left-attention biases, scores were unrelated to side-of-hold. Nor were there sex differences. The results support left-hold selectivity but not the attention hypothesis, with or without the element of emotion. They also raise questions about the contribution of sex-of-holder. We conclude with suggestions for addressing these issues.

On teaching infants "the right use of their hands": Advice and reassurance from Mary Palmer Tyler's The Maternal Physician (1811).

For parents anxious "lest their children should be left-handed", the American author Mary Palmer Tyler offered advice and reassurance in her 1811 child-care manual The Maternal Physician. This article provides a brief biography of Tyler and the text of her remarks, along with notes on the text and the author's sources.

In fencing, what gives left-handers the edge? Views from the present and the distant past.

Recent studies show that in the sport of fencing left-handers have an advantage over right-handers. This was recognised by fencing masters as early as the sixteenth century. They also agreed that the advantage was due to left-handers' numbers-that being a minority gave them more opportunities to compete against right-handers than right-handers had against them. Fencing masters today have reached the same conclusion, as have laterality researchers, who see the advantage as an example of what is now called a "frequency-dependent" effect. However, some researchers have also suggested other possibilities that relate the advantage to natural differences in ability. This article presents a sampling of views of fencing masters from the past, along with a summary and analysis of explanations, old and new.

Side biases for holding and carrying infants: Reports from the past and possible lessons for today.

Most adults hold human infants on the left side, with the infant's head to the left of their own body midline. The discovery of this bias is credited to Lee Salk, who first reported it in 1960, but the same was reported at least 300 years earlier and many times again through the early decades of the twentieth century. Along with the left-side reports, however, others named the right as the preferred side. Authors on each side explained the preference and foresaw consequences for the infant: different ones in each case. This article describes the two kinds of reports, asks whether and how they might be reconciled, and discusses their possible lessons for theory and research today.

Why are infants held on the left? A test of the attention hypothesis with a doll, a book, and a bag.

Most adults, especially women, hold infants and objects representing infants, such as dolls, preferentially on the left side. The attention hypothesis credits the effect to left-directed attention for perception of emotionally salient targets, faces being prime examples. Support comes from studies showing stronger left visual hemispace (LVH) biases in left-holders than right-holders on the Chimeric Faces Test (CFT), but control tests with non-social/emotional objects are needed. We therefore observed young women holding a doll, a book, and a bag, and compared their scores with their performance on the CFT. We also assessed their handedness to check on its possible role. Overall, only the doll elicited a significant side bias, with 57% of all holds on the left, 2% in the middle, and 41% on the right. On the CFT, only left-holders had an LVH bias, whereas right-holders had no bias in either direction. Only the doll-hold scores were consistently related to CFT scores, and for none of the objects was handedness related to side-of-hold.

Probing the human brain with stimulating electrodes: the story of Roberts Bartholow's (1874) experiment on Mary Rafferty.

Roberts Bartholow's 1874 experiment on Mary Rafferty is widely cited as the first demonstration, by direct application of stimulating electrodes, of the motor excitability of the human cerebral cortex. The many accounts of the experiment, however, leave certain questions and details unexamined or unresolved, especially about Bartholow's goals, the nature and quality of the evidence, and the experiment's role in the history of theory and research on localisation of function. In this article, we try to fill these gaps and to tell the full story. We describe Bartholow's career up to 1874, review the theoretical and empirical background for the experiment, and present Bartholow's own account of the experiment as well as those of his supporters and critics. We then present our own analysis, assess the experiment's influence on contemporaneous scientific opinion about cortical excitability, and trace its citation record into our own time. We also review and assess ethical criticisms of Bartholow and their effects on his career, and we close by discussing the role we think the experiment deserves to play in the history of theory and research on cortical excitability.

Adults' preferences for side-of-hold as portrayed in paintings of the Madonna and Child.

Most women hold infants on their left side. They do the same when depicted in works of art. Does the latter accurately reflect the real-life bias, the artist's own aesthetic preference, or something else, such as the artist's handedness, sex, direction of attentional bias, or even the artist's own side-preference for holding infants? As a first step to finding out, we showed 272 young adults (85 men, 187 women) 20 pairs of paintings of the Madonna and Child, the original on one side, its mirror-reversal on the other, and asked which one they preferred. Along with assessing the effects of the variables already mentioned, we used equal numbers of paintings originally depicting left-holds and right-holds to control for the possible effects of differences between the paintings other than side-of-hold itself, such as in their colour scheme, background details, and the type of hold shown (e.g., cradle vs seated on lap). Each pair was presented twice, once with the original on the left, once on the right, for a total of 40 trials. Women and men alike more often preferred left-hold images, but the difference was significant only for women. Preferences were also stronger for original left-hold paintings than for the mirror-reversals of original right-hold paintings, suggesting that the originals differed in ways affecting preference beyond those we tried to control. Overall preference for left-hold images was enhanced when the images were on the viewer's left. As for the other variables, they were for the most part unrelated to preferences. The reasons for the preference thus remain unclear but it is evidently affected by multiple variables, with at least some clearly different from those affecting side-of-hold preferences of real mothers holding real infants.

The Discovery of Cerebral Specialization.

Of the main principles of human neuropsychology, the best known may be cerebral specialization: the left and right hemispheres play different roles in language and other higher-order functions. This chapter discusses when and how and by whom the differences were found. It begins with an account of Gall's cortical localization theory, which set the stage. It then describes the discoveries themselves, reviews how the differences were explained, and concludes with a summary of further developments.

Does Music Matter? A Look at the Issues and the Evidence.

Does music matter? Judging from the ever-diminishing support for music education in public funding, the message is that it is just a frill to be cast aside for more pressing needs. The pleasure of listening to music is worthy in itself and reason enough for support, but what happens when people are more deeply engaged, such as when they learn to read music and play an instrument? Can more material rewards follow for cognition, language, and emotion, and for social and physical well-being? This essay presents an overview of issues and evidence from a broad range of disciplines and age groups.

Within-individual variability in neurocognitive performance: age- and sex-related differences in children and youths from ages 8 to 21.

OBJECTIVE: The transition from childhood to adulthood is characterized by improved motor and cognitive performance in many domains. Developmental studies focus on average performance in single domains but ignore consistency of performance across domains. Within-individual variability (WIV) provides an index of that evenness and is a potential marker of development. METHOD: We gave a computerized battery of 14 neurocognitive tests to 9138 youths ages 8-21 from the Philadelphia Neurodevelopmental Cohort. RESULTS: As expected, performance improved with age, with both accuracy and speed peaking in adulthood. WIV, however, showed a U-shaped course: highest in childhood, declining yearly into mid-adolescence, and increasing again into adulthood. Young females outperformed and were less variable than males, but by early adulthood male performance matched that of females despite being more variable. CONCLUSION: We conclude that WIV declines from childhood to adolescence as developmental lags are overcome, and then increases into adulthood reflecting the emergence of cognitive specializations related to skill-honing and brain maturation.

Are sensation seeking and emotion processing related to or distinct from cognitive control in children with ADHD?

This study evaluated the relationship of (a) reactive inhibition and right-lateralized emotion processing to each other and (b) to executive control of response suppression, and (c) with regard to ADHD in 134 children ages 7-12 years. Reactive inhibition was indexed by child ratings of sensation seeking on the Sensation Seeking Scales, executive control by the Stop Signal Task, emotion processing by performance on the Chimeric Faces Test, and ADHD by parent- and teacher-reported symptoms. The results were consistent with a two-process model in which executive control, conceived as a right-hemisphere lateralized function, was distinct from sensation seeking and lateralized emotion processing. Supporting this distinction, ADHD was associated with executive control, but not with sensation seeking/reactive inhibition or lateralized emotion processing. The findings suggest that ADHD cannot be understood as a global right-lateralized neuropsychological weakness, but rather that it involves only particular functions that may be right lateralized. Findings further suggest that risk for comorbid disorders in ADHD (e.g., conduct disorder or mood disorders) may increase as a function of independent factors such as temperament. Mechanisms underlying executive inhibition and emotional processing could be functionally independent yet interact to multiply psychopathological risk in some children (leading, for example, to comorbid disorders).

Mothers' and fathers' lateral biases for holding their newborn infants: a study of images from the World Wide Web.

Photographic and direct-observation studies show that most adults hold infants on the left side. This basic directional effect is well established, but other details are still uncorroborated, uncertain, or inconsistent across studies. These include the overall strength of the bias, the role of the sex, parental status, and experience of the holder, and the sex and age of the infant. Given their importance for understanding the bias, we sought further information from a large sample of photographs of mothers and fathers, some of them first-time parents, others not, holding their infants in the first minutes, hours, or days after birth. The results confirmed the basic directional effect and provided information on the other variables. They also raise questions for further research, especially as it pertains to the use of photographs vs direct observation.

What to do about your child's handedness? Advice from five eighteenth-century authors, and some questions for today.

On the question "What to do about your child's handedness?", parents have never lacked for advice. Over more than two millennia, however, their advisors have rarely spoken with one voice. Instead, they have disagreed on virtually everything, including the desirability of handedness, its origins in nature or nurture, and especially the acceptability and treatment of left-handedness. After briefly describing such disagreements from classical times, this article presents and analyses new examples from the works of five authors in the eighteenth century, three from England ("An Eminent Physician", William Cadogan, and John Hill) and two from France (Nicholas Andry and Jean-Jacques Rousseau). It then presents similar examples from more recent authors, and it concludes by asking what advice about handedness the current generation of laterality researchers would be prepared to offer.

Lateral biases for holding infants: early opinions, observations, and explanations, with some possible lessons for theory and research today.

In 1962, the psychologist Lee Salk reported finding that 80% of mothers held their infants on the left side of their body, so that the infant's head was to their left. Salk's finding has been amply confirmed, with new studies of mothers as well as other adults reporting figures for left-side holding ranging from 60 to 85% (e.g., de Chateau, 1983; Harris & Fitzgerald, 1985; Harris, Almerigi, & Kirsch, 2000). New studies also suggest that the bias is only for holding infants (or infant dolls), not for books, packages, or other objects (e.g., Almerigi, Carbary, & Harris, 2001; Rheingold & Keene, 1965). The possibility that it is unique to infants (or their likenesses) is what gives it special interest for investigators who study laterality of function. The discovery of the bias is often credited to Salk, but it would be more accurate to say that he rediscovered it because it was first noted at least two hundred years earlier, then, evidently, forgotten, only to be rediscovered and again forgotten several times through the early decades of the twentieth century. Over this period, however, not all agreed that the preferred side was the left: a nearly equal number said it was the right. Each group also proposed explanations for why one or the other side was preferred. They also foresaw different consequences for the infant being held. In the 1980s, I briefly described some of the early reports in essays on the history of theories and research on laterality of function (Harris, 1980, 1983). A manuscript now in preparation provides a more comprehensive description and evaluation of these reports and suggests certain lessons they may hold for current theory and research. The poster proposed for TENNET XII will summarize the main points of this new review and analysis. The poster will be organized into 6 sections, with bulleted text accompanied by drawings, photographs, and other illustrations. The plan is to make the story as visual as possible.

Most adults show opposite-side biases in the imagined holding of infants and objects.

Three hundred university undergraduates were asked to imagine holding in their arms first an object (either an "expensive vase" or an "old shoebox") and then a young infant. For all three tasks, side biases were found that were significantly different from chance and from one another: 81% of the subjects reported holding the imagined vase in their right arm, 64% reported holding the imagined shoebox in their right arm, and 66% reported holding the imagined infant in their left arm. These results further support the hypothesis that the left-side bias is unique to infants and, for the first time, establish this through direct comparisons of holding-side biases for infants and objects within subjects. The sex and handedness of the holder as well as the qualities of the imagined object also were found to contribute to the side and strength of the bias.

Task difficulty reduces the left visual hemispace bias for judgments of emotion in chimeric faces.

A prior study (Carbary, Almerigi, & Harris, 2001) of adults' judgments of emotional chimeric faces showed that the left visual hemispace (LVH) bias normally found on a free-viewing chimeric faces test is reduced when the task is judged to be difficult. Taking into account theory and research on hemispheric differences in styles, or strategies, of information processing, we proposed that the reduction was related to a change in these strategies. Two new experiments are presented that independently manipulate task difficulty and show the same task difficulty-related effect as in our prior study. Data are also presented suggesting that the strategy most commonly adopted for difficult judgments is part-based or feature-oriented, whereas the strategy most commonly adopted for easy judgments is reliance on "first impression."

The contribution of postural bias to lateral preferences for holding human infants.

When asked to hold an infant, 60-85% of adults hold on their left, so that the infant's head is to the left of their midline (Brüser, 1981; de Chateau, 1983; Saling & Tyson, 1981). The same group bias has been found even when persons are merely asked to imagine holding an infant (Nakamichi & Takeda, 1995; Harris, Almerigi, & Kirsch, 2000). A number of variables have been found to contribute modestly to the bias, including the sex and handedness of the holder. In the current study, the role of a new variable is investigated, namely, the feeling of comfort for holding an infant on a particular side as indexed by one's foot preference for acts of stabilizing or postural support. To test this hypothesis, 282 right-handed college students (218 women, 64 men) were given the imagine-hold task along with 4 questions about their foot preference for posture and balance. The results showed that, at least for women, the two measures were modestly but significantly related.