Is the link between forebrain size and feeding innovations caused by confounding variables? A study of Australian and North American birds

The short notes of ornithology journals feature new and unusual feeding behaviours, which, when systematically collated, could provide a quantitative estimate of behavioural flexibility in different bird groups. Previous studies suggest that taxonomic variation in the frequency of new behaviours (innovations) is correlated with variation in relative forebrain size. Recent work on primates shows, however, that observer bias can affect innovation frequency. We assess this possibility in birds via three estimates in North America and Australia: the number of full-length papers in academic journals, the frequency of photographs in birding magazines and a questionnaire on reporting bias given to ornithologists at a meeting. We also look at sampling effects due to single journal sources by doing a split-half analysis of our North American database (The Wilson Bulletin vs. six other journals) and adding three new Australian journals to the one we had used previously. In multiple regressions that also included species number per taxon, none of the potential biases could account for the correlation between forebrain size and innovation frequency. Species number was the best predictor of full-length paper frequency, which was the best predictor of photograph numbers. Ornithologists are not preferentially interested in innovative, large-brained taxa, suggesting that the correlation between innovations and neural substrate size is not a spurious effect of the biases examined here. Accepted after revision: 27 July 2001 Electronic Publication     

Happiness Trends Under Democracy: Where Will the New South African

Five years after South Africa's first democratic elections in 1994, life satisfaction and happiness still reflect societal divides sowed by apartheid social engineering. The paper reports the indicators: life satisfaction, happiness and expectations for the future, from national surveys conducted between 1983 and 1999 for the South African Quality-of-Life Trends Project. Post-election euphoria, which saw all South Africans happy and satisfied with life for a brief moment in 1994, raises the question where the new set-level of subjective well-being will eventually come to rest. In 1999, in spite of some gains in living conditions, the level of life satisfaction of blacks has not risen above the mid-point and happiness is only slightly above the mid-point. Meanwhile, whites, who have forfeited their political dominance, continue to score above the mid-point on happiness and life satisfaction. The paper draws on the literature, particularly on quality-of-life trends in reunified Germany and paradoxical trends in African-American life satisfaction when discussing the dynamics underlying South African subjective well-being. It is argued that coping mechanisms may play an important role in determining levels of subjective well-being in the complex situation of South Africa.     

Night waking in 6-month-old infants and maternal depressive symptoms

Relations between night waking in infants and depressive symptoms in their mothers at 6 months postpartum were examined using the data from the National Institute for Child Health and Human Development Study of Early Child Care. Although more depressive symptoms were only weakly correlated with a higher frequency of infant waking, longer wake times, and more total time awake, the rate of clinically significant depression scores was about double in mothers of chronically waking infants in comparison with mothers whose infants did not awaken during the night. The value of comparing subgroups to elucidate relations identified through correlations is discussed.     

Aging and individual differences in binding during sentence understanding: Evidence from temporary and global syntactic attachment ambiguities

We report an investigation of aging and individual differences in binding information during sentence understanding. An age-continuous sample of adults (N = 91), ranging from 18 to 81 years of age, read sentences in which a relative clause could be attached high to a head noun NP1, attached low to its modifying prepositional phrase NP2 (e.g., The son of the princess who scratched himself/herself in public was humiliated), or in which the attachment site of the relative clause was ultimately indeterminate (e.g., The maid of the princess who scratched herself in public was humiliated). Word-by-word reading times and comprehension (e.g., who scratched?) were measured. A series of mixed-effects models were fit to the data, revealing: (1) that, on average, NP1-attached sentences were harder to process and comprehend than NP2-attached sentences; (2) that these average effects were independently moderated by verbal working memory capacity and reading experience, with effects that were most pronounced in the oldest participants and; (3) that readers on average did not allocate extra time to resolve global ambiguities, though older adults with higher working memory span did. Findings are discussed in relation to current models of lifespan cognitive development, working memory, language experience, and the role of prosodic segmentation strategies in reading. Collectively, these data suggest that aging brings differences in sentence understanding, and these differences may depend on independent influences of verbal working memory capacity and reading experience.     

Infants’ ability to respond to depth from the retinal size of human faces: Comparing monocular and binocular preferential-looking

To examine sensitivity to pictorial depth cues in young infants (4 and 5 months-of-age), we compared monocular and binocular preferential looking to a display on which two faces were equidistantly presented and one was larger than the other, depicting depth from the size of human faces. Because human faces vary little in size, the correlation between retinal size and distance can provide depth information. As a result, adults perceive a larger face as closer than a smaller one. Although binocular information for depth provided information that the faces in our display were equidistant, under monocular viewing, no such information was provided. Rather, the size of the faces indicated that one was closer than the other. Infants are known to look longer at apparently closer objects. Therefore, we hypothesized that infants would look longer at a larger face in the monocular than in the binocular condition if they perceived depth from the size of human faces. Because the displays were identical in the two conditions, any difference in looking-behavior between monocular and binocular viewing indicated sensitivity to depth information. Results showed that 5-month-old infants preferred the larger, apparently closer, face in the monocular condition compared to the binocular condition when static displays were presented. In addition, when presented with a dynamic display, 4-month-old infants showed a stronger ‘closer’ preference in the monocular condition compared to the binocular condition. This was not the case when the faces were inverted. These results suggest that even 4-month-old infants respond to depth information from a depth cue that may require learning, the size of faces.     

Left-hemisphere activation is associated with enhanced vocal pitch error detection in musicians with absolute pitch

The ability to process auditory feedback for vocal pitch control is crucial during speaking and singing. Previous studies have suggested that musicians with absolute pitch (AP) develop specialized left-hemisphere mechanisms for pitch processing. The present study adopted an auditory feedback pitch perturbation paradigm combined with ERP recordings to test the hypothesis whether the neural mechanisms of the left-hemisphere enhance vocal pitch error detection and control in AP musicians compared with relative pitch (RP) musicians and non-musicians (NM). Results showed a stronger N1 response to pitch-shifted voice feedback in the right-hemisphere for both AP and RP musicians compared with the NM group. However, the left-hemisphere P2 component activation was greater in AP and RP musicians compared with NMs and also for the AP compared with RP musicians. The NM group was slower in generating compensatory vocal reactions to feedback pitch perturbation compared with musicians, and they failed to re-adjust their vocal pitch after the feedback perturbation was removed. These findings suggest that in the earlier stages of cortical neural processing, the right hemisphere is more active in musicians for detecting pitch changes in voice feedback. In the later stages, the left-hemisphere is more active during the processing of auditory feedback for vocal motor control and seems to involve specialized mechanisms that facilitate pitch processing in the AP compared with RP musicians. These findings indicate that the left hemisphere mechanisms of AP ability are associated with improved auditory feedback pitch processing during vocal pitch control in tasks such as speaking or singing.     

Interethnic Factors as Predictors of the Subjective Well‐Being of Minority Individuals in a Context of Recent Societal Changes

Our research examined the impact of contextual intergroup variables on the subjective well‐being of ethnic Russians in Estonia (N = 190) who have experienced major social changes with the demise of the Soviet Union. A mediational model was tested where aspects of intergroup relations (i.e., relative deprivation, status legitimization, and temporal comparisons) acted as mediators of the influence of cultural identity and representations of history on subjective well‐being. Preliminary analyses indicated polemical representations of history in which Estonian historical narratives are established around the struggle for independence, and Russian representations of history are consolidated around victory in World War II. Mediation analyses demonstrated that the importance of Russian history increased the perceptions of relative deprivation, status delegitimization, and the frequency of temporal comparisons, which negatively affected life satisfaction. At the same time, the importance of Estonian history led to positive perceptions of the intergroup situation and, in turn, to greater subjective well‐being. The effect of Russian identity on well‐being was mediated by delegitimizing beliefs, but not by relative deprivation and temporal comparisons. Estonian identity did not exert a significant effect on the proposed mediators. The research demonstrates the salience of the effects of contextual intergroup factors on subjective well‐being, and the article discusses implications for the study of intergroup relations and subjective well‐being.     

Measurement of the relative strain ratios normal to the crystal planes in Cu thin films using grazing incidence X-ray diffraction

The relative strain normal to the crystal planes in Cu thin films has been experimentally measured using grazing incidence X-ray diffraction. This was performed by measuring the ratio of the strain exerted in the same specific (hkl) crystal plane parallel and perpendicular to the film surface. The strain ratios of the (1?1?1), (2?0?0), (2?2?0) and (3?0?0) planes were found to be –0.804, –1.324, –1.003, and –1.369, respectively. These values are within experimental error of those calculated theoretically under the assumptions of plane stress conditions.     

Increased conspiracy beliefs among ethnic and Muslim minorities

In the present study, we tested whether Muslim minority members are more susceptible to conspiracy theories than majority members in the Netherlands. We examined conspiracy theories that are relevant (portraying the Muslim community as victim or Jewish people as perpetrators) and irrelevant for participants' Muslim identity (about the 2007 financial crisis, and other theories such as that the moon landings were fake). Results revealed that Muslims believed both identity‐relevant and irrelevant conspiracy theories more strongly than non‐Muslims. These differences could not be attributed to the contents of Muslim faith: Ethnic minority status exerted similar effects independent of Muslim identity. Instead, evidence suggested that feelings of both personal and group‐based deprivation independently contribute to belief in conspiracy theories. We conclude that feelings of deprivation lead marginalized minority members to perceive the social and political system as rigged, stimulating belief in both identity‐relevant and irrelevant conspiracy theories.