A lot of information used in aging research relies on self-reports. Surveys or questionnaires are used to assess quality of life, attitudes toward aging, experiences of aging, subjective well-being, symptomatology, health behaviors, financial information, medication adherence, etc. Growing evidence suggests that older and younger respondents are differentially affected by questionnaire features and the cognitive tasks that question answering pose. This research has shown that age-related changes in cognitive and communicative functioning can lead to agerelated differences in self-reports that are erroneously interpreted as real age differences in attitudes and behaviors. The current review highlights how the processes underlying respondents' self-report change as a function of respondents' age; it updates our previous reviews of this literature.Keywords Aging Á Self-reports Á Surveys Á Questionnaires Á Questionnaire features Á Survey methodology A lot of information used in aging research relies on self-reports. Surveys or questionnaires are used to assess quality of life, attitudes toward aging, experiences of aging, subjective well-being, symptomatology, health behaviors, financial information, medication adherence, etc. Over the past 50 years, a strong body of research has uncovered many potential sources of response biases in surveys and has shown that apparently minor variations in question format, question order, or the position of response options can systematically bias responses and lead to false reports of attitudes and behaviors (for reviews see Schwarz 1999a; Sudman et al. 1996;Tourangeau et al. 2000;Abeele et al. 2013;Krosnick et al. 2006). Growing evidence suggests that older and younger respondents are differentially affected by questionnaire features (Schwarz et al. 1999;Yoon et al. 2010). This research has shown that age-related changes in cognitive and communicative functioning can lead to age-related differences in self-reports that are erroneously interpreted as real age differences in attitudes and behaviors. The current review highlights how the processes underlying respondents' self-report change as a function of respondents' age; it updates our previous reviews of this literature (Schwarz 2005;Schwarz et al. 1999;Schwarz and Knäuper 2000). Notably, this review concludes that age-related differences in question or response option comprehension and memory retrieval can lead to erroneous conclusions about age differences in opinions or behaviors. Yet, the examples identified over the last 20 years have not yet led to substantial changes in survey research that systematically address these problems. Also, the available research is still limited in quantity and quality, as detailed below.

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Polyethylene production through catalytic ethylene polymerization is one of the most common processes in the chemical industry. The popular Cossee-Arlman mechanism hypothesizes that the ethylene be directly inserted into the metal–carbon bond during chain growth, which has been awaiting microscopic and spatiotemporal experimental confirmation. Here, we report an in situ visualization of ethylene polymerization by scanning tunneling microscopy on a carburized iron single-crystal surface. We observed that ethylene polymerization proceeds on a specific triangular iron site at the boundary between two carbide domains. Without an activator, an intermediate, attributed to surface-anchored ethylidene (CHCH 3 ), serves as the chain initiator (self-initiation), which subsequently grows by ethylene insertion. Our finding provides direct experimental evidence of the ethylene polymerization pathway at the molecular level.

Fractals are found in nature and play important roles in biological functions. However, it is challenging to controllably prepare biomolecule fractals. In this study, a series of Sierpinśki triangles with global organizational chirality is successfully constructed by the coassembly of L-tryptophan and 1,3-bi(4-pyridyl)benzene molecules on Ag(111). The chirality is switched when replacing L-tryptophan by D-tryptophan. The fractal structures are characterized by low-temperature scanning tunneling microscopy at the single-molecule level. Density functional theory calculations reveal that intermolecular hydrogen bonds stabilize the Sierpinśki triangles.