Maternal behavior, paternal behavior, and pup survival in CD-1 albino mice (Mus musculus) in three different housing conditions

Parental behavior, food consumption, and pup development in litters of CD-1 albino mice (Mus musculus) with single mothers or paired mothers in 3 different housing conditions were compared. Fewer pups survived when parents were required to run in a wheel to obtain food, and these pups had lower weights than pups in the wheel-noncontingent and no-wheel groups. The presence of the male facilitated pup survival in the wheel-contingent group but had no effect on pup growth. Mice in the wheel-contingent group ran more revolutions than those in the wheel-noncontingent group and spent less time in parental care. In the wheel-contingent group, males spent more time running and ate less food than females, suggesting that males may indirectly facilitate pup development by providing food for the mother. The results suggest that the presence of the male increases pup care and may facilitate maternal behavior under appropriate environmental conditions.     

Developmental Trends in False Memory Across Adolescence and Young Adulthood: A Comparison of DRM and Memory Conformity Paradigms

Little is known about the reliability of eyewitness memory among adolescents as most memory research has focused primarily on adults and young children. A number of studies recently have emerged outlining conditions where memory suggestibility increases from early childhood to adulthood. These developmental reversals are found in semantic association tasks such as the Deese–Roediger–McDermott (DRM) paradigm and have not yet been thoroughly investigated among adolescents. In the current study, we examined DRM performance among 11–21 year olds (N = 245). Extending the work comparing children and adults, false memory on the DRM task increased with age. False memory on the DRM task was not associated with false memory on a memory conformity task. The different memory processes involved with the tasks and the implications for legal psychology are discussed. Copyright © 2015 John Wiley & Sons, Ltd.     

Concept learning set‐size functions for Clark's nutcrackers

Same/Different abstract‐concept learning by Clark's nutcrackers (Nucifraga columbiana) was tested with novel stimuli following learning of training set expansion (8, 16, 32, 64, 128, 256, 512, and 1024 picture items). The resulting set‐size function was compared to those from rhesus monkeys (Macaca mulatta), capuchin monkeys (Cebus apella), and pigeons (Columba livia). Nutcrackers showed partial concept learning following initial eight‐item set learning, unlike the other species (Magnotti, Katz, Wright, & Kelly, 2015). The mean function for the nutcrackers' novel‐stimulus transfer increased linearly as a function of the logarithm of training set size, which intersected its baseline function at the 128‐item set size. Thus, nutcrackers on average achieved full concept learning (i.e., transfer statistically equivalent to baseline performance) somewhere between set sizes of 64 to 128 items, similar to full concept learning by monkeys. Pigeons required a somewhat larger training set (256 items) for full concept learning, but results from other experiments (initial training and transfer with 32‐ and 64‐item set sizes) suggested carryover effects with smaller set sizes may have artificially prolonged the pigeon's full concept learning. We find it remarkable that these diverse species with very different neural architectures can fully learn this same/different abstract concept, and (at least under some conditions) do so with roughly similar sets sizes (64‐128 items) and numbers of training exemplars, despite initial concept learning advantages (nutcrackers), learning disadvantages (pigeons), or increasing baselines (monkeys).     

Personality Correlates of Midlife Cardiometabolic Risk: The Explanatory Role of Higher‐Order Factors of the Five‐Factor Model

Varying associations are reported between Five‐Factor Model (FFM) personality traits and cardiovascular disease risk. Here, we further examine dispositional correlates of cardiometabolic risk within a hierarchical model of personality that proposes higher‐order traits of Stability (shared variance of Agreeableness, Conscientiousness, inverse Neuroticism) and Plasticity (Extraversion, Openness), and we test hypothesized mediation via biological and behavioral factors. In an observational study of 856 community volunteers aged 30–54 years (46% male, 86% Caucasian), latent variable FFM traits (using multiple‐informant reports) and aggregated cardiometabolic risk (indicators: insulin resistance, dyslipidemia, blood pressure, adiposity) were estimated using confirmatory factor analysis (CFA). The cardiometabolic factor was regressed on each personality factor or higher‐order trait. Cross‐sectional indirect effects via systemic inflammation, cardiac autonomic control, and physical activity were tested. CFA models confirmed the Stability “meta‐trait,” but not Plasticity. Lower Stability was associated with heightened cardiometabolic risk. This association was accounted for by inflammation, autonomic function, and physical activity. Among FFM traits, only Openness was associated with risk over and above Stability, and, unlike Stability, this relationship was unexplained by the intervening variables. A Stability meta‐trait covaries with midlife cardiometabolic risk, and this association is accounted for by three candidate biological and behavioral factors.