Contribution to the special issue on Reptile cognition: Chemically mediated self-recognition in sibling juvenile common gartersnakes (Thamnophis sirtalis) reared on same or different diets: evidence for a chemical mirror?

Although self-recognition or self-awareness has been studied with the visually-based mirror test, passed by several species, primarily apes, the possibility of a chemically-based analogue is controversial. Prior studies suggested that chemical self-recognition may occur in some squamate reptiles. To evaluate this possibility, we studied 24 individually housed gartersnakes, Thamnophis sirtalis, raised from birth on either earthworm or fish diets and tested 12 male and 12 female snakes with cage liners that were either clean, their own, or from same-sex siblings fed their own or the opposite diet. Tongue flicking and activity were recorded in 30-minute video-recorded trials in a balanced design. After initial habituation to the stimuli, male, but not female, snakes discriminated between their own stimuli and those from littermates fed the same diet. Combined with other data and studies, the possibility that a chemical ‘mirror’ form of self-recognition exists in squamate reptiles is supported.

Applications of statistical experimental designs to improve statistical inference in weed management

In a balanced design, researchers allocate the same number of units across all treatment groups. It has been believed as a rule of thumb among some researchers in agriculture. Sometimes, an unbalanced design outperforms a balanced design. Given a specific parameter of interest, researchers can design an experiment by unevenly distributing experimental units to increase statistical information about the parameter of interest. An additional way of improving an experiment is an adaptive design (e.g., spending the total sample size in multiple steps). It is helpful to have some knowledge about the parameter of interest to design an experiment. In the initial phase of an experiment, a researcher may spend a portion of the total sample size to learn about the parameter of interest. In the later phase, the remaining portion of the sample size can be distributed in order to gain more information about the parameter of interest. Though such ideas have existed in statistical literature, they have not been applied broadly in agricultural studies. In this article, we used simulations to demonstrate the superiority of the experimental designs over the balanced designs under three practical situations: comparing two groups, studying a dose-response relationship with right-censored data, and studying a synergetic effect of two treatments. The simulations showed that an objective-specific design provides smaller error in parameter estimation and higher statistical power in hypothesis testing when compared to a balanced design. We also conducted an adaptive experimental design applied to a dose-response study with right-censored data to quantify the effect of ethanol on weed control. Retrospective simulations supported the benefit of this adaptive design as well. All researchers face different practical situations, and appropriate experimental designs will help utilize available resources efficiently.

Behavioral and Brain Responses Highlight the Role of Usage in the Preparation of Multiword Utterances for Production

Usage-based theories assume that all aspects of language processing are shaped by the distributional properties of the language. The frequency not only of words but also of larger chunks plays a major role in language processing. These theories predict that the frequency of phrases influences the time needed to prepare these phrases for production and their acoustic duration. By contrast, dominant psycholinguistic models of utterance production predict no such effects. In these models, the system keeps track of the frequency of individual words but not of co-occurrences. This study investigates the extent to which the frequency of phrases impacts naming latencies and acoustic duration with a balanced design, where the same words are recombined to build high- and low-frequency phrases. The brain signal of participants is recorded so as to obtain information on the electrophysiological bases and functional locus of frequency effects. Forty-seven participants named pictures using high- and low-frequency adjective–noun phrases. Naming latencies were shorter for high-frequency than low-frequency phrases. There was no evidence that phrase frequency impacted acoustic duration. The electrophysiological signal differed between high- and low-frequency phrases in time windows that do not overlap with conceptualization or articulation processes. These findings suggest that phrase frequency influences the preparation of phrases for production, irrespective of the lexical properties of the constituents, and that this effect originates at least partly when speakers access and encode linguistic representations. Moreover, this study provides information on how the brain signal recorded during the preparation of utterances changes with the frequency of word combinations.

Response processes in L2 writing tasks with Internet access

Technology has changed modern L2 written communication in many ways, but how these changes have affected our understanding of the L2 writing construct needs further investigation (Weigle, 2002). Given that the Internet provides access to numerous resources available to L2 writers, the Danish Ministry of Education conducted pilots to modernize the school-leaving exams by including an L2 writing assessment in French with Internet access (DAMVAD, 2013). This study is guided by questions related to (1) differences in students' writing performance with Internet access (IA) and without Internet access (WIA), (2) students' writing behavior when they have IA or WIA, and (3) students' perceptions of the writing assessment with IA. Using a balanced design, two writing tasks in a WIA and an IA version were administered to ninth-grade L2 learners of French (N=32). Scores, window tracker logs, and a student survey were used in the analysis. Results suggested that while students strongly preferred the IA tasks, the task format (IA or WIA) did not affect their scores. The students did not use online resources beyond dictionary and conjugation sites, for either the IA or the WIA task.

Harnessing the Power of Sex Differences: What a Difference Ten Years Did Not Make

Sex differences exist in a variety of neurological and psychiatric diseases in terms of prevalence, manifestation, and treatment but most past research has been conducted in males. Multiple mandates have been initiated across funding agencies (National Institute of Health, Horizon Europe, Canadian Institute for Health Research) and scientific publishers (Sex and Gender Equity in Research) for biomedical and clinical research to include both males and females in research and reporting. Although more studies are including males and females in their research there are issues in how studies are incorporating males and females in their experiments, as about a third of studies that use males and females do not report sample size and only half are conducting any analysis by sex. Furthermore, what has been lacking in the literature is a detailed assessment of not only how sex is reported in papers (e.g. sample sizes disclosed, balanced design, sex used consistently throughout the experiments) but also how the variable sex is included in any analyses (e.g. covariate). Here we investigated all papers in 2009 and 2019 in three high ranking journals for each of Neuroscience and Psychiatry. We found that there was a 30% increase in the percentage of papers that included both sexes from 2009 to 2019 such that 68% of studies in Neuroscience and Psychiatry used both males and females in 2019. Despite this increase, in 2019 only 19% of all studies used an optimal design for discovery of possible sex differences and only 5% analyzed with sex as a discovery variable. Of the studies that used males and females - 25% of studies do not disclose sample sizes, 36% of studies used an unbalanced design, and 15% of studies did not use both sexes consistently throughout the paper. The percentage of single sex papers remains unchanged across the ten years at 3% for female-only studies compared to 27% for male-only studies across both disciplines. Neuroscience had fewer papers that analyzed by sex at 20% compared to 61% of Psychiatry papers. We hope that these data will make it evident that more needs to be done to improve the inclusion of males and females in future studies to improve the health of men and women.

Start on the Right Foot: Choice in a Complex Early Environment Boosts Coping Abilities in the Domestic Fowl Chick

Early experience of a complex environment can improve biologically relevant traits related to coping abilities. However, the mechanisms underlying these positive effects are not well explored. We hypothesised that the possibility to express a choice, leading to increased control over the environment, could play an important role. In a balanced design, laying hen hatchlings were reared either in a ‘No-Choice’ environment (single litter and perch type) or a ‘Choice’ environment (four different litter and perch types). Immunological and behavioural indicators of birds’ coping abilities were explored at three weeks of age. Chicks from Choice environments had higher natural antibody titres, lower H/L ratios, required more attempts for tonic immobility induction and were more successful gaining novel food rewards in a repeated challenge test. Results imply that their improved natural immune response better prepared Choice chicks for coping with pathogenic challenges, that they experienced less chronic stress and were less fearful. To conclude, the increased potential for control and stimulation arising from making decisions in an early complex environment seemed to better prepare birds for a variety of challenges to come, boosting their adaptive capacities and their ability to make the most of opportunities.