arXiv subjects

Edwin S. Dalmaijer

Publications and source records attributed to Edwin S. Dalmaijer.

4 recordsLinked to original sources

arXiv2025

A tutorial on electrogastrography using low-cost hardware and open-source software

Electrogastrography is the recording of changes in electric potential caused by the stomach's pacemaker region, typically through several cutaneous sensors placed on the abdomen. It is a worthwhile technique in medical and psychological research, but also relatively niche. Here we present a tutorial on the acquisition and analysis of the human electrogastrogram. Because dedicated equipment and software can be prohibitively expensive, we demonstrate how data can be acquired using a low-cost OpenBCI Ganglion amplifier. We also present a processing pipeline that minimises attrition, which is particularly helpful for low-cost equipment but also applicable to top-of-the-line hardware. Our approach comprises outlier rejection, frequency filtering, movement filtering, and noise reduction using independent component analysis. Where traditional approaches include a subjective step in which only one channel is manually selected for further analysis, our pipeline recomposes the electrogastrogram from all recorded channels after automatic rejection of nuisance components. The main benefits of this approach are reduced attrition, retention of data from all recorded channels, and reduced influence of researcher bias. In addition to our tutorial on the method, we offer a proof-of-principle in which our approach leads to reduced data rejection compared to established methods. We aimed to describe each step in sufficient detail to be implemented in any programming language. In addition, we made an open-source Python package freely available for ease of use.

q-bio.NC↗

arXiv2023

Cumulative culture spontaneously emerges in artificial navigators who are social and memory-guided

Cumulative cultural evolution occurs when adaptive innovations are passed down to consecutive generations through social learning. This process has shaped human technological innovation, but also occurs in non-human species. While it is traditionally argued that cumulative culture relies on high-fidelity social transmission and advanced cognitive skills, here I show that a much simpler system suffices. Cumulative culture spontaneously emerged in artificial agents who navigate with a minimal cognitive architecture of goal-direction, social proximity, and route memory. Within each generation, naive individuals benefitted from being paired with experienced navigators because they could follow previously established routes. Crucially, experienced navigators also benefitted from the presence of naive individuals through regression to the goal. As experienced agents followed their memorised path, their naive counterparts (unhindered by route memory) were more likely to err towards than away from the goal, and thus biased the pair in that direction. This improved route efficiency within each generation. In control experiments, cumulative culture was attenuated when agents' social proximity or route memory were lesioned, whereas eliminating goal-direction only reduced efficiency. These results demonstrate that cumulative cultural evolution occurs even in the absence of sophisticated communication or thought. One interpretation of this finding is that current definitions are too loose, and should be narrowed. An alternative conclusion is that rudimentary cumulative culture is an emergent property of systems that seek social proximity and have an imprecise memory capacity, providing a flexible complement to traditional evolutionary mechanisms.

q-bio.PE↗

arXiv2022

The human behavioural immune system is a product of cultural evolution

Disgust is a basic emotion that serves to avoid contaminants, and is central to the behavioural immune system. While disgust-motivated avoidance occurs in bonobos and chimpanzees, humans show uniquely high levels of contamination sensitivity. Current theory postulates that human disgust is primarily a genetic adaptation, side-lining social transmission and denying parental modelling. Here, we test whether this strong view is warranted by simulating 100000 years of cultural and biological evolution in various scenarios. We modelled disgust as a trait that governed the extent to which individuals forewent potentially contaminated nutrition. This lowered their risk of gastrointestinal illness, at the cost of increasing starvation risk and birth-interval. As environmental levels and costs of contamination rose, so did relative fitness of high-disgust individuals. Evolutionary shifts in disgust as polygenic trait occurred as a consequence of germ-cell mutations, but were most prominent in populations with high initial genetic variance. Crucially, cultural transmission between generations operated at a higher rate, even if parental modelling was eliminated. This study serves not only as evidence of cultural evolution shaping the behavioural immune system, but also as an illustration of emerging theories that paint affective and cognitive mechanisms as socially transmitted rather than biologically determined functions.

q-bio.PE↗

arXiv2021

Banana for scale: Gauging trends in academic interest by normalising publication rates to common and innocuous keywords

Many academics use yearly publication numbers to quantify academic interest for their research topic. While such visualisations are ubiquitous in grant applications, manuscript introductions, and review articles, they fail to account for the rapid growth in scientific publications. As a result, any search term will likely show an increase in supposed "academic interest". One proposed solution is to normalise yearly publication rates by field size, but this is arduous and difficult. Here, we propose an simpler index that normalises keywords of interest by a ubiquitous and innocuous keyword, such as "banana". Alternatively, one could opt for field-specific keywords or hierarchical structures (e.g. PubMed's Medical Subject Headings, MeSH) to compute "interest market share". Using this approach, we uncovered plausible trends in academic interest in examples from the medical literature. In neuroimaging, we found that not the supplementary motor area (as was previously claimed), but the prefrontal cortex is the most interesting part of the brain. In cancer research, we found a contemporary preference for cancers with high prevalence and clinical severity, and notable declines in interest for more treatable or likely benign neoplasms. Finally, we found that interest in respiratory viral infections spiked when strains showed potential for pandemic involvement, with SARS-CoV-2 and the COVID-19 pandemic being the most extreme example. In sum, the time is ripe for a quick and easy method to quantify trends in academic interest for anecdotal purposes. We provide such a method, along with software for researchers looking to implement it in their own writing.

cs.DL↗