Edwin Dalmaijer

@dalmaijer.bsky.social

808 Followers 669 Following

Cognitive neuroscientist with many interests, including why our stomachs churn when we feel disgust. I also write books on programming; teach Python, statistics, and machine learning; and develop open-source software. https://www.dalmaijer.org

Variation on the classic meme of Ralph Wiggum sitting in a bus, chuckling, and then saying "I'm in danger!" Wiggum is wearing a mortar board. Next to him we can see a LinkedIn screenshot that says "Education Administrator at University of Bristol viewed your profile."
Watch wrapped around a person’s wrist.
Peppa pig font: “Mediation: Three regressions in a trench coat.”
Peppa Pig and her family (Daddy Pig, Peppa, George, Mummy Pig) at a picnic. The picnic cloth in the centre has a bowl of sweets and a tea pot. The caption reads “I use AI for essays” and the sub-caption “Eat my slop, piggies!”
Screenshot of a paper in The Journal of Educational Research, published by Taylor & Francis, with the title “Dose local students’ presence affects remote students’ performance in blended synchronous learning?” “Dose” should have been “Does”; “affects” should have been “affect”.
Image illustrating sensor placement. The reference sensor is placed on the xiphoid process (just under the sternum), the ground is placed on the left costal margin (just under the bottom rib), and sensors one through four are place over where the stomach would be. Sensor 3 is midway through the umbilicus (navel) and the reference sensor. Sensor 4 is roughly three centimetres from sensor 3 to participant-right. Sensors 2 is also roughly three centimetres away from sensor 3, but along a 45 degree angle upwards and to participant-left. Sensor 1 lies 3 centimetres further from sensor 2, along the same 45 degree line.
Meme of a cat with what looks like a smile on its slightly tilted head, captioned “I CAN HAS CHEEZBURGER?”
A three by four grid of example stimuli found in the experimental buffet. The first column shows edible insects: meal worms, crickets, and buffalo worms. The second column shows novel savoury snacks for participants in the UK and Austria: Haldiram's Mullu Murukku, roasted broad beans, and Wah-Yuen fried dough. The third column shows common savoury snacks for the same participants: tortilla chips, crisps, and peanuts. The last column shows visually matched non-foods: Lego, wooden buttons, and wooden clothes pegs.
A three by four grid of example stimuli found in the experimental buffet. The first column shows edible insects: meal worms, crickets, and buffalo worms. The second column shows novel savoury snacks for participants in the UK and Austria: Haldiram's Mullu Murukku, roasted broad beans, and Wah-Yuen fried dough. The third column shows common savoury snacks for the same participants: tortilla chips, crisps, and peanuts. The last column shows visually matched non-foods: Lego, wooden buttons, and wooden clothes pegs.
Figure from the preprint with two rows of visualised perceived embodiment, one for the non-political and one for the political emotion. Disgust is perceived by participants to be embodied in the stomach, whereas political disgust was in the chest. This overlaps very closely with political anger, suggesting the two overlap. (And maybe that “political disgust” is not necessarily actual disgust!)
Paragraph from Edgar et al. (2024, PLOS ONE): “The summarised studies mostly rely on self-report measures of disgust elicited by written or picture stimuli. Such self-report measures can have excellent psychometric properties, for example the internal consistency [6] and external agreement with others’ ratings [20] of the Three-Domain Disgust Scale, or the high test-retest reliability of self-reported disgust for images [12]. While experimental tasks are often less reliable than self-report measures [21], behavioural disgust avoidance measured in preferential looking tasks has excellent internal consistency, Spearman-Brown ρ = 0.81 to 0.94 and Cronbach’s α = 0.78 to 0.91 [22], and test-retest reliability equal to self-reported disgust ratings [12]. Behavioural disgust avoidance correlates with self-reported disgust sensitivity, R = 0.28 to R = 0.34 [12], and with self-reported disgust ratings for stimuli, R = 0.19 to 0.50 [22]. However, a major difference between self-report and behavioural measures of disgust avoidance is that self-reported disgust shows a very large (Cohen’s d = 1.25) placebo effect, whereas oculomotor avoidance (gaze dwell time) in preferential looking tasks only shows a small to medium (Cohen’s d = 0.44) effect [23].”
People have exactly one canonical full name. People have exactly one full name which they go by. People have, at this point in time, exactly one canonical full name. People have, at this point in time, one full name which they go by. People have exactly N names, for any value of N. People’s names fit within a certain defined amount of space. People’s names do not change. People’s names change, but only at a certain enumerated set of events. People’s names are written in ASCII. People’s names are written in any single character set. People’s names are all mapped in Unicode code points. People’s names are case sensitive. People’s names are case insensitive. People’s names sometimes have prefixes or suffixes, but you can safely ignore those. People’s names do not contain numbers. People’s names are not written in ALL CAPS. People’s names are not written in all lower case letters.
The image is a screenshot of the title, authors, and abstract of the paper. Title: "Testing the utility of Mouseview.js for measuring associations between alcohol related attentional bias and problematic alcohol use". Abstract: "Objectives: This study examined the utility of Mouseview.js, an alternative to webcam-based eye-tracking, to assess associations between alcohol-related attentional bias and problematic alcohol use. Methods: Canadians recruited through Academic Prolific (N = 526) completed an online free-viewing task using Mouseview.js to measure biased attention to alcohol-related images. Eighteen alcohol-related images were paired with neutral images matched on visual characteristics. Attentional bias was estimated as the differences in trial-level dwell times for the image pairs. The sample consisted of 132 non-drinkers, 241 recreational drinkers, and 153 problematic drinkers. Participants’ mean age was 33.5 years, 50.8% were men, and 40.4 % identified as a racialized minority. Multi-level modelling was used for statistical analyses. Results: The difference in dwell times between alcohol-related and neutral images was larger for problematic drinkers compared to non-drinkers, B = 3.75, z = 2.61, p = .009. There were no significant differences between recreational drinkers and non-drinkers, or between recreational and problematic drinkers. Reliability for dwell times and dwell time differences ranged from acceptable (≥0.70) to good (≥0.80). Conclusions: There was an attentional bias for alcohol-related images among problematic drinkers relative to non-drinkers and the Mouseview.js indices of bias demonstrated adequate reliability. These findings provide preliminary support for the utility of Mouseview.js as a measure of attentional bias in problematic drinkers. With further validation studies, Mouseview.js may prove to be a powerful tool for conducting high-powered online studies of attentional biases associated with addictive behaviors."
Photo of a projector screen showing the results of a Mario Kart race. Two players are shown, one as Wario in first place and another as Peach in third place.
This is a version of the "The More You Know" meme: a screenshot from NBC public service announcement showing a shooting star with a rainbow trail that underscores blue text that says "The More You Know". In this version, the shooting star has the Death Star from Star Wars superimposed, and a Battle Droid seems to be heroically jumping into the frame (from the left) while holding their blaster ready for shooting.
Text from a paper by Flohr-Devaud and Neumann (2025, Translational Issues in Psychological Science, doi: https://doi.org/10.1037/tps0000469 ). The screenshot offers a larger extract from the Methods section to show the "Sample" heading for context, but the crucial bit is "Paramedics (40 male, 24 female, one diver) from a German emergency service organization (M age = 33.25, SD = 12.87) participated." The section "one diver" is highlighted for the purpose of this post (but not in the original paper).
Figure comprised of three subplots. Each subplot represents a third of the sample, here ordered by the healthiness ratings that participants gave to foods in each category. Each panel shows three lines, each depicting gastric power along its typical frequencies (x-axis, ranging from 1 to 10 cycles per minute). Each line represents a food type: "healthy" (in green), "unhealthy" (in yellow), and "disgusting" (in brown). The important point is that normogastric power is higher for those who gave low healthiness ratings, gastric power is high for unhealthy foods and low for healthy foods. However, those who gave high healthiness ratings show higher gastric power for healthy foods. (Note that the presentation in three groups is just for visualisation; the actual statistical analysis treats orthorexia as continuous variable and shows an interaction between it and food conditions.)
Figure comprised of three subplots. Each subplot represents a third of the sample, here ordered by orthorexia scores. Each panel shows three lines, each depicting gastric power along its typical frequencies (x-axis, ranging from 1 to 10 cycles per minute). Each line represents a food type: "healthy" (in green), "unhealthy" (in yellow), and "disgusting" (in brown). The important point is that normogastric power is higher for healthy compared to unhealthy foods for those who score lower on orthorexic traits. However, for those high on orthorexic traits, this difference disappears. (Note that the presentation in three groups is just for visualisation; the actual statistical analysis treats orthorexia as continuous variable and shows an interaction between it and food conditions.)
Perfect figure for an album cover, depicting nine faces in a 3x3 grid. The middle face looks directly at the viewer, and each other face is looking away in the direction they are in from the central face (e.g. top-left is looking towards top-left). The faces are made up of facial landmarks (grey disks), from each of which originates a coefficient vector. This line is longer and brighter for stronger effects. In this case, that effect is an interaction between orthorexic traits and facial responses to disgusting foods (compared to healthy ones). The largest effects are around the nose, indicating pulling up of the levator labii. There is also a bit of squinting and brow furrowing.
This is a figure depicting a series of 15 box plots with density estimates. There are three ratings along the x-axis (healthiness, disgust, familiarity, pleasantness, and desire to eat). Each rating is given for 45 stimuli, 15 each in three food categories: "healthy" (in green), "unhealthy" (in yellow), and "disgusting" (in brown). Healthy foods received higher healthiness ratings; disgusting foods received higher disgust ratings; and familiarity, pleasantness, and desire to eat show very similar distributions between healthy and unhealthy foods (but all are lower for disgusting foods!).
Photo taken from a seat in the Tinbergen’s main lecture theatre, looking out onto the speaker area. Five people, including the Heads of Departments in the Tinbergen and several university officials, are at the front. The speakers are informing staff of the Tinbergen closure, and answering questions.
Yet another image from "Doing Good: The Life of Toronto's General Hospital" by J.T.H. Connor. It shows an official photograph of two rows of physicians: nine standing in the back row, and five seated in the front row. The caption reads: "Although medicine remained an exquisitely male domain, in the twentieth century women started to breach its ranks. Dr Pearl Jane Sproule (seated left) was among the first to be appointed to the hospital's house staff; from 1924 to 1940, she was chief of the ear, nose, and throat department of Toronto's Women's College Hospital. Dr J.N.E. Brown, then medical superintendent, is seated centre."
The image is again from the book "Doing good : the life of Toronto's General Hospital" by J.T.H. Connor. It shows ten physicians sat at a table. They are wearing black suits, most with their white cotes still on. Some appear to be smoking or eating, and one is draped over another. The caption reads "Members of the house staff had their own quarters in the hospital. As this 1898 glimpse of 'off-duty' behaviour illustrates, the manly pursuit of boxing, the consumption of beer, and the enjoyment of a good cigar contributed to 'male bonding'."
The image is a screenshot from a 2001 edition of the Journal of the American Medical Association (JAMA), volume 285, number 17. It shows fourteen physicians, posing for a group photo in their white coats. What makes this photo unique, is that all fourteen men are holding newborn babies. The photo caption reads: "“Even while ‘on duty,’ residents might indulge themselves to show the tender side of their masculine nature. Here members of house staff in 1904-5 pose with babies born in the Burnside Lying-In wing.” From: Doing Good: The Life of Toronto’s General Hospital, by J. T. H. Connor, 342 pp, with illus, $60, ISBN 0-8020-4774-2, Toronto, Ontario, Canada, University of Toronto Press, 2001. Reprinted by permission of University Health Network, Toronto, Ontario, Canada."
The image is a graph with six sub-plots, each in a new row, top-to-bottom: Pupil size (arbitrary units), anger, disgust, fear, happy, and sad (all emotions rated 1-9). The x-axis shows the stimulus numbers, each coding for a different 30-second sound-stimulus from Experiment 2 in the paper. A box-plot with distribution estimate is visible for each stimulus-rating combination. Low ratings almost always showing strong agreement within each stimulus, but higher ratings show variability. For example, stimulus 19 was almost exclusively rated low on anger, disgust, fear, and sadness; but while its happiness rating was reasonably high on average (about 6), there was still substantial variability (especially in the 5-9 range). Key take-aways from the plot are that ratings are variable but have some agreement, that stimuli can be rated high for more than one emotion, and that high disgust ratings mostly occured for stimuli that are also higher in pupil size.
The image is a graph that shows five lines (one for each emotion), punctuated with small dots for uncorrected statistical significance and bigger dots for statistical significance after multiple-comparisons correction. The x-axis is labelled "Time (seconds)" and runs from just before 0 to 30 seconds. The y-axis reads "Standardised beta coefficient" and runs from just under -0.15 to 0.3. A dotted line spans across y=0, and labels indicate that positive values mean that "Emotion predicts larger pupil" and negative values that "Emotion predicts smaller pupil". Anger (in red) shows a negative trajectory from ~5 seconds after stimulus onset, with some bits statistically different from 0. Fear (purple) is indistinguishable from 0, until it is associated with larger pupils in the last 2-3 seconds. Sadness is somewhat positively associated with pupil size, but not after multiple-comparisons correction. Happiness is associated with relative pupil dilation from ~3 seconds until the end of the stimulus. Disgust is by far the most prominent predictor of larger pupil size, with standardised coefficients about twice as high as for happiness.
Image is a photo with a view from the back of a conference room, looking at students speaking in front of a projector slide that says “BPS Southwest Undergraduate Conference 2025”.
This photo shows a pair of shoes, seemingly at the end of crossed legs (not visible). On the tip of the toes is a robin, stood straight up, with its head turned so that one eye looks into the camera.
Histogram showing a roughly normal distribution that is centred on 0.5. The x-label is "N(top&bottom) / N(top)", the y-label is "N observations". The face colour of the bars is hot pink.
The cover of Service Model by Adrian Tchaikovsky. The background shows a modern skyline against a sunset-coloured sky. The foreground shows a robot hand that is shaped like a human's. The hand is delicately holding a cup that is slightly cracked and a has some thick red liquid along the rim.
Photo shows a very busy podium during a DragonForce performance. A woman plays guitar on the viewer’s left, and a man sings (or shouts?) on the right. On the front of the podium, fireworks are going off (bright and towards white, possibly magnesium-based). From the back of the podium, but looming over it, are two giant dragons with open mouths full of teeth. In the foreground, the audience is visible.
Graph showing three groups: non-parent controls, parents to exclusively milk-fed babies, and parents to weaning or weaned children. The three groups show no difference on general disgust sensitivity (measured with the revised Disgust Scale questionnaire), but parents do self-report lower disgust sensitivity for parent-specific items and diaper changes.
A 12-panel figure, with each panel showing the outcomes of a preferential looking task. In this task, participants were shown two stimuli (one neutral, one disgusting), and could freely look at each. Each graph shows the differences in dwell time between the two stimuli, as a function of time in each trial (10 seconds). Most panels show a brief initial bias towards the disgusting stimulus, followed by sustained bias away from it ("disgust avoidance"). The top row shows this for non-parent controls, across all four columns: regular bodily-effluvia, meconium diapers, milk-fed baby diapers, and weaning baby diapers. The bottom row shows the same categories, but for parents. This group shows no bias away from any of the disgusting stimuli! The middle row shows parents to exclusively milk-fed (i.e. very young) babies, and (surprisingly!) shows as much disgust avoidance as the non-parent control group.
Photo of, literally, the snottiest baby you will ever see. They are looking directly at the camera, and the entirety of the space between their nose and mouth is snot. Literally all of it. It’s bulging out, it’s green, it’s flowing into their mouth. Frankly, it makes you wonder why the parent who took the photo decided to do that rather than actually wiping this poor child’s nose.
Google Maps screenshot that shows the storefront to "Frying Nemo" with a logo that closely matches that of the children's film "Finding Nemo".
Video of the same four-panel figure as from the first post in this thread. The top-left panel now draws routes as pairs of artificial navigators find their way. The bottom panels show each individual's internal components: goal-directed, social (towards other agent), memory (towards memorised landmark), and continuity (straight ahead). As the agents move, their distributions shift around, showing us how they choose to continue their paths.
Figure 3 from Dalmaijer (2024, PLOS Biology). Each panel shows the difference in route efficiency between naive agents in the experimental condition (generational turnover) and the first 12 journeys from agents in the pair control condition (without generational turnover). Positive differences indicate that naive agents had better route efficiency compared to control. Each panel represents a combination of w_goal and w_social parameters, while darker lines indicate higher levels of w_memory. Lines represent averages across 50 independent runs and their shaded areas the 95% confidence interval. The graph shows quite a complex pattern, but in general higher memory weights are typically associated with better-than-control performance for naive individuals. This suggests they are helped by their experienced counterparts when learning a new route.
The "is this a butterfly?" meme in which a man looks at object and asks "Is this a ...?" In this case, the man is looking at a graph of inter-generational route improvements in pigeons and asking "Is this cumulative culture?"
Link, from the video game Tears of the Kingdom, walks up to what looks like a big counterweight trebuchet (using stabilisers as counter-weights). When he activates the contraption, it blows up, sending him flying atop his control stick. At the end of its journey, the control stick slides across the ground, moves slightly round, and stops with Link completely unharmed despite the huge explosion.
Graph with data from a preferential looking task in children aged 5-13 years. Time is on the x-axis and a measure of behavioural disgust approach/avoidance is on the y-axis. Three lines are shown: the first presentation of a stimulus (light green), and its two repetitions (increasingly darker green). The data shows that children initially looked more at disgusting stimuli, but from about 1 second into a trial they showed a bias towards neutral stimuli. This suggests they preferred to avoid looking at disgusting stimuli in exactly the same pattern that adults show.
Top-down map view of Bangladesh. Dhaka is in the centre of the map, showing Matlab is in its south-south-western direction.