From the good people at Numberphile;
Current Directions in Psychological Science has just published a special issue on cognition in dogs! Here is a list of the articles:
Ádám Miklósi and Enikő Kubinyi
Current Trends in Canine Problem-Solving and Cognition
Rosalind Arden, Miles K. Bensky, and Mark J. Adams
A Review of Cognitive Abilities in Dogs, 1911 Through 2016: More Individual Differences, Please!
William A. Roberts and Krista Macpherson
Of Dogs and Men
Juliane Kaminski and Patrizia Piotti
Current Trends in Dog-Human Communication: Do Dogs Inform?
Monique A. R. Udell and Lauren Brubaker
Are Dogs Social Generalists? Canine Social Cognition, Attachment, and the Dog-Human Bond
Per Jensen, Mia E. Persson, Dominic Wright, Martin Johnsson, Ann-Sofie Sundman, and Lina S. V. Roth
The Genetics of How Dogs Became Our Social Allies
How Dogs Perceive and Understand Us
Clive D. L. Wynne
What Is Special About Dog Cognition?
Sarah Beurms and Holly Christine Miller
Sharing More Than the Sofa: What Dogs Can Teach Us About Human Self-Control
Thomas R. Zentall and Kristina F. Pattison
Now You See It, Now You Don’t: Object Permanence in Dogs
Gregory S. Berns and Peter F. Cook
Why Did the Dog Walk Into the MRI?
In some patients with chronic physical complaints, detailed examination fails to reveal a well-recognized underlying disease process. In this situation, the physician may suspect a psychological cause. In this review, we critically evaluated the evidence for this causal claim, focusing on complaints presenting as neurological disorders. There were four main conclusions. First, patients with these complaints frequently exhibit psychopathology but not consistently more often than patients with a comparable “organic” diagnosis, so a causal role cannot be inferred. Second, these patients report a high incidence of adverse life experiences, but again, there is insufficient evidence to indicate a causal role for any particular type of experience. Third, although psychogenic illnesses are believed to be more responsive to psychological interventions than comparable “organic” illnesses, there is currently no evidence to support this claim. Finally, recent evidence suggests that biological and physical factors play a much greater causal role in these illnesses than previously believed. We conclude that there is currently little evidential support for psychogenic theories of illness in the neurological domain. In future research, researchers need to take a wider view concerning the etiology of these illnesses.
From the paper’s conclusion:
Given our current limited understanding of medical disease and its markers, it is perhaps not surprising that not all physical complaints can be associated with a specific, well-recognized disease process. In these circumstances, it is tempting to offer a psychological explanation. However, in this review, we have argued that such explanations are not currently supported by the evidence, at least not in the domains considered here. Further, these explanations may be harmful for the patient. To find better treatments for these illnesses, researchers and practitioners may need to retire those overworked psychological explanations that are commonly invoked in the face of uncertainty and instead adopt a completely fresh perspective. Such an approach may lead to a much deeper understanding of this perplexing collection of illnesses.
A surprising finding published in the most recent issue of Clinical Psychological Science:
Seasonal affective disorder (SAD) is based on the theory that some depressions occur seasonally in response to reduced sunlight. SAD has attracted cultural and research attention for more than 30 years and influenced the DSM through inclusion of the seasonal variation modifier for the major depression diagnosis. This study was designed to determine if a seasonally related pattern of occurrence of major depression could be demonstrated in a population-based study. A cross-sectional U.S. survey of adults completed the Patient Health Questionnaire–8 Depression Scale. Regression models were used to determine if depression was related to measures of sunlight exposure. Depression was unrelated to latitude, season, or sunlight. Results do not support the validity of a seasonal modifier in major depression. The idea of seasonal depression may be strongly rooted in folk psychology, but it is not supported by objective data. Consideration should be given to discontinuing seasonal variation as a diagnostic modifier of major depression.
Here’s one passage from this very interesting paper:
There have been other reports that support this finding and cast doubt on sunlight exposure as a causal factor in depression. Hansen et al. (2008) reported no increase in depression in northern Norway during the twomonth-long “dark period” (p. 121). A large-scale study of residents of Tromsø, Norway, a city north of the arctic circle and also subject to the two-month polar night, found neither an increase in self-reported mental distress during the polar night nor a decrease in reported mental distress during the polar day (Johnsen, Wynn, & Bratlid, 2012).
When I was a kid, there were a number of popular books touting the benefits of isometric exercise. It seemed like a great idea, exercise without equipment, sweat, or repetition. As I remember them, the books would feature highly muscled individuals performing the exercises. Now, I realize that these people must have gained their muscular physiques from workouts with weights, but at the time I was quite convinced.
Naturally, I have become suspicious of claims that you can exercise without exertion. But this article by Dr. Mirkin suggests that passive exercise may have benefits for otherwise inactive people:
The exciting new concept is that passive exercise — sitting on a motor-driven stationary bicycle and letting the pedals move the person’s legs for 30 minutes — burns extra calories and lowers blood sugar and insulin levels in inactive people (Med Sci Sprts Ex, Sept, 2016;48(9):1821-1828). Having their legs moved by motor-driven pedals increases insulin sensitivity by lowering blood sugar rises after eating.
I always enjoyed reading the late Seth Robert’s blog. He never hesitated to question orthodoxies and always had some interesting new idea. However, some of the things he advocated were troubling. One example, of this was the butter brain hypothesis, the idea that consumption of butter might improve cognitive performance.
The idea is not implausible. The brain, after all, contains many lipids and the idea that consuming certain lipids might improve its performance does not sound unreasonable. The problem is butter is high in saturated fats and has been linked to heart disease.
I know, I know, many recent news reports tell us that “butter is safe” or that “butter is back.” These kind of person-bites-dog stories are popular in the media, but the science around saturated fats and cardiovascular disease is well established.
Here is an article from the New York Times reflecting on evolution and the dietary needs of the brain.
And here is a recent paper on the dangers of saturated fats. The abstract reads:
In recent years, many nutrition news headlines exclaimed that saturated fat was not linked to heart disease, leaving the public confused about whether to limit intake, as has been the dietary recommendation for several decades. However, a more nuanced look at the evidence indicates that high saturated fat diets are in fact not benign with respect to heart disease risk. Dietary recommendations should emphasize replacing saturated fats typical in red and processed meats, and certain tropical oils and dairy forms, with healthier polyunsaturated and monounsaturated fat-rich foods, such as nuts, olive oil, and fatty fish, as well as healthy sources of carbohydrates, such as fiber-rich whole-grain foods, rather than refined-grain and sugar-laden foods.
Dr. Greger explains: