Monthly Archives: March 2021

Animal experiments on whether pose and expression control mood

Amy Cuddy promoted power poses which she claimed boosted confidence and success. Replication of her results failed (the effects were not found in other psychology studies), then succeeded again, so the debate continues. Similarly, adopting a smiling expression makes people happier. Measuring the psychological effects of posture and expression is complicated in humans. For example, due to experimenter demand effects. Animals are simpler and cheaper to experiment with, but I did not find any animal experiments on power poses on Google Scholar on 28.03.2021.

The idea of the experiment is to move the animal into a confident or scared pose and measure the resulting behaviour, stress hormones, dominance hormones, maybe scan the brain. Potentially mood-affecting poses differ between animals, but are well-known for common pets. Lifting a dog’s tail up its back is a confident pose. Moving the tail side to side or putting the chest close to the ground and butt up in a “play-with-me bow” is happy, excited. Putting the dog’s tail between the legs is scared. Moving the dog’s gums back to bare its teeth is angry. Arching a cat’s back is angry. Curling the cat up and half-closing its eyes is contented.

The main problem is that the animal may resist being moved into these poses or get stressed by the unfamiliar treatment. A period of habituation training is needed, but if the pose has an effect, then part of this effect realises during the habituation. In this case, the measured effect size is attenuated, i.e. the pre- and post-treatment mood and behaviour look similar.

A similar experiment in people is to have a person or a robot move the limbs of the participants of the experiment into power poses instead of asking them to assume the pose. The excuse or distraction from the true purpose of the experiment may be light physical exercise, physical therapy or massage. This includes a facial massage, which may stretch the face into a smile or compress into a frown. The usual questionnaires and measurements may be administered after moving the body or face into these poses or expressions.

Improving the accuracy of waist circumference measurement

Waistline needs to be measured for clothes size determination and health evaluation, but the instructions to do it are vague: keep the stomach neutral, neither sucked in nor bulged out, hold the measuring tape not too loosely nor too tight. A person’s waist expands and contracts with the breath, so at which point of the breath cycle should the measurement be taken? How much tension should the measuring tape have?

Averaging several measurements would be more accurate than a single vaguely defined one, both in the sense of replication across different measurers and in the sense of corresponding to the physical quantity of interest (health status, tightness of the clothes). One simple way is to average the measured perimeter of a maximally sucked-in gut and a maximally pushed-out gut.

A better measure, but quite difficult to take, is to average the waist circumference across the whole cycle of breathing in and out, for several cycles. A device to do this would be a loop of flexible measuring tape pulled into a roll by a spring, similarly to a construction measuring tape made of metal. The roll would contain electronics which continuously record how much tape is in the roll, therefore the length of the loop outside the roll. The length data could be averaged to obtain the average waistline.

A more modern method is to use two cameras pointed at the person from two sides at waist height, recording a 3D video of the waist over the breath cycle. The video could then be averaged on a computer to find the mean volume. Whole-body volume could be determined similarly – no need for Archimedes’ Eureka method of submerging the body in a bathtub with a volume scale on it. The volume and the weight determine the density of the body, which gives partial information about its fat percentage.