Monday, October 24, 2016

Philippine Wonders, Kalesa and Horse Blinders

Famous for its festival themed carriages and floral accessories, the kalesa- a big-wheeled inclinced cart capable of accommodating around four people, mostly the illustrados of earlier times in the Philippines,has transcended ages and while it is not utilized as frequent as before, it is still kept as a heritage milestone particularly in Vigan and Intramuros.

As a kid riding a kalesa, I was anxious thinking that the horse will easily panic because of the busy environment and flip us over as it paces the streets of rushing cars coming in from all directions. It appears that calmness has much to do with their blinders (or their limited vision and, consequently, perception).


Species of the family Equidae (horses and relatives) are prey animals and, by design, are gifted with lateral eyes-meaning that their eyes are positioned at both sides of the head- giving them a wide field of view compared to frontal eyed animals like humans whose vision are vivid but limited in area scope. Though sacrificing binocular disparity and thus a less vivid perception of visual stimuli, horses are easily aware and can also respond immediately to approaching threat covered by the animal’s almost 350 degree visual field with approximately 65° of binocular vision and 285° of combined monocular vision (Sellnow n.d.).


Horses, whose family has the largest set of eyes of all mammals (Soemmerring, 1971) have the ability to see through each eye independently. While monocular vision configures the horse’s vision to a flat motion picture, it is beneficial in identifying movement especially those from afar. This lets the horse to immediately notice potential forms of danger like predators (Miller, 1999). But such feature is disabled in the case of the kalsesa as it can only see incoming traffic from one direction. Horses' binocular vision (though a limited one) is useful for three-dimension vision.

In a study by Dziezyc, and colleagues (2011), they tried to determine the effect of ocular blinders on driving horses’ heart rate to visual and auditory stimuli. A balanced crossover trial with eight horses of different breeds randomly assigned to either wear blinders or not, and in which order, were subjected to repeated sequences of four distinct stimuli (chain rattle, cap gun, umbrella opening, and shaking of aluminum can containing coins). Two weeks later, this process was repeated but reversing the order of the horses who wore blinders. Their results showed that wearing blinders was generally directly related to decreased heart rate if subjected to either a familiar auditory or to either familiar or unfamiliar visual stimuli. It is only in the case of the presentation of unfamiliar sounds that created an increase in heart rate to blinder-equipped horses. Overall, blinders function to decrease tension and stress in horses by limiting their field of vision; particularly monocular vision that is equipped with long distance motion sensitivity which also coordinates to both their "modified" perception and behavior. The authors suggest that horses that showed panic were those most probably having poor vision caused by trauma or disease. Blinders focus the vision of the horse, not damage their visual acuity; hence their awareness of what there "is" through a limited scope, results to a calmer state.

Safety is an important aspect especially in the field of transportation; and in the case of the kalesa, horse blinders play an important role. In my realization, the use of blinders for horses has its advantages and disadvantages. One positive is that it explains why horses are able to focus only on what’s ahead and not easily get blundered; secondly, binocular vision takes superior use than monocular vision; hence giving the animal more vivid vision; and lastly is a visual field that is analogous to Donald Hoffman's interface theory- which states that what organisms see are those that are beneficial to their survival or function; and that is more relevant than seeing the "truth" per se. For the kalesa horse, seeing the road ahead is the most important thing than seeing all vehicles swishing in all directions which may cause panic. A disadvantage to this method is that it goes against the nature of horses; and that it has its ability to sense danger from different directions decreased. However, this limitation is compensated by the kutsero- or the kalesa driver- as he serves as an extension to the horse’s limited visual modality.


Riding a kalesa is not as dangerous and nerve-wrecking as our younger selves thought. Now that we understand its dynamics more (thank you blinders), perhaps we would like to refresh the experience of a kalesa ride as we bring with us this knowledge. It’s just that today's kalesas are slowly going extinct as they pace their way out of the cities; making their case to perhaps remain as wonders.

  

References

Dziezyc, J., Taylor, L., Boggess, M. M., & Scott, H. M. (2011). The effect of ocular blinkers on the horses’ reactions to four different visual and audible stimuli: Results of a crossover trial. Veterinary Ophthalmology, 14(5), 327-332. doi:10.1111/j.1463-5224.2011.00880.x

Hanggi, E. B. (1999). Interocular transfer in horses  (Equus caballus). Journal of Equine Veterinary  Science, 19(8), 518-524.

Miller, R. M. (1999). Understanding the Ancient Secrets of the Horse’s Mind. Russell Meerdink Co. Timney, B., and Macuda, T. 2001. Vision and hearing in horses. Journal of American Veterinary Medical Association, Vol. 218, #10.

Soemmerring DW. (1971). A comment on the horizontal sections of eyes in man and animals. Anderson SR, Munk O, eds. Schepelern HD, transl. Copenhagen: Bogtrykkeriet Forum.                                

Sellnow, Happy Trails, p. 46


Images:
http://www.deviantart.com/tag/kalesa?offset=132


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