If you Google the phrase “synesthesia and ontology”, the first link that appears is by Berit Brogaard, but not for the reason you might think. To most reasonable people’s astonishment, not even Brit has written something on the intersection of synesthesia and ontology. The link only arises because her CV is so extensive that it includes two separate papers, one on synesthesia—”Synesthesia as Automatic, High-Level Visual Memory” and the other on ontology—”An Emotion Ontology Based on the Perceived Response Theory.” Ontology is the study of being, matter or existence. Ontologists spend their days with questions about what, in fact, exists. For example, disputes have emerged over the question, “Do abstract entities such as numbers or properties exist?” Now, when we mix synesthesia and ontology, my question is that if synesthesia is true, do we have to revise our ontological system and if so, how much? Consider that an ontologist walks up to a conversation between two people with grapheme-color synesthesia talking about the color of a particular number such as 3. As one person says that the number ‘3’ is blue for her, the other synesthete says that when she sees ‘3’, it’s red. Yet, the color of the number does not exist based on their wishes or preferences; rather ‘3’ really seems blue for one synesthete and red for another. Then… Enter ontology. Upon hearing this conversation between two synesthetes, an ontologist aligned with Rudolph Carnap’s view would say, “Numbers exist in our linguistic frameworks insofar as they are pragmatically useful in our practices in mathematics and physics.”  Then a sympathizer of Willard Quine’s view would say, “Numbers exist insofar as they accord with our best total system of beliefs in which logic and mathematics is at the center.” Both ontologists accept the existence of numbers, but then, what can they say about the first-person reports of synesthetes?  Perhaps, ontologists would say that they their total systems are to be revised in the same way that science is revised given the current evidence. Given results from the Synesthesia Battery Tests and other empirical data, synesthesia appears to nicely blend with our ontological commitments. Yet, given Quine’s view on revising our total system of beliefs, a further issue arises. Quine holds that any and all of our beliefs are tested by empirical evidence. For the total system of beliefs, the areas of logic, mathematics and meanings of terms are at the center and less significant areas are at the periphery. Revising beliefs in the center is much more difficult than revising beliefs on the border of the web of beliefs. Kyle Stanford characterizes how we revising our system of beliefs occurs: “A mismatch between what the web as a...

A visual search is a task that involves searching for an object in a subject’s field of vision (the target) among other objects or features (the distractors). For example, people often search for a coffee mug among other cups in a cupboard or a face in a crowd. Since people are subject to these visual searches every day, researchers are interested in understanding how this process works. We use visual search tasks to test the role of attention in moderating how the mind focuses on particular objects of our perception. One type of study involves measuring the time it takes for a subject to find a target among distractors, called the reaction time (RT). Research has shown that RT increases with the difficulty of the task. For example, it typically takes much longer to find a face among a crowd of 100 people than it does to find the same face among 10 people. When we study this in the lab, we often use a matrix consisting of targets and distractors and ask a subject to locate the target while a computer measures RT (see Fig. 1). Fig. 1: The more distractors there are, the longer it takes to find the letter B in the array. One interesting phenomenon of some visual search tasks is what we call the pop-out effect. The most obvious example of this is when one target is significantly different in color or shape than a set of distractors (See Fig. 2). This difference seemingly causes graphemes to “pop out” from the matrix. In these cases RT tends to decrease dramatically. Fig. 2: Both the red X and the O shape can be found efficiently. Research has now turned to determining whether synesthetes are subject to a synesthetic pop-out effect. Grapheme-color synesthetes attribute particular colors to letters or numbers. Could these synesthetic properties affect RT in visual search tasks? Research suggests these properties in fact do make visual searches more efficient. An example of this involves using a matrix made up of targets arranged in a particular shape among a group of distractors (see Fig. 3). The subject is asked to determine the shape that the targets make while a computer measures RT. Grapheme-color synesthetes have a shorter RT than non-synesthetes. But what’s really cool about this task is that synesthetes take significantly longer to name the shape if the targets and distractors evoke the same synesthetic colors. These studies have been taken to prove that synesthesia is a very real phenomenon—synesthesia’s effect on RT is not merely a heuristic. Fig. 3: When normal subjects are presented with the figure on the left, it takes them several seconds to identify the hidden shape. Some grapheme-color...