Ezequiel Morsella Ph.D.

Consciousness and the Brain

Three Clues About Consciousness

Three observations reveal much about the nature of consciousness and the brain.

Posted Aug 08, 2018

(This is Part 1 of a two-part blog series.)

One need not be a scientist to notice that most of the contents of our conscious mind—that is, most of the things we are aware of—arise independently of our intentions. This is obvious in the case of most percepts and urges. For example, one sees an ice cream sundae and, if hungry, desires it. To one, the percept and the urge "just happen.” These percepts and urges are created, not by us, but by sophisticated processes in the brain, mechanisms working behind the scenes. We could be construed as the recipients, and not the architects, of such “mental representations." These representations may also be spontaneous, out-of-the-blue memories or even sophisticated insights, as in the aha moments we have all experienced. That conscious contents arise independently of our intentions or desires is explained by the notion of "encapsulation.” We cannot turn off percepts of urges at will, at least not without some difficulty. These contents are usually insulated or “encapsulated" from our beliefs and desires. (This is actually a good thing: See here.) 

Encapsulation is believed to underlie many visual illusions: For instance, one might know that the two lines composing the Müller-Lyer illusion are of equal length, but this does not change at all how the lines appear to one. 

Wikipedia PD
Müller-Lyer Illusion
Source: Wikipedia PD

One line certainly looks longer than the other line! Similarly, one might know that an ice cream sundae is something that should not be desired, but this usually does little to weaken the cravings one experiences when such a treat is placed before one. 

Wikipedia PD
Source: Wikipedia PD

Encapsulation is Clue Number One about the nature of consciousness and the complex processes underlying its varied contents.

Although most conscious contents arise involuntarily, effortlessly, and are encapsulated, overt behavior might not always reflect this. For example, regarding urges, one could desire to do X but nonetheless do Y. And regarding percepts, one could assert with certainty that the lines in the Müller-Lyer illusion are in fact equal in length (because one measured them), despite one’s distorted perceptions of the lines. According to some theories (e.g., Passive Frame Theory), this ability in overt behavior to override encapsulation is thanks to the functional properties of the conscious field, which permits all conscious contents (however encapsulated each may be) to influence behavior collectively at one moment in time (this is Clue Number Two about consciousness).

The last clue concerns the at one moment in time phrase in the last sentence. At one moment in time, the conscious field is limited in how much “collective influence” there can be, due in part to the limitations of the various (unconscious) systems that are working behind the scenes to input conscious contents into the field. If a content cannot participate in the field at one moment in time, then it cannot guide voluntary behavior or decision making at that moment. One might be unaware of this important limitation, for the conscious field often has the absence of information without any clues about such an absence or about anything having gone awry, as occurs in dreams and in the Müller-Lyer illusion.


Morsella, E., Godwin, C. A., Jantz, T. K., Krieger, S. C., & Gazzaley, A. (2016). Homing in on consciousness in the nervous system: An action-based synthesis. Behavioral and Brain Sciences [Target Article], 39, 1-17.