Archive for the ‘Philosophy of Mind’ Category

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First-Mate Z

December 21, 2012
Shaun: "If this thing doesn't have intentionality, how does it have a brain eating goal?"Ed: "Who cares! I just wish he'd jog on."

Shaun: “If this thing doesn’t have intentionality, how does it have a brain-eating goal?”
Ed: “Who cares! Let’s just tell him to jog on.”

First-Mate Z

or

How Your Inner Zombie Rules Your World

by Mike Stayton

In this essay I argue that mental modularity can explain the existence and function of our inner zombie mind. I will first explicate a modular hypothesis that attempts to account for complex unconscious actions.This will be followed by experimental and clinical research providing support for the hypothesis. To close I provide further explanation why modularity of mind can make sense of the zombie and conscious minds.

Most have seen a zombie on film. But what characteristics do these living dead creatures share and on what basis can I claim that we are all part zombie? Other than an insatiable taste for brains, classic zombies uniformly tend to exhibit slow clumsy movement, blank stares through glazed eyes, and general absence of sensations, feelings and a general lack of mental awareness in general.

Few realize that within each of us lies an active zombie. Sufferers of somnambulism, commonly known as sleepwalkers, regularly exhibit these same zombie-like characteristics. Sleepwalkers rise from bed and engage in unconscious activities ranging from preparing a meal to driving a car. The expression of these and similar unconscious actions are the manifestations I speak of as the actions of the zombie within. Somnambulism illustrates the existence of low-level mechanisms capable of controlling actions behind the back of conscious awareness.

Christof Koch claims that “zombie agents” are the mental mechanisms responsible for the unconscious processing of background information and activation of automatic motor operations. These zombie agents control the sleepwalker’s automatic “zombie behaviors.”[1] Surprisingly, the same zombie agents run quietly in the background of our own waking minds. To provide evidence for this, we must observe subjects whose conscious sensations have been restricted, allowing the zombie behaviors to shine through. Before we do this we will examine Goodale and Milner’s (G&D) modular hypothesis.

Goodale and Milner’s Modular Hypothesis

Perceptual research is providing a bulk of the current information regarding unconscious mechanisms. In Sight Unseen, G&D argue that there are two distinct visual systems – the ventral and dorsal streams. The ventral stream specializes in gathering information about the world around us and is responsible for providing conscious perception. The function of the dorsal stream is vision for action. These streams corroborate to give us the dual abilities of gathering information and interacting with our environment.

The ventral stream is scene-based, providing us with a cognitive photograph of the world. Its function is to construct a useful knowledge-based representation of our environment. The ventral stream forwards information to higher-level cognitive areas for identification and categorization. This information is then stored in longer-term memory. The snap-shot-like ability allows us to remember and think of the past, present and future, in turn giving us the ability to plan. Ventral perception provides relative, object-based, metrics comparing objects in terms of each other, e.g. bigger/smaller than, closer/further than. Its higher-level connections provide us with information necessary for correctly identifying people and objects. Accurate identification requires a high level of processing causing this stream to run relatively slowly. The ventral stream provides intentionality – the content for our thoughts.

The dorsal stream relates to what I am calling zombie agents. It provides the information necessary for action. To do this, it processes the immediate present, allowing us to interact with our environment in real-time. In addition, it relies on more precise egocentric metrics based on the relation between agent and object. While the ventral stream informs us that our spoon is further than our cereal bowl, this pictorial knowledge is not sufficient to accurately guide our hand to our spoon. We need to know the exact location of objects to act upon them. Such precise metrics are accomplished by a derivation comparing an object in relation to the known location of the hand and assisted by visual stereopsis. Because the relation between an agent and his environment is in constant flux, especially during agent action, the dorsal stream is required to process information at near-instantaneous speeds. This immediacy negates any need for long-term memory. It instead utilizes only enough unconscious episodic memory for accomplishing the task at hand. Object-specific details are also unnecessary.

Evidence for the Everyday Zombie

It is these zombie agents that enable the unconscious sleepwalker to avoid stubbing his toe. Night walking experiments[2] show it is possible to navigate your environment without conscious attention to the surroundings. The subject attempts to walk in the dark, outside, while focusing his attention on a phosphorescent sphere suspended from the bill of his baseball cap. This purposeful fixation directs the subject’s attention away from his environment. Eventually, the subject is able to move confidently through the dark while successfully avoiding ground-level obstacles. Not only can your inner zombie process visual feedback without conscious vision, but it can also signal the appropriate feed-forward responses to coordinate the plethora of complex mechanisms required for navigating your environment while simultaneously preventing you from tripping over the ottoman.

Koch explains nightwalking[3] by positing that the dorsal stream is the mechanism monitoring the extreme lower visual peripheries and controlling the coordination and placement of the feet. Zombie agents are all that is needed for successful navigation. Koch states that higher-level categorization, controlled by scene-based consciousness, is unnecessary at the periphery of vision.

Visual agnosia patients can see but have a strange inability to visually recognize certain aspects of objects. One patient, called DF, can see colors and textures, navigate her environment and grasp and catch objects. She cannot, however, differentiate the shapes and orientation of objects. Despite the inability to discern whether an object is vertical or horizontal, she can correctly orient her hand to insert a card into a randomly angled slot. Furthermore, she can’t tell a smaller from a larger object but her grip correctly adjusts to the size of an object in the process of grasping it. The ability to grasp indicates that DF’s quick processing zombie brain is functioning to correctly adjust her grip in real time as her hand moves closer to the object. Additional support can be derived from the fact that she can correctly orient her hand to perform an action on an object, all the while lacking the ability to conceptualize and discuss the same objects orientation. This evidence indicates damage to the ventral stream.

On the opposing end of the spectrum, a patient called IG suffers from dorsal stream damage. IG lacks the zombie agents necessary to perform actions in real-time. She has difficulty scaling the size of her grasp when reaching for items, but accurately scales it when delayed and forced to pantomime the action from memory. These two opposing afflictions show a direct correlation between ventral and dorsal actions. DF can perform immediate tasks better because her zombie agents are functional. IG can complete delayed tasks better because she has a relatively intact ventral stream.

What’s the meaning of this?

            The separability of our zombie and conscious agents in terms of function, as exposed by experimental and clinical research, provides positive evidence for a modularity of mind thesis. One version of this theory[4] states that the mind is composed of a central system, responsible for high-level processes, combined with additional modules providing low-level processing. The conscious mind would be what we might relate to the central system while the automatic zombie agents would be the auxiliary modules. We have seen that the central system may not have access to all information from zombie modules. This mental sequestration is called informational encapsulation. Informational encapsulation explains why visual illusions cannot be rationalized even though we know it to be an illusion. Physical and conceptual modularity would explain why damage to certain areas of the brain causes consequences such as those illustrated above.

Each module plays its own crucial role in directing our actions and thought processes. The zombie directs precise movements and expeditiously scans for both potential interests and dangers. Simultaneously the conscious brain is free to tackle more complex intellectual and memory-heavy challenges.  If one of these modules is damaged an individual may continue to function, although certain functions may be impaired. Damage to the conscious central system may impair our ability to think and plan, while damage to a zombie module inhibits our ability to interact in real-time. It is only through cooperation that operations of the highest and most complex cognitive capacities can occur.

All of this knowledge can be deepened with biological evidence showing that cognitively lesser animals, such as reptiles, possess physical components related to visual dorsal streams but lack evidence for the more complex ventral streams.[5]  This may indicate that the ventral stream, including consciousness, is a more recent evolutionary advancement that is unnecessary for living beings. It is a feature that most likely survived due to the benefits gained from its ability to process complex information, without detrimental loss of cognitive or neuromotor resources. By splitting the total computations between them, the parallel processing of modular unconscious and conscious agents allow us to process a huge amount of information. The role of the zombie is to free up resources allowing consciousness to do what it does best. Considering the conscious mind as the captain of a ship, he is allowed to deliberate, analyze, judge and plan. The only reason he has the resources for this is thanks to First Mate Zombie automatically handling much of the day-to-day operations. So, if you ever find you literally cannot walk and chew gum at the same time, it might be time to see your friendly neighborhood neuroscientist to see if you have a zombie problem.


[1] Koch, Christof. 2004. The quest for consciousness: a neurobiological approach. Denver, Colo: Roberts and Co, 206.

[2] Koch, Christof. 2004. The quest for consciousness: a neurobiological approach. Denver, Colo: Roberts and Co, 210.

[3] Koch, Christof. 2004. The quest for consciousness: a neurobiological approach. Denver, Colo: Roberts and Co, 211.

[4] Crane, Tim. 2003. The mechanical mind: a philosophical introduction to minds, machines, and mental representation. London: Routledge, 150-152.

[5] Ramachandran, V. S., Christopher Rawlence, Emma Crichton-Miller, and Rena Baskin. 2007. Secrets of the mind. Boston, Mass: WGBH Boston Video.

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