Role of Representations in Cognition

Q: What roles do representations play in learning?

The philosophical theories regarding the nature of learning process revolved around the idea that the process associated stimulus traces that connected the internal representations of stimuli that repeatedly occur together in time and space. The term representation refers to something that symbolizes or presents likeness of something to the mind or senses.

According to the author, the term is used in its mathematical sense. He says that learning should be studied in the framework of representation. Studying animals, he developed a framework that linked quantities computed and stored by the nervous system representing aspects of the animal's environment to the animal's relationship with that environment. The brain is said to represent an aspect of the environment when there is a functioning isomorphism between an aspect of the environment and a brain process that adapts the animal's behavior to it.

Again he uses the mathematical definition of isomorphism saying that they are formal correspondences between distinct systems of mathematical study; often with one being an object not well understood and another more richly developed system. And a functioning isomorphism is one in which the capacity of one system to represent another is put to use. This system, he puts to use in order to study learning in animals. He says that the representation of space and time is crucial. Representation of space is through representation of the geometric relationships among surfaces in the animal's environment and its momentary geometric relationship to them and representation of time is through representation of time at which events have occurred and the representation of temporal intervals. This means that there is an orderly mapping from entities in the environment to entities in the nervous system. These neuro-physiological entities enter the neuro-physiological processes that correspond in their formal characteristics to external processes. All this together constitute a neural system that is isomorphic to an environmental system. Distinct systems of neural variables and neural processes model distinct aspects of the environment, thus forming neural subsystems. Each of these subsystems serves to adapt the animal's behavior to the aspect of the environment modeled by that module. These neural modules accumulate information about the world overtime and this accumulation of information is called learning.

Furthermore he says that while navigating through our environment (space), both, humans and animals use the process of estimating and updating their position by gauging the speed, direction and time of movement. This helps them construct a map of their environment and using that they can pilot themselves and orient themselves to their targeted destination. For example, a rat has a map which preserves the distance and angle and using this map the rat establishes its position within the environment that it perceives. These maps are impenetrable to non geometric data. The rats use the map by translating and rotating its position so that it is congruent to the currently perceived shape of the environment and its corresponding representation on the map.

Similarly, both, humans and animals have representation for time: the time at which individual events take place and the temporal intervals that separate these events; since time is a fundamental behavioral matrix. This ability enables them to represent the temporal structure of experience. This allows the creature to adapt its behavior to the temporal structure of the events in its behavioral space. It is said that all creatures have internal clocks that are triggered by rhythmic biochemical processes. The existence of an array of internal rhythmic processes with different periods provides a biological foundation for representing the time of occurrence of an event. These internal oscillations synchronize with external oscillations. The representations of the temporal intervals are generated by 1) subtracting the time of occurrence of the earlier event from the time of occurrence of the later event and 2) starting a rhythmic pulse generator ('a neuro-physiological multi-vibrator' as described by Church and Gibbon) when the first event occurs and counting the number of pulses generated until the second event. There is a difference between phase sense and interval sense. Phase sense refers to the ability of anticipating events that occur at fixed times while interval sense refers to the ability to respond to something that occurs after a fixed amount of time has elapsed after the occurrence of an event that may happen at any time. Behavior based on elapsed interval s could derive from computations performed on recorded phases of occurrence. In both the cases new computations considerations come into play when one considers behaviors based on learned time intervals, which may commence with the occurrence of a temporarily arbitrary time signal, one to which no endogenous oscillation is linked. Therefore, it is important to distinguish between the representation of time of occurrence and the representation of temporal intervals.

The author also states that animals are capable of one - to - one mapping of numerosity of events to behavior - controlling entities; meaning that the internal operations performed on the representations of temporal intervals include operations isomorphic to decision and subtraction. The ability of representing the numerosity of the items encountered in a given period along with the duration of the interval, during experiments where rats were rewarded with food, enables them to compute a representation of the rate at which items were encountered - i.e. food. This is vital for rational decision making - i.e. where to look for food depending upon the rate of encounter with it.

This information about the representation of space, time and numbers was then applied to the theory of classical conditioning which states that learning occurs due to the pairing of two stimuli in space and time and the tendency of responding to one stimulus as if it