Author: des5656

Shaping and Successive Approximations

Operant conditioning is learning that occurs based on the consequences of behavior and involve the learning of new actions. It commonly uses reinforcement and punishment to influence behavior. Reinforcement is anything that increases the desired behavior, while punishment is anything that decreases the undesired behavior. Additionally, there is both positive and negative types for reinforcement and punishment. Positive is when something pleasant is added, while negative is when something unpleasant is removed. For example, when your mom is nagging you to clean your room, and then you clean it, so she stops nagging; the nagging is the negative reinforcement because the stimulus is removed (nagging) to increase the desired behavior (cleaning your room).

One type of operant conditioning that is used is called shaping, which is how reinforcers guide behavior closer towards a desired behavior. This is how dogs are trained. Complex behaviors are able to be created through this technique. By using successive approximations, or “middle steps,” animals are able to be trained to do complex behaviors such as discriminating many types of objects and events.

I trained my dog, Hudson (pictured above), to play dead using shaping and successive approximations. I used a high-value treat as positive reinforcement when Hudson completed the desired behavior. We started by having him lay down from a standing position. This was easy because he had learned to lie down previously. Then we had him roll onto his back with his feet up. This was a little more challenging because it was not necessarily biologically predisposed to voluntarily lying on his back. This took about 2 days to get him to do correctly. Then we also taught him to “come alive” which was his release phase. This did not take long for him to learn. Through shaping and using in between steps to teach him, Hudson successfully learned to play dead and come alive!

 

Implicit Memory

Implicit (procedural) memory is a kind of long-term memory which includes known actions and skills that cannot be described. It can also be referred to as unconscious or automatic memory because it utilizes previous experiences to remember skills without actually recalling the past event. Conversely, explicit (declarative) memories are another kind of long-term memory which involves conscious thinking to retrieve memories of past experiences. Explicit memories are easily described in words. While explicit memories are processed in the hippocampus (a neural center in the limbic system), implicit memories are processed in part by the cerebellum. The cerebellum, or “little brain,” is used to coordinate voluntary movement, such as the skills stored as implicit memories. In addition, the prefrontal cortex, parietal cortex, and basal ganglia are also involved in learning motor skills, which are stored as implicit memories. The image below illustrates the location of the limbic system and the cerebellum, among other structures.

Injury to areas of the brain that are involved in implicit memories, like the cerebellum or basal ganglia, can affect implicit learning. These kinds of memories are formed and reinforced by repeated signals across synapses. Implicit memories vary in complexity, therefore vary in the complexity in the neural pathways. Through repeating the skill, the pathways are reinforced so much so that the actions may become unconscious and automatic.

When I was learning how to drive a manual car, my brother struggled to describe how and where the clutch engages. He told me you have to feel it engage. He also said that it takes a lot of practice to get the car to move without stalling, but the more you do it, the easier it gets. Moreover, the more you drive, the smoother your transitions when switching gears. After learning, I tried describing how to drive manual to my sister before we got in the car, but I found it very challenging and ended up telling her you learn through trial and error. Additionally, after being away at school for a semester, I came home and jumped in our manual car to go to the store. Without thinking I started and about halfway there, I realized how quickly and thoughtlessly the skill came back, even though I had only driven the car for two months before I left for school. Driving a car is an example of an implicit memory. The difficulty in describing how to drive a manual car and the unconscious retrieval of the skill displays how driving a car a skill stored as an implicit memory.

 

Works Cited 

“Cartoon Human Brain Anatomy in a Cut Vector Image.” VectorStock.

Cherry, Kendra. “What’s the Difference Between Implicit and Explicit Long-Term Memory?” Verywell Mind, Verywell Mind, 29 Aug. 2019.

Zimmermann, Kim Ann. “Procedural Memory: Definition and Examples.” LiveScience, Purch, 22 Feb. 2014.

Reflexes

Reflexes are the automatic response of a muscle, caused by a stimulus and does not involve consciousness. The stimulus could be a hot stove or something sharp that excites an afferent nerve causing the muscle movement. Afferent nerves are sensory neurons which carry information from the stimuli to the central nervous system (CNS). In the case of reflexes, the afferent nerve carries the impulse to the spinal cord, where instead of just traveling up the spinal cord and to the brain, an efferent nerve (which transmits information from the CNS to out muscles) carries a signal straight from the spinal cord back out to the muscle, causing a response to the stimulus–without thought. At the same time, the signal is sent up the spinal cord to the brain, where the information of the stimulus is then processed. Because the signal takes more time to get to the brain, by the time the brain has processed that you’ve burned your hand, for example, you’ve pulled it away. The image displayed below is called a reflex arc, as described above, it involves a stimulus to the skin, the information moving via an afferent nerve to the spinal cord, straight back out via an efferent nerve to the muscle.

In my experience, I can think of many times my reflexes have prevented severe injury. Over the summer, I cooked for my family. While in the kitchen, I went to move a tray of roasted veggies to make space for the dish I was holding and forgot that the tray was still hot from the oven. Before I knew it, I had quickly taken my hand away from the tray. At that point, I registered the pain of my hand and the burn. This is a good example of how the reflex arc works faster than your brain in registering the stimulus.

Works Cited

Noback, Charles R, and Graham Ratcliff. “Human Nervous System.” Encyclopædia Britannica, Encyclopædia Britannica, Inc., 19 June 2019.

Helixitta. “Two Neuron Reflex Arc.” Wikipedia, 11 May 2019.