1. What’s Tinbergen’s concept of displacement behavior? Can you think of a good example of such behavior in humans?
According to Tinbergen displacement behavior arises when we observe an irrelevant movement entirely out of context. More specifically, he says that displacement is when an animal is in the process of executing a specific behavior, under the motivation of taking this behavior to execution, or a specific instinct “a”- we observe a movement that belongs to a different instinct, instinct b, or a different motivated behavior. Therefore, this activity has been displaced, from instinct “b” to instinct “a”. This results in the execution of a complete irrelevant act during an incorrect context. For example, Tinbergen mentions an example of a displaced activity is when two skylarks are engaged in combat and then suddenly, they peck at the ground as if feeding. The skylarks, in fighting motivation, present activities of feeding motivation and thus exemplify displacement behavior. Specific examples of the different types of displacement behaviors are the following: foraging, drinking, nest-building, eating, preening, care of the body, bathe, and scratching.
These displacement activities arise randomly in unacceptable contexts, and sometimes are representations of frustration, like when primates start scratching their fur, which in man, according to Tinbergen would be exemplified like nervous scratching of the head, biting nails, hair fixing, and scratching behind the ears.
Some additional examples of displacement behaviors in man are in the context of sexual behavior. For instance, non-traditional sucking in children, such as thumb-sucking or pacifier sucking. These activities seem to be a type of displacement behavior that might appear in any instance “a” and it would be displaced from the child’s feeding behavior towards the mother. It has also been observed that thumb sucking appears in substitution of a display of attachment behavior in an unacceptable context. For instance, when the child’s attachment behavior is frustrated, when the mother is absent for example, non-traditional sucking or any other similar oral activity occurs and is reflected as a displacement behavior.
2. What can vonHolst’s stimulation experiments tell us that we cannot obtain from mere observation of natural behavior? What kind of evidence does he use to show the strength of drives or what other drives are operating?
vonHolst uses a series of stimulation experiments in chickens in order to be able to comprehend the questions of “how” and “why” animals do certain behaviors. He says that there are two ways we can decipher the “how” and “why”, the first is careful observation and the second is the technical mastery of electrical stimulation of regions in the brainstem. He uses chickens as they display clear forms of social behavior and social hierarchies and thus are great study subjects. His experiments were able to analyze and measure certain behaviors. With observation we are able to classify behaviors into simple and complex and are able to attempt to predict when these occur. However, using stimulation we are able to understand those behaviors that occur spontaneously, and understand how stimulating different areas of the brainstem concurrently, alternating between one and the other, can cause different, new, patterns of behavior.
For example, stimulating certain areas of the brainstem, vonHolst found out that if there is any kind of object present, and the electrical stimulation is strong enough, some chickens experienced hallucinations and evoked aggressive behaviors towards the present object. If there was no object present, these hallucinations would not occur and thus, the chicken would instead look around and peck the ground several times; vonHolst compares this behavior to an angry man who may hit a table with his fist if who or what is causing his anger is out of reach. After his experiments vonHolst reached the following conclusions: if we stimulate two brain areas at the same time the following things might occur: a) If the two areas incite two antagonistic behaviors, and they both have the same intensity they cancel each other out b) Two antagonistic behaviors, but one is stronger than the other, usually that behavior trumps the other, even if the weaker behavior has a stronger voltage c) If the animal has a strong drive (chicken with urge to sit but stimulated to stand) and the stimulation passes a certain voltage threshold, one activity dominates over the other (intermediate curve idea) d) The two behaviors occur in full strength and alternate e) The stimulation of the two behaviors generates a third, new unrelated behavior f) The two behaviors combine and generate a hybrid behavior g) The animal is able to balance between the two behaviors rhythmically h) One movement is added to the other.
He uses his own experiments with Chickens as evidence of these behavioral trends; he modified his procedure in order to test for strength of certain drives over others and show any underlying drives. One of the ways he did this was by testing for the effects of stimulation at different depths and with varying strengths, this revealed that simple, individual actions can be produced by stimulation, but that complex actions that require the use of hierarchical systems are not generated by stimulation. However, individual acts within these complex behaviors can take place during/after stimulation. Lastly, he also uses the experiments with the chicken that already has the urge to sit down and is later stimulated to generate the drive to stand up to demonstrate the strength of other drives that are already operating. These experiments produce his theory that the intermediate curve helps determine whether or not a certain voltage is enough to cause standing or weak enough to allow for sitting.
3. How does control theory shed light on attachment behavior?
In Bowlby’s: A Control Systems Approach to Attachment Behavior, the significance of attachment behavior and its function were widely discussed. One of Bowlby’s main points surrounds the fact that proximity to a specific goal-object would serve as the reference signal. This conclusion was reached after a series of observations of mother-child interactions in a park. It was observed that in usual mother-child interactions of children between 1-3years old, they do not allow for more than 200 feet between them without trying to correct that, or depending on the child’s age, displaying some sort of signaling behavior. Using a control systems approach, the mother’s behavior of constantly checking on a child is simply part of a negative feedback loop in which she is trying to correct the error signal caused by too much distance between her and her child or too much time without making sure he is okay.
One of the main examples on how control systems helps shed light on attachment is when a baby starts crying, which according to Bowlby serves as a signaling behavior. As a baby, the child does not have enough control to seek the mother or on his own fix the error signal, if she is too far away or not in sight, so instead of approaching the mother, the child’s cries serves as the output in his control system because its goal-directed effect is that the mother will go towards the child, essentially reducing the error signal. In these situations, a child usually does not stop crying until he is in contact with his mother, and likewise if the error signal is the other way around, and the mother is the one that needs the child, her attachment behavior will not terminate, or be inhibited, until she is in contact or displays some sort of signaling behavior with her child. Applying control systems to attachment behavior helps us comprehend the purpose of a child’s, sometimes incessant, crying, or of a mother’s, sometimes coddling, hovering.
However, I do wonder how we can be sure that this control system is based solely on proximity, because certainly this system is not as simple as the temperature control system. This attachment control system depends on the mother’s hormones, mother/child’s emotions and on contextual information, if they are in a familiar/unfamiliar or safe/unsafe context; we cannot oversimplify it by saying that it functions as a machine but applying the control systems approach does indeed help clarify certain forms of behavior.
4. Why do we need a hedonic/incentive system? Why isn’t homeostatic control sufficient?
A hedonic system serves to put forth goal-directed actions. Homeostatic control, on the other hand, would not keep getting activated if it is already stable, or nearly stable, as its purpose is reducing error signals to maintain within an acceptable range from the set reference signal. Whereas, hedonic systems activate every time we “like” or “want” something. According to Berridge and Kringelbach’s paper: Pleasure Systems in the Brain” hedonic/incentive systems have evolutionary origins. They argue that these hedonic system reactions were selected by evolution due to their functions related to survival. For instance, it is due to hedonic systems that we are able to selectively choose the food we eat and are able to discover what we like and do not like, via orofacial “liking” responses. Due to this, we are able to consume the more energy dense foods and also choose the ones most appealing to us. However, if we would just use Homeostatic control, we would consume enough food to reduce our energy deficiency without considering what we would consume. If we consider that homeostatic control would simply make us consume enough food, we would not be taking into consideration calorie intake or even if a food is of our liking or not. Thanks to pleasure systems, monkeys, humans and even rats are able to display orofacial responses of liking and disgust, which serve to classify foods we should consume and ones we should not.
Thinking evolutionarily, this could have begun as the ability to discern, based on taste or smell, if any berries or food sources were safe to consume or not. Thus, the ability to activate the pleasure system would allow animals to differentiate edible foods and venomous foods. If these animals did not develop this system, they would only have they homeostatic control system, which would elicit food consumption behavior regardless of the item, which ends up being counter-intuitive if the item provokes disgust or even worse-if it is poisonous. This is one of the main ways in which having the hedonic system provides the animal characteristics that increase its survival, making it more fit, over the ones that just have homeostatic control. According to Berridge, what most probably occurred over time was that this system increased fitness and thus was passed on by the process of selection and eventually it just became part of our current systems and now, has become a part of our emotional expressions as well.
5. Elaborate on Ernst Mayr’s statement based on what you learned in class.
Ernst Mayr underscores one of the main argumentative conflicts in current neuroscience: do animals have a certain degree of consciousness or are they purely mechanistic? In order to make sense of his argument this question draws upon several different concepts: vitalism, mechanism, linear causation and the calculation problem within traditional control systems. To start, vitalism is the concept that stems from the idea that all functions of living organisms are due to a vital principle distinct from biochemical processes. On the other hand, mechanism is the theory all biological processes can be reduced to the fundamental physical and chemical mechanisms, and it relies on the concept of linear causation. Linear causation argues that the cause must precede the effects in time, which would mean for example that increasing acid would cause an increased scratching response. However, the contrary to this idea would be negative feedback within the control systems theory. Control systems use a perceptual signal as the input of the function, a reference signal as a fixed setpoint of acceptable values, and an error signal calculated by a comparator that is what helps determine the output. The process through which we determine the output is negative feedback loops, where the organism determines if the output was able to reduce the error signal and if it was not the organism is able to set forth a new output through hierarchical control systems. These concepts are essential for the understanding of Mayr’s claim.
Mechanists believe in linear causation and argue that animals and other complex living systems do not have any form of consciousness or intentionality in their actions and the only material forces that act upon them are those that are physico-chemical. However, Mayr claims that these same scientists disagree with the idea that animals are nothing but machines, thus Mayr argues that since the explanations that only use physical sciences oversimplify complex living systems that the most precise way to comprehend them is through negative feedback. This oversimplification comes to light in the theory of the “calculation problem” which is the idea that the output of the final common path must always vary according to the changes introduced by the unknown disturbances. Thereby, if the source of these disturbances is unpredictable, the brain would not be able to decipher how much output to produce and when. Hence, the argument of linear causation would be discredited because we could not have the input precede the output. On the contrary, negative feedback takes into consideration that complex living systems do have the level of consciousness necessary to generate goal-corrected behaviors and thus be able to, through negative feedback loops, stabilize their error signals and ultimately control their behavior through output. In conclusion, due to the calculation problem and the limitations of linear causation, we cannot assume complex living systems are merely machines and thus, negative feedback loops provide the most precise explanation for their complex behaviors.
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