Introduction:
Learning to Change
Chapter 1
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Survival depends on the ability to cope with change.
Natural Selection: Features that contribute to survival are selected by the environment.
Evolution in the Lab and Field: Mating ritual of fruit flies and the peppered moth
Mutations are abrupt changes in genes
Natural Selection
*
Natural Selection – Survival depends on the ability to cope with change. Charles Darwin (1859) On the Origin of Species suggested that there are tremendous variations within and among species. Some variations are well suited for current conditions and some are not, which determines the likelihood of reproduction and survival. Therefore, features that contribute to survival are selected by the environment (Natural Selection). Evolution is a product of natural selection. He noticed that, using farm animals, selective breeding with a specific variation resulted in offspring with that characteristic. He suggested that this process may occur for all species. A thick coat of fur can be an asset or a liability depending on climatic conditions.
Evolution in the Lab – Fruit flies were raised in total darkness to disrupt there normal mating ritual (a dance that requires sight). After 14 generations, a new mating ritual was formed directly due to the change in the environment.
Evolution in the Field – The Peppered moth primarily use to be a single light color (the color of the tree bark to protect them from birds). A rare species of black moths began to be noticed (which would be detrimental because they would be easy prey). However, due to pollution, the bark of trees in certain areas began to change color (became more black). It now is not uncommon, regarding polluted areas, to only see the black type of the moth.
Human beings are different colors depending on the environment in which they live/ancestry (close to the equator leads to darker skin due to more melanin content to protect the skin from the sun).
Mutations – Natural selection accounts for much of the variations among/within species, but abrupt changes in genes also contribute to change/adaptation. These changes are caused by exposure to certain chemicals, radiation, and possibly viral infections.Mutations can occur in any cell, but when it occurs in reproductive cells, the mutation is passed on to the next generation (the characteristic may or may not be overt in future offspring). Most mutations are of no consequence (eye color variation). Some mutations are harmful and selected out (2 headed snake). However, some mutations are adaptive, such as resistance to disease.
Behavior also is subject to natural selection. As the environment changes, adaptive behaviors are selected and maladaptive behaviors are eliminated.
This is a a relationship between a specific event and a simple response to that event.
Reflexes are necessary for survival, but we do not notice them until they fail.
Sensitization and Habituation
Spontaneous Recovery is the awakening of a habituated response
Reflexes
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A Reflex is a relationship between a specific event and a simple response to that event. They appear at birth or arise during predictable stages of development. They are necessary for adaptation and survival. Many reflexes protect the organism from injury, such as automatically and immediately dropping a hot pan, sneezing to expel irritants, and the vomit reflex. Salivation immediately begins when food is placed in the mouth, which is the first step of digestion. The presence of food combined with saliva triggers swallowing, and swallowing triggers peristalsis, or the rhythmic motion of the esophagus to carry food to the stomach. The simple act of eating is a chain of reflexes.
We do not notice reflexes until they fail (allergic reaction, disease, and injury). This occurs when excessive amounts of drugs have been ingested (depress the CNS). Death from alcohol can occur when it interferes with the respiratory reflex (inhale/exhale).
Reflexes are stereotypic, whereby they are invariant regarding form frequency, strength, and time of appearance during development.
Sensitization the elicitation of a reflex response that leads to an increase in intensity/probability of subsequent elicitations. For example, if loud sounding thunder startled you, you will be more likely to be startled by subsequent sounds (even if the sounds are less intense, such as dropping a plastic mug on a ceramic floor).
Habituation Repeatedly eliciting a reflex response results in the decrease in intensity/probability of the response. This is why, during a horror movie, repeatedly trying to startle a friend eventually does not arouse the startle response.
Spontaneous Recovery: Sometimes, a response that has been habituated will spontaneously appear in full intensity of probability.
Fixed Action Patterns (FAPs)
FAPs are an inherited series of interrelated acts
They are reliably elicited by specific events known as releasers.
Do they apply to humans?
*
Fixed Action Patterns (FAPs) – (use to be referred to as instincts) an inherited series of interrelated acts. They are similar to reflexes whereby they have a genetic basis, little variability from person to person, and can be reliably elicited by a specific event. However, FAPs are more complex (long series of reflex like acts), are more variable, and involve the entire organism rather than a few muscles or glands. Some FAPs help to protect against a predator, such as when a cat is confronted with a dog it often engages in a series of behaviors, such as arching the back, flicking the tail, growling and hissing (this makes the cat seem bigger and more formidable to the attacker).
FAPs are reliably elicited (species engages in the behavior automatically) by specific events known as releasers. The Male Stickleback fish will be aggressive toward or attack other Male Stickleback fish, whereby they will engage in a series of behaviors similar to the cat example. The releasing stimulus is a red coloration of the abdomen of the male fish, and the aggressive response can be elicited by anything of this color.
Are there FAPs in Humans? It is hard to say! Darwin (1874) suggested social, self preservation, vengeance, and lust instincts. Other instincts suggested were the maternal instinct, territorial instinct, etc (actually, at one time, almost every behavior was considered instinctual). Currently, it is believed that humans do not engage in FAPs. There is too much complexity and variability in human behavior for it to be considered an FAP. For example, the maternal instinct was considered universal. However, the expression of this “so called” instinct is variable, whereby some mothers “hover” and other mothers “ignore.” If this was an instinct, the expression would be stereotypic. As well, in western societies are choosing to have children later in life, which would not occur if this behavior was governed by an FAP (automatic).
General Behavior Traits
These are strongly influenced by genes and include aggression, hoarding, anxiety, introversion, etc.
Behavior traits can be elicited by a wide variety of situations/stimuli.
Behavior traits show great variability regarding their expression.
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The role of genes in general behavior traits – Traits that are strongly influenced by genes include aggression, hoarding, anxiety, introversion, sexual activity etc. Behavior traits occur in a wide variety of situations, and therefore, do not have a specific releasing stimulus. For example, aggressive behavior can be elicited by a variety of stimuli. Behavior traits are more variable than FAPs ( a spider spinning a web does it the same way every single time and it’s web is almost identical to other webs of the same species. Aggressive behavior, for example, tends to differ in expression across humans, and differs in expression from situation to situation within the same human.
If a behavior is selected by the environment over several generations, it can profoundly change the species.Trut (1999) began the study 40+ years ago, whereby foxes were selectively bred based on general behavior characteristics. They selected the “dog” general behavior trait (least fearful and aggressive toward humans). They became more like dogs than foxes whereby they liked humans and approached them. As well, physical characteristics of the foxes became dog-like – floppy ears, various fur color patterns, and an upright tail. Therefore, behavior traits must be genetically linked to physical characteristics (the environment selects one feature and produces another). Identical twins reared apart share the same career interests, art/music/hobby interests, etc, which suggests the role of heredity in general behavior traits. The probability of of expressing many forms of illness associated with maladaptive behavior traits are proportional to how close in relation one is to a family member afflicted by the illness (depression, anxiety, reading disorders, and even criminality). It may first seem puzzling as to why this behavior has not been selected-out. Can you think of a time/situation when/where aggressive behavior may be adaptive? (war) When would agoraphobia be adaptive (fear of open spaces)? (prehistoric times).
The point – whether a behavior is adaptive or not depends on the environment, which means that the same behavior can be adaptive and maladaptive depending on the environment.
Limits of Natural Selection
There are two major problems with Natural Selection:
Natural selection is slow and
Evolved change that was useful in the past can become a hindrance in the future
*
The problem with natural selection is that it is slow – it is of limited value for coping with abrupt changes. For example, the Ebola virus only recently threatens the western world because of tourism, but it is unlikely that the environment will select immunity before severe consequences ensue.
Another problem is that an evolved change that was helpful can become a hindrance in the future.
For example, salty and sweet foods are necessary for survival, and during human development, humans that gravitated toward this food survived. However, this type of food is abundant now and the tendency to gravitate toward them, which endangers health. Sexual appetites follow the same route, where children use to die extremely early so it was necessary to copulate frequently (now, we are overpopulated and are manifesting diseases due to sexual activity).
Learning: Evolved Modifiability
Learning is a change in behavior due to experience.
The last line of defense for survival is learning.
Learning has directly shaped the physical environment.
*
Learning is a change in behavior due to experience. It is an evolved mechanism for coping with a changing environment. Learning does not give a person the tendency to behave in a specific way in a specific environment; it gives the individual the tendency to modify behavior to suit the situation (evolved modifiability). When reflexes, FAPs, and general behavior traits are inadequate for coping with change, the last line of defense is learning. For example, avoiding poisonous foods is partly innate and partly based on what one has learned in life (some foods, although not toxic to most, are avoided because of a learning situation that occurred in the past).
Learning not only is necessary for survival, it also is necessary for achieving the “high-life.” Learning has directly shaped the physical environment (we create our own safe environments, whereby learning is solely responsible for this achievement).
Is behavior inherited or learned?
The debate wrongly implies that the answer must be one or the other.
The ability to learn is a product of both learning and heredity.
Nature and Nurture
*
This is the biggest argument with regard to behavior (is behavior inherited or learned?). The debate wrongly implies that the answer must be one or the other. However, heredity and learning are intimately linked. Deviant behaviors can be selectively bred in animals, but healthy animals can become deviant after exposure to deviance.
The Semai of Malaya are passive and don’t have a word for murder. However, when they were recruited for war by the British in the 1950’s, they became unusually fierce warriors. However, not all Semai became fierce warriors. This suggests that aggressiveness is learned and inherited. Whether cats were reared to either see their mothers kill rats or not determined whether the offspring would kill rats (86% vs. 45%; Kuo, 1930). Again, not all cats reared without exposure to rat killing refused to kill a rat.
The ability to learn is a product of both learning and heredity. For example, animals reared in complex/enriched environments develop bigger brains and learn faster. Humans tend to be similar to their parents with regard to IQ (genetic), but this changes with development/learning.
*
*
Natural Selection – Survival depends on the ability to cope with change. Charles Darwin (1859) On the Origin of Species suggested that there are tremendous variations within and among species. Some variations are well suited for current conditions and some are not, which determines the likelihood of reproduction and survival. Therefore, features that contribute to survival are selected by the environment (Natural Selection). Evolution is a product of natural selection. He noticed that, using farm animals, selective breeding with a specific variation resulted in offspring with that characteristic. He suggested that this process may occur for all species. A thick coat of fur can be an asset or a liability depending on climatic conditions.
Evolution in the Lab – Fruit flies were raised in total darkness to disrupt there normal mating ritual (a dance that requires sight). After 14 generations, a new mating ritual was formed directly due to the change in the environment.
Evolution in the Field – The Peppered moth primarily use to be a single light color (the color of the tree bark to protect them from birds). A rare species of black moths began to be noticed (which would be detrimental because they would be easy prey). However, due to pollution, the bark of trees in certain areas began to change color (became more black). It now is not uncommon, regarding polluted areas, to only see the black type of the moth.
Human beings are different colors depending on the environment in which they live/ancestry (close to the equator leads to darker skin due to more melanin content to protect the skin from the sun).
Mutations – Natural selection accounts for much of the variations among/within species, but abrupt changes in genes also contribute to change/adaptation. These changes are caused by exposure to certain chemicals, radiation, and possibly viral infections.Mutations can occur in any cell, but when it occurs in reproductive cells, the mutation is passed on to the next generation (the characteristic may or may not be overt in future offspring). Most mutations are of no consequence (eye color variation). Some mutations are harmful and selected out (2 headed snake). However, some mutations are adaptive, such as resistance to disease.
Behavior also is subject to natural selection. As the environment changes, adaptive behaviors are selected and maladaptive behaviors are eliminated.
*
A Reflex is a relationship between a specific event and a simple response to that event. They appear at birth or arise during predictable stages of development. They are necessary for adaptation and survival. Many reflexes protect the organism from injury, such as automatically and immediately dropping a hot pan, sneezing to expel irritants, and the vomit reflex. Salivation immediately begins when food is placed in the mouth, which is the first step of digestion. The presence of food combined with saliva triggers swallowing, and swallowing triggers peristalsis, or the rhythmic motion of the esophagus to carry food to the stomach. The simple act of eating is a chain of reflexes.
We do not notice reflexes until they fail (allergic reaction, disease, and injury). This occurs when excessive amounts of drugs have been ingested (depress the CNS). Death from alcohol can occur when it interferes with the respiratory reflex (inhale/exhale).
Reflexes are stereotypic, whereby they are invariant regarding form frequency, strength, and time of appearance during development.
Sensitization the elicitation of a reflex response that leads to an increase in intensity/probability of subsequent elicitations. For example, if loud sounding thunder startled you, you will be more likely to be startled by subsequent sounds (even if the sounds are less intense, such as dropping a plastic mug on a ceramic floor).
Habituation Repeatedly eliciting a reflex response results in the decrease in intensity/probability of the response. This is why, during a horror movie, repeatedly trying to startle a friend eventually does not arouse the startle response.
Spontaneous Recovery: Sometimes, a response that has been habituated will spontaneously appear in full intensity of probability.
*
Fixed Action Patterns (FAPs) – (use to be referred to as instincts) an inherited series of interrelated acts. They are similar to reflexes whereby they have a genetic basis, little variability from person to person, and can be reliably elicited by a specific event. However, FAPs are more complex (long series of reflex like acts), are more variable, and involve the entire organism rather than a few muscles or glands. Some FAPs help to protect against a predator, such as when a cat is confronted with a dog it often engages in a series of behaviors, such as arching the back, flicking the tail, growling and hissing (this makes the cat seem bigger and more formidable to the attacker).
FAPs are reliably elicited (species engages in the behavior automatically) by specific events known as releasers. The Male Stickleback fish will be aggressive toward or attack other Male Stickleback fish, whereby they will engage in a series of behaviors similar to the cat example. The releasing stimulus is a red coloration of the abdomen of the male fish, and the aggressive response can be elicited by anything of this color.
Are there FAPs in Humans? It is hard to say! Darwin (1874) suggested social, self preservation, vengeance, and lust instincts. Other instincts suggested were the maternal instinct, territorial instinct, etc (actually, at one time, almost every behavior was considered instinctual). Currently, it is believed that humans do not engage in FAPs. There is too much complexity and variability in human behavior for it to be considered an FAP. For example, the maternal instinct was considered universal. However, the expression of this “so called” instinct is variable, whereby some mothers “hover” and other mothers “ignore.” If this was an instinct, the expression would be stereotypic. As well, in western societies are choosing to have children later in life, which would not occur if this behavior was governed by an FAP (automatic).
*
The role of genes in general behavior traits – Traits that are strongly influenced by genes include aggression, hoarding, anxiety, introversion, sexual activity etc. Behavior traits occur in a wide variety of situations, and therefore, do not have a specific releasing stimulus. For example, aggressive behavior can be elicited by a variety of stimuli. Behavior traits are more variable than FAPs ( a spider spinning a web does it the same way every single time and it’s web is almost identical to other webs of the same species. Aggressive behavior, for example, tends to differ in expression across humans, and differs in expression from situation to situation within the same human.
If a behavior is selected by the environment over several generations, it can profoundly change the species.Trut (1999) began the study 40+ years ago, whereby foxes were selectively bred based on general behavior characteristics. They selected the “dog” general behavior trait (least fearful and aggressive toward humans). They became more like dogs than foxes whereby they liked humans and approached them. As well, physical characteristics of the foxes became dog-like – floppy ears, various fur color patterns, and an upright tail. Therefore, behavior traits must be genetically linked to physical characteristics (the environment selects one feature and produces another). Identical twins reared apart share the same career interests, art/music/hobby interests, etc, which suggests the role of heredity in general behavior traits. The probability of of expressing many forms of illness associated with maladaptive behavior traits are proportional to how close in relation one is to a family member afflicted by the illness (depression, anxiety, reading disorders, and even criminality). It may first seem puzzling as to why this behavior has not been selected-out. Can you think of a time/situation when/where aggressive behavior may be adaptive? (war) When would agoraphobia be adaptive (fear of open spaces)? (prehistoric times).
The point – whether a behavior is adaptive or not depends on the environment, which means that the same behavior can be adaptive and maladaptive depending on the environment.
*
The problem with natural selection is that it is slow – it is of limited value for coping with abrupt changes. For example, the Ebola virus only recently threatens the western world because of tourism, but it is unlikely that the environment will select immunity before severe consequences ensue.
Another problem is that an evolved change that was helpful can become a hindrance in the future.
For example, salty and sweet foods are necessary for survival, and during human development, humans that gravitated toward this food survived. However, this type of food is abundant now and the tendency to gravitate toward them, which endangers health. Sexual appetites follow the same route, where children use to die extremely early so it was necessary to copulate frequently (now, we are overpopulated and are manifesting diseases due to sexual activity).
*
Learning is a change in behavior due to experience. It is an evolved mechanism for coping with a changing environment. Learning does not give a person the tendency to behave in a specific way in a specific environment; it gives the individual the tendency to modify behavior to suit the situation (evolved modifiability). When reflexes, FAPs, and general behavior traits are inadequate for coping with change, the last line of defense is learning. For example, avoiding poisonous foods is partly innate and partly based on what one has learned in life (some foods, although not toxic to most, are avoided because of a learning situation that occurred in the past).
Learning not only is necessary for survival, it also is necessary for achieving the “high-life.” Learning has directly shaped the physical environment (we create our own safe environments, whereby learning is solely responsible for this achievement).
*
This is the biggest argument with regard to behavior (is behavior inherited or learned?). The debate wrongly implies that the answer must be one or the other. However, heredity and learning are intimately linked. Deviant behaviors can be selectively bred in animals, but healthy animals can become deviant after exposure to deviance.
The Semai of Malaya are passive and don’t have a word for murder. However, when they were recruited for war by the British in the 1950’s, they became unusually fierce warriors. However, not all Semai became fierce warriors. This suggests that aggressiveness is learned and inherited. Whether cats were reared to either see their mothers kill rats or not determined whether the offspring would kill rats (86% vs. 45%; Kuo, 1930). Again, not all cats reared without exposure to rat killing refused to kill a rat.
The ability to learn is a product of both learning and heredity. For example, animals reared in complex/enriched environments develop bigger brains and learn faster. Humans tend to be similar to their parents with regard to IQ (genetic), but this changes with development/learning.