Psychology
Chapter 3
Genetics and evolutionary foundations of behaviour
Adaption refers to modifications as a result of changed life circumstances.
Evolution is a long-term adaptive process.
How genes affect behavior
Genes are associated with behavior (they never produce or control behavior directly).
All the effects that genes have on behavior occur through their role in building and modifying the physical structures of the body. Those structures, interacting with the environment, produce behavior.
All genes that contribute to the body’s development are “for” behavior. Since all parts of the body are involved in behavior.
Genes provide the codes for proteins
Genes affect the body’s development (only) through their influence on the production of protein molecules.
Structural proteins; forms the structure of every cell of the body.
Enzymes; controls the rate of every chemical reaction in every cell.
Genes are components of extremely long molecules of a substance called DNA (deoxyribonucleic acid).
These molecules exist in the egg and sperm cells that join to from a new individual. And they replicate themselves during each cell division in the course of the body’s growth and development.
A replica of your whole DNA molecules exists in the nucleus of each of your body’s cells, where it serves to code for and regulate the production of protein molecules.
Each protein molecule consists of a long chain of smaller molecules. Those are amino acids.
A single protein molecule may contain from several hundred to many thousand amino acids in its chain.
There are a total of 20 distinct amino acids in every from of life on earth (and they can be arranged in countless sequences to from different protein molecules).
Some DNA serve as templates (as molds or patterns) for producing RNA. RNA severs as a template for producing protein molecules.
A gene is segment of a DNA molecule that contains the code that dictates the particular sequence of amino acids for a single type of protein.
A human being has between 20.000 and 25.000 genes.
Most of the DNA in human cells does not code for proteins.
Genes work only through interaction with the environment
The effects of genes are entwined with the effects of the environment.
Environment; every aspect of an individual and his or her surroundings except the genes themselves. (Everything! Even the internal chemical environment of the individual)
Environmental effects also help to turn genes ‘on’ and ‘off’ resulting in bodily changes that alter the individual’s behavioral capacity (always happens, in childhood and adulthood).
One’s body and behavioral capacities result from a continuous, complex interplay between genes and environment.
Genes are always expressed in a context!
Experience activates genes, which produce proteins, which alter the function of some of the neural circuits in the brain and thereby change the manner in which the individual behaves.
Distinction between genotype and phenotype
The same gene can have different effects, depending on the environment and the mix of other genes.
Two individuals with the same genotype can be different in phenotype as a result of differences in their environments.
How genes are passed along in sexual reproduction
Genes do provide codes for building proteins,
And they serve as the biological units of heredity
Genes are replicated and passed along from parents to offspring. They are the cause of offspring’s’ resemblance to parents.
Genetic material (DNA) exists in each cell in structures called chromosomes. Those are usually dispersed throughout the cell nucleus (kern).
The normal human cell has 23 pairs of chromosomes.
22 of these pairs are true pairs in both male and female (each chromosome looks like its mate and contains similar genes). The remaining pair is made up of the sex chromosomes. XX is female and XY is male.
Production of genetically diverse egg and sperm cells
Mitosis; the process when cells divide to produce new cells other than egg or sperm cells.
Each chromosome precisely replicates itself and then the cell divides (with one copy of each chromosome moving in each of the two cell nuclei thus formed.
Because of this, all body cells (except for egg and sperm cells) are genetically identical to another. The differences of cells in your body (skin and brain) arise from the differential activation in their genes.
Meiosis; the process when cells divide to produce egg or sperm cells.
In meiosis, the cells are not genetically alike.
During meiosis, each chromosome replicates itself once, but then the cell divides twice. Before this cell division, the chromosomes of each pair line up next to one another and exchange genetic material in a random manner. They do not contain precisely the same genes.
The genetic diversity of offspring
When a sperm and an egg cell untie, they from a new cell, the zygote (which contains the full complement of 23 paired chromosomes). One member of each pair comes from each parent.
The value of sex, lies in the production of genetically diverse offspring. In a changing world, genes have better chance of surviving if they are rearranged at each generation in many different ways (to produce different kinds of bodies). Parents reduce the chance of all the offspring dying by a change of the environment.
Identical twins.
When two bundles of cells separate from each other during the early mitotic divisions following the formation of a zygote. (Monozygotic (good spelling) twins).
Fraternal twins
Dizygotic twins
Originate from two zygotes, each formed from different egg and sperm cells.
Consequences of the fact that genes come in pairs
Two genes that occupy the same locus (location) on a pair of chromosomes are sometimes identical and sometimes not.
When identical; the individual is homozygous at that locus.
Not identical; the individual is heterozygous at that locus.
Different genes that can occupy the same locus (and thus can potentially pair with each other) are called alleles.
A dominant gene (or allele); one that will produce its observable effects in either the homozygous or the heterozygous condition.
A recessive gene (or allele); one that will produce its effects in the homozygous condition only.
Some pairs of genes blends their effects.
Mendelian pattern of heredity
Gregor Mendel
Developed the idea that the units of heredity come in pairs and that one member of a pair can be dominant over the other.
The double-edged sword of sickle-cell anemia
Some genetic conditions (like sickle cell anemia) carry both risk and benefits for the individuals born with them.
Variation in genes contributes to the variation in behavior
Some behavioral characteristics are inherited indicative of control by a single pair of genes.
Most behavioral characteristics depend on many genes.
Polygenic characteristics and selective breeding
Characteristics that derive from variation at a single gene locus are typically categorical in nature. (Those are characteristic that sharply differentiate one group from another).
Most anatomical and behavioral differences among individuals of any species are measurable in degree, not type. They are continuous (the measures taken from individuals do not fall into two or more distinct groups, but can lie anywhere within the observed range of scores). A normal distribution.
Polygenic characteristics; characteristics that vary in a continuous way and are generally affected by many genes. Of course these traits are also influenced by variation in the environment.
Selective breeding for behavioral characteristics in animals
To the degree that individuals within a species differ in any measurable characteristic because of differences in their genes, that characteristic can be modified by selective breeding.
For single-gene characteristics the effects of selective breeding are immediate
For polygenic characteristics the effects are gradual and cumulate over generations.
A few words about epigenetics
Genes are only part of the story.
Epigenetics examines gene-regulating activity that doesn’t involve changes to the DNA code and that can persist through one or more generations.
We inherit from our parents not only DNA, but also a variety of chemical markers that regulate genes (turning them on at certain times and off at others. And determining how much protein they produce).
Early experience can alter behavior and be transmitted to future generations (all without any changes in the genes themselves).
Darwin’s insight: selective breeding occurs in nature
Breeding in nature is selective and can produce changes in living things over generations.
Natural selection.
Is dictated by the obstacles to reproduction that are imposed by the natural environment (anything that prevent an organism from producing offspring). Organisms that have characteristics that help them overcome such obstacles are more likely to have offspring.
Four concepts of natural selection:
Genetic diversity provides the material for natural selection
Darwin knew nothing about genes.
The genetic variability on which natural selection acts has two main sources:
Mutations are errors that occasionally and unpredictably occur during DNA replication, causing the replica to be not identical to the original.
Mutation is the ultimate source of all genetic variation.
Occasionally a mutation is useful, producing a protein that affects the organism’s development in a way that increases its ability to reproduce. Because of its effects on reproduction, the gene arising from such a mutation increases in frequency from generation to generation. At the level of the gene, this is evolution.
Environmental change provides the force for natural selection
Evolution is spurred by changes in the environment.
Evolution can occur in speed depending on the rate and nature of environmental change and on the degree to which genetic variability already exists in a population.
Evolution has no foresight
Evolution has no foresight.
Evolution has no planned end no organism is ‘more evolved’.
Evolution has no moral force.
Functionalism: the attempt to explain behavior in terms of what it accomplishes for the behaving individual.
Distal and proximate explanations for behavior
Two kinds of explanations of behavioral. Both are needed to understand behavior.
Distal and proximate explanations complement each other
Limitations on functionalist thinking
Four reasons why a particular trait or behavior may not be functionalism
Some traits are vestigial
Some traits that evolved because they served the needs of our ancestors are no longer functional today, yet they remain. → Vestigial characteristics.
This is relevant to psychologists when applied to our inherited drives or motives.
Some traits are side effects of natural selection for other traits
Useless changes can come about in evolution as by-products of natural selection for other useful changes.
(For example the belly button)
It is possible that some human capacities came about in side effects of the evolution of other capacities.
Some traits result simply from chance
Some inheritable characteristics that result from just one or two mutations are inconsequential for survival and reproduction.
(For example the shape of nose)
Genetic drift: trough chance alone
Evolved mechanisms cannot deal effectively with every situation
Even evolved mechanisms, like guild, are not useful in every situation in which they are active
Species-typical behaviors in humans
Species-typical behavior are products of evolution, but they are influenced by learning.
Human emotional expressions as examples of species-typical behaviors
Specific facial expressions accompany specific emotional states in humans. Those are universal.
People can identify each emotion more easily and accurately when it is expressed by members of their own culture.
The role of learning in the development of species-typical behavior
The role of learning is obvious in our two most characteristic species-specific behaviors. Manner of walking and language.
Biological preparedness as the basis for species-typical behaviors
The difference between behaviors that we call species-typical and those we don’t has to do with their degree of biological preparedness.
Natural selection has equipped each species with anatomical structures that ensure that normal individuals of the species will be physical able to perform their species-typical behaviors and will be motivated to learn what they must for adequate performance.
Species-typical behavior is a relative concept
No behavior stems just from biological preparedness. Some sort of experience with the environment is always involved.
Any behavior that an individual can produce must make use of the individual’s inherited biological capacities.
Two forms of cross-species comparison: Homologies and Analogies
A homology: any similarity that exits because of the different species common ancestry.
The more closely related two species are, the more homologies they show.
An Analogy: any similarity that stems from convergent evolution.
Convergent evolution occurs when different species (because of some similarity in their habitats or lifestyles) independently evolve a common characteristic.
(For example, groups of animals that can fly).
The value for psychology of studying homologies
Homologies are useful for research on the physiological mechanisms of behavior because convergent evolution can produce similar behavior that operate through different mechanisms.
Also useful for inferring the pathways along which species-typical behaviors evolved.
The value for psychology of studying analogies
Analogies are useful for making inferences about the distal functions of species-typical behavior.
Four mating classes
(poly = many, mono = one, gyn = female, andr = male)
A theory relating mating patterns to parental investment
Robert Trivers (1972)
A theory relating courtship and mating patterns to sex differences in amount of parental investment.
Parental investment is the time, energy and risk to survival that are involved in producing, feeding and otherwise caring for each offspring.
In general, for species in which parental investment is unequal, the more parentally invested sex will be a) more vigorously competed for than the other and b) more discriminating than the other when choosing mates.
Polygyny is related to high female and low male parental investment
When the evolutionary advantage in mating with multiple partners is greater for males, than for females, a pattern evolves in which males complete with one another to mate with as many females as they can.
The more polygynous a species, the greater is the average size difference between males and females.
Polyandry is related to high male and low female parental investment
Mostly by birds and fish.
Once the eggs are laid, they can be cared for by either parent. Depending on other conditions, evolution can lead to greater male than female parental investment.
Monogamy is related to equivalent male and female parental investment
When the two sexes make approximately equal investments in their young, their degree of competition for mates will also be approximately equal. Monogamy will prevail.
This is most likely to come about when conditions make it impossible for a single adult to raise the young, but quite possible for two to raise them.
Social monogamy does not necessarily imply sexual monogamy.
Promiscuity is related to investment in the group
Because any male in the colony could be the father, each male’s evolutionary interest lies not in attacking the young but helping to protect and care for the group as a whole.
What about human mating patterns?
Largely monogamous, partly polygynous species
Humans fall on the boundary between monogamy and polygyny.
Another clue to Homo sapiens prehistorically patterns comes from a comparative analysis of different types of white blood cells.
The more sexual partners a one has, the stronger one’s immune system needs to be to combat infection. The human immune system is between polygynous and monogamous.
The role of emotions in human mating systems
Our biological equipment that predisposes us for mating bonds includes brain mechanisms that promote the twin emotions of romantic love and sexual jealousy. Those are found in every culture that has been studied.
Love tends to create mating bonds, jealousy tends to preserve such bonds by motivating each member of a mated pair to act in ways designed to prevent the other from having an affair with someone else.
Other animals that form long-termed mating bonds show evidence of emotions that are functionally similar to human love and jealousy.
Lust tends to motivates to engage surreptitiously in sex outside of such bonds.
A woman who has sex with men other than her husband may benefit evolutionary:
Human beings, like other animals, are motivated both to hurt and help one another in the struggle to survive and reproduce.
Completion is the foundation for aggression.
Sex differences in aggression
Aggression a behavior intended to harm another member of the same species.
Brain mechanisms that motivate and organize such behavior are evolved because they help animals acquire and retain resources needed to survive and reproduce.
Polygynous males and polyandrous females fight over mates. Monogamous males fight to prevent other males from copulating with their mates (and the other way around). Promiscuous females fight to keep immigrating females from competing for resources.
Why male primates are generally more violent than female primates
Male primates are more likely to maim or kill their opponents.
Most of the violence perpetrated by male primates has to do directly or indirectly with sex.
The female at battle risks not only her life, but also that of any fetus she is gestating or young she is nursing
Male violence in humans
Humans are no exception to the usual primate rule.
Men are more violent.
Patterns of helping
Helping is any behavior that increases the survival chance or reproductive capacity of another individual.
Two forms:
Two theories of altruism:
The kin selection theory of altruism
Behavior that seems to be altruistic came about through natural selection because it preferentially helps close relatives, who are genetically most similar to the helper.
What actually survives over evolutionary time is not the individual but the individual’s genes.
Any gene that promotes the production and preservation of copies of itself can be a fit gene, from the vantage point of natural selection, even if it reduces the survival chances of a particular carrier of the gene.
Animals help kin more than nonkin.
The reciprocity theory of apparent altruism
The reciprocity theory provides an account of how acts of apparent altruism can arise even among nonkin.
Behavior seems to be altruistic are actually forms of long-term cooperation.
Genetically induced tendency to help nonkin can evolve if:
Final words of caution: two fallacies to avoid
1 Natural selection is not a moral force
2 Our genes do not control our behavior in ways that are independent of the environment
The naturalistic fallacy
The equation of natural, with moral or right.
Such equations are logically indefensible because nature itself is neither moral nor immoral except as judged by us.
Deterministic fallacy
The assumption that genetic influences on our behavior take the form of genetic control of our behavior, which we can do nothing about.
This mistake is assuming or implying that genes influence behavior directly rather than through the indirect means of working with the environment to build or modify biological structures that then, in interplay with the environment, produce behavior.
We humans can control our environment and therefor ourselves.
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Foundations for the study of psychology - a summary of chapter 1 of Psychology by Gray and Bjorklund (7th edition)
Psychology
Chapter 1
Foundations of the study of psychology
Psychology is the science of behaviour of the mind.
Behaviour is the observable action of a person or animal
Mind refers to an individual’s subjective experiences.
Dualism
René Descartes (1596-1650)
Important about him: the body is like a complicated machine, a machinal control of movements. Quite complex behaviours can occur trough purely machinal means.
Nonhuman animals have no souls.
Thought (Descartes defined as conscious deliberation and judgment) is ascribed to the soul.
Body and soul communicate through the pineal body.
Increased understanding of reflexes
The basic arrangement of the nervous system.
Some suggest that all human behaviour occurs through reflexes. → reflexology by I. M Sechenov (1863-1935) This inspired Pavlov.
The concept of localization of function in the brain
The idea that specific parts of the brain serve specific functions in the production of mental experience and behaviour.
Johannes Müller (1838-1965)
Different qualities of sensory experience come about because the nerves from different sense organs excite different parts of the brain. (We experience vison if this part of the brain is active).
Pierre Flourens (1824-1965)
Experiences on animals. Brain damage on different parts of the brain causes different deficits on animals abilities to move.
Paul Broca (1861-1965)
Publics effidence that people who suffer brain damage on specific parts of the brain lose the ability to speak, but do not lose other mental abilities
Methods of psychology - a summary of chapter 2 of Psychology by Gray and Bjorklund (7th edition)Psychology
Chapter 2
Methods of psychology
In psychology, the data are usually measures or descriptions of some form of behaviour produces by humans or other animals.
A fact (or observation) is an objective statement, usually based on direct observation, that reasonable observers agree is true. In psychology, facts are usually particular behaviours, or reliable patterns of behaviours, for persons or animals.
A theory is an idea, or conceptual model, that is designed to explain existing facts and make predictions about new facts that might be discovered.
Any prediction about new facts that is made from a theory is called a hypothesis.
Facts lead to theories, which leads to hypothesis, which are tested by experiments, which leads to new fact. It is a cycle of science.
Each of this dimensions can vary form the others, resulting in any possible combination.
Research design
Researches design a study to test a hypothesis, choosing the design that best fits the conditions the researcher wants to control.
Also in three basic types.
Genetics and evolutionary foundations of behaviour - a summary of chapter 3 of Psychology by Gray and Bjorklund (7th edition)Psychology
Chapter 3
Genetics and evolutionary foundations of behaviour
Adaption refers to modifications as a result of changed life circumstances.
Evolution is a long-term adaptive process.
How genes affect behavior
Genes are associated with behavior (they never produce or control behavior directly).
All the effects that genes have on behavior occur through their role in building and modifying the physical structures of the body. Those structures, interacting with the environment, produce behavior.
All genes that contribute to the body’s development are “for” behavior. Since all parts of the body are involved in behavior.
Genes provide the codes for proteins
Genes affect the body’s development (only) through their influence on the production of protein molecules.
Structural proteins; forms the structure of every cell of the body.
Enzymes; controls the rate of every chemical reaction in every cell.
Genes are components of extremely long molecules of a substance called DNA (deoxyribonucleic acid).
These molecules exist in the egg and sperm cells that join to from a new individual. And they replicate themselves during each cell division in the course of the body’s growth and development.
A replica of your whole DNA molecules exists in the nucleus of each of your body’s cells, where it serves to code for and regulate the production of protein molecules.
Each protein molecule consists of a long chain of smaller molecules. Those are amino acids.
A single protein molecule may contain from several hundred to many thousand amino acids in its chain.
There are a total of 20 distinct amino acids in every from of life on earth (and they can be arranged in countless sequences to from different protein molecules).
Some DNA serve as templates (as molds or patterns) for producing RNA. RNA severs as a template for producing protein molecules.
A gene is segment of a DNA molecule that contains the code that dictates the particular sequence of amino acids for a single type of protein.
A human being has between 20.000 and 25.000 genes.
Most of the DNA in human cells does not code for proteins.
Genes work only through interaction with the environment
The effects of genes are
.....read more Basic processes of learning - a summary of chapter 4 of Psychology by Gray and Bjorklund (7th edition)Psychology
Chapter 4
Basic processes of learning
To survive, animals must adapt to their environments.
Evolution by natural selection, is the slow long-term adaptive process that equips each species for life within a certain range of environmental conditions.
Environments changes and individuals must adapt to these changes over their lifetimes. Animals must learn.
Learning: any process through which experience at one time can alter an individual’s behavior at a future time.
Experience refers to any effects of the environment that are mediated by the individual’s sensory systems.
Behavior at a future time refers to any subsequent behavior that is not part of the individual’s immediate response to the sensory stimulation during the learning experience.
Classical conditioning
Classical conditioning is a learning processes that creates new reflexes.
A reflex is a simple, relatively automatic stimulus-response sequence mediated by the nervous system.
A stimulus results in a response.
To be considered a reflex, the response to a stimulus must be mediated by the nervous system. Because reflexes are mediated by the nervous system, they can be modified by experience.
Habituation: a decline in the magnitude of a reflexive response when the stimulus is repeated several times in succession. Not all reflexes undergo habituation.
Habituation is one of the simplest forms of learning. It does not produce a new stimulus-response sequence, but only weakens an already existing one.
Classical conditioning is a form of reflex learning that does produce a new stimulus-response sequence.
(First described by Ivan Pavlov)
Fundamentals of classical conditioning
The procedure and generality of classical conditioning
The stimulus (the bell sound by Pavlov) is a conditioned stimulus.
The response to the (condtionised stimulus, the bell) stimulus is a conditioned response.
The original stimulus (natural, before doing anything) is an unconditioned stimulus with an unconditioned response.
The procedure is called classical conditioning or Pavlovian conditioning
Pavlov concluded that, any environmental event that the animal could detect could become a conditioned stimulus of salivation. Of course classical conditioning is not limited to salivary responses.
Extinction of conditioned responses and recovery from extinction
Pavlov found that, without food, the bell elicited less and less salvation on each trial, and eventually none at all. This phenomenon is called extinction.
Extinction does not return the animal to the unconditioned state.
The mere passage of time following extinction can partially renew the conditioned response. This is called spontaneous recovery.
A single pairing of the conditioned stimulus with the unconditioned stimulus can fully renew the
The neural control of behavior - a summary of chapter 5 of Psychology by Gray and Bjorklund (7th edition)Psychology
Chapter 5
The neural control of behavior
Behavior is a product of the body’s machinery, especially the nervous system.
Neurons, the building blocks of the brain
The brain contains roughly 80 to 100 billion nerve cells, or neurons, and roughly 100 trillion synapses between neurons.
These are all more-or-less active, and their collective activity monitors our internal and external environments, creates all of our mental experiences, and controls all of our behavior.
The magic of this nervous system, lies in the organization of their multitudes.
Each neuron is itself a complex decision-making machine.
Each neuron receives information from multiple sources, integrates that information, and sends its response out to many other neurons or, in some cases, muscle cells or glands.
Three basic varieties of neurons, and structures common to them
The brain and spinal cord make up the central nervous system.
Extensions from the central nervous system, called nerves, make up the peripheral nervous system.
A neuron is a single cell of the nervous system
A nerve is a bundle of many neurons (or a bundle consisting of the axons of many neurons) within the peripheral nervous system.
Nerves connect the central nervous system to the body’s sensory organs, muscles and glands.
The central nervous system and peripheral nervous system are parts of an integrated whole.
Neurons come in a wide variety of shapes and sizes and serve countless specific functions.
They can be grouped into three categories according to their functions and their locations in the overall layout of the nervous system.
All neurons contain the same basic parts.
Mechanisms of motivation and emotion - a summary of chapter 6 of Psychology by Gray and Bjorklund (7th edition)Introduction to psychology
Chapter 6
Mechanisms of motivation and emotion
Motivation: the entire constellation of factors, some inside the organism and some outside, that cause an individual to behave in a particular way at a particular time.
Motivational state, or drive.
An internal condition that orients an individual toward a specific category of goals that can change over time in a reversible way. (The drive an increase and decrease).
Different drives direct a person toward different goals.
Those are hypothetical constructs! We infer the existence from the animal’s behavior.
Motivated behavior is directed toward incentives, the sought-after objects or ends that exist in the external environment.
Incentives are also called reinforces.
Drives and incentives complement one another in the control of behavior. If one is weak, the other must be strong to motivate the goal-directed action.
They also influence each other’s strength. A strong drive can enhance the attractiveness of a particular object.
A strong incentive can strengthen a drive.
Varieties of drives
In general, drives motivate us toward goals that promote our survival and reproduction. Some drives promote survival by helping us maintain the internal bodily conditions that are essential for life.
Drives that help preserve homeostasis.
Homeostasis: the constancy of internal conditions that the body must actively maintain.
Maintaining homeostasis involves the organism’s outward behavior as well as its internal processes.
The basic physiological underpinning for some drives is a loss of homeostasis, which acts on the nervous system to induce behavior designed to correct the imbalance.
Limitations of homeostasis: regulatory and nonregulatory drives
Homeostasis is not enough for understanding many drives.
Two general classes of drives:
A functional classification of mammalian drives
Five categories of mammalian drives:
The psychology of vision - a summary of chapter 8 of Psychology by Gray and Bjorklund (7th edition)Psychology
Chapter 8 (in part)
The psychology of vision
The purpose of human vision is to identify meaningful objects and actions.
Your visual system has sorted all the points and graduations that are present in the reflected light into useful renditions of the objects. It has provided you’re with all the information you need to reach out and touch, or pick up, whichever object you want to use next.
Vision researchers generally conceive of object perception as a type of unconscious problem solving, in which sensory information provides clues that are analyzed using information that is already stored in the person’s head.
The detection and integration of stimulus features
Any object that we see can be thought of as consisting of a set of elementary stimulus features, including the various straight and curved lines that form the object’s contours, the brightness and color of the light that the object reflects and the object’s movement or lack of movements with respect to the background.
Feature detection in the visual cortex
Ganglion cells of the optic nerve run to the thalamus and form synapses with other neurons that carry their output to the primary visual area of the cerebral cortex.
Within the primary visual area, millions of neurons are involved in analyzing the sensory input.
Different neurons respond to different patterns.
Edge detectors: neurons that respond best to stimuli that contains a straight contour separating a black patch from a white patch.
Bar detectors: respond best to a narrow white bar against a black background, or a narrow black bar against a
white background.
Any edge detector or bar detector responds best to a particular orientation of the edge or bar.
Neurons in the primary visual cortex are sensitive not just to the orientation of visual stimuli, but also to other visual features, including color and rate of movement. (One neuron might respond best to a yellow bar on a blue background, tilted 15 degrees clockwise and moving slowly from left to right).
Taken as a whole, the neurons of the primary visual cortex and nearby areas seem to keep track of all the bits and pieces of visual information that would be available in a scene.
Because of their sensitivity to the elementary features of a scene, these neurons are referred to as feature detectors.
Treisman’s two-stage feature-integration theory of perception
The feature-integration theory.
Any perceived stimulus (even a simple one such as an X) consist of a number of distinct primitive sensory features, like color and the slant of its individual lines.
To perceive the stimulus as
Memory and attention - a summary of chapter 9 of Psychology by Gray and Bjorklund (7th edition)Psychology
Chapter 9
Memory and attention
Information-processing theories are built on a set of assumptions concerning how humans acquire, store and retrieve information.
Key assumptions:
The model we use to portray the mind as containing three types of memory stores.
Each store is characterized by its function, its capacity and its duration.
In addition to the stores, the model specifies a set of control processes.
Those govern the processing of information within stores and the movement of information from one store to another.
Sensory memory: the brief prolongation of sensory experience
This trace is called sensory memory.
A separate sensory-memory store is believed to exist for each sensory system (like vision, hearing, touch, smell and taste), but only those for vision and hearing have been studied extensively.
Each sensory store is presumed to hold, very briefly, all the sensory input that enters that sensory system, whether or not the person is paying attention to that input.
The function of the store, presumably, is to hold on to sensory information, in its original sensory form, long enough for it to be analyzed by unconscious mental processes and for a decision to be made about whether or not to bring that information into the short-term store.
Most of the information in our sensory store does not enter into our consciousness.
We become conscious only of those items that are transformed, by the selective process of attention, into working memory.
The short-term store: conscious perception and thought
Information in the sensory store that is attended to moves into the short-term store.
Each item fades quickly and is lost within seconds when it is no longer actively attended to or thought about.
This is conceived of as the major workplace of the mind (working memory).
Working memory has been used to refer to the process of storing and transforming information being held in the short-term store. It is the seat of conscious thought.
Information can enter the short-term store form both the sensory-memory store
.....read more Reasoning and intelligence - a summary of chapter 10 of Psychology by Gray and Bjorklund (7th edition)Psychology
Chapter 10
Reasoning and intelligence
Reasoning: The process by which we use our memories in adaptive ways
Intelligence: our general capacity to reason
We reason by using our memories of previous experiences to make sense of present experiences or to plan the future.
To do so, we must perceive the similarities among various events we have experienced.
Fast and slow thinking
Cognitive processes could be placed on a continuum from automatic to effortful.
It is useful to think of any cognitive process as falling somewhere along this continuum.
When solving problems, people have two general ways of processing. (Dual-processing theories).
In many cases, when presented with a problem, you cannot shut of the ‘fast’ system, even if it may interfere with your arriving at the correct solution to a problem via the ‘slow’ system. (Like the stroop interference effect).
The ‘fast’ implicit system effortlessly produces impressions, feelings and intuitions that the ‘slow’ explicit system considers.
The effortful ‘slow’ system has potential control over the ‘fast’ system. (But when making routine decisions, the ‘fast’ system is in control. Like reading and making sense of language). The fast system even makes simple decisions, some of which are in contradiction to the correct solution that can only be derived by using the slow system.
Fast processing is not unique to humans. But no other species comes close to the effortful, explicit cognition displayed in Homo sapiens.
Analogies as foundation for reasoning
Two kinds of reasoning that depend quite explicitly on identifying similarities are:
The development of body, thought and language - a summary of chapter 11 of Psychology by Gray and Bjorklund (7th edition)Psychology
Chapter 11
The development of body, thought and language
Prenatal development
Zygotic, embryonic and fetal phases
The prenatal period is conventionally divided into three phases:
By the end of the 12th week after conception, all the organs are formed, though not functioning well, and are in same proportion to each other as in a full-term newborn, just smaller.
The external genitalia begin to differentiate between males and females between the 9th weeks but are not fully formed until about the 12th week.
In the 8th week, the embryo begins to move and activity increases by 12 weeks.
Fetuses ‘behave’ and are able to perceive some stimuli.
By 6 months fetuses respond to their mothers’ heartbeat and sounds from outside the womb, including language.
The effects of experience during the prenatal period
Although embryos and fetuses are sheltered from the outside world they are nonetheless subject to the effects of experience.
Teratogens: environmental agents that cause harm during prenatal development.
Most teratogens are in the form of substances that get into the embryo’s or fetus’s system from the mother through the umbilical cord.
A teratogen’s potential effect on prenatal development depends on how early or late in pregnancy the exposure occurs. If
Social development - a summary of chapter 12 of Psychology by Gray and Bjorklund (7th edition)Psychology
Chapter 12
Social development
The natural human environment is a social environment.
Social development: the changing nature of our relationships with others over the course of life.
Human infants are completely dependent on caregivers for survival. But they are not passively dependent.
They enter the world biologically prepared to learn who their caregivers are and to elicit from them the help they need. By the time they are born, babies already prefer the voices of their own mother over other voices (and the smell of their own mother). Newborns signal distress through fussing and crying.
By the time they are three months old, they express clearly and effectively their emotions through their facial expressions. And they respond differentially to such expressions in others.
Though such actions, infants help build emotional bonds between themselves and those on whom they most directly depend, and then they use those caregivers as a base from which to explore the world.
Attachment: such emotional bonds.
Attachment to caregivers
Harlow’s monkeys raised with surrogate mothers
Providing adequate nutrition and other physical necessities is not enough. Infants also need close contact with comforting caregivers.
The form and functions of human infants’ attachment
Bowlby observed attachment behaviors in young humans, from 8 months to 3 years of age.
Children show distress when their mothers left them. Especially in an unfamiliar environment. They showed pleasure when reunited with their mothers, showed distress when approached by a stranger unless reassured or comforted by their mothers and where likely to explore an unfamiliar environment when in the presence of their mothers than when alone.
Bowlby contended that attachment is a universal human phenomenon with a biological foundation that derives from natural selection. Infants are potentially in danger when out of sight of caregivers, especially in a novel environment.
Attachment is strengthen at about the age 6 to 8 months, when infants begin to move around on their own.
The strange-situation measure of attachment quality
Mary Ainsworth developed the strange-situation test.
Infants in this test are:
Social psychology - a summary of chapter 13 of Psychology by Gray and Bjorklund (7th edition)Psychology
Chapter 13
Social psychology
Humans are naturally interested in assessing the personality characteristics and attitudes of other humans they encounter.
This drive has clear adaptive functions. Other people can help us or hurt us in our life endeavors. Understanding others helps us predict their behavior and decide how to interact with them.
The accuracy of judgments of others sometimes suffers from certain consistent mistakes, or biases.
These biases occur most often when we are not using our full mental recourses, or have only limited information with which to reason, or have unconscious motives for reaching particular conclusions.
Making attributions from observed behavior
Actions are directly observable, and thoughts are not. Judgments about the personalities of people we encounter are based largely on what we observe of their actions.
Any judgment about another person is, in essence, a claim about causation. It is an implicit claim that the person is caused in part by some more or less permanent characteristic of the person.
Any claim about causation is an attribution. A claim about the cause of someone’s behavior.
The logic of attributing behavior to the person or the situation.
To build a useful picture of a person on the basis of his or her actions, you must decide which actions imply something unique about the person and which actions would be expected of anyone under similar situations.
When behavior is clearly appropriate to the environmental situation, people commonly attribute the behavior to the situation.
Three questions in making an attribution
Social influences on behavior - a summary of chapter 14 of Psychology by Gray and Bjorklund (7th edition)Psychology
Chapter 14
Social influences on behavior
Human behavior is influenced powerful by the social environment in which it occurs.
We behave as we do not just because of who we are, but also because of the social situations in which we find ourselves.
Social pressure: the entire set of psychological forces that are exerted on us by others whether real or imagined.
We are most strongly influenced by those people who are physically or psychologically closed to us.
Social pressure arises from the ways we interpret and respond emotionally to the social situations around us.
It promotes our social acceptability and helps create order and predictability in social interactions.
Facilitating and interfering effects of an audience
Social facilitation: the enhancing effect of an audience on task performance.
Social interference: a decline in performance when observers are present.
Facilitation of ‘easy’ tasks, interference with ‘hard’ ones
The presence of others facilitates performance of dominant actions and interferes with performance of nondominant actions.
Dominant actions: actions that are so simple, speciestypical, or well learned that they can be produced automatically, with little consciously thought
Nondominant actins: actions that require considerable conscious thought or attention
The presence of an audience increases a person’s level of drive or arousal.
The arousal increases the person’s effort, which facilitates dominant tasks where the amount of effort determines the degree of success.
The arousal interferes with controlled, calm, conscious thought and attention and thereby worsens performance of nondominant actions.
Evaluation anxiety as a basis for social interference
The primary cause of social interference is evaluation anxiety.
Social interference increases when the observer are high in status or expertise and are present explicitly to evaluate. It also increases when subjects are made to feel unconfident and more anxious about their ability.
It decreases when subjects feel confident about their ability.
Choking under pressure: the working-memory explanation
‘Choking’ is especially likely to occur with tasks that make strong demands on working memory.
The worry takes space out of the memory span.
Choking on academic tests
Distracting and disturbing thoughts flood their minds and interfere with performance on tests.
With sufficient pressure, choking can even occur in students who normally do not suffer from tests anxiety. It occurs specifically with tests items that make the highest demands on working memory.
Stereotype threat as a special cause of choking
Stereotype threat: threat that test-takers experience when they
.....read more Personality - a summary of chapter 15 of Psychology by Gray and Bjorklund (7th edition)Psychology
Chapter 15
Personality
Personality refers to a person’s general style of interacting with the world, especially with other people.
The development during childhood of chronic patterns of behavior that differ from one individual to another.
The most central concept in personality psychology is the trait. This is a relatively stable predisposition to behave in a certain way.
This is considered to be part of the person, not the environment.
States (other than traits) of motivation and emotion are, defined as inner entities than can be inferred from observed behavior. Traits are enduring, but states are temporary.
A trait might be defined as an enduring attribute that describes one’s likelihood of entering temporarily into a particular state.
Traits are dimensions along which people differ by degree.
Trait theories: efficient systems for describing personalities
The goal of any trait theory of personality is to specify a manageable set of distinct personality dimensions that can be used to summarize the fundamental psychological differences among individuals.
Factor analyses as a tool for identifying an efficient set of traits
Factor analyses: a method of analyzing patterns of correlations in order to extract mathematically defined factors, which underlie and help make sense of those patterns.
Steps:
Factor analyses tells us that two dimensions of personality are relatively independent of each other.
Cattell’s pioneering use of factor analysis to develop trait theory
Cattell:
An infinite number of different personalities can be formed from a finite number of traits.
He identified 16 basic trait dimensions and made a questionnaire called the 16 PF questionnaire to measure them.
The five-factor model of personality
The five-factor model (or big five theory)
A person’s personality is most efficiently described in terms of his or her
Mental Disorders - a summary of chapter 16 of Psychology by Gray and Bjorklund (7th edition)Psychology
Chapter 16
Mental Disorders
Before clinicians can diagnose a psychological disorder, the must evaluate the behavior in terms of four themes, the four D’s.
The diagnostic and statistical manual of mental disorders (DSM)
Specifies criteria for deciding what is officially a ‘disorder’ and what is not.
It is a work in process.
What is a mental disorder?
Mental disorder has no really satisfying definition.
Categorizing and diagnosing metal disorders
Diagnosis: the process of assigning a label to a person’s mental disorder.
To be of value, any system of diagnosis must be reliable and valid.
The quest for reliability
The reliability of a diagnostic system: the extent to which different diagnosticians, all trained in the use of the system, reach the same conclusion when they independently diagnose the same individual.
To test alternative ways of diagnosing each disorder, they conducted field studies in which people who might have a particular disorder were diagnosed independently by a number of clinicians or researchers using each of several alternative diagnostic systems.
The systems that produced the greatest reliability were retained.
All the criteria are based on observable characteristics or self-descriptions by the person being diagnosed.
The Question of validity
The validity of a diagnostic system is an index of the extent to which the categories it identifies are clinically meaningful.
This is based on extensive research. To conduct the research needed to determine whether or not a diagnosis is valid, one must fists form a tentative, reliable diagnostic system.
The results of such studies may lead to new means of defining and diagnosing the disorder or to new subcategories of the disorder, leading to increased diagnostic validity.
Systems for classifying mental disorders:
The DSM
The Word Health Organization (WHO) has developed the International Classification of Diseases (ICD-10)
Possible dangers in Labeling
Diagnosing and labeling may be essential for the scientific study of metal disorders, but labels
.....read more Treatment - a summary of chapter 17 of Psychology by Gray and Bjorklund (7th edition)Psychology
Chapter 17
Treatment
What to do with individuals with severe mental disorders? A brief history
A major chance in the treatment of people with severe mental disorders occurred in the 1950s, inspired by several factors;
A positive development: assertive community treatment
Since the 1970s, an increasing number of communities have developed outreach programs, often referred to as assertive community treatment (ACT) programs, and aimed at helping individuals with severe mental illness wherever they are in the community.
Each person with mental illness in need is assigned to a multidisciplinary treatment team. Someone on the team is available at any time of the day to respond to crises.
Each patient is visited at least twice a week by a team member, who checks on his or her health, sees if any services are needed, and offers counseling when that seems appropriate.
The team meets frequently with family members who are involved with the patient, to support them in their care for the patient.
Structure of the mental health system
Mental health professionals
Mental health professionals are those who have received special training and certification to work with people who have psychological problems or mental disorders.
The primary categories;
Relieve the disorder by directly altering bodily processes.
Drugs
Drugs for mental disorders are far from unmixed blessings.
They nearly always produce undesirable side effects.
Antipsychotic drugs
Used to treat schizophrenia and other disorders in which psychotic symptoms predominate.
Such drug reduce and in some cases abolish the hallucinations, delusions, and bizarre actions that characterize the active phase of schizophrenia and they reduce the need for hospitalization.
All antipsychotic drugs in use today decrease the activity of the neurotransmitter dopamine at certain synapses in the brain, which is believed to be responsible for the reduction in psychotic symptoms.
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