IB Psychology Biological approach

Distributive processing

The theory that behavior is the result of interaction between several parts of the brain and not strictly localized to a singular part of the brain.

Equipotentiality

the theory that the brain has the capacity in the case of injury to transfer functional memory from the damaged portion of the brain to other undamaged portions of the brain.

Localization of function

The theory that behaviors have their origin in specific areas of the brain. Damage to that part of the brain would result in an inability to carry out that behavior.

Relative localization

The theory that although one part of the brain may play a key role in a behavior, several parts of the brain also play a lesser role in that behavior.

Strict localization

The theory that behaviors can be attributed to a single area of the brain.

Apoptosis

Neuronal cell death

Cortical remapping

when one area of the brain assumes the functions of another part of the brain which has been damaged.

Neurogenesis

the process by which new neurons are formed in the brain.

Long-term potentiation

The repeated firing of a neuron strengthens the connection. In other words, neurons that fire together, wire together. This is the biological explanation of why rehearsal leads to memory consolidation.

Neural network

The human brain consists of neurons or nerve cells that transmit the information received from our senses. Many such nerve cells are arranged together in our brains to form a network of neurons. These neurons pass electrical impulses from one neuron to another.

Neuroplasticity

the ability of neural networks in the brain to change through growth (dendritic branching) and reorganization (cortical remapping). These changes range from individual neuron pathways to making new connections as a result of environmental stimulation.

Synaptic pruning

Also known as neuronal pruning, this is a natural process where the brain eliminates extra synapses. Synaptic pruning is thought to be the brain's way of removing connections that are no longer needed.

Artifacts

something observed in a scientific investigation or experiment that is not naturally present but occurs as a result of the investigative procedure. In brain scanning, this is where activity appears in the brain that is not the result of the IV, but potentially the result of anxiety caused by being in the scanner or by noise or other activity of the scanner itself.

Functional imaging

the study of human brain function based on analysis of data acquired using Electroencephalography (EEG), functional Magnetic Resonance Imaging (fMRI), or Positron Emission Tomography (PET).

Pixel counting

Pixel counting consists of counting the pixels in the images provided by the MRI scans. A pixel is simply a two-dimensional measurement that allows researchers to calculate the area of different parts of the brain.

Positron Emission Tomography (PET)

a functional imaging technique that uses radioactive substances known as radiotracers to visualize and measure changes in metabolic processes.

Structural imaging

imaging approaches that are specialized for the visualization and analysis of anatomical properties of the brain.

Voxel-based morphometry

VBM is a technique using MRI that allows researchers to measure to the volume of areas of the brain.

Agonist

a chemical or a drug that binds to receptors in the brain and causes a reaction. Agonists can occur naturally in the body as hormones and neurotransmitters (endogenous agonists) or come from exterior sources like drugs (exogenous agonists).

Antagonist

A chemical or drug that binds to receptors in the brain and prevents a neurotransmitter or hormone from having an effect on behavior. For example, scopolamine is an antagonist for acetylcholine.

Excitatory function

When a neurotransmitter increases the likelihood that the neuron will fire an action potential. This depends on the receptor site. Many neurotransmitters are excitatory when they act on some receptor sites, and inhibitory when they act on others. For example, serotonin is an excitatory neurotransmitter that regulates sleep and wakefulness and is found in neurons in the pons and upper brain stem - but it is inhibitory in mood and emotion.

Inhibitory function

When a neurotransmitter decreases the likelihood that the neuron will fire an action potential. This depends on the receptor site. Many neurotransmitters are inhibitory when they act on some receptor sites, and excitatory when they act on others. For example, serotonin is an inhibitory neurotransmitter when it is involved in emotion and mood, but excitatory in sleep and wakefulness.

Neurotransmitter

A neurotransmitter is a chemical messenger that carries signals between neurons. Neurotransmitters are released from the terminal buttons at the end of an axon after the action potential has sent an electrical charge down the neuron. The neurotransmitter then crosses the synaptic gap to reach the receptor site on another neuron.

Reuptake

The reabsorption of a neurotransmitter by the terminal buttons of the pre-synaptic neuron after it has performed its function of transmitting a neural impulse. This prevents the further activity of the neurotransmitter. Prozac is an SSRI - that is, a selective serotonin reuptake inhibitor, allowing more serotonin to remain in the synaptic gap.

Cortisol

a stress hormone that is secreted by the adrenal cortex. Responsible for the breakdown of glucose in the fight-or-flight response. Appears to be linked to hippocampal cell loss and memory dysfunction.

Hormone

A chemical released by a gland directly into the bloodstream which has an effect on behavior.

HPA axis

a complex set of interactions between two parts of the brain—the hypothalamus and the pituitary glands—and the adrenal glands that are located at the top of each kidney. This is the basis of the human stress response.

Permissive effect

When the mere presence of the hormone allows for a behavior, rather than the amount of the hormone. In the case of testosterone, Sapolsky argues that it is not how much testosterone an animal has that determines whether it is aggressive, it is whether they have testosterone.

Target cells

A target cell responds to a hormone because it bears receptors for the hormone. In other words, a particular cell is a target cell for a hormone if it contains functional receptors for that hormone.

Androstadienone [AND]

a steroid that has been described as a putative pheromone in men.

Co-dominant inheritance

a form of inheritance wherein the alleles of a gene pair in a heterozygote are fully expressed. As a result, the phenotype of the offspring is a combination of the phenotype of the parents. Thus, the trait is neither dominant nor recessive.

Estratetraenol [EST]

a steroid that has been described as a putative pheromone in women.

MHC

a group of genes that code for proteins found on the surfaces of cells that help the immune system recognize foreign substances.

Pheromone

a chemical substance produced and released into the environment by an animal affecting the behavior or physiology of others of its own species.

Putative pheromone

this is the term used to communicate the idea that the example is "potentially" a human pheromone, but it is not definitive.

Signaling pheromones

chemical substances that produce rapid behavioral effects, such as mating

Concordance rate

the probability that the same trait will be present in both members of a pair of twins.

Dizygotic twins

The clinical term for fraternal twins; this occurs when two fertilized eggs are implanted in the uterus wall at the same time. When two eggs are independently fertilized by two different sperm cells, fraternal twins result. The genetic similarity is the same as any other siblings

Kinship study

Usually known as a family study or "pedigree study" - this is a study that looks at the frequency of a trait within a family in order to determine the likelihood that the trait may be inherited.

Monozygotic twins

The clinical term for identical twins; they share 100% of their DNA.

Candidate gene

a gene whose function is known that is hypothesized to be associated with a particular disorder or behavior.

Diathesis-stress model

attempts to explain a disorder as the result of an interaction between a predisposition and stress caused by life experiences.

Gene expression

the process by which the instructions in our DNA are converted into a functional product; in psychology, this is when a gene is "turned on" or "off", resulting in a behavior.

Genetic vulnerability

An underlying inherited susceptibility - that is, the theory that you may have genes that may make you more likely to have certain traits if those genes are exposed to the appropriate environmental stressors.

Genomewide Association Study

an examination of genetic variants in a large sample of individuals to see if any variant is associated with a trait.

Linkage analysis

Matching genetic variations (polymorphisms) with the frequency of a behavior

Polymorphism

a genetic variation (mutation) resulting in the occurrence of several different forms or types of individuals among the members of a single species.

Transgenic mice

:mice that have had a single gene changed or removed

Adaptation

The adjustment or changes in behavior, physiology, and structure of an organism to become more suited to an environment.

Inclusive fitness

the theory that helping out someone in your gene pool increases the overall probability that the genes in your gene pool will be passed down to the next generation

Natural selection

the process whereby organisms better adapted to their environment tend to survive and produce more offspring.

Sexual selection

members of one biological sex choose mates of the other sex to mate with (intersexual selection), and compete with members of the same sex for access to members of the opposite sex (intrasexual selection).

Attrition rate

The percent of an original sample that drops out of a study over time. If too many participants drop out, or if too many of one type of participant drop out, the sample may become less representative of the target population.

Quasi-experiment

The researcher manipulates an independent variable and measures its effect on a dependent variable, but participants are not randomly allocated to conditions; they are assigned to conditions based on pre-existing traits.

Natural experiment

The researcher uses a pre-test /post-test design but does not manipulate the independent variable. The IV is naturally occurring. Participants are also not randomly allocated to groups.

Deception by omission

When the researchers do not explain all the details of a study to avoid demand characteristics. The participants are not told anything that is untrue, but the lack of detail means that they are not giving informed consent.

Deception by commission

When the researchers give incorrect information to the participants about the study. This could include giving them a false aim of the study.