In evolutionary psychology, culture also has a major effect on psychological adaptations. For example, status within one’s group is important in all cultures for achieving reproductive success, because higher status makes someone more attractive to mates.

Gene Selection Theory

Sexual selection occurs through two processes. The first, intrasexual competition, occurs when members of one sex compete against each other, and the winner gets to mate with a member of the opposite sex. The second process of sexual selection is preferential mate choice, also called intersexual selection. In this process, if members of one sex are attracted to certain qualities in mates—such as brilliant plumage, signs of good health, or even intelligence—those desired qualities get passed on in greater numbers, simply because their possessors mate more often.

There are others that advocate for using nonhuman animal subjects because nonhuman animal subjects many times will have distinct advantages over human subjects.

One of the keys to behaving in an ethical manner is to ensure that one has given informed consent to be a subject in a study. Obviously, animals are unable to give consent.

Alternatively, cortical mapping can now occur through surgically implanted subdural strip and grid electrodes that will allow the researchers/doctors to stimulate the brain areas in between surgeries, as opposed to during surgery

direct cortical stimulation, occurs when a researcher applies a small electrical current directly to the brain itself.

esearchers are able to correlate the deficits in function with the area of damage

A lesion is a site of damage in the brain. In neuroscience, we conduct lesion studies on both animals and human subjects. In animals, lesions can be made in a specific area by the researcher.

The researcher can tell exactly where the activity is coming from and exactly when the activity is occurring.

single cell recordings have excellent spatial and temporal resolution.

single cell recordings allows for us to record the activity of a cell, at least in theory

These techniques are different from what was previously discussed in that they are more invasive, techniques that require entering the brain as opposed to taking measurements from the skull.

TMS is a noninvasive method that causes depolarization or hyperpolarization in neurons near the scalp.

Example of fMRI analyses overlaid on an sMRI image. Area 1 (orange) indicates an increase in the BOLD signal, and Area 2 (blue) indicates a decrease in the BOLD signal. We infer that neural activity increased in the Area 1 and decreased in Area 2.

The assumption is that blood flow in the brain is related to the activity level in that area of the brain.

fMRI measures the change in the concentration of oxygenated hemoglobin, which is known as the blood-oxygen-level-dependent (BOLD) signal.

The assumption is that blood flow in the brain is related to the activity level in that area of the brain.

Indirect brain imaging techniques rely on an assumption that activity in the brain correlates to something else that we are able to measure. In these cases, these techniques measure blood flow in the brain.

EEG and MEG both have excellent temporal resolution and are useful when someone is particularly interested in studying the timing of brain activity. For example, if someone is reading a sentence that ends with an unexpected word, how long after reading the unexpected word does the brain react to it?

Due to the fact that the magnetic fields of interest are so small, special rooms that are shielded from magnetic fields in the environment are needed in order to avoid contamination of the signal being measured

However, the MEG recording apparatus is much more expensive than EEG, so MEG is much less widely available.

While EEG is lacking with respect to spatial resolution, one major advantage of EEG is its temporal resolution. Data can be recorded thousands of times per second, allowing researchers to document events that happen in less than a millisecond

Electroencephalography (EEG) is one technique for studying brain activity. This technique uses at least two and up to 256 electrodes to measure the difference in electrical charge (the voltage) between pairs of points on the head. These electrodes are typically fastened to a flexible cap (similar to a swimming cap) that is placed on the participant’s head. Figure 2.3.12.3.1\PageIndex{1} shows a patient wearing such a cap. From the scalp, the electrodes measure the electrical activity that is naturally occurring within the brain. They do not introduce any new electrical activity.

The patient must be enclosed in a metal tube-like device for the duration of the scan, sometimes as long as thirty minutes, which can be uncomfortable and impractical for ill patients. The device is also so noisy that, even with earplugs, patients can become anxious or even fearful. These problems have been overcome somewhat with the development of “open” MRI scanning, which does not require the patient to be entirely enclosed in the metal tube.

Magnetic resonance imaging (MRI) is a noninvasive medical imaging technique based on a phenomenon of nuclear physics discovered in the 1930s, in which matter exposed to magnetic fields and radio waves was found to emit radio signals. In 1970, a physician and researcher named Raymond Damadian noticed that malignant (cancerous) tissue gave off different signals than normal body tissue

The main disadvantage of CT scanning is that it exposes patients to a dose of radiation many times higher than that of X-rays. Whether this is particularly dangerous is still being debated (McCollough et al., 2015).

Tomography refers to imaging by sections. Computed (or computerized) tomography (CT) is a noninvasive imaging technique that uses computers to analyze several cross-sectional X-rays in order to reveal small details about structures in the body. The technique was invented in the 1970s and is based on the principle that, as X-rays pass through the body, they are absorbed or reflected at different levels. In the technique, a patient lies on a motorized platform while a computerized axial tomography (CAT) scanner rotates 360 degrees around the patient, taking X-ray images.

In contrast, more modern medical imaging technologies produce data that are integrated and analyzed by computers to produce three-dimensional (3D)

X-rays are capable of damaging cells and initiating changes that can lead to cancer

Functional MRI of a teenage brain conducting a working memory test. The regions in red and yellow, primarily in the frontal lobe and occipital lobe, are the most active.

They may ask “When does this activity occur?” Or “Where does this activity occur?” Some techniques are better for answering one of these questions, whereas other techniques are better for answering the other question.

Functional imaging techniques allow researchers to learn about the brain activity during various tasks by creating images based on the electrical activity or the absorption of various substances that occurs while a subject is engaging in a task.

Structural imaging techniques

invasive