Psychology by P. Gray and D. F., Bjorkland (eight edition) – Summary chapter 5

Slower changing components of the mind are referred to as behavioural states (e.g: variations in motivation, emotion).

Motivation refers to the entire constellation of factors, inside and outside of the organism, that causes an individual to behave in a particular way at a particular time. Motivational state or drive refers to an internal condition that orients an individual toward a specific category of goals that can change over time in a reversible way (the drive can increase and decrease).

Motivated behaviour is directed towards incentives or reinforcers. The motivational state for searching for food is hunger, but the incentive is the food itself. Drives and incentives complement each other and influence each other’s strength.

Homeostasis is the constancy of internal conditions that the body must actively maintain. The loss of homeostasis is the psychological foundation of drives because this loss acts on the nervous system to induce behaviour designed to correct the imbalance.

There are two general classes of drives: regulatory drives and nonregulatory drives. There are five categories of mammalian drives:

1. Regulatory drives
   These are drives that promote survival by helping to maintain the body’s homeostasis.
2. Safety drives
   These are drives that motivate an animal to stay safe (e.g: fear, anger).
3. Reproductive drives
   These are drives that motivate an individual to reproduce and keep the offspring safe.
4. Social drives
   These are drives that promote cooperation and friendship.
5. Educative drives
   These are drives that motivate an individual to play and to explore.

Things such as art, music and literature can be seen as an extension of the educative drive, but it can also be seen as something that taps into our already existing drives.

The central-state theory of drives states that different drives correspond to neural activity in different sets of neurons in the brain. A set of neurons in which activity constitutes a drive is called a central drive system. For a set of neurons to be a central drive system, it must receive and integrate the various signals that can raise or lower the drive state. Besides that, it must act on all the neural processes that would be involved in carrying out the motivated behaviour; it must direct perceptual mechanisms toward stimuli related to the goal and motor mechanisms toward producing the appropriate movements. The hypothalamus is believed to be the hub of many central drive systems because it fits the exact description and has a strong connection with the pituitary gland.

The term ‘reward’ has three interrelated meanings.

1. Wanting
   A reward is something that we want. Wanting is measured by the amount of effort an individual will exert to get the reward. Dopamine is crucial in the wanting part, as individuals show an increase of dopamine right before they get the reward, but not after they’ve received the reward.
2. Liking
   A reward is something that we like. Liking refers to the subjective feeling of pleasure. Endorphin is crucial for an individual to like the reward.
3. Reinforcer
   A reward is something that affects learning.

Animals will work the hardest to stimulate a tract in the brain called the medial forebrain bundle. The neurons of this tract that are most crucial for this rewarding effect have their cell bodies in nuclei in the midbrain and synaptic terminals in a large nucleus in the basal ganglia called the nucleus accumbens. Damage to the medial forebrain bundle or the nucleus accumbens destroys all motivated behaviour.

Dopamine release promotes long-term potentiation of neural connections with the nucleus accumbens and LTP is believed to be part of the cellular basis for learning throughout the brain, thus dopamine plays an important role in learning. When a reward is unexpected, the dopamine release immediately after the reward helps to reinforce an association between the reward and any stimulus or response that happened to precede it.

Drugs often release dopamine in the brain in a manner that normally only happens if a reward is unexpected. This causes some sort of ‘super-learning’, where the individual starts to learn all the environmental cues to the drug, which causes dopamine release and thus a strong urge to get the drug when they are in the same environment again. The liking of a drug reduces over time, but the wanting only grows stronger.

Regulatory drives make use of feedback control (e.g: a thermostat. It will increase the temperature if the temperature is below a certain level and it will do nothing if the temperature is above a certain level). The arcuate nucleus, which lies in the centre of the lowest portion of the hypothalamus, very close to the pituitary gland, is the master control centre for appetite and weight regulation. There are several ways the body tells a person that he’s either hungry or satiated:

1. Hungry
   Appetite-stimulating neurons release the neurotransmitter NPY, which is the most potent appetite stimulator yet discovered.
2. Satiated
   There is a higher body temperature. There is an increased blood level of glucose and the stomach temporarily grows. The release of certain hormones, such as PYY.  Appetite-suppressing neurons stimulate these effects. The hormone leptin produced by fat cells reduces appetite (individuals without the hormone leptin become incredibly obese). Leptin reduces appetite up to a certain level.

Within a culture, differences in body weight result mostly from the difference in genes, but across cultures, environment plays a larger role. The evidence for this statement comes from the following things: the weight of adopted children correlate much more strongly with the weight of their adoptive parents and genetically similar Indians in two different environments differed greatly in weight. The prenatal diet is very important for the future bodyweight of the offspring. Sensory-specific satiety is when an individual has had enough of one taste or type of food and will feel satiated, but the hunger mechanisms can easily be activated again because of the availability of other food. Classical conditioned cues can also cause the hunger mechanisms to be activated.

Testosterone is crucial for maintaining the sex drive in males. The amount of testosterone that men secrete into their blood is affected by psychological conditions. Estrogen and progesterone produce the menstrual cycle in humans and the oestrous cycle in other mammals. This cycle controls ovulation. The female sexual drive and behaviour are tightly controlled by the oestrous cycle.

In rats, the ventromedial area of the hypothalamus plays a role in sexual behaviour analogous to the preoptic area in the male. Most female animals seek a partner to copulate when they are fertile, while many primates also seek out sexual partners when they are not fertile. Their sexual drive during non-fertile times doesn’t depend on androgens, a category of hormones including testosterone. Arousability refers to the capacity to become sexually aroused in response to appropriate stimuli. Proceptivity refers to the person’s motivation to seek out and initiate sexual activity.

Sex hormones influence sexual drive and behaviour through two different kinds of effects on the brain: activating and differentiating. Activating effects are the kinds of effects that occur during and after puberty. Differentiating effects are effects that occur before and immediately after birth and cause the brain to develop in a male or female direction. They are responsible for the biological differences between males and females in sexual drive and orientation. The hormone testosterone causes the male to develop like a male during the foetal stage. It develops the male sex drive and develops the brain in a male-like manner.

A theory states that falling in love involves three primary emotional systems that evolved to support mating, reproduction and parenting:

1. Lust
   This is becoming sexually excited by members of the opposite sex (driven by androgen hormones, such as testosterone)
2. Attraction
   This consists of strong emotions toward the other
3. Attachment
   This is the feeling of closeness and anxiety when separated (associated with the hormones vasopressin and oxytocin)

Sexual orientation consists of at least three components:

1. Sexual / romantic attraction
   To which sex do people feel most attracted?
2. Sexual behaviour
   With which sex do people have voluntary sexual acts?
3. Sexual identity
   How do people describe themselves sexually?

Genes play a role in sexual orientation, but not the sole role. The prenatal development can also play a role in the sexual orientation, as this can cause differences in the amount of testosterone available to the foetus’s brain. The most consistent, nongenetic influence on sexual orientation is the fraternal birth-order effect on male homosexuality. The more older brothers a man has, the greater is the likelihood of his sexual orientation being homosexual.

Alpha waves are relatively slow, large and regular waves. These waves occur when someone is awake but has his eyes closed. If a person concentrates on something, the EEG pattern changes to low amplitude, fast, irregular waves called beta waves. A slow, irregular, high-amplitude kind of wave is called a delta wave. When a person falls asleep they generally go through four stages:

1. Stage 1 (brief transition)
2. Stage 2 (sleep spindles)
3. Stage 3 (delta waves start to occur)
4. Stage 4 (delta waves)

After stage four, a sleeping person returns to stage 3 and 2 and then a new type of sleep occurs: REM sleep (rapid-eye-movement sleep). During REM sleep dreams occur and there are small twitches of muscles during this type of sleep. Also, the eyes move rapidly under the eyelids. REM sleep also marks the onset of a new sleep cycle. Stage 2, 3 and 4 are referred to as non-REM sleep. A person generally goes through five sleep cycles. At first, the non-REM-sleep will become deeper and after the second sleep cycle, the sleep will rapidly become lighter.

If a person is awakened during REM sleep, the person will often report a true dream. If a person is awakened during non-REM sleep, the person will often only report sleep thought, which lacks the vivid sensory and motor hallucinations of true dreams (more alike to daytime thinking). A person is not completely irresponsive during sleep and although the eyes are closed, the other sensory channels remain open (e.g: a parent can sleep through a thunderstorm but awakens when they hear their child cry). The sleeping person’s brain sorts out sounds by meaning to some degree. All mental activity during sleep is quickly forgotten. 

There are several theories about the functions of sleep:

1. Preservation and protection theory
   This theory states that the function of sleep is to protect the individual and preserve energy at times when there is relatively little value to being awake and considerable danger. Evidence for this comes from the different time of awakening of animals with different feeding patterns and the amount of sleep they get.
2. Body-Restoration theory
   This theory states that the body wears out during the day and needs sleep to restore it. There is little to no evidence that the amount of energy an individual uses in a day affects the number of hours that the individual sleeps.
3. Brain-Maintenance theory of REM sleep
   This theory states that REM sleep provides regular exercise to groups of neurons in the brain. Synapses can degenerate if they go too long without being active, so neural activity during REM sleep may help preserve important circuits. Evidence for this theory is found in foetuses, which spend almost 24 hours a day in REM sleep.

It is unclear whether dreams serve any purpose, but it could just be the side effect of psychological changes that occur during REM sleep. Neurons in visual and motor areas of the brain become active during REM sleep and dreams could just be the result of those neurons activating.

Nonsomniacs are people who barely need any sleep. Insomniacs are people who need a normal amount of sleep but have great difficulty sleeping at night

The sleep drive is promoted by neural mechanisms located in the hypothalamus. A repetitive biological change that continues at close to a 24-hour cycle in the absence of external cues is called circadian rhythm. The clock that controls the circadian rhythm of sleep in all mammals is located in a specific nucleus of the hypothalamus called the suprachiasmatic nucleus. This nucleus contains rhythm generating neurons, controls a daily rhythm of the body temperature and secretes melatonin through the pineal gland. Light synchronizes the internal clock with the light-dark cycle.

An emotion is a subjective feeling that is mentally directed toward some object. That object can be another person, an object, an idea or concept. Self-conscious emotions are emotions
that depend on the individual’s self-awareness.

The feeling associated with emotion, independent of the object, is referred to as affect (tense). If an emotional feeling is not attached to an object but rather experienced as free-floating and it lasts for a sufficiently long period, it is referred to as a mood (e.g: depressed). It is possible to regulate emotions. Emotions can be recognized through facial expression, voice and body language. Emotions are also not independent of cognitions (e.g: heart rate that increases when someone is happy).

The discrete emotion theory states that basic emotions are innate and associated with distinctive bodily and facial reactions. Emotions could have an evolutionary purpose. They also promote our survival and reproduction through their capacity to communicate our intentions and needs to others. The social setting affects our emotions and our emotions affect our behaviour. Emotional states are accompanied by peripheral changes in the body.

James’s theory of emotion states that the bodily reaction precedes the emotion (e.g: we see a bear, we interpret the danger, there is a bodily reaction and then we feel fear). The common-sense theory states that the emotion precedes the bodily reaction (e.g: we see a bear, we interpret danger, we feel fear and there is a bodily reaction). In an emergency situation, there is no time for conscious reflection. The body reacts immediately.

Schachter’s Cognition-Plus-Feedback Theory states that the feeling of an emotion depends not just on sensory feedback pertaining to the body’s response, but also on the person’s perception and thoughts about the environmental event that presumably evoked that response. The perception and thought about the environment influence the type of emotion felt (e.g: we see a bear, we interpret danger and this causes a bodily reaction. We interpret danger and this causes us to feel fear and the strength of the bodily reaction determines the intensity of the fear. In other words, the interpretation determines bodily reaction, which determines the intensity and the interpretation also determines the type of emotion we feel).

Mimicking emotion causes people to feel that emotion earlier than people who do not mimic a certain emotion. The amygdala is the brain’s early warning system. It receives sensory input by way of two routes: a very rapid subcortical route and a slower cortical route. Through the subcortical route, it analyses information before it has been processed by sensory areas of the cerebral cortex. Through the cortical route, it analyses in more detail.

The removal of the amygdala causes psychic blindness. Individuals with physic blindness seem indifferent to the psychological significance of objects. Sensory areas of the cortex are essential for conscious perception of stimuli, but not for unconscious emotional responses to them. The amygdala is essential for unconscious emotional responses and the prefrontal cortex is essential for the full conscious experience of emotions and the ability to act in deliberate, planned ways based on those emotions. There is greater neural activity in the right prefrontal cortex when experiencing withdrawal emotions and there is greater neural activity in the left prefrontal cortex when experiencing approach emotions.