Chapter 11: Motivation and Emotion
11.1 - Hunger and Eating
The study of motivation concerns the physiological and psychological
processes underlying the initiation of behaviors that direct organisms
towards specific goal.
These initiating factors, or motives, include the thoughts, feelings, sensations,
and bodily process that lead to goal-directed behaviour.
Homeostasis, the body’s physiological processes that allow it to maintain
consistent internal states in response to the outer environment.
These states include physiological needs such as appropriate body
temperature as well as indicators of hunger and thirst.
Drives - the
triggers that tell
us we may be
cause us to seek
out what is
needed, such as
Incentives (or goals) the stimuli we seek to reduce the drives such as social
approval and companionship, food, water, and other needs.
Physiological aspects of hunger
Hunger - the motivation to eat - with a growling stomach.
Satiation - the point in a meal when we are no longer motivated to eat.
The on and off switches involved in hunger can be found in a few regions of
Researches have found that electrically stimulating the lateral hypothalamus
causes rats to begin to eat; serve “on” switch.
In contrast, ventromedial region of the hypothalamus appears to serve as the
The para-ventricular nucleus of the hypothalamus, also signals that it is time to
stop eating by inhibiting the lateral hypothalamus.
The hypothalamus also takes on the job of monitoring blood chemistry for
indicators of the levels of sugars and hormones involved in energy.
Glucose, a sugar that serves as the primary energy source for the brain and
the rest of the body.
Highly specialized neurons called glucostats can detect glucose levels in the fluid outside of the cell.
Insulin, a hormone secreted
by the pancreas, helps cells
store this circulating
glucose for future use.
Ghrelin, s hormone
secreted in the stomach
that stimulates stomach
Another key chemical in
regulating hunger is
Psychological aspects of hunger.
Ordinary sucrose - plain white granulated sugar can stimulate release of the
neurotransmitter dopamine in the nucleus accumbens, a brain region
associated with the reinforcing effects of the substances such as
amphetamines and cocaine
Tastes, textures, and eating.
While chemical receptors in the mouth and nose
are detecting the tastes and smells of food, touch
receptors in the mouth are detecting the textures
of the food and relaying this information to the
orbitofrontal cortex, which in turn contributes info
to the overall sensation of eating.
Tube feeling, a technique used with hospitalized
patients who cannot chew or swallow on their
Food variety and eating.
Unit bias, the tendency to assume that the unit of sale or portioning is an
appropriate amount to consume.
Eating and the social context.
Three main factors:
A. Social facilitation: eating more.
B. Impression management: eating less. ; minimal eating norm suggests that
another aspect of good manners.
C. Modeling: eating whatever they eat.
Eating is not just a matter of maintaining homeostasis. It is best described as a behaviour motivated by biological, social, and
individual psychological factors.
Disorders of eating
Obesity is an disorder of positive energy balance in which energy intake
exceeds energy expenditure.
One problem is that both the drive to eat and the incentive value of food
increases with deprivation
Anorexia and Bulimia
Anorexia nervosa , an eating disorder that involves (1) self-starvation, (2)
intense fear of weight gain and a distorted perception of body image, and (3)
a denial of the serious consequences of severely low weight.
Other problems associated with an anorexia include consecutive los of
menstrual periods (amenorrhea), and for males a loss of sexual motivation.
Occur during mid and late adolescence
Bulimia nervosa, is an eating disorder that is characterized by periods of
food deprivation, binge-eating, and purging.
Occur during late adolescence and young adulthood.
11.2 - Sexual Motivation
Libido - the motivation for sexual activity and pleasure.
Human sexual behaviour: psychological and biological influences.
Psychological measures of sexual motivation.
Alfred Kinsey, began his research on human sexuality by interviewing his
students about their sexual histories. Biological measures of Sex.
Participants were monitored with heart rate and blood pressure equipment,
as well as with more peculiar devices such as the penile plethysmopgraph,
which are designed to measure blood flow to the genitalia in men and
The sexual response cycle, describes the phases of physiological change
during sexual activity, which comprises four primary stages: excitement,
plateau, orgasm, and resolution.
Refractory period, a time period during which erection and orgasm are noy
of the breasts,
nerves to send
signals to the
in turn, stimulates the pituitary gland to release a hormone called oxytocin,
which plays a role in orgasm and post orgasm physiological.
In males, this may include erectile dysfunction (ED) - the inability to achieve or
maintain an erection.
ED is often caused by cardiovascular problems such as hypertension.
For females, physiological problems may lad to lack of arousal or painful
intercourse. Sex and technology
Cybersex - that is the use of the internet and computer equipment for
sending sexually explicit images and messages to a partner.
Sexual Orientation: Biology and environment
Sexual orientation is a consistent preference for sexual relations with
members of the opposite sex (heterosexuality), same sex (homosexuality), or
either sex (bisexuality).
E.g., desire, emotions, identification
Sexual orientation and the brain.
Researchers have also been intrigued by findings suggesting that a band of
nerve fibers connecting the left and ri