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Psychology

<OpenstaxParagraph>
	In 1966, William <OpenstaxTerm>Masters</OpenstaxTerm> and Virginia <OpenstaxTerm>Johnson</OpenstaxTerm> published a book detailing the results of their observations of nearly 700 people who agreed to participate in their study of physiological responses during sexual behavior. Unlike Kinsey, who used personal interviews and surveys to collect data, Masters and Johnson observed people having intercourse in a variety of positions, and they observed people masturbating, manually or with the aid of a device. While this was occurring, researchers recorded measurements of physiological variables, such as blood pressure and respiration rate, as well as measurements of sexual arousal, such as vaginal lubrication and penile tumescence (swelling associated with an erection). In total, Masters and Johnson observed nearly 10,000 sexual acts as a part of their research (Hock, 2008).
</OpenstaxParagraph>
<OpenstaxParagraph>
	Based on these observations, Masters and Johnson divided the <OpenstaxTerm>sexual response cycle</OpenstaxTerm> into four phases that are fairly similar for most people: excitement, plateau, orgasm, and resolution (<a href="#Figure_10_03_SexReponse">Figure 10.17</a>). The <OpenstaxTerm>excitement</OpenstaxTerm> phase is the arousal phase of the sexual response cycle, and it is marked by erection of the penis or clitoris and lubrication and expansion of the vaginal canal. During <OpenstaxTerm>plateau</OpenstaxTerm>, the vagina swells further and blood flow to the labia minora increases, and the penis becomes fully erect and may exhibit pre-ejaculatory fluid. People experience increases in muscle tone during this time. <OpenstaxTerm>Orgasm</OpenstaxTerm> is marked in females by rhythmic contractions of the pelvis and uterus along with increased muscle tension. In males, pelvic contractions are accompanied by a buildup of seminal fluid near the urethra that is ultimately forced out by contractions of genital muscles, (i.e., ejaculation). <OpenstaxTerm>Resolution</OpenstaxTerm> is the relatively rapid return to an unaroused state accompanied by a decrease in blood pressure and muscular relaxation. The <OpenstaxTerm>refractory period</OpenstaxTerm> is a period of time that follows an orgasm during which an individual is incapable of experiencing another orgasm. The duration of the refractory period can vary dramatically from individual to individual with some refractory periods as short as several minutes and others as long as a day. As people age, their refractory periods tend to span longer periods of time.
</OpenstaxParagraph>
<OpenstaxFigure id="Figure_10_03_SexReponse" src="https://openstax.org/apps/archive/20240226.174525/resources/8779b02770677c3a72128d975437df4299869513" alt="A graph titled “Sexual response cycle” has an x-axis labeled “time” and a y-axis labeled “arousal.” Four phases are depicted. In the “excitement” phase the arousal level increases from the bottom to midway on the graph. In the “plateau” phase the arousal level remains mostly steady at the midpoint of the graph and then begins to rise at the end of the plateau phase. At the “orgasm” phase, the arousal level sharply increases, peaks at the top of the graph, and then declines to the midway point. In the “resolution” phase the graph drops from the midway point to the bottom." mediaType="image/jpeg" width="487" height="349" />
<OpenstaxFigureText width="487">
	<strong>Figure 10.17</strong> This graph illustrates the different phases of the sexual response cycle as described by Masters and Johnson.
</OpenstaxFigureText>
<OpenstaxParagraph>
	In addition to the insights that their research provided with regards to the sexual response cycle and the multi-orgasmic potential of females, Masters and Johnson also collected important information about reproductive anatomy. Their research demonstrated the oft-cited statistic of the average size of a flaccid and an erect penis (3 and 6 inches, respectively) as well as dispelling long-held beliefs about relationships between the size of an erect penis and its ability to provide sexual pleasure to a partner. Furthermore, they determined that the vagina is a very elastic structure that can conform to penises of various sizes (Hock, 2008). In a similar manner to Kinsey’s work and other studies, Masters and Johnson’s research has been criticized, built on, and in some cases proven wrong. The research represents an important element of the history of sexual research, and is not viewed as entirely accurate today.
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10.3.3 Masters and Johnson’s Research

1 Introduction to Psychology

1.1 What Is Psychology?

1.1.1 Why Study Psychology?

1.2 History of Psychology

1.2.1 Wundt and Structuralism

1.2.2 Functionalism

1.2.3 Freud and Psychoanalytic Theory

1.2.4 Wertheimer, Koffka, Köhler, and Gestalt Psychology

1.2.5 Pavlov, Watson, Skinner, and Behaviorism

1.2.6 Maslow, Rogers, and Humanism

1.2.7 The Cognitive Revolution

1.2.8 Multicultural And Cross-Cultural Psychology

1.2.9 Women in Psychology

1.3 Contemporary Psychology

1.3.1 Biopsychology and Evolutionary Psychology

1.3.2 Sensation and Perception

1.3.3 Cognitive Psychology

1.3.4 Developmental Psychology

1.3.5 Personality Psychology

1.3.6 Social Psychology

1.3.7 Industrial-Organizational Psychology

1.3.8 Health Psychology

1.3.9 Sport and Exercise Psychology

1.3.10 Clinical Psychology

1.3.11 Forensic Psychology

1.4 Careers in Psychology

1.4.1 Other Careers in Academic Settings

1.4.2 Career Options Outside of Academic Settings

2 Psychological Research

2.1 Why Is Research Important?

2.1.1 Use of Research Information

2.1.2 NOTABLE RESEARCHERS

2.1.3 The Process of Scientific Research

2.2 Approaches to Research

2.2.1 Clinical or Case Studies

2.2.2 Naturalistic Observation

2.2.3 Surveys

2.2.4 Archival Research

2.2.5 Longitudinal and Cross-Sectional Research

2.3 Analyzing Findings

2.3.1 Correlational Research

2.3.2 Causality: Conducting Experiments and Using the Data

2.3.3 Reliability and Validity

2.4 Ethics

2.4.1 Research Involving Human Participants

2.4.2 Research Involving Animal Subjects

3 Biopsychology

3.1 Human Genetics

3.1.1 Genetic Variation

3.1.2 Gene-Environment Interactions

3.2 Cells of the Nervous System

3.2.1 Neuron Structure

3.2.2 Neuronal Communication

3.2.3 Neurotransmitters and Drugs

3.3 Parts of the Nervous System

3.3.1 Peripheral Nervous System

3.4 The Brain and Spinal Cord

3.4.1 The Spinal Cord

3.4.2 The Two Hemispheres

3.4.3 Forebrain Structures

3.4.4 Midbrain and Hindbrain Structures

3.4.5 Brain Imaging

3.5 The Endocrine System

3.5.1 Major Glands

4 States of Consciousness

4.1 What Is Consciousness?

4.1.1 Biological Rhythms

4.1.2 Problems With Circadian Rhythms

4.2 Sleep and Why We Sleep

4.2.1 What is Sleep?

4.2.2 Why Do We Sleep?

4.3 Stages of Sleep

4.3.1 NREM Stages of Sleep

4.3.2 REM Sleep

4.4 Sleep Problems and Disorders

4.4.1 Insomnia

4.4.2 Parasomnias

4.4.3 Sleep Apnea

4.4.4 Narcolepsy

4.5 Substance Use and Abuse

4.5.1 Substance Use Disorders

4.5.2 Drug Categories

4.6 Other States of Consciousness

4.6.1 Hypnosis

4.6.2 Meditation

5 Sensation and Perception

5.1 Sensation versus Perception

5.1.1 Sensation

5.1.2 Perception

5.2 Waves and Wavelengths

5.2.1 Amplitude and Wavelength

5.2.2 Light Waves

5.2.3 Sound Waves

5.3 Vision

5.3.1 Anatomy of the Visual System

5.3.2 Color and Depth Perception

5.4 Hearing

5.4.1 Anatomy of the Auditory System

5.4.2 Pitch Perception

Question	Answer
phase of the sexual response cycle that involves sexual arousal	excitement
peak phase of the sexual response cycle associated with rhythmic muscle contractions (and ejaculation)	orgasm
phase of the sexual response cycle that falls between excitement and orgasm	plateau
time immediately following an orgasm during which an individual is incapable of experiencing another orgasm	refractory period
phase of the sexual response cycle following orgasm during which the body returns to its unaroused state	resolution
divided into 4 phases including excitement, plateau, orgasm, and resolution	sexual response cycle