Influences on the Development of Psychology: A Historical Overview
Influences on the Development of Psychology
Scientific Influences
Much of the methodology used in psychological research was adapted from other sciences, including physics, chemistry, biology, and physiology. Chapter 2 will discuss these methodologies in detail, but it’s worth briefly mentioning some of the key contributions.
Physics and chemistry provided methodology and insights into sensations and perceptions, which quickly became part of the developing field of physiology. The biological theory of evolution provided a foundation for comparative psychology, which compares the behavior of different species. Biology also contributed information about genetics and heredity, which psychologists used to understand the influence of these factors on behavior. Thus, psychology’s methodology, research areas, and justifications for study were often drawn from older disciplines.
Medical Influences
Medicine played a significant, albeit indirect, role in the early development of psychology. Until the early 1800s, individuals exhibiting abnormal behavior were often considered possessed by the devil. In the early 1800s, medical interest in abnormal behavior began with the treatment of physical illnesses believed to cause these patterns.
After 1800, attitudes shifted, and abnormal patterns were classified as mental illnesses, leading to changes in treatment approaches. This shift facilitated the development of psychiatry, which had a profound impact on the emergence of clinical psychology. Much of the content of psychiatry and clinical psychology originated from the medical tradition.
Example: The Medical Model in Psychiatry
To become a psychiatrist, one must first complete undergraduate studies, then earn a medical degree, followed by specialized training. Due to psychiatry’s strong medical orientation, it has adopted what’s known as the medical model. This model allows psychiatrists to treat clients as “sick” individuals. However, many psychiatrists and psychologists do not fully embrace this concept of “sickness” and prefer terms like “abnormal behavior patterns” to describe the responses they observe and treat.
Non-Scientific and Pseudo-Scientific Influences
Some areas of psychological study emerged because researchers sought to disprove commonly held beliefs about behavior. These formulations, often lacking scientific rigor, were given sophisticated names like physiognomy, phrenology, or typology.
Physiognomists believed that facial and head features revealed personality traits. Phrenologists created “maps” of the human skull to classify brain functions and their effects on behavior. Typologists attempted to correlate body type with behavioral characteristics. Although these speculations were eventually debunked (e.g., that fat people are not always happy), the questions they raised led to investigations that broadened our understanding of behavior. Psychological studies were often designed to refute these non-scientific claims.
Perception: The First Human Activity in Psychological Characteristics
Perception is a fundamental human activity. It’s a broad term encompassing various experiences, such as hearing birds singing, watching an eclipse, or feeling muscle pain.
- Perception Defined: Perception is the act of becoming aware of a physical stimulus, either internal or external. Our senses respond to physical or chemical elements that stimulate specific areas of our neural receptors.
- Example: Auditory Perception: In auditory perception, the process begins with the movement of molecules (sound waves) that stimulate the ear’s receptors. This generates nerve impulses that travel to the brain, where they are interpreted as “birdsong” or other auditory phenomena.
- Active Perception: Perception is not a passive reception of external stimuli. It involves an active response from the perceiver, including attention, stimulus selection, integration, and interpretation.
- Individual Differences: Individual differences in perception are evident in areas like sensory acuity, predisposition to notice certain stimuli, susceptibility to sensory fatigue, and interpretation of stimuli. For example, some individuals can discriminate between subtle shades of color or musical tones, while others cannot.
- Objective and Subjective Factors: Perception is influenced by both the objective nature of the stimulus and the characteristics of the perceiver.
- Limitations of Perception: Our sensory systems have limitations. We cannot perceive all changes in the physical environment. Some animals can detect stimuli that are beyond our range of perception.
- Subliminal Perception: Subliminal perception occurs when stimuli are below the threshold of conscious awareness, either due to their speed or minimal intensity. This phenomenon has been used in advertising to influence consumer behavior by incorporating subliminal images in films or commercials.
- Interpretation and Integration: Perception involves the interpretation and integration of stimuli. We perceive characteristics like light or sound, which are effects of physical agents on our bodies, not the agents themselves.
- Subjectivity of Perception: We perceive stimuli as pleasant or repulsive, but these qualities are not inherent in the stimuli themselves. For example, what we find repulsive might be appealing to other organisms.
- Perception of Distance and Time: We perceive objects based on their distance from us. We may see objects that no longer exist because their light waves, emitted in the past, continue to reach our retinas (e.g., when we see stars).