Critical thinking thinking that does not blindly accept arguments and conclusions. Rather, it examines assumptions, discerns hidden values, evaluates evidence, and assesses conclusions.
theory an explanation using an integrated set of principles that organizes observations and predicts behaviors or events.
Critical Thinking The scientific attitude prepares us to think smarter. Smart thinking, called critical thinking, examines assumptions, discerns hidden values, evaluates evidence, and assesses conclusions. Whether reading a news report or listening to a conversation, critical think- ers ask questions. Like scientists, they wonder, How do they know that? What is this person’s agenda? Is the conclusion based on anecdote and gut feelings, or on evidence? Does the evidence justify a cause – effect conclusion? What alternative explanations are possible?
Has psychology’s critical inquiry been open to surprising findings? The answer, as ensuing chapters illustrate, is plainly Yes. Believe it or not, massive losses of brain tissue early in life may have minimal long-term effects (see Chapter 2). Within days, new- borns can recognize their mother’s odor and voice (see Chapter 4). After brain damage, a person may be able to learn new skills yet be unaware of such learning (see Chapter 8). Diverse groups—men and women, old and young, rich and middle class, those with disabilities and without—report roughly comparable levels of personal happiness (see Chapter 11).
And has critical inquiry convincingly debunked popular presumptions? The answer, as ensuing chapters also illustrate, is again Yes. The evidence indicates that sleepwalk- ers are not acting out their dreams (see Chapter 3). Our past experiences are not all recorded verbatim in our brains; with brain stimulation or hypnosis, one cannot simply “hit the replay button” and relive long-buried or repressed memories (see Chapter 8). Most people do not suffer from unrealistically low self-esteem, and high self-esteem is not all good (see Chapter 12). Opposites do not generally attract (see Chapter 13). In each of these instances and more, what psychological science has learned is not what is widely believed.
How does the scientific attitude contribute to critical thinking?
ANSWER: The scientific attitude combines (1) curiosity about the world around us, (2) skepticism toward various claims and ideas, and (3) humility about one’s own understanding. Evaluating evidence, assessing conclusions, and examining our own assumptions are essential parts of critical thinking.
How Do Psychologists Ask and Answer Questions? Psychologists arm their scientific attitude with the scientific method—a self-correcting process for evaluating ideas with observation and analysis. In its attempt to describe and explain human nature, psychological science welcomes hunches and plausible – sounding theories. And it puts them to the test. If a theory works—if the data support its predictions—so much the better for that theory. If the predictions fail, the theory will be revised or rejected.
The Scientific Method
How do theories advance psychological science?
In everyday conversation, we often use theory to mean “mere hunch.” In science, a theory explains with principles that organize observations and predict
behaviors or events. By organizing isolated facts, a theory simplifies. By linking facts with deeper principles, a theory offers a useful summary. As we connect the observed dots, a coherent picture emerges.
A good theory about sleep deprivation’s effects on memory, for example, helps us organize countless sleep-related observations into a short list of principles. Imagine that we observe over and over that people with good sleep habits tend to answer questions accurately in class, and they do well at test time. We might therefore theorize that sleep improves memory. So far so good: Our sleep-retention principle neatly summarizes a list of facts about the effects of sleep loss.
Yet no matter how reasonable a theory may sound—and it does seem reasonable to suggest that sleep loss could affect memory—we must put it to the test. A good theory produces testable predictions, called hypotheses. By enabling us to test and to reject or revise our theory, such predictions direct research. They specify what results would support the theory and what results would disconfirm it. To test our theory about the effects of sleep on memory, we might assess people’s retention of course materials after a good night’s sleep, or a shortened night’s sleep (FIGURE 1.2).
Our theories can bias our observations. Having theorized that better memory springs from more sleep, we may see what we expect: We may perceive sleepy people’s com- ments as less insightful. The urge to see what we expect is ever – present, both inside and outside the laboratory, as when people’s views of climate change influence their inter- pretation of local weather events.
As a check on their biases, psychologists report their research with precise opera- tional definitions of procedures and concepts. Hunger, for example, might be defined as “hours without eating,” generosity as “money contributed,” sleep loss as “hours less” than one’s natural sleep. Using these carefully worded statements, others can replicate (repeat) the original observations with different participants, materials, and circum- stances. If they get similar results, confidence in the finding’s reliability grows. The first study of hindsight bias aroused psychologists’ curiosity. Now, after many successful rep- lications with different people and questions, we feel sure of the phenomenon’s power.
In the end, our theory will be useful if it (1) organizes a range of self – reports and observations, and (2) implies predictions that anyone can use to check the theory or to derive practical applications. (Does people’s sleep predict their retention?) Eventually, our research may lead to a revised theory that better organizes and predicts what we know. Or, our research may be replicated and supported by similar findings. (This has been the case for sleep and memory studies, as you will see in Chapter 3.)
As we will see next, we can test our hypotheses and refine our theories using descriptive methods (which describe behaviors, often through case studies, naturalistic