KEY THEME

Thinking is a broad term that refers to how we use knowledge to analyze situations, solve problems, and make decisions.

KEY QUESTIONS

Cognition is a general term that refers to the mental activities involved in acquiring, retaining, and using knowledge. In previous chapters, we’ve looked at fundamental cognitive processes such as perception, learning, and memory. These processes are critical in order for us to acquire and retain new knowledge.

In this chapter, we will focus on how we use that knowledge to analyze situations, solve problems, make decisions, and use language. As you’ll see, such cognitive abilities are widely regarded as key dimensions of intelligence—a concept that we will also explore.

In the most general sense, thinking is involved in all conscious mental activity, whether it is acquiring new knowledge, reasoning, planning ahead, or daydreaming. More narrowly, we can say that thinking involves manipulating mental representations of information in order to draw inferences and conclusions. Thinking, then, involves active mental processes and is often directed toward some goal, purpose, or conclusion.

What exactly is it that we think with? Two important forms of mental representations are mental images and concepts. We’ll look first at mental images.

MENTAL IMAGES

When you read the Prologue, did you form a mental image of the view from the deck of a cabin perched above a river valley? Or of a steep hiking trail, lined with wildflowers and butterflies? Or Sandy and Tom sitting in front of their computers and exchanging instant messages? The stories we tell in our prologues typically lend themselves to the creation of mental images. Formally, a mental image is a mental representation of objects or events that are not physically present. Does the brain process mental images in the same way that it processes physical perceptions? We discuss this question in the Focus on Neuroscience on page 274, “Seeing Faces and Places in the Mind’s Eye.”

We often rely on mental images to accomplish some cognitive task. For example, try reciting the letters of the alphabet that consist of only curved lines. To accomplish this task, you have to mentally visualize and then inspect an image of each letter of the alphabet.

Typically, the term mental images refers to visual “pictures.” However, people can also form mental representations that involve senses other than vision (Cattaneo & Vecchi, 2008; Palmiero & others, 2009). For example, you can probably easily create a mental representation for the taste of a chocolate milk shake, the smell of freshly popped popcorn, or the feel of cold, wet clothing sticking to your skin. Nonetheless, most research on mental images has looked at how we manipulate visual images, and we’ll focus on visual images in our discussion here.

Do people manipulate mental images in the same way that they manipulate their visual images of actual objects? Suppose we gave you a map of the United States and asked you to visually locate San Francisco. Then suppose we asked you to fix your gaze on another city. If the other city was far away from San Francisco (like New York), it would take you longer to visually locate it than if it was close by (like Los Angeles). If you were scanning a mental image rather than an actual map, would it also take you longer to scan across a greater distance?

In a classic study by Stephen Kosslyn and his colleagues (1978), participants first viewed and memorized a map of a fictitious island with distinct locations, such as a lake, a hut, a rock, and grass (see FIGURE 7.1). After the map was removed, participants were asked to imagine a specific location on the island, such as the sandy beach. Then a second location, such as the rock, was named. The participants mentally scanned across their mental image of the map and pushed a button when they reached the rock.

The researchers found that the amount of time it took to mentally scan to the new location was directly related to the distance between the two points. The greater the distance between the two points, the longer it took to scan the mental image of the map (Kosslyn & others, 1978). It seems, then, that we tend to scan a mental image in much the same way that we visually scan an actual image (Kosslyn & Thompson, 2000).

However, we don’t simply look at mental images in our minds. Sometimes thinking involves the manipulation of mental images. For example, try the problem in FIGURE 7.2 at the bottom of the page, and then continue reading.

It probably took you longer to determine that the 3 in the middle was backward than to determine that the 3 on the far left was backward. Determining which 3s were backward required you to mentally rotate each one to an upright position. Just as it takes time to rotate a physical object, it takes time to mentally rotate an image. Furthermore, the greater the degree of rotation required, the longer it takes you to rotate the image mentally (Wohlschläger & Wohlschläger, 1998). Thus, it probably took you longer to mentally rotate the 3 in the middle, which you had to rotate 180 degrees, than it did to mentally rotate the 3 on the far left, which you had to rotate only 60 degrees.

Collectively, research seems to indicate that we manipulate mental images in much the same way we manipulate the actual objects they represent (Gardony & others, 2014; Rosenbaum & others, 2001). However, mental images are not perfect duplicates of our actual sensory experience. The mental images we use in thinking have some features in common with actual visual images, but they are not like photographs. Instead, they are memories of visual images. And, like other memories, visual images are actively constructed and potentially subject to error (Cattaneo & Vecchi, 2008).

CONCEPTS

Along with mental images, thinking also involves the use of concepts. A concept is a mental category we have formed to group objects, events, or situations that share similar features or characteristics. Concepts provide a kind of mental shorthand, economizing the cognitive effort required for thinking and communicating.

Using concepts makes it easier to communicate with others, remember information, and learn new information. For example, the concept “food” might include anything from a sardine to a rutabaga. Although very different, we can still group rutabagas and sardines together because they share the central feature of being edible. If someone introduces us to a new delicacy and tells us it is food, we immediately know that it is something to eat—even if it is something we’ve never seen before.

Adding to the efficiency of our thinking is our tendency to organize the concepts we hold into orderly hierarchies composed of main categories and subcategories (Markman & Gentner, 2001). Thus, a very general concept, such as “furniture,” can be mentally divided into a variety of subcategories: tables, chairs, lamps, and so forth. As we learn the key properties that define general concepts, we also learn how members of the concept are related to one another.

How are concepts formed? When we form a concept by learning the rule or features that define the particular concept, it is called a formal concept. Children are taught the specific rules or features that define many simple formal concepts, such as geometric shapes. These defining rules or features can be simple or complex. In either case, the rules are logical but rigid. If the defining features, or attributes, are present, then the object is included as a member or example of that concept. For some formal concepts, this rigid all-or-nothing categorization procedure works well. For example, a substance can be categorized as a solid, liquid, or gas. The rules defining these formal concepts are very clear-cut.

However, as psychologist Eleanor Rosch (1973) pointed out, the features that define categories of natural objects and events in everyday life are seldom as clear-cut as the features that define formal concepts. A natural concept is a concept formed as a result of everyday experience rather than by logically determining whether an object or event fits a specific set of rules. Rosch suggested that, unlike formal concepts, natural concepts have “fuzzy boundaries.” That is, the rules or attributes that define natural concepts are not always sharply defined.

Because natural concepts have fuzzy boundaries, it’s often easier to classify some members of natural concepts than others (Rosch & Mervis, 1975). To illustrate this point, think about the defining features or rules that you usually associate with the natural concept “vehicle.” With virtually no hesitation, you can say that a car, truck, and bus are all examples of this natural concept. How about a sled? A wheelbarrow? A raft? An elevator? It probably took you a few seconds to determine whether these objects were also vehicles. Why are some members of natural concepts easier to classify than others?

According to Rosch (1978), some members are better representatives of a natural concept than are others. The “best,” or most typical, instance of a particular concept is called a prototype (Mervis & Rosch, 1981; Rosch, 1978). According to prototype theories of classification, we tend to determine whether an object is an instance of a natural concept by comparing it to the prototype we have developed rather than by logically evaluating whether the defining features are present or absent (Minda & Smith, 2001, 2011).

The more closely an item matches the prototype, the more quickly we can identify it as being an example of that concept (Rosch & Mervis, 1975). For example, it usually takes us longer to identify an olive or a coconut as being a fruit because they are so dissimilar from our prototype of a typical fruit, like an apple or an orange (see TABLE 7.1).

Some researchers believe that we don’t classify a new instance by comparing it to a single “best example” or prototype. Instead, they believe that we store memories of individual instances, called exemplars, of a concept (Nosofsky & Zaki, 2002; Voorspoels & others, 2008). Then, when we encounter a new object, we compare it to the exemplars that we have stored in memory to determine whether it belongs to that category (Nosofsky & others, 2011). So, if you’re trying to decide whether a coconut is a fruit, you compare it to your memories of other items that you know to be fruits. Is it like an apple? An orange? How about a peach? Or a cantaloupe?

As the two building blocks of thinking, mental images and concepts help us impose order on the phenomena we encounter and think about. We often rely on this knowledge when we engage in complex cognitive tasks, such as solving problems and making decisions, which we’ll consider next.