By the middle of the 20th century it had become clear that the classic behaviorist approach was inadequate for the exploration of many psychological processes. Language acquisition, selective attention, and working memory cannot be understood in terms of relations between stimuli and responses, however complex the relationships postulated.
The demonstration that some cognitive processes are unconscious requires that we move even further from behaviorism. If we want to explore the whole range of conscious and unconscious cognitive processes we will not be able to do so by focusing on overt behavior alone. We must not assume that a subject making purposeful, goal-directed actions is necessarily aware of the stimuli eliciting the action or even of the action itself. We must supplement behavioral observations with subjective reports. We have to ask the subject, "Did you see the stimulus? Did you move your hand?"
During the decades in which psychology was dominated by behaviorism, subjective reports were not considered an appropriate source of data. As a result, methods for recording subjective reports lag far behind methods for studying overt behavior. Regrettably, many studies of cognitive processes still make no systematic attempt to record subjective experience because of the long tradition of excluding subjective reports. One hundred years ago introspection was the major method for obtaining data in psychology. How else could one study consciousness? However, different schools of psychology obtained different results and, as John B. Watson emphasized, there seemed to be no objective way of deciding who was right. How can you independently confirm subjective experience? Thus the method fell into disrepute.
Subjective reports are usually verbal—our subject tells us in words what the experience was like for him or her. But they need not be verbal. In many experiments a human subject may indicate that he or she has seen the stimulus by pressing a button. Pressing a button is an observable behavior, but the behavior is an indicator of a conscious thought.
This kind of nonverbal report can also be used in experiments with monkeys. When presented with an ambiguous figure such as the Rubin vase, a monkey can be trained to press one button when it sees the face and another button when it sees the vase. The choice about which button to press must be based on introspection. Robert Hampton used this technique in a memory experiment. A monkey was asked to distinguish familiar and new objects. This task is typically presented in a forced-choice format. The monkey (or person) is presented with a familiar object and a new object and has to choose the familiar one. A correct choice might occur because the familiar object is consciously recognized. If no conscious recognition occurs then the monkey (or person) must guess. Some of these guesses may be right, because of cues arising from unconscious processes, but many will be wrong.
Incorrect guesses can be avoided if the response "Don't know" is permitted (indicated by not pressing either button). With this format the proportion of button presses that are wrong should be reduced because guesses have been eliminated. Here again the behavior of pressing the button is partially based on introspection: If I am aware that I do not know the answer, I will not press a button. Monkeys are able to improve their performance (and thus get more food rewards) when given the opportunity not to make a choice, suggesting that they know when they are guessing.
Brain Imaging Can Corroborate Subjective Reports
The problem of verifying subjective reports can be partially addressed with the use of brain imaging. Brain imaging studies have shown that neural activity occurs in localized areas of the brain during mental activity unaccompanied by any overt behavior. The content of such mental activity, such as imagining or daydreaming, can only be known from the subject's reports.
If we scan a subject while he says he is imagining moving his hand, activity will be detected in many parts of the motor system. In most motor regions this activity is less intense than the activity associated with an actual movement, but it is well above resting levels. Similarly, if a subject reports that she is imagining a face she has recently seen, activity can be detected in the "face recognition area" of the fusiform gyrus (Figure 61–10). In these examples the observed neural activity detected by the scanner provides independent confirmation of the experience reported by the subject. The content of consciousness can, in certain limited cases, be inferred from patterns of neural activity.
Imagining a face or a place correlates with activity in specific areas of the brain.
Subjects were scanned while they viewed or imagined faces and houses. In the first block subjects alternately viewed a face or a house. When viewing a face, brain activity increases in the fusiform face area of the inferior temporal lobe (FFA). When viewing a house, brain activity increases in the parahippocampal place area of the inferior temporal cortex (PPA). In the next block subjects alternately imagined a face or a house. The same brain regions are active during both the imagining and direct viewing of faces and houses, although the activity is less pronounced during the imagined viewing. (Reproduced, with permission, from O'Craven and Kanwisher 2000.)
Malingering and Hysteria Can Lead to Unreliable Subjective Reports
When we record reports of subjective experience we are using the subject like a meter. Just as a meter can convert electrical resistance into the position of a pointer on a dial (reading 100 ohms) so a subject can convert the wavelength of a light source into the report of a color ("I see red.")
But there is a critical way in which the meter is not like a person. The meter does not experience red and cannot communicate meaning. And, while the meter might be faulty, it can never pretend to see red when it is really seeing blue. Most of the time we presume that subjective reports are true, that is, the subject is trying as far as possible to give an accurate description of his experience. But in some circumstances subjects might say "blue" even though what they saw was red. How could this arise and what is the status of the subjective report in such cases?
Consider a patient who has become amnesic as a result of extensive damage to the medial temporal cortex. Shown a photograph of someone whom he sees every day on the ward, the patient denies ever having seen this person before. But physiological measurements (electroencephalogram or skin conductance) made at the same time show a response to the photo (but not to photos of people he has not seen before). We conclude that conscious memory processes have been damaged while unconscious processes remain intact. This patient's subjective report is an accurate account of his conscious experience, but there are things he "knows" that do not enter consciousness.
Another patient is brought in having been found wandering on the street. There is no evidence of brain damage, but he has lost his memory to the extent of no longer knowing anything about himself or his history. He, too, denies any knowledge of the familiar people he is shown in photographs, but when tested he shows physiological responses to these familiar people. In this case, because of the lack of detectable brain damage (and other features of the memory loss), we begin to wonder about the truthfulness of his statements. Perhaps the physiological responses indicate that he does consciously recognize people. Subsequently the patient is identified by the police, and we discover that he is wanted for a serious crime committed in the neighboring county. Our doubts about the reliability of his reports increase. Finally, our suspicions are confirmed when he foolishly tells a fellow patient, "It's so easy to fool those clinical psychologists."
In this case we have direct evidence that the patient was deliberately misleading us about his conscious experience. In many ways the ability to deceive is the pinnacle of all human attainments, for to deceive others we must not only be conscious of our own mental state but also of their state. Is there some way we could have discovered from our patient's behavior that he was deceiving us? One approach is to use a memory test of the kind discussed earlier. The patient studies a list of words. He then sees a new list consisting of the words he has just studied and new words, and he must decide whether each word is old or new. A genuine amnesic would not recognize any of the words. He would have to guess. Through unconscious priming effects he might perform slightly better than chance. The malingering patient can recognize the old words but will have a strong tendency to deny that he has seen them before. Unless he is very sophisticated, he may perform worse than chance. It seems we can distinguish between the genuine amnesic and the malingerer.
A third kind of patient also simulates amnesia (or some other disorder) but does so unconsciously and thus is not a malingerer. Such a case would be called hysterical or psychogenic amnesia. Like the malingerer his performance on the recognition test is worse than chance. Nonetheless, he is not aware of his simulation. The same mechanism probably occurs in normal people who have been hypnotized and then told that they have no memory for what has just happened. This phenomenon is sometimes referred to as a dissociated state; that part of the mind that records experiences and makes verbal reports has become dissociated from the part that is creating the simulation. Hysterical simulations can create sensory loss, such as hysterical blindness, and motor disorders, such as hysterical paralysis or hysterical dystonia, as well as hysterical memory loss.
We are still a long way from understanding the cognitive processes or underlying physiology of these disorders. A key problem is how to distinguish hysteria from malingering. From the standpoint of conscious experience the two disorders are quite different: The malingerer is aware that he is simulating whereas the hysterical patient is not. Yet the patients' subjective reports and overt behavior in the two cases are very similar. Is there no measure that can distinguish between these different disorders? This may be one situation where studies of neural activity are the only way to make the critical distinction between these different states of consciousness.