Intending to Remember: Rapid Mobilization of Attention Enhances Memory Richard A. BlockMontana State University
Introduction: Two Questions Is intending to remember information effective or even necessary for remembering? If intending to remember improves memory, how quickly can attentional resources be allocated to enhance remembering?
Brief History Issues concerning intentional- versus incidental- memory began to be studied in the late 1800s. By the 1960s, some researchers concluded that “intent per se is not a significant variable in learning” (Postman, 1964). This view was supported in the mid-1970s: Research on levels-of-processing suggested that memory depends on the “depth” of an orienting task but not much on whether or not subjects are instructed to remember the presented information.
Limitations of Previous Research Research on intent to remember has been limited in two main ways: • Nearly all previous researchers have used verbal stimuli, such as words. We used pictorial stimuli. • Nearly all previous researchers have used relatively long stimulus durations or repeated presentations. We used much shorter durations (0.5-3.0 s).
Intention and Automaticity The concept of intention is closely related to that of automaticity (automatic vs. controlled processes): • Incidental memory requires component processes that occur automatically. • Intentional memory involves component processes that are controlled, although automatic processes may also be involved.
Criteria for Automaticity Several criteria must be met to conclude that a process is automatic. These include: • It cannot be suppressed. • It is not influenced by arousal, stress, or concurrent information-processing demands. • It cannot be improved by training or feedback. • It does not vary much as a function of age, sex, education, and so on. • It occurs without intention, and information that is encoded incidentally is no different from information that is encoded intentionally.
Human Face Encoding We began by investigating effects of intent on recognition memory for human faces. This provides a relatively strong test of effects of intent because many of the component processes in face encoding are thought to occur automatically.
Intentions: Methodological Issues In order to minimize the likelihood that people in an incidental-memory condition may deliberately try to remember stimuli, one of two methods must be used: • A cover story, in which a person is told a plausible story that does not involve memory. • A cover task, in which a person performs a task that does not involve memory (as in most levels-of-processing experiments).
Experiment 1: Face Encoding Experiment 1 investigated whether encoding faces is automatic, controlled, or both. • We used a cover story: Subjects were told that we were studying how a person’s mood is affected by crowds of people and that we would show pictures of faces and later ask them to report their mood. • Half the subjects were told that memory for faces would be tested later (intentional memory); the other half were not (incidental memory).
Effect on Face Recognition Recognition performance was better in the intentional than in the incidental condition.
Experiment 2: Speed of Face Encoding Experiment 2 investigated the speed of controlled (intentional) encoding of faces. • We used a cover task: All subjects were told that they would see pictures of cars, chairs, faces, and birds and that their task was to try to count the total number of cars. • Only subjects in the intentional-memory condition were told that their memory for faces would also be tested later.
Materials and Procedure Here are some examples of the four types of pictures: In a randomly ordered series, half the pictures of each type were presented for 1 s, and half were presented for 3 s. Thanks to Shlomo Bentin for the pictures.
Effect on Face Recognition Face recognition was better in the intentional condition at both durations.
Experiment 3: Speed of Bird Encoding Experiment 3 investigated the speed of controlled (intentional) encoding of bird pictures. • We again used a “counting-cars” cover task. • Subjects in the intentional-memory condition were told that their memory for birds would also be tested later. • The materials and procedure were otherwise identical to the previous experiment.
Effect on Bird Recognition Bird recognition was better in the intentional condition and at the longer duration.
Experiment 4: Human vs. Ape vs. Bird Experiment 4 compared the speed of controlled (intentional) encoding of human faces, ape faces, and birds. • We again used a cover task: All subjects were told that they would see cars, birds, human faces, and ape faces and that they should count the total number of cars they saw. • Subjects in three intentional-memory conditions were told that their memory for either human faces, ape faces, or birds would be tested later. • Subjects in three incidental-memory conditions were not told about memory but were tested on either human faces, ape faces, or birds.
Materials and Procedure Here are some examples of the four types of pictures: In a randomly ordered series, half the pictures of each type were presented for 0.5 s and half for 2.0 s. Note this reduction in stimulus duration from Experiment 3.
Effect on OVERALL Recognition The effect of intent was small (d=0.33) but significant at 0.5 s and medium (d=0.49) at 2.0 s.
Effect on BIRD Recognition Intentional memory improved bird recognition (although only significantly at 2.0 s).
Effect on APE-FACE Recognition Intentional memory improved ape-face recognition at both 0.5 s and 2.0 s.
Effect on HUMAN-FACE Recognition Intentional memory improved human-face recognition (although only significantly at 2.0 s).
Intending to Remember: Explanations • Rehearsal is not a likely explanation, because people apparently cannot rehearse pictures. How does intent to remember work? • Depth of processing is also not a likely explanation. How can people deeply process a stimulus in about 500 ms, even if they know what deep processing entails? • Perhaps people can rapidly (within 500 ms) mobilize attentional resources. They may also be engaging in conservation of attentional resources over the relatively long (5-10 s) periods separating to-be-remembered stimuli.
Attentional Gate Model Reeves and Sperling (1986) found evidence for a so-called attentional gate that can “open” within 400 ms, allowing effective short-term memory encoding of information. In addition to providing much-needed evidence on intending to remember, our findings support this notion.
Psychophysiological Evidence Human face encoding is linked to the N170 component of the ERP (Gauthier & Curby, 2005), suggesting that automatic face encoding occurs quickly. Does intentionality have a subsequent effect (i.e., within the range from 170 to 500 ms)? In contrast to pictures viewed under incidental conditions, those viewed under intentional-memory conditions produce ERP changes in the range of 250-450 ms (Noldy et al., 1990). Our memory data support and extend these findings.
Face Encoding Revisited Human face encoding apparently relies on automatic processing, as reflected in N170 component of the ERP. However, beginning at about 500 ms, intent to remember a face enhances subsequent memory, presumably as a result of a rapid allocation of attentional resources. Similar effects are seen for other pictorial stimuli (ape faces and birds), although they may lack the automatic, early (N170) component.
Summary and Conclusions Intentional encoding of pictorial information enhances subsequent recognition memory, even at short (500 ms) stimulus durations. Manipulating intentional- versus incidental-memory reveals whether or not some component stimulus-encoding processes are controlled. Previous conclusions about intending to remember, based mainly on verbal materials presented for longer durations, should be viewed with caution. Attentional resources may be rapidly mobilized in order to enhance subsequent remembering of information.
Acknowledgements At Tel Aviv University, my colleague— DAN ZAKAY I thank many researchers who assisted me. At Montana State University, student researchers— MELISSA BANKS FRANK BOSCO MATTHEW CLONINGER JEREMY FLEMING CATHERINE GAULT ERIK JOHNSON AARON RICHMOND TYSON ROTH
Some References Gauthier, I., & Curby, K. M. (2005). A perceptual traffic jam on Highway N170: Interference between face and car expertise. Current Directions in Psychological Science, 14, 30-33. Hyde, T. S., & Jenkins, J. J. (1973). Recall for words as a function of semantic, graphic, and syntactic orienting tasks. Journal of Verbal Learning and Verbal Behavior, 12, 471-480. Kahneman, D. (1973). Attention and effort. Englewood Cliffs, NJ: Prentice-Hall. Myers, G. C. (1913). A study in incidental memory. Archives of Psychology, 4. Noldy, N. E., Stelmack, R. M., & Campbell, K. B. (1990). Event-related potentials and recognition memory for pictures and words: The effects of intentional and incidental learning. Psychophysiology, 27, 417-428. Postman, L. (1964). Short-term memory and incidental learning. In A. W. Melton (Ed.), Categories of human learning. New York: Academic Press. Reeves, A., & Sperling, G. (1986). Attention gating in short-term visual memory. Psychological Review, 93, 180-206.