The effect of bizarre material on memory has been a topic of interest and controversial debate. The bizarreness effect is the effect that bizarre, or uncommon material, is better remembered than common material (i.e. a low frequency word such as “integral” in a list of high frequency words). It has been extensively studied and many different experiments have been conducted to determine the causal processes in the displaying of the effect. Although it is generally thought to be the effect that bizarre material is remembered better than common material, it is a much more complex cognitive process with restrictions and specific parameters that present the effect in memory. Since there is empirical evidence for these conditions for the bizarreness effect to be displayed, it can be said that bizarreness in material does in fact help memory, but only in specific contexts. Evidence for retrieval and encoding effects on the processes of bizarre material have sparked ongoing debates. Although different experiments have supported both encoding and retrieval significance in the bizarreness effect, it can be assumed that both play a role in creating this effect on memory.
Bizarre material can display strengthening effects on memory, under certain conditions. Studies and empirical tests have been conducted to determine the effect of word positioning effects on bizarre material. It has been shown that when bizarre material is presented in mixed lists with common material, the bizarre material is better remembered. Yet when bizarre material and common material are not presented in a mixed fashion, memory for the two groups was not distinctively different (Einstein & McDaniel, 1987). Other restraints are present as well, such as the lack of a distinction between recall of bizarre material and common material in cued recall. The distinction only seems to be prominent in free recall. Other studies by McDaniel and Einstein, Kroll and his associates, and more have shown that the bizarreness effect is produced only under very specific conditions in an experiment and is very fragile and complicated. (Lamay, 1998). The benefits of distinctiveness, or bizarreness, also can only be fully utilized when processing in a visual way. In Bahrick’s (1975) high school names and faces test, results showed that memory of specific faces in free recall was better than memory of individuals names over the course of 50 years. Subjects retained about 80% memory of their classmate’s faces even after 40 years. The visual distinctive processing helped their memory. (Bahrick, Bahrick, & Wittlinger, 1975). This makes a strong case against this bizarreness effect as an aid in memory for use in academic studies. The dispute over encoding views of the bizarreness effect and retrieval views has been ongoing and each view overlaps with the other.
The encoding view of the bizarreness effect takes a strong stance for one level of processing in account for the memory phenomenon. This shows that when material is presented in a fashion that sparks attention to the different stimuli of bizarre material to common, it is encoded more strongly. The presence of a different stimulus is what drives the memory to be more distinctive. This being stated, the view also holds with the parameter set up for the bizarreness effect of mixed lists. Without the presence of common material, bizarre material becomes muted (Dornburg 2005). The mixed lists account for the accentuating of unusual material, giving the bizarre material more processing. (Merry, 1980; Woolen & Cox 1981). It is believed that bizarre material receives more processing due to other aspects, such as how unusual terms go away from expectations, and how individuals favor studying bizarre material over common material. (Hirshman 1989, Watkins 2000). Other suggestions such as how bizarre material, requiring more mental effort for imaging, increase the memorable encoding in bizarre images and items. (Margres 1987). This plays back into the situational fragility of the bizarreness effect, as some studies have shown that without processing information in a visual way, the bizarre effects are not as prominent. Thus, greater memory of bizarre material can only be prevalent when encoded in specific ways. This provides more evidence for the role of encoding in the bizarreness effects, showing that certain encoding strategies determine the outcome of the effect. Robinson-Riegler et. al. (1994) found that the bizarreness effect does not occur with complex sentences, due to the reduction of imageability. It might also be thought that some people are more of image thinkers and encoders, but McDaniels studies showed no difference between high imagery thinkers and low imagery thinkers in the bizarreness effect. They tested this by first setting up a mixed factorial of original complex sentences set up by Kroll’s experiment in 1986. They then modified the sentences to contain more concrete and less complex modifiers in the sentences. If the adjective concreteness or the degree of bizarreness were key in the bizarreness effect, the revised concrete sentences would produce the effect. The sentences that were given to subjects were in sets of two lists, containing six common sentences and six bizarre ones. One list had sentences from Kroll et. al, containing unusual elaborative words, and one list had the revised sentences. They were asked to form a mental image of the sentence, then to rate the vividness of the image. They then were asked to complete a questionnaire in five minutes, relating to their verbal expression and fluency, use of imagery etc. They then were tested on recall of the sentences. The results showed that in the newly revised sentences, a bizarreness effect was not produced. This showed that the imageability of adjectives is not a key to the bizarreness effect, yet imageability was only beneficial to subjects who used imagery as a key to memory often. Thus, encoding is only helpful when actively processing information visually. The encoding view is thus weak and only relevant under very certain circumstances. The encoding view does have legitimate stances, yet it fails to take into account the retrieval role on the bizarreness effect.
The retrieval view of the bizarreness effect takes into consideration the importance of retrieving bizarre information instead of the encoding processes. It holds that distinctiveness plays a part in retrieval advantages, since the stimuli in a retrieval set hold different features than common material. (Brown 2002). The explanation of mixed lists in a retrieval view stance is very similar to an encoding view stance, stating that since the bizarre stimuli are not distinctive in unmixed lists making retrieval of it indistinctive from other material. They are only similar in regards to distinctiveness, but at different memory stages. (Cox & Wollen, 1981; Hauk, Walsh, & Kroll, 1976; Senter S. Hoffman, 1976; Wollen, Weber & Lowry, 1972). This is similar to Dornburg’s (2005) statement about how bizarre. Material becomes muted in encoding, stating that when all items are either common or bizarre, the material becomes indistinct; mixed lists were necessary to produce the effect. To separate encoding and retrieval to test the importance of both in the bizarreness effect, (McDaniel, Dornburg, and Guynn, 2005) set up unmixed encoding sets paired with unmixed and mixed retrieval sets and mixed encoding paired with unmixed and mixed retrieval sets. They had the subjects perform recall three times, in succession. They used this multiple recall to test the idea that bizarre items have a more extensive encoding than common items. Subjects were asked to read sentences, one at a time, and to create a mental picture of the sentences context. They rated the vividness of the image on a scale from 1 to 5. Subjects then did math problems for 5 minutes as a distracter task. This led them to be able to independently test the effects of encoding and retrieval on bizarre material in mixed sets during free recall. They noticed a very clear distinctive influence on retrieval for bizarre material, and a less distinct slight influence on encoding. The repeated test procedure did not result in more extensive encoding of bizarre material than common material, supporting the retrieval view. Under free recall, there was no significant advantage under recall of the material as pure lists. The results of this significant and recent experiment lean more toward a retrieval role in the bizarreness effect, and certainly the effect cannot be displayed without distinct retrieval roles. The differential encoding of bizarre and common sentences was not significant enough to account for the strong bizarreness effects usually reported in free recall. Identical encoding conditions showed inconsistent bizarreness effects, and were dependent n the retrieval conditions. When items were encoded in unmixed lists and then retrieved in mixed lists, the bizarreness effect was displayed, reaffirming the latter. There are small advantages of bizarre items when there is no mixing in retrieval, though, showing a slight involvement of encoding in the effect (McDaniel & Geraci, in press, Worthen, in press). Although this study’s results force observers to lean more toward the importance of retrieval processes in the bizarreness effect, it also creates more confusion, as it doesn’t completely dispel encoding processes.
Reifer and Lamay also proposed that common items are stored much better in memory than bizarre material, yet bizarre material is retrieved better from memory. (Lamay, 1998). This theory was shown through Riefer and Rouder’s multinomial processing-tree model in 1992. Their model showed that bizarre items were retrieved better, but not stored better, than common items were (Lamay 1998). Lamay’s use of this model displayed results showing that bizarre material was recalled much better when displayed as singletons than common items were. The test involved subjects in six groups ranging from 10 to 14 people, presenting sentences on slides one at a time. The subjects saw sentences that were either all common or all bizarre. After they were presented the sentences, they were given a three-minute distracter task of finding small differences in pairs of pictures, thus inhibiting their visual memory encoding. This would provide to test the retrieval account for the bizarreness effect. They were then told to freely recall all noun pairs, and if they couldn’t remember item pairs to write individual items. They were presented with the first noun pair, and told to recall the second noun from each pair. This test and theory leans slightly more toward the retrieval view of the effect, as it shows the importance of retrieval in bizarre material, yet it does not dispel the importance of encoding in common material. Evidence from this also helps dispel the bizarreness effect as a method for academic studies, as material should be stored better for future use. Although more recent studies have been more in favor of retrieval importance in the bizarreness effect, encoding has not been completely disregarded in the effect. The evidence presented, though, shows a clearly distinct role of retrieval instead of an encoding view on the bizarreness effect.
For such a controversial, high interest, and widely studied memory phenomenon, the bizarreness effect has little applicable use in catalyzing studies and memory. It requires specific conditions, such as visual processing, mixed common and bizarre material, and free recall. It can be set up quite easily in a controlled experiment, but seems virtually useless in aiding personal memory. It can be vaguely related to certain daily processes, such as remembering visually distinct objects. It may be a link to understanding permanent memory., but no experiments have tested the effect on memory longer than ten minutes. More recently conducted studies have been slightly more in favor of supporting retrieval importance in the bizarreness effect, yet the studies have not completely gotten rid of interest and support of encoding processes and prevalent in the effect. It is safe to assume that both encoding and retrieval play important roles on producing the bizarreness effect, under the correct conditions of course, but studies mainly support the bizarreness effect support a retrieval process more than an encoding one. It seems that with further studies, more information might hold retrieval as the key cause, as the majority of recent studies support retrieval views, but encoding has not completely been dispelled as playing some role in producing the bizarreness effect.
Bahrick H.P., Bahrick, P.O., & Wittlinger, R.P. (1975) Fifty years of memory for names and faces: A cross-sectional approach. In Journal of Experimental Psychology: General 104 (1).
Brown, G.D.A., Neath, I., & Chater, N. (2002). A ratio model of scale-invariant memory and identification. Manuscript submitted for publication.
Dornburg, Courtney C., Guynn, Melissa J., & McDaniel, Mark A. (2005). Disentangling encoding versus retrieval explanations of the bizarreness effect: Implications for distinctiveness. In Memory & Cognition 33 (2). (pp. 270-279)
Einstein, G.O., & McDaniel, M.A. (1987). Distinctiveness and the mnemonic benefit of bizarre imagery. In M.A. McDaniel & M. Pressley (Eds.) Imagery and related mnemonic processes: Theories, individual differences, and applications (pp. 77-102). New York: Springer Verlag.
Hauk, P.D., Walsh, C.C., & Kroll, N.E.A. (1976). Visual imagery mnemonics: Common vs. bizarre mental images. Bulletin of the Psychonomic Society,7, (pp. 160-162).
Hirshman, E.L., Whelley, M.M., & Palij, M. (1989). An investigation of paradoxical memory effects. Journal of Memory & Language,28, (pp. 594-609).
Lamay, Mary L. & Riefer, David M. (1998). Memory for common and bizarre stimuli: A storage-retrieval analysis.In Psychonomic Bulliten Review 5 (2). (pp. 3123-17). San Bernardino, California.
McDaniel, M.A., & Gerachi, L. (in press). Encoding and retrieval processes in distinctiveness effects: Toward an integrative framework. In R.R. Hunt & J.B. Worthen (Eds.), Distinctiveness and memory. New York: Oxford University Press.
McDaniel, Mark A. & Bridget Robinson-Riegler. (1994) Further constraints on the bizarreness effect: Elaboration at encoding. In Memory & Cognition 22 (6). (pp. 702-712).
Merry, R. (1980). Image bizarreness in incidental learning. Psychological Reports,46, (pp. 427-430)
Watkins, M.J., LeCompte, D.C., & Kim, K. (2000). Role of study strategy in recall o mixed lists of common and rare words. Journal of Experimental Psychology: Learning, Memory & Cognition,26. (pp. 239-245).
Wollen, K.A., & Cox, S.D. (1981) Sentence cuing and the effectiveness of bizarre imagery. Journal of Experimental Psychology: Human Learning & Memory,7, (pp. 386-392).
Wollen, K.A., Weber, A., & Lowry, D.H. (1972). Bizarreness versus interaction of mental images as determinants of learning. Cognitive Psychology,3, (pp. 518-523).
Worthen, J.B., Starns, J.J., & Loveland, J.M. (in press). Influence of orienting task on memory for bizarre and common stimuli: Evidence against a surprise-based explanation. In S.P. Shohov (Ed.), Leading edge research in cognitive psychology. Hauppage, NY: Nova Science.