False Memories From Semantic Associates are Reduced by Item-Method Directed Forgetting Instructions JANE STOUT SARAH TAUBER In item-method directed forgetting studies, participants are shown a series of words and given a corresponding instruction to either remember or forget each word. This DANIEL P. C ORTS * method has consistently lead to superior memory for to-be-remembered (TBR) words relative to to-be-forgotten (TBF) words. The present experiment examined the effects Augustana College of item-method directed forgetting in the context of the Deese, Roediger, and McDermott (DRM) false memory paradigm. Participants were shown lists of words that con- tained both semantically related (DRM) words and unrelated words. False mem- ory for a strong semantic associate occurred significantly more often when they were told to remember DRM words than when they were told to forget DRM words. The results support the notion that directed forgetting effects using this procedure are due to differential encoding and rehearsal of remember and forget items. irected Forgetting studies typically involve explicit nition test (Basden, Basden, & Gargano, 1993; Block, directions to forget or remember each item in 1971; Timmins, 1974). This suggests that the previ- Da series of words. Two procedures referred to ously studied TBF items are inhibited during retrieval as list-method and item-method directed forgetting have but a recognition test can release this inhibition. been used to measure the effect of these instructions Bjork (1970, 1972) argued that differential on memory. The list-method involves an instruction to rehearsal accounts for directed forgetting in the item- forget an already studied list of words and remember a method through two procedures: (a) the segregation second word list whereas the item-method utilizes a of TBR items from TBF items and then, (b) selective word-by-word memory instruction. Research using these rehearsal for TBR items rather than TBF items due procedures has shown that participants consistently to a word-by-word memory instruction. Past research recall significantly more words that they were trying to has supported this notion by demonstrating superior remember when compared to words that they had been recall and recognition for TBR items when compared instructed to forget (for reviews, see Bjork, Bjork, & to that of TBF items (e.g., Davis & Okada, 1971; Anderson, 1998; Johnson, 1994). MacLeod, 1975). In essence, TBF words are less acces- Researchers have attempted to explain these sible by all measures. This trend suggests that item- directed forgetting effects by mental processes referred method directed forgetting effects may be due to poor to as retrieval inhibition in the list-method and differ- encoding rather than actually forgetting TBF items. ential rehearsal in the item-method. Bjork et al. (1998) Research has examined factors that can influence posit that retrieval inhibition is the inability to inten- participants’ ability to demonstrate item-method tionally retrieve the memories that are otherwise avail- directed forgetting effects including depth of pro- able to influence behavior. Research has shown that cessing and memory cue position (Horton & Petruk, participants demonstrate superior recall for items on 1980; Wetzel, 1975), memory cue delay time (Bjork the to-be-remembered (TBR) list in comparison to & Geiselman, 1978; Wetzel & Hunt, 1977), and cate- items on the to-be-forgotten (TBF) list, but this effect no longer exists when participants are give a recog- * Faculty supervisor Winter 2005 ¨ PSI CHI JOURNAL OF UNDERGRADUATE RESEARCH 127 Copyright 2005 by Psi Chi, The National Honor Society in Psychology (Vol. 10, No. 4, 127–132 / ISSN 1089-4136). FALSE MEMORIES FROM SEMANTIC ASSOCIATES ¨ Stout, Tauber, and Corts gorical relatedness of words (Wilson, Kipp, & Chapman, uli, the latter refers to the meaning or general theme 2003; Horton & Petruk, 1980). The results of such of incoming stimuli. In the context of the DRM pro- inquiries indicate that manipulating the amount of cedure, false memory for critical lures is based on a and/or type of encoding for TBF words can diminish “gist” representation as a result of the weakening of directed forgetting effects. The fact that more encod- “verbatim” memory for presented words. Brainerd, ing and deeper processing reduce directed forgetting Reyna, Reese, and Kail (2001) proposed an extension effects is consistent with the differential rehearsal to fuzzy trace theory in which two processes called explanation. direct access and reconstruction are involved during retrieval. The direct access process corresponds with False Memories and the DRM Paradigm verbatim traces in which information is read directly Past research has also focused on the effects of from memory. The reconstruction process usually the list-method on false memory creation using the occurs after direct access and is slower and less accu- Deese-Roediger-McDermott (DRM) procedure (Cokely, rate. This is because participants attempt to construct 2003; Kimball & Bjork, 2002; Seamon, Chun, Shulman, themes or meanings from the studied ideas, which Toner, & Caglar, 2002). In order to study false mem- results in memory errors. ory occurrence in semantic memory, Roediger and McDermott (1995) used a series of word lists each DRM and Directed Forgetting containing fifteen semantically related words. In this Several recent attempts have been made to under- procedure, known as the DRM procedure, words are stand how intentional forgetting might affect false all semantically associated with what is called the crit- recollection from DRM lists. On the surface, it would ical lure. This refers to the word that is most strongly seem that being instructed to forget a list of words associated with the words on the list but is absent from would lead to fewer true and false memories. However, the actual list. For example, items such as bed, snooze, two studies using list-method directed forgetting found doze, rest, etc., are all strongly associated with the crit- just the opposite. Kimball and Bjork (2002) reported ical lure sleep. When participants are tested for mem- that false recall of a critical lure actually increased ory of the DRM lists, a significant proportion under directed forgetting, even as correct memories consistently and falsely recalls and recognizes the crit- decreased. Seamon et al. (2002) reported similar ical lure, thus constituting a false memory. For instance, results, and viewed the outcome as support for a fuzzy- Roediger and McDermott (1995, Experiment 1) found trace approach to the DRM procedure. Both reported that during recognition tests, participants were con- that when inhibiting TBF items, the critical lure fident that they had been shown the critical lure over becomes more available to memory. In contrast, Cokely half of the time (.58), which is comparable to their (2003) attributed a significant portion of the increase confidence in the actual studied words (.75). in false recall to the specific method of presentation One theory that attempts to explain this effect is rather than retrieval inhibition alone. In his experi- the Implicit Activation Hypothesis. Proposed by ments, study time for each word was reduced, and as Underwood (1965), this theory indicates that seman- a result, both true recall of TBF items and false recall tically-related words are activated during the encoding of semantic associates decreased in this study. Thus, process. Nonstudied critical words are activated because Cokely indicated that in some circumstances, directed they have the highest associates and are therefore forgetting instructions could reduce false memories as likely to be falsely remembered later. As an extension well as veridical ones. to this idea, Roediger McDermott, and Robinson While DRM effects interact with presentation for- (1998) argued that an activation/monitoring error mat in list-method directed forgetting, there is little evi- can result in this type of false memory. That is, when dence as to how DRM effects might or might not occur completing a memory test, participants sometimes when cues are presented individually. Because the are unable to distinguish an activated semantic asso- processes for directed forgetting vary according to ciate from previously studied words. Thus, Roediger method, the present research incorporated the DRM et al. extended Underwood’s hypothesis to include procedure into item-method directed forgetting in an active memory search at retrieval, which may con- order to observe the effects of differential rehearsal on fuse internal and external activation for critical lures false memory creation. Because the item-method and lead to memory error. focuses mainly on encoding processes that lead to typ- An alternative explanation lies in Brainerd and ical directed forgetting effects, we were particularly Renya’s (1998) fuzzy trace theory. It states that memory interested in the effects of minimal encoding on the is based on both verbatim and gist memory. While the creation of false memories for semantically related former refers to detailed perceptual memory for stim- words. If the DRM procedure relies on the activation 128 PSI CHI JOURNAL OF UNDERGRADUATE RESEARCH ¨ Winter 2005 Copyright 2005 by Psi Chi, The National Honor Society in Psychology (Vol. 10, No. 4, 127–132 / ISSN 1089-4136). FALSE MEMORIES FROM SEMANTIC ASSOCIATES ¨ Stout, Tauber, and Corts TABLE 1 a different set of 10 unrelated words. Again, the DRM words were TBF in one presentation and TBR