Withdrawal of spatial overt attention following intentional forgetting: evidence from eye movements.

Eye movements were measured to examine whether item-method directed forgetting involved a spatial overt attention shift. Experiment 1 showed that participants' eyes were moved away from the study word following the forget and ignore cues, but not the remember cue. Experiment 2 revealed that the eyes were moved away from the area that covered by the study word even when the study word disappeared upon the presentation of the memory cue. Both the study word and memory cue were presented auditorily in Experiment 3. In all experiments, the to-be-remembered words were recalled better than both to-be-forgotten and to-be-ignored words. More importantly, mental effort, as indexed by the pupil size, increased following the remember, as compared with the forget and ignore cues. These findings are discussed in terms of controlling spatial overt attention after encoding to withdraw attention from irrelevant information and to allocate cognitive resources to relevant information for long-term retention.

The eye movement measure of memory and its relationship with explicit measures.

This study examined whether the eye movement can be used to measure memory of past events and its relationship with the explicit measures. In Experiment 1, after studying a list of Chinese characters, the participants received a recognition memory test. For each trial the participants had to indicate, among one studied character and two nonstudied homonyms, which character they had studied. Participants' eye movements were monitored while they viewed the three-character test display. Both the time-course and response-locked measures showed that participants viewed the studied character longer than the nonstudied character regardless of their explicit response. Experiment 2 used a wagering task to assess participants' conscious awareness and found that wagering points predicted viewing time for the target better than the recognition accuracy did. These findings suggest that the effect of memory on viewing time occurs automatically and is weakly associated with subsequent conscious awareness of the studied event.

How do we forget negative events? The role of attentional, cognitive, and metacognitive control.

Four experiments using the item-method directed forgetting procedure examined how people intentionally forget significant negative emotional events. The cued-recall test showed that the directed forgetting effect was smaller for negative events than for neutral events. For both negative and neutral events, post-forgetting probe reaction times were longer than post-remembering probe reaction times on a speeded spatial judgement task, suggesting that forgetting was more demanding than remembering within seconds after the memory cue. As compared with the control group, participants who performed a secondary task after the memory cue forgot fewer negative events and did not show the directed forgetting effect. Finally, participants allocated more study time to forgetting negative events than neutral events. Results are discussed in terms of attentional and metacognitive mechanisms that involve the attenuated directed forgetting effect for emotional self-relevant events.

Divided attention facilitates intentional forgetting: evidence from item-method directed forgetting.

This study examined the effects of post-cue interval and cognitive load on item-method directed forgetting. The results of Experiment 1 (free recall test) and Experiment 2 (cued recall test) showed that forget item retention increased as the post-cue interval increased. Moreover, increasing the cognitive load of participants by asking them to perform a secondary counting task did not impair, but rather facilitated, the intentional forgetting of the studied item under long post-cue interval conditions. These results and analyses of recall gains from the additional use of the independent cue suggest that the improved recall of forget items caused by an increase in the post-cue interval came from an automatic process, and that after receiving the forget cue, participants did not engage a suppression operation that was resource-demanded. The current findings suggest that forgetting is more effective when participants perform a secondary task after receiving the forget cue.

Can intentional forgetting reduce false memory? Effects of list-level and item-level forgetting.

This study examined whether false memory produced by the learning of lists of categorized and associative materials could be reduced by directed forgetting. The number of items within a list that participants were asked to remember or forget was manipulated, while the length of the list remained constant. Experiment 1a used categorized lists and Experiment 1b used associative lists; the participants performed immediate free recall and cued recall tests. For both the categorized and associative lists, the rate of false recall increased upon increasing the proportion of "forget" (F) words. After removing the immediate recall test, Experiment 2 found that intentionally forgetting part of the studied list reduced false memory, whereas forgetting the whole studied list did not. The results are discussed in terms of the list-level-vs.-item-level inhibition in semantic activation and the role of monitoring in reducing false memory.

Effects of post-cue interval on intentional forgetting.

This study examined the effect of post-cue interval on directed forgetting and suppression. Experiments 1 and 2 used the item method of directed forgetting. The interval between the cue to remember/forget (R/F) and the presence of the next item was manipulated. As the post-cue interval increased, the rates of hits and 'remember' responses on the recognition test also increased not only for R items but also for F items, suggesting that participants did not stop processing F items after the F cue. Experiment 3 manipulated both the number of response/suppression attempts and the duration of response/suppression for each word pair during the response/suppression phase. The results showed that increasing the number of suppression attempts led to worse recall in the subsequent memory test. However, increasing the duration of suppression reduced the suppression effect. These results provide insights into a key factor for successful intentional forgetting and suppression.

Costs and benefits in item-method directed forgetting: differential effects of encoding and retrieval.

This study examined how encoding and retrieval factors affected directed forgetting costs and benefits in an item-method procedure. Experiment 1 used a typical item-method procedure and revealed a levels-of-processing effect in overall recall. However, the deep encoding condition showed a smaller directed forgetting effect than the shallow encoding conditions. More importantly, "remember" (R) words were selectively rehearsed as indicated by greater recall from the primacy portion of the list and more apt to be recalled before "forget" (F) words. Experiment 2 showed that a deep encoding operation reduced directed forgetting costs and that directed forgetting benefits occurred only when R words were recalled before F words. These findings supported the hypotheses that encoding manipulation affected directed forgetting costs and that directed forgetting benefits were associated with output order bias. Results were discussed in terms of mechanisms that produce item-method directed forgetting.

Post-event information presented in a question form eliminates the misinformation effect.

This study investigated the influences of sentence surface forms on the misinformation effect. After viewing a film clip, participants received a post-event narrative describing the events in the film. Critical sentences in the post-event narrative, presented in either a statement or a question form, contained misinformation instead of questions with embedded false presuppositions; thus participants did not have to answer questions about the original event. During the final cued-recall test, participants were informed that any relevant information presented in the post-event narrative was not in the original event and that they should not report it. Consistent with previous findings, Experiment 1 demonstrated that post-event information presented as an affirmative statement produced the misinformation effect. More importantly, post-event information presented in a question form, regardless of whether it contained a misleading or studied item, increased the recall of correct information and reduced false recall. Experiment 2 replicated the main finding and ruled out an alternative explanation based on the salience of misleading items. Post-event information presented in a question form created a condition similar to that which produces the testing effect.

Intentional forgetting reduces color-naming interference: evidence from item-method directed forgetting.

In an item-method-directed forgetting task, Chinese words were presented individually, each followed by an instruction to remember or forget. Colored probe items were presented following each memory instruction requiring a speeded color-naming response. Half of the probe items were novel and unrelated to the preceding study item, whereas the remaining half of the probe items were a repetition of the preceding study item. Repeated probe items were either identical to the preceding study item (E1, E2), a phonetic reproduction of the preceding study item (E3), or perceptually matched to the preceding study item (E4). Color-naming interference was calculated by subtracting color-naming reaction times made in response to a string of meaningless symbols from that of the novel and repeated conditions. Across all experiments, participants recalled more to-be-remembered (TBR) than to-be-forgotten (TBF) study words. More importantly, Experiments 1 and 2 found that color-naming interference was reduced for repeated TBF words relative to repeated TBR words. Experiments 3 and 4 further found that this effect occurred at the perceptual rather than semantic level. These findings suggest that participants may bias processing resources away from the perceptual representation of to-be-forgotten information.

Cognitive load hypothesis of item-method directed forgetting.

This study examined the effect of the processing demands of to-be-remembered (TBR) words on item-method directed forgetting. Experiment 1 found that a standard memory group remembered fewer to-be-forgotten (TBF) words than a naming group, in which participants simply named the TBR words during the study phase, even though both groups were equally instructed to forget the TBF words. Experiment 2 manipulated the number of TBR words in the study list, keeping the number of TBF words constant, and found that TBF word forgetting was more difficult in the few TBR words condition than the more TBR words condition. The same pattern was found in the result of Experiment 3 when a cued recall test, instead of a free recall test, was used. In all the experiments, participants were asked to recall the TBF words before the TBR words. These findings are consistent with the cognitive load hypothesis that it is easier to forget when there are fewer cognitive resources available during encoding.

Effects of aging and education on false memory.

This study examined the effects of aging and education on participants' false memory for words that were not presented. Three age groups of participants with either a high or low education level were asked to study lists of semantically related words. Both age and education were found to affect veridical and false memory, as indicated in the recall and recognition of the studied word and nonstudied lures. A low education level had a negative effect on memory performance for both young and middle-aged adults. Older adults with a high level of education had a higher level of false memory than those with a lower education level. The results of this study are discussed in terms of the importance of education on false memory and mechanisms that create false memory of words in older adults.

Factors influencing the intention to utilize out-of-pocket health checkup services: A sample of citizens from 12 townships of Taichung County in Taiwan.

BACKGROUND: Taiwan started its National Health Insurance (NHI) system in 1995. However, until now, most cancer screening tests and preventive care have been out-of-pocket (OOP) medical items excluded from the coverage of NHI. The aim of this study was to explore the factors influencing an individual's intention to utilize OOP health checkups. METHODS: A cross-sectional research method was adopted in this study. Based on the theory of planned behavior, a questionnaire was developed and used to survey purposively sampled residents (n = 940) from 12 randomly selected townships in Taichung County, Taiwan, from August to September 2006. Descriptive statics and linear regression were conducted to analyze the collected data. RESULTS: Our results showed that result evaluation (beta = 0.092), behavioral beliefs (beta = 0.088), behavioral norms of people with experience in utilizing OOP health checkups (beta = 0.116), perceived convenience (beta = 0.273), and worry about illness and perceived health (beta = 0.110) were important factors influencing the intention to utilize OOP health checkups. Age, education and acceptable health checkup charges were also related. CONCLUSION: Reinforcing disease- and health checkup-related knowledge may positively influence an individual's intention to utilize OOP health checkups. In addition, improving perceived convenience and reducing disease-screening barriers can intensify the individual's intention to use OOP health checkups. The influence of age, education level and OOP checkup charges should also be taken into consideration when related policies are formulated.

Lexical association and false memory for words in two cultures.

This study examined the relationship between language experience and false memory produced by the DRM paradigm. The word lists used in Stadler, et al. (Memory & Cognition, 27, 494-500, 1999) were first translated into Chinese. False recall and false recognition for critical non-presented targets were then tested on a group of Chinese users. The average co-occurrence rate of the list word and the critical word was calculated based on two large Chinese corpuses. List-level analyses revealed that the correlation between the American and Taiwanese participants was significant only in false recognition. More importantly, the co-occurrence rate was significantly correlated with false recall and recognition of Taiwanese participants, and not of American participants. In addition, the backward association strength based on Nelson et al. (The University of South Florida word association, rhyme and word fragment norms, 1999) was significantly correlated with false recall of American participants and not of Taiwanese participants. Results are discussed in terms of the relationship between language experiences and lexical association in creating false memory for word lists.

Analyzing recognition performance with sparse data.

Experiments in which recognition performance is measured sometimes involve only a small number of observations per subject, rendering d' analysis unreliable (Schooler & Shiffrin, 2005). Here, we introduce, in signal detection models, subject-specific random variables to account for heterogeneous hit and false alarm rates among individuals. Population d' effects for comparing groups are estimated, in this approach, by pooling information from a sample of subjects across experimental conditions. The method is validated by a simulation study and is illustrated with an analysis of the effect of neutral and emotional words on recognition performance, employing the emotional Stroop task (Lee & Shih, 2007).

False memory and schizophrenia: evidence for gist memory impairment.

BACKGROUND: In this study we examined patients' false memory, that is memory for a non-presented event, to search for a further source of converging evidence for the impairment of semantic memory in individuals with schizophrenia. In two experiments we compared the pattern of false memory created by the Deese-Roediger-McDermott (DRM) paradigm between individuals with schizophrenia and those of a normal control group. METHOD: Experiment 1 tested participants on both recall and recognition of lists of semantically related words. Experiment 2 adopted the meaning recognition test, in addition to the standard recognition test, to assess the participants' gist memory. RESULTS: Individuals with schizophrenia performed worse than normal controls on both recall and recognition of studied words. The schizophrenia patients had higher rates of false recall and false recognition for semantically unrelated words than did the normal controls, suggesting an abnormal pattern of semantic activation in the former group. More importantly, no differences were found between the two groups with regard to false recall and false recognition of semantically related words. When the participants were tested for meaning recognition, however, the schizophrenia patients gave fewer 'old' responses to non-studied semantically related words than did the control group, indicating an impaired gist memory in schizophrenia patients. CONCLUSIONS: When asked to consciously retrieve word lists, individuals with schizophrenia showed impairment not only in item-specific memory but also in gist memory. The pattern of results is consistent with the storage deficit view of semantic memory in schizophrenia.

Correlation between different memory systems and striatal dopamine D2/D3 receptor density: a single photon emission computed tomography study.

OBJECTIVE: Although studies have indicated that the human basal ganglia have a specific role in different memory systems, the functional significance of the striatal dopamine activities for the basal ganglia remains less clear. This study assessed the relationship between measures of striatal dopamine activities and indices of different memory systems in healthy individuals. METHOD: Single photon emission computed tomography and [123I]IBZM (iodobenzamide) were used to assess the striatal dopamine D2/D3 receptor density in 62 healthy volunteers aged between 19 and 61 years. All subjects underwent a Wechsler Memory Scale-Revised test. RESULTS: Dopamine D2/D3 receptor densities in the striatum decline with age. Stepwise regression analysis showed that verbal delayed recall and working memory account for most of the variance in dopamine D2/D3 measurements. These relationships remain significantly after controlling for age effects. CONCLUSIONS: Brain striatal dopamine activities are also significantly associated with various memory systems, in addition to motor functions. This may explain why patients with neuropsychiatric disorders may have both memory and motor impairments.

Levels of processing and phonological priming in Chinese character completion tests.

This study investigated the level of processing (LoP) effect in the Chinese character completion task. Stem cues, either graphemically or phonetically related to a target character, were used to generate two different kinds of perceptual tests. By giving participants either direct or indirect instructions, the character completion tests could be either an explicit or an implicit memory test. For the implicit test, LoP effects were not found between Read and Generation conditions, whereas the Physical conditioni did not produce priming. In addition, no priming was found when participants received graphemic cues during the test. For the explicit test, on the other hand, a standard pattern of LoP effects was found between the Physical, Read, and Generation conditions. Results are discussed in terms of the importance of lexical access for character completion tests and the role of phonology in processing Chinese characters.