Think/no-think Research Articles

Inhibition and interference in the think/no-think task

Five experiments using the think/no-think (TNT) procedure investigated the effect of the no-think and substitute instructions on cued recall. In Experiment 1, when unrelated A-B paired associates were studied and cued for recall with A items, recall rates were reliably enhanced in the think condition and reliably impaired below baseline in the no-think condition. In Experiments 2 and 5, final recall was cued with B items, leading to reliably higher recall rates, as compared with baseline, in both the think and no-think conditions. This pattern indicates backward priming of no-think items. In Experiments 3 and 4, the no-think instruction was replaced with a thought substitution instruction, and participants were asked to think of another word instead of the studied one when they saw the no-think cued items. As in Experiments 1 and 2, the same amount of forgetting of B items was observed when A items were the cues, but in contrast to Experiment 2, there was no increase in the recall performance of A items when B items were the cues. These results suggest that not thinking of studied items or, alternatively, thinking of a substitute item to avoid a target item may involve different processes: the former featuring inhibition and the latter interference.

Inhibitory control of memory retrieval and motor processing associated with the right lateral prefrontal cortex: Evidence from deficits in individuals with ADHD

Studies of inhibitory control have focused on inhibition of motor responses. Individuals with ADHD consistently show reductions in inhibitory control and exhibit reduced activity of rLPFC activity compared to controls when performing such tasks. Recently these same brain regions have been implicated in the inhibition of memory retrieval. The degree to which inhibition of motor responses and inhibition of memory retrieval might involve overlapping systems has been relatively unexplored. The current study examined whether inhibitory difficulties in ADHD extend to inhibitory control over memory retrieval. During fMRI 16 individuals with ADHD and 16 controls performed the Think/No-Think (TNT) task. Behaviorally, the Stop Signal Reaction Time task (SSRT) was used to assess inhibitory control over motor responses. To link both of these measures to behavior, the severity of inattentive and hyperactive symptomatology was also assessed. Behaviorally, ADHD individuals had specific difficulty in inhibiting, but not in elaborating/increasing memory retrieval, which was correlated with symptom severity and longer SSRT. Additionally, ADHD individuals showed reduced activity in rLPFC during the TNT, as compared to control individuals. Moreover, unlike controls, in whom the correlation between activity of the rMFG and hippocampus predicts inhibitory success, no such correlation was observed for ADHD individuals. Moreover, decreased activity in rIFG in individuals with ADHD predicted a decrease in the ability to inhibit motor responses. These results suggest that inhibitory functions of rLPFC include control over both memory and motoric processes. They also suggest that inhibitory deficits in individuals with ADHD extend to the memory domain.

Testing the repression hypothesis: Effects of emotional valence on memory suppression in the think – No think task

It has been proposed that performance in the think – no think (TNT) task represents a laboratory analogue of the voluntary form of memory repression. The central prediction of this repression hypothesis is that performance in the TNT task will be influenced by emotional characteristics of the material to be remembered. This prediction was tested in two experiments by asking participants to learn paired associates in which the first item was either emotionally positive (e.g. joy) or emotionally negative (e.g. hatred). The second word was always emotionally neutral (e.g. socks). Consistent with the repression hypothesis, significant memory suppression was observed in both experiments following ‘no think’ instructions for memories associated with emotionally negative material. No suppression was observed for memories associated with emotionally positive information. Implications of these findings for the relationship between performance in the TNT task and the controversial notion of memory repression are considered.

Memory suppression is an active process that improves over childhood.

We all have memories that we prefer not to think about. The ability to suppress retrieval of unwanted memories has been documented in behavioral and neuroimaging research using the Think/No-Think (TNT) paradigm with adults. Attempts to stop memory retrieval are associated with increased activation of lateral prefrontal cortex (PFC) and concomitant reduced activation in medial temporal lobe (MTL) structures. However, the extent to which children have the ability to actively suppress their memories is unknown. This study investigated memory suppression in middle childhood using the TNT paradigm. Forty children aged 8–12 and 30 young adults were instructed either to remember (Think) or suppress (No-Think) the memory of the second word of previously studied word-pairs, when presented with the first member as a reminder. They then performed two different cued recall tasks, testing their memory for the second word in each pair after the TNT phase using the same first studied word within the pair as a cue (intra-list cue) and also an independent cue (extra-list cue). Children exhibited age-related improvements in memory suppression from age 8 to 12 in both memory tests, against a backdrop of overall improvements in declarative memory over this age range. These findings suggest that memory suppression is an active process that develops during late childhood, likely due to an age-related refinement in the ability to engage PFC to down-regulate activity in areas involved in episodic retrieval.

ERP Evidence for Intentional Suppression of Traumatic Events in Repressors

Event Abstract Back to Event ERP Evidence for Intentional Suppression of Traumatic Events in Repressors Deok-Yong Kim1* and J.H Lee1 1 Clinical Neuro-Psychology Lab., Department of Psychology, Chung-Ang University, South Korea Posttraumatic stress disorder (PTSD) is a common reaction to traumatic events, and one of the core features is reexperiencing the trauma via intrusive symptoms, such as repetitive thoughts, images, and memories. Reexperiencing mainly consists of sensory impressions, such as vivid visual images of the traumatic event. The repressive coping style refers to a habitual style of avoidant coping with aversive events. For repressors, the suppression of intrusive thoughts is initially successful, but the long term consequences of suppression are maladaptive as they tend to utilize more distraction strategies when presented with negative stimuli than non-repressor groups. The Think/No-Think (TNT) paradigm was used to investigate characteristics of the memory suppression. The TNT paradigm is a method for measuring intentional inhibition of unwanted memories, and it suggests that trying to not think about information could reduce subsequent recall of information. We used the TNT paradigm to determine whether repressors use intentional memory inhibition or not. Event-Related Potentials (ERPs) can be used to show the process of memory inhibition strategies used by repressors and nonrepressors. The present study will investigate differences in memory suppression between repressor and nonrepressor groups during recording of ERPs for trauma-related pictures. The participants were 4 undergraduates (2 repressors and 2 nonrepressors) from an initial 75 students who were chosen on the basis of their scores on the State-Trait Anxiety Inventory and the Marlowe-Crowne Social Desirability Scale. Material used 48 pairs of neutral-words and pictures of motorbike accidents were from the TNT paradigm. Participants first watched a motorbike accidents video clip for 5 minutes. The TNT paradigm consisted of three phases. In the initial learning phase, participants learned word-picture pairs to a criterion of 50% accuracy in responding to pictures among nine examples when provided with a word (cue). In the second TNT phase, they were instructed to either think about or suppress the target picture when cued during recording of ERPs. The last phase was a final recognition test of all the target pictures, regardless of the prior TNT instructions. The present study is ongoing, and these analyses reflect data for 4 participants. In the behavioral data, pictures in the no-think condition were less remembered in the final recognition test than in the initial recognition test. The ERP results show that parietal region amplitude of repressors was higher than that of nonrepressors early (approximately 300 ms) in the recordings (Fig 1.). These results indicate that increased cognitive processing for repressors during the suppression of pictures, because the distraction strategy required more cognitive effort besides just processing the target pictures. We have investigated the abilities of memory suppression in repressors. Examination of the ERPs suggests that the distraction strategies used during intentional inhibition are shown by the difference in amplitude between groups. In the poster presentation, we will discuss how the repressive coping style could be used to control images of, or thoughts about, the trauma. This work was supported by the Korea Science and Engineering Foundation (KOSEF) grant funded by the Korea government(MOST)(No. M10740030003-07N4003-00310)(No. R01-2007-000-20777-0). kim tn_kim Conference: 10th International Conference on Cognitive Neuroscience, Bodrum, Turkey, 1 Sep - 5 Sep, 2008. Presentation Type: Poster Presentation Topic: Memory & Learning Citation: Kim D and Lee J (2008). ERP Evidence for Intentional Suppression of Traumatic Events in Repressors. Conference Abstract: 10th International Conference on Cognitive Neuroscience. doi: 10.3389/conf.neuro.09.2009.01.287 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 09 Dec 2008; Published Online: 09 Dec 2008. * Correspondence: Deok-Yong Kim, Clinical Neuro-Psychology Lab., Department of Psychology, Chung-Ang University, Seoul, South Korea, dyongkim@gmail.com Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Deok-Yong Kim J.H Lee Google Deok-Yong Kim J.H Lee Google Scholar Deok-Yong Kim J.H Lee PubMed Deok-Yong Kim J.H Lee Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Inhibition of inappropriate responses is preserved in the think-no-think and impaired in the random number generation tasks in schizophrenia

We examined the ability of 23 schizophrenia patients and 24 healthy controls to exert intentional inhibition of prepotent responses in the Think-No-Think (TNT) paired-associate learning paradigm (Anderson & Green, 2001). TNT manipulates the frequency (1, 8, 16 times) of intentional attempts to suppress (inhibit) some target words and to respond to most cue words. Following a TNT practice-phase, recall of suppressed words was tested in two ways, using the same cue words initially learned, and the category name plus letter-stem of the target words. Inhibition of prepotent responses was also examined in a random number generation (RNG) task. In TNT, speed results showed longer reaction times after 16 suppress attempts in patients, not in controls, reflecting increased difficulty with retrieving the memory traces of the overridden items. In accuracy, no between-groups differences were evidenced, and overall patterns replicated those of Anderson & Green. In RNG, patients produced more stereotyped responses and ascending and descending counting than controls, pointing to on-line failures to inhibit prepotent responses. These findings suggest that schizophrenia patients' difficulties to inhibit prepotent responses appear specific, not widespread, the intentional inhibition addressed in TNT being preserved, and on-line inhibition in RNG being impaired.

Dissociation and memory suppression: A comparison of high and low dissociative individuals’ performance on the Think–No Think task

The present study examined whether high and low dissociative individuals differ in their ability to keep target stimuli out of their awareness (suppression) and how this relates to their memory of those targets during a later cued recall task. The prediction was that high dissociators display a general inability to focus attention and that their distractibility undermines successful suppression, thereby enhancing memory for suppressed items. College students with high ( n = 35) and low ( n = 33) scores on the Dissociative Experiences Scale participated in a Dutch version of Anderson and Green’s (2001) Think–No Think (TNT) task. Overall, a significant suppression effect emerged. However, no differences between high and low dissociators were observed. Thus, the present results do not confirm that dissociation is linked to heightened distractibility.