1. The maturation of familiarity and recollection in episodic memory: An ERP developmental approach Marianne de Chastelaine 1, David Friedman 1, Yael M. Cycowicz 2, Cort Horton 1 & Brenda Malcolm 1 1 Cognitive Electrophysiology Laboratory, and 2 Division of Brain Stimulation, New York State Psychiatric Institute, NY, NY  Recognition memory is thought to be supported by two qualitatively distinct processes: an acontextual sense of familiarity and the retrieval of contextual details (recollection). ERP studies of recognition memory have identified old/new or episodic memory (EM) effects thought to reflect these underlying processes: (i) Familiarity – associated with an enhanced positivity over frontal sites between approx. 300-500ms post-stimulus (i.e., the ‘early frontal EM effect’); (ii) Recollection – associated with an enhanced positivity over parietal sites typically measured between 500-700ms post-stimulus (i.e., the ‘parietal EM effect’).  Recollection is thought to involve the use of control processes that guide and monitor the retrieval of task-relevant contextual details while familiarity-based recognition is held to be automatically driven (1). Thus, as the development of cognitive control continues throughout childhood (2), recollection is thought to show a longer developmental trajectory than familiarity (3).  To investigate the development of familiarity- and recollection-based recognition, we assessed modulations of behavioral and ERP indices of these processes in children and adults by the memory strength engendered by repetition. Participants memorized the same 40 unfamiliar and, initially, unnamable symbol-like stimuli, which they viewed in each of 4 study/test blocks (Fig. 1). New items differed for each test (4).  We hypothesized that, for both groups, old/new judgments would, initially, be based on familiarity whereas, with repetition, adults would increasingly rely upon recollection. We predicted that children’s performance would be worse than that of adults and that this would be due to a specific deficit in recollection-based rather than familiarity-based processing. INTRODUCTION AIMS AND PREDICTIONS METHODS BEHAVIORAL RESULTS  Study items were always presented in the same spatial location (left/right of fixation).  At test, separate old/new, remember/know and source (location) judgments were solicited. Old items attracting remember judgments are assumed to have been recollected whereas those attracting know judgments are assumed to be familiar only. Participants:  16 children (9-11; M: 9.6); 16 adults (20-25; M: 22.6) Test NewOld Study RightLeft Fig. 1 DISCUSSION ERP RESULTS old new F3 Pz Test 1Test 2Test 3Test 4 + - 5μv5μv A B C Adults  Between 300-500ms (black shading), frontal and parietal EM effects were found in all 4 tests for adults and in Tests 3 and 4 for children – for adults, these effects were maximal over frontal sites in Test 1 (A), and, for both groups, maximal over parietal sites in Test 4 (B). Between 500- 700ms (grey shading), parietal EM effects (C) were found in all 4 tests for children and adults.  For both age groups, the parietal EM effect was found to increase in amplitude and onset at an earlier time point with each repetition [children – Test 1: 520ms; Test 2: 460ms; Test 3: 400ms; Test 4: 300ms; adults – Test 1: 360ms; Test 2: 320ms; Test 3: 260ms; Test 4: 240ms]. SCALP DISTRIBUTION OF EM (OLD-NEW) EFFECTS  For adults, during the 300-500ms latency region only, the scalp distribution of EM effects changed across Tests from a frontal maximum in Test 1 to a parietal maximum in Test 4. The scalp distribution of EM effects also differed between the 300-500ms and 500-700ms latency regions only in Tests 1 and 2 for adults and only in Test 3 for children. 300-500ms 500-700ms μvμv + 2.00 - 2.00 μvμv + 4.00 - 4.00 300-500ms 500-700ms Test 1Test 2Test 3Test 4 Adults Children  Relative to adults, children recognized fewer recollected (remembered) items and also endorsed fewer old items on the basis of familiarity alone (known). Thus, it would appear that children’s difficulty in discriminating between old and new items was due to a reduction in both familiarity- and recollection-based recognition.  The lack of a reliable early frontal EM effect in children until the third test further suggests that the maturation of familiarity-based recognition may be more delayed and, perhaps, less automatically driven than previously thought. In fact, relative to recollected old items, the finding of slower RTs to old items that were simply familiar supports the idea that decisions presumably based on familiarity require additional monitoring due to this information being relatively impoverished (5).  The data suggest that, with each repetition, children and adults relied upon recollection to a greater degree to make the recognition judgment and that, as the memory traces strengthened, there was increasingly rapid access to these contextual details. Given that, by Test 4, the parietal EM effect had onset at 240ms post-stimulus in adults, it does not seem plausible that such rapid recollection could have been supported by the slow, controlled processing predicted on the basis of many dual- process models. In line with a number of recent behavioral findings, the data suggest that the retrieval of contextual details may, instead, sometimes be obligatory (6).  We conclude that children’s impoverished recognition performance is not due to problems with the retrieval of episodic information per se, but a general difficulty in efficiently monitoring and organizing this information in order to make more informed ‘old’ decisions. In contrast, adults’ superior performance reflects their flexible and interchangeable use of familiarity and recollection as required by the task demands.  Adults’ old/new discrimination (Pr) was higher overall than children’s (Table 1), although both groups showed increases in accuracy across the 4 tests. For both groups, RTs to old and new items decreased across the 4 tests. While adults’ response bias (Br) became increasingly more liberal with each test repetition, for children, it remained conservative across tests.  Compared to children, adults recognized more old items that were remembered, as well as simply known. For both groups, proportions of correctly identified old items attracting remember and correct source judgments increased across the four tests (Figs. 2 & 3). Responses to old items associated with remember and correct source judgments were faster than those to old items attracting know and incorrect source judgments (not shown). References: 1.Yonelinas. (2002). Journal of Memory and Language 46, 441–517. 2.Zelazo, P. D., & Müller, U. (2002). In U. Goswami (Ed.), Handbook of childhood cognitive development (pp. 445-469). Oxford: Blackwell. 3. Cycowicz. (2000). Biological Psychology, 54, 145-174. 4. Johnson, Pfefferbaum, & Kopell. (1985). Psychophysiology, 22, 497-507. 5. Henson, Rugg, Shallice, Josephs & Dolan. (1999). The Journal of Neuroscience, 19, 3962-2972. 6. Gardiner, Konstantinou, Karayianni & Gregg. (2005). Experimental Psychology, 52(2), 140-149. Children Adults Proportion of old items Source Correct Source Incorrect Proportion of old items Source Correct Source Incorrect Proportion of old items Remember Know Proportion of old items Remember Know Fig. 2 Fig. 3 0 + - 5μv5μv F3 Pz 01000 0 0 B C Children EEG recording (test phase): 62 Ag/AgCl electrodes ref: linked mastoids continuous, DC-100 Hz 500 Hz sampling rate epoch: 2000ms (100ms pre-stim baseline) stimulus duration: 500ms 1234 Tests 1234 1234 1234 Table 1