300 350 400 450 500 550 600 0 0.5 1 1.5 2 2.5 3 3.5 Novelty 300 350 400 450 500 550 600 0 0.5 1 1.5 2 2.5 3 3.5 d ' minRT Familiarity r = -.48; p < .05 r = -.67; p < .01 0 0.5 1 1.5 2 2.5 3 3.5 0 0.5 1 1.5 2 2.5 Accuracy (D') Familiarity Nov el ty r = .67; p < .01 -1 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1 -1 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1 Nov el ty Familiarity Bias (C)
DISCUSSION & CONCLUSION
INTRODUCTION
Emma Delhaye
a,b, Christine Bastin
b, Christopher Moulin
c, Gabriel
Besson
a, & Emmanuel Barbeau
aHYPOTHESES
RESULTS
REFERENCES
[1] Besson, G., Ceccaldi, M., Didic, M., & Barbeau, E. J. (2012). The speed of visual recognition memory. Visual Cognition, 20(10), 1131–1152.
[2] Besson, G., Ceccaldi, M., Tramoni, E., Felician, O., Didic, M., & Barbeau, E. J. (2015). Fast, but not slow, familiarity is preserved in patients with amnestic Mild Cognitive Impairment. Cortex, 65, 36-49 ACKNOWLEDGMENTS
Leonardo da Vinci European Programme
Bridging familiarity-based recognition memory and
novelty detection: a matter of timing
CYCLOTRON RESEARCH CENTRE | BRAIN AND COGNITION RESEARCH CENTRE | Emma Delhaye | Emma.Delhaye@ulg.ac.be
a Centre de Recherche Cerveau et Cognition, Université de Toulouse, CNRS CERCO UMR 5549, France b Centre de Recherches du Cyclotron, Université de Liège, Belgique
c Laboratoire d’Etude de l’Apprentissage et du Développement, Université de Bourgogne, CNRS UMR 5022, France
Memory and novelty detection are thoroughly intertwined since novelty detection relies on the capacity to distinguish what is already known from what is not. However, the computational mechanism underlying novelty detection is not understood yet: do novelty and familiarity (i.e., retrieval based on stimulus strength) signals stem from a same unique mechanism as the two ends of a single continuum or from two distinct processes?
Different hypotheses arise from these two options concerning their temporal dynamics. In the first case, both processes should display a similar rapid temporal dynamics with similar characteristics. The second case would rather suggest dissociations between novelty and familiarity temporal dynamics, novelty being longer than familiarity.
METHODS
Although the observed differences in both accuracy and minimal reaction time would suggest a dissociation between novelty detection and familiarity, a further interpretation suggest that these differences are mainly due to an inverse symmetry in the response bias, explaining both a better performance and shorter reaction time for familiarity. As for the correlations, they rather tend to show clear similarities between novelty detection and familiarity-based recognition memory. Taken together, these results lead us to argue in favor of a unique familiarity/novelty discrimination system as the two ends of a single continuum.
Participants: 20 healthy subjects (mean age: 23 ± 3 (SD), range: 20-32; 13 females, 1 left-handed)
Procedure: 10 blocks of a recognition memory task
• Study: 30 items/block • Test:
30 targets & 30 distractors/block
2 conditions: familiarity versus novelty detection 5 blocks/condition, counterbalanced across
participants
Speed and Accuracy Boosting procedure (SAB) [1, 2] :
new task that constraints subjects to use their fastest strategy
Minimal reaction time: time at which the number of correct answers (hits) significantly outnumbers the number of false alarms (FA)
* p < .05 *** p < .001
r = -.56; p < .05
Correlations Performance
Accuracy Minimal reaction time
Across trials distribution of hits and FA
Target: HIT Distractor: FA Go! F ix ation c ross + St im ulus DEA DLINE No-go Target: MISS Distractor: CR N ex t trial + 0 100 200 300 400 500 600 0 1 2 3 4 5 6 7 8 390 489 Nb of answ er s (% ) RT(ms) 410 488 0 100 200 300 400 500 600 0 0.5 1 1.5 2 2.5 3 3.5 Cumulated d' Familiarity Novelty
