Click here for papers organized by topic

In Press

Spunt, R. P. & Lieberman, M. D. (in press). Dissociating modality-specific and supramodal neural systems for action understanding. Journal of Neuroscience. pdf

Muscatell, K. A., Morelli, S. A., Falk, E. B., Way, B. M., Pfeifer, J. H., Galinsky, A. D., Lieberman, M. D., Dapretto, M., & Eisenberger, N. I. (in press). Social status modulates neural activity in the mentalizing network. Neuroimage. pdf

Falk, E. B., Berkman, E. T., & Lieberman, M. D. (in press). From neural responses to population behavior: Neural focus group predicts population level media effects. Psychological Science. pdf & supplemtal materials

Lieberman, M. D. (in press). A geographical history of social cognitive neuroscience. Neuroimage (invited paper for the journal's 20th anniversary issue). pdf

Gee, D. G., Karlsgodt, K. H., Bearden, C. E., Lieberman, M. D., Belger, A., Perkins, D. O., Olvet, D. M., Cornblatt, B. A., Constable, T., Woods, S. W., Addington, J., Cadenhead, K. S., McGlashan, T. H., Seidman, L. J., Tsuang, M. T., Walker, E. F., & Cannon, T. D. (in press). Altered age-related trajectories of amygdala-prefrontal circuitry in adolescents at clinical high risk for psychosis: A preliminary study. Schizophrenia Research. pdf

Payer, D. E., Baicy, K., Lieberman, M. D., & London, E. D. (in press). Overlapping neural substrates between intentional and incidental down-regulation of negative emotions. Emotion. pdf

Lieberman, M. D. (in press). Self-knowledge: From philosophy to neuroscience to psychology. S. Vazire & T. D. Wilson (Eds.) Handbook of Self-knowledge. pdf

Cohen, J. R., Berkman, E. T., & Lieberman, M. D. (in press). Intentional and incidental self-control in ventrolateral PFC. To appear in Oxford Handbook of Frontal Lobe Function . pdf

Falk, E. & Lieberman, M. D. (in press). The neural bases of attitudes. In F. Krueger & J. Grafman (Eds.). The neural basis of human belief systems. Psychology Press. pdf

2012

Meyer, M. L., Spunt, R. P., Berkman, E. T., Taylor, S. E., & Lieberman, M. D. (2012). Social working memory: An fMRI study of parametric increases in social cognitive effort. Proceedings of the National Academy of Sciences, 109, 1883-1888. pdf

Falk, E. B., Spunt, R. P., & Lieberman, M. D. (2012). Ascribing beliefs to ingroup and outgroup political candidates: Neural correlates of perspective taking, issue importance, and days until the election. Philosophical Transactions of the Royal Society, 367, 731-743. pdf

Spunt, R. P. & Lieberman, M. D. (2012). An integrative model of the neural systems supporting the comprehension of observed emotional behavior. Neuroimage, 59, 3050-3059. pdf

Burklund, L. J. & Lieberman, M. D. (2012). Advances in functional neuroimaging of psychopathology. Philosophy, Psychiatry, & Psychology, 18, 333-337. pdf

Masten, C. L., Telzer, E. H., Fuligni, A. J., LIeberman, M. D., & Eisenberger, N. I. (2012). Time spent with friends in adolescence relates to less neural sensitivity to later peer rejection. Social Cognitive and Affective Neuroscience, 7, 106-114. pdf

Rameson, L. T., Morelli, S. A., & Lieberman, M. D. (2012). The neural correlates of empathy: Experience, automaticity, and prosocial behavior. Journal of Cognitive Neuroscience, 24, 235-245. pdf

Foland-Ross, L. C., Bookheimer, S. Y., Lieberman, M. D., Sugar, C. A., Townsend, J., Fischer, J., Torrisi, S., Penfold, C., Madsen, S. K., Thompson, P. M. & Altshuler, L. (2012). Normal amygala activation but deficient ventrolateral prefrontal activation in adults with bipolar disorder during euthymia. Neuroimage, 59, 738-744. pdf

2011

Jarcho, J. M., Berkman, E. T. & Lieberman, M. D. (2011). The neural basis of rationalization: Cognitive dissonance reduction during decision-making. Social Cognitive and Affective Neuroscience, 6, 460-467. Link to abstract/paper

Eisenberger, N.I., Master, S.L., Inagaki, T.K., Taylor, S.E., Shirinyan, D., Lieberman, M.D., & Naliboff, B. (2011). Attachment figures activate a safety signal-related neural region and reduce pain experience. Proceedings of the National Academy of Sciences, 108, 11721-11726. pdf

Telzer, E. H., Masten, C. L., Berkman, E. T., & Lieberman, M. D. (2011). Neural regions associated with self control and mentalizing are recruited during prosocial behaviors towards the family. NeuroImage, 58, 242-249. pdf

Lieberman, M. D., Inagaki, T. K., Tabibnia, G., & Crockett, M. J. (2011). Subjective responses to emotional stimuli during labeling, reappraisal, and distraction. Emotion, 11, 468-480. pdf

Berkman, E. T., Falk, E. B., & Lieberman, M. D. (2011). In the trenches of real-world self-control: Neural correlates of breaking the link between craving and smoking. Psychological Science, 22, 498-506 . pdf

Falk, E. B., Berkman, E. T., Whalen, D., & LIeberman, M. D. (2011). Neural activity during health messaging predicts reductions in smoking above and beyond self-report. Health Psychology,30, 177-185. pdf

Berkman, E.T. & Lieberman, M.D. (2011). What's outside the black box?: The status of behavioral outcomes in neuroscience research. Psychological Inquiry, 22, 100-107. pdf

Meyer, M. L., Berkman, E. T., Karremans, J. C., & Lieberman, M. D. (2011). Incidental regulation of attraction: The neural basis of the derogation of attractive alternatives in romantic relationships. Cognition and Emotion, 25, 490-505. pdf

Payer, D. E., Lieberman, M. D., & London, E. D. (2011). Neural correlates of affect processing and aggression in methamphetamine dependence. Archives of General Psychiatry, 68, 271-282. pdf

Berkman, E.T., Dickenson, J., Falk, E.B., & Lieberman, M.D. (2011). Using SMS text messaging to assess moderators of smoking reduction: Validating a new tool for ecological measurement of health behaviors. Health Psychology, 30, 186-194. pdf

Lieberman, M. D. (2011). SCAN heads to kindergarten. Social Cognitive and Affective Neuroscience, 6, 1. pdf

Spunt, R. P., Satpute, A. B., & Lieberman, M. D. (2011). Identifying the what, why, and how of an observed action: An fMRI study of mentalizing and mechanizing during action observation. Journal of Cognitive Neuroscience, 23, 63-74. pdf

Lieberman, M. D. (2011). Why symbolic processing of affect can disrupt negative affect: Social cognitive and affective neuroscience investigations. To appear in A. Todorov, S. T. Fiske, & D. Prentice (Eds.) Social Neuroscience: Toward understanding the underpinnings of the social mind. Oxford University Press. PDF

2010

Foland-Ross, L. C., Altshuler, L. L., Bookheimer, S. Y., Lieberman, M. D., Townsend, J., et al. (2010) Amygdala reactivity in healthy adults is correlated with prefrontal cortical thickness. Journal of Neuroscience, 30, 16673-16678. pdf

Spunt, R. P., Falk, E., & Lieberman, M. D. (2010). Dissociable neural systems support retrieval of "how" and "why" action knowledge. Psychological Science, 21, 1593-1598. pdf

Crockett, M. J., Clark, L., Lieberman, M. D., Tabibnia, G., & Robbins, T. W. (2010). Impulsive choice and altruistic punishment are correlated and increase in tandem with serotonin depletion. Emotion, 10, 855-862. pdf

Telzer, E. H., Masten, C. L, Berkman, E. T., Lieberman, M. D., & Fuligni, A. J. (2010). Gaining while giving: An fMRI study of the rewards of family assistance among White and Latino youth. Social Neuroscience, 5508-516. pdf

Way, B., & Lieberman, M. D. (2010). Is there a genetic contribution to cultural differences? Collectivism, individualism, and genetic markers of social sensitivity. Social Cognitive and Affective Neuroscience, 5, 203-211. Link to abstract/paper

Falk, E. B., Berkman, E. T., Mann, T., Harrison, B, & Lieberman, M. D. (2010). Predicting persuasion-induced behavior change from the brain. Journal of Neuroscience, 30, 8421-8424. article pdf and supplemental pdf

Falk, E., Rameson, L., Berkman, E., Liao, B., Kang, Y., Inagaki, T. K., & Lieberman, M. (2010). The neural corelates of persuasion: A common network across cultures and media. Journal of Cognitive Neuroscience, 22, 2447-2459. pdf

Lieberman, M. D. (2010). Social cognitive neuroscience. S. T. Fiske, D. T. Gilbert, & G. Lindzey (Eds). Handbook of Social Psychology (5th ed.) (pp. 143-193). New York, NY: McGraw-Hill. pdf

Berkman, E.T., & Lieberman, M.D. (2010). Approaching the bad and avoiding the good: Lateral prefrontal cortical asymmetry distinguishes between action and valence. Journal of Cognitive Neuroscience, 22, 1970-1979. pdf

Way, B. M., Creswell, J. D., Eisenberger, N. I., & Lieberman, M. D. (2010). Dispositional mindfulness and depressive symptomatology: Correlations with limbic and self-referential neural activity during rest. Emotion, 10 12-24.

Rameson, L., Satpute, A., & Lieberman, M. (2010). The neural corelates of implicit and explicit self-relevant processing. NeuroImage, 50, 701-708. pdf

Cohen, J. R. & Lieberman, M. D. (2010). The common neural basis of exerting self-control in multiple domains. In Y. Trope, R. Hassin, & K. N. Ochsner (eds.) Self-control (141-160). pdf

2009

Lieberman, M., & Cunningham, W. A. (2009). Type I and Type II error concerns in fMRI research: Re-balancing the scale. Social Cognitive and Affective Neuroscience, 4, 423-428. pdf

Lieberman, M. D. (2009). The Brains' Braking System (and how to 'use your words' to tap into it). Neuroleadership, 2, 9-14. PDF

Master, S. L., Eisenberger, N. I., Taylor, S. E., Naliboff, B. D., Shirinyan, D., & Lieberman, M. D. (2009). A picture's worth: Partner photographs reduce experimentally induced pain. Psychological Science, 20, 1316-1318. pdf

Lieberman, M. D. (2009). What makes big ideas sticky?. In M. Brockman (Ed), What's next? Dispatches on the future of science. New York, NY: Vintage Books. pdf

Lieberman, M. D., & Eisenberger, N. I. (2009). Pains and pleasures of social life. Science, 323, 890-891. PDF

Pfeifer, J. H., Masten, C. L., Borofsky, L. A., Dapretto, M., Fuligni, A. J., & Lieberman, M. D. (2009). Neural correlates of direct and reflected self-appraisals in adolescents and adults: When social perspective taking informs self-perception. Child Development, 80, 1016-1038. pdf

Pfeifer, J. H., Dapretto, M., & Lieberman, M. D. (2009). The neural foundations of evaluative self-knowledge in middle childhood, early adolescence, and adulthood. In P. D. Zelago, M. Chandler, & E. Crone (Eds.) Developmental Social Cognitive Neuroscience (141-163). New York, NY: Psychology Press. PDF

Berkman, E.T., & Lieberman, M.D. (2009). Using neuroscience to broaden emotion regulation: Theoretical and methodological considerations. Social and Personality Psychology Compass, 3, 475-493. pdf

Berkman, E. T., Burklund, L., & Lieberman, M. D. (2009). Inhibitory spillover: Intentional motor inhibition produces incidental limbic inhibition via right inferior frontal cortex. Neuroimage, 47, 705-712. pdf

Lieberman, M. D., Berkman, E. T., & Wager, T. D. (2009). Correlations in social neuroscience aren't voodoo: A reply to Vul et al. Perspectives on Psychological Science, 4, 299-307.

Berkman, E., Lieberman, M. D., & Gable, S. L. (2009). BIS, BAS, and response conflict: Testing predictions of the revised reinforcement sensitivity theory. Personality and Individual Differences, 46, 586-591. PDF

Amodio, D. M. & Lieberman, M. D. (2009). Pictures in our heads: Contributions of fMRI to the study of prejudice and stereotyping. In T. Nelson (ed.) Handbook of Prejudice and Discrimination (pp. 345-363). Taylor & Francis. pdf

Rameson, L. T., & Lieberman, M. D. (2009). Empathy: A social cognitive neuroscience approach. Social and Personality Psychology Compass. pdf

Berkman, E., & Lieberman, M. D. (2009). The neuroscience of goal pursuit: Bridging gaps between theory and data. In G. Moskowitz & H. Grant (Eds.) The Psychology of Goals (98-126). New York, NY: Guilford Press. PDF

Lieberman, M. D. (2009). What zombies can't do: A social cognitive neuroscience approach to the irreducibility of reflective consciousness. In J. Evans & K. Frankish (Eds.) In Two Minds: Dual Process and Beyond (pp. 219-316). New York, NY: Oxford University Press. pdf

Lieberman, M. D. (2009). Gut Feelings. In D. Sander & K. Scherer (Eds.) Oxford Companion to Emotion and the Affective Sciences (pp. 200-201). Oxford: Oxford University Press. pdf

2008

Lieberman, M. D. & Eisenberger, N. I. (2008). The pains and pleasures of social life: A social cognitive neuroscience approach. Neuroleadership. pdf

O'Connor, M. F., Wellisch, D. K., Stanton, A. L., Eisenberger, N. I., Irwin, M. R., & Lieberman, M. D. (2008). Craving love? Enduring grief activates brain's reward center. NeuroImage, 42, 969-972. pdf

Crockett, M. J., Clark, L., Tabibnia, G., Lieberman, M. D., & Robbins, T. W. (2008). Serotonin modulates behavioral reactions to unfairness. Science, 320, 1739. pdf and Supporting Online Material

Taylor, S. E., Burklund, L. J., Eisenberger, N. I., Lehman, B. J., Hilmert, C. J., & Lieberman, M. D. (2008). Neural bases of moderation of cortisol stress responses by psychosocial resources. Journal of Personality and Social Psychology, 95, 197-211. pdf

Lieberman, M. D. (2008). Thank yous and welcomes: SCAN turns two. Social Cognitive and Affective Neuroscience, 3, 191. pdf

Jarcho, J. M., Chang, L., Berman, S. M., Suyenobu, B., Naliboff, B. D., Lieberman, M. D., Ameen, V. Z., Mandelkern, M. A., & Mayer, E. A. (2008). Neural and psychological predictors of treatment response in irritable bowel syndrome patients with a 5-HT3 receptor antagonist-a pilot study. Alimentary Pharmacology & Therapeutics, 28,344-352. pdf

Tabibnia, G. T., Lieberman, M. D., & Craske, M. G. (2008). The lasting effect of words on feelings: Words may facilitate exposure effects to threatening images. Emotion, 8, 307-317. pdf

Tabibnia, G., Satpute, A. B., & Lieberman, M. D. (2008). The sunny side of fairness: Preference for fairness activates reward circuitry (and disregarding unfairness activates self-control circuitry). Psychological Science, 19, 339-347. pdf

Eisenberger, N. I., Way, B., Taylor, S. E., & Lieberman, M. D. (2008). MAOA, gender differences and social exclusion: response to Gallardo-Pujol et al. Biological Psychiatry, 63, e11. pdf

Payer, D. E., Lieberman, M. D., Monterosso, J. R., Xu, J., Fong, T. W., & London, E. D. (2008). Differences in cortical activity between methamphetamine-dependent and healthy individuals performing a facial affect matching task. Drug and Alcohol Dependence, 93, 93-102. pdf

2007

Tabibnia, G., & Lieberman, M. D. (2007). Fairness and cooperation are rewarding: evidence from social cognitive neuroscience. Annals of the New York Academy of Sciences, 1118, 90-101. PDF

Eisenberger, N. I., Gable, S. L., & Lieberman, M. D. (2007). fMRI responses relate to differences in real-world social experience. Emotion, 7, 745-754. PDF

Rameson, L. & Lieberman, M. D. (2007.) Thinking about the self from a social cognitive neuroscience perspective. Psychological Inquiry, 18, 117-122. PDF

Pfeifer, J. H., Lieberman, M. D., & Dapretto, M. (2007). "I know you are but what am I?!": An fMRI study of self-knowledge retrieval during childhood. Journal of Cognitive Neuroscience, 19, 1323-1337. PDF

Burklund, L. J., Eisenberger, N. I., & Lieberman, M. D. (2007.) The face of rejection: Rejection sensitivity moderates dorsal anterior cingulate activity to disapproving facial expressions. Social Neuroscience, 2, 238-253. PDF

Creswell, J. D., Way, B. M., Eisenberger, N. I., & Lieberman, M. D. (2007). Neural correlates of dispositional mindfulness during affect labeling. Psychosomatic Medicine, 69, 560-565. PDF

Eisenberger, N. I., Way, B. M., Taylor, S. E., Welch, W. T., & Lieberman, M. D. (2007). Understanding genetic risk for aggression: Clues from the brain's response to social exclusion. Biological Psychiatry, 61, 1100-1108. PDF

Eisenberger, N. I., Taylor, S. E., Gable, S. L., Hilmert, C. J., & Lieberman, M. D. (2007). Neural pathways link social support to attenuated neuroendocrine stress response. NeuroImage, 35, 1601-1612. PDF

Lieberman, M. D., Eisenberger, N. I., Crockett, M. J., Tom, S. M., Pfeifer, J. H., & Way, B. M. (2007). Putting feelings into words: Affect labeling disrupts amygdala activity to affective stimuli. Psychological Science, 18, 421-428. PDF

Lieberman, M. D. (2007). Social cognitive neuroscience: A review of core processes. Annual Review of Psychology, 58, 259-89. PDF

Lieberman, M. D. (2007). The X- and C-systems: The neural basis of automatic and controlled social cognition. In E. Harmon-Jones & P. Winkelman (Eds.), Fundamentals of Social Neuroscience (pp. 290-315). New York: Guilford. PDF

Lieberman, M. D. (2007). Social cognitive neuroscience. In R.F. Baumeister & K. D. Vohs (Eds.), Encyclopedia of Social Psychology, Thousand Oaks, CA: Sage Press. PDF

2006

Lieberman, M. D. (2006). Neural basis of situational context effects on social perception. Social Cognitive Affective Neuroscience, 1, 73-74. PDF

Lieberman, M. D. (2006). Social cognitive and affective neuroscience: When opposites attract. Social Cognitive Affective Neuroscience, 1, 1-2. PDF

Eisenberger, N. I., Jarcho, J. M., Lieberman, M. D., & Naliboff, B. D. (2006). An experimental study of shared sensitivity to physical pain and social rejection. Pain, 126, 132-138. PDF

Satpute, A.B., & Lieberman, M. D. (2006). Integrating automatic and controlled processing into neurocognitive models of social cognition. Brain Research, 1079, 86-97. PDF

Taylor, S. E., Eisenberger, N. I., Saxbe, D., Lehman, B. J., & Lieberman, M. D. (2006). Neural bases of regulatory deficits associated with childhood family stress. Biological Psychiatry, 60, 269-301. PDF

2005

Lieberman, M. D. (2005). Principles, processes, and puzzles of social cognition: An introduction for the special issue on social cognitive neuroscience. NeuroImage, 28, 745-756. PDF

Lieberman, M. D., & Pfeifer, J. H. (2005). The self and social perception: Three kinds of questions in social cognitive neuroscience. In A. Easton & N. Emery (Eds.), Cognitive Neuroscience of Emotional and Social Behavior (pp. 195-235). Philadelphia: Psychology Press. PDF

Lieberman, M. D., & Eisenberger, N. I. (2005). A pain by any other name (rejection, exclusion, ostracism), still hurts the same: The role of dorsal anterior cingulate in social and physical pain. In J. T. Cacioppo, P. Visser, & C. Pickett (Eds.), Social Neuroscience: People Thinking About People (pp. 167-187). Cambridge, MA: MIT Press. PDF

Lieberman, M. D., Hariri, A., Jarcho, J. M., Eisenberger, N. I., & Bookheimer, S. Y. (2005). An fMRI investigation of race-related amygdala activity in African-American and Caucasian-American individuals. Nature Neuroscience, 8, 720-2. PDF and Supplementary Note

Eisenberger, N. I., Lieberman, M. D., & Satpute, A. B. (2005). Personality from a controlled processing perspective: An fMRI study of neuroticism, extraversion, and self-consciousness. Cognitive, Affective, and Behavioral Neuroscience, 5, 169-181. PDF

Eisenberger, N. I., & Lieberman, M. D. (2005). Broken hearts and broken bones: The neurocognitive overlap between social pain and physical pain. In K. D. Williams, J. P. Forgas, & W. von Hippel (Eds.), The Social Outcast: Ostracism, Social Exclusion Rejection, and Bullying (pp. 109-127). New York: Cambridge University Press. PDF

Lieberman, M. D., Jarcho, J. M., & Obayashi, J. (2005). Attributional inference across cultures: Similar automatic attributions and different controlled corrections. Personality and Social Psychology Bulletin, 31, 889-901. PDF

2004

Lieberman, M. D., & Eisenberger, N. I. (2004). The neural alarm system: behavior and beyond. Reply to Ullsperger et al. Trends in Cognitive Sciences, 8, 446-447. PDF

Lieberman, M. D., & Eisenberger, N. I. (2004). Conflict and habit: A social cognitive neuroscience approach to the self. In A. Tesser, J. V. Wood, & D. A. Stapel (Eds.), On Building, Defending and Regulating the Self: A Psychological Perspective (pp. 77-102). New York, NY: Psychology Press. PDF

Lieberman, M. D., Jarcho, J. M., & Satpute, A. B. (2004). Evidence-based and intuition-based self-knowledge: An fMRI study. Journal of Personality and Social Psychology, 87, 421-35. PDF

Eisenberger, N. I., & Lieberman, M. D. (2004). Why rejection hurts: a common neural alarm system for physical and social pain. Trends in Cognitive Sciences, 8, 294-300. PDF

Lieberman, M. D., Jarcho, J. M., Berman, S., Naliboff, B., Suyenobu, B. Y., Mandelkern, M. & Mayer, E. (2004). The neural correlates of placebo effects: A disruption account. NeuroImage, 22, 447-455. PDF

Lieberman, M. D., Chang, G. Y., Chiao, J., Bookheimer, S. Y., & Knowlton, B. J. (2004). An event-related fMRI study of artificial grammar learning in a balanced chunk strength design. Journal of Cognitive Neuroscience, 16, 427-438. PDF

Iacoboni, M., Lieberman, M. D., Knowlton, B. J., Molnar-Szakacs, I., Moritz, M., Throop, C. J., & Fiske, A. P. (2004). Watching social interactions produces dorsomedial prefrontal and medial parietal BOLD fMRI signal increases compared to a resting baseline. NeuroImage, 21, 1167-1173. PDF

Gilbert, D. T., Lieberman, M. D., Morewedge, C. K., & Wilson, T. D. (2004). The peculiar longevity of things not so bad. Psychological Science, 15, 14-19. PDF

2000-2003

Eisenberger, N. I., Lieberman, M. D., & Williams, K. D. (2003). Does rejection hurt? An fMRI study of social exclusion. Science, 302, 290-292. PDF and Animation

Lieberman, M. D., Schreiber, D., & Ochsner, K. N. (2003). Is political thinking like riding a bicycle? How cognitive neuroscience can inform research on political thinking. Political Psychology, 24, 681-704. PDF

Lieberman, M. D. (2003). Reflective and reflexive judgment processes: A social cognitive neuroscience approach. In J. P. Forgas, K. R. Williams, & W. von Hippel (Eds.), Social judgments: Implicit and explicit processes (pp. 44-67). New York: Cambridge University Press. PDF

Lieberman, M. D., Gaunt, R., Gilbert, D. T., & Trope, Y. (2002). Reflection and reflexion: A social cognitive neuroscience approach to attributional inference. Advances in Experimental Social Psychology, 34, 199-249. PDF

Ochsner, K. N., & Lieberman, M. D. (2001). The emergence of social cognitive neuroscience. American Psychologist, 56, 717-734. pdf

Lieberman, M. D., Ochsner, K. N., Gilbert, D. T., & Schacter, D. L. (2001). Do amnesics exhibit cognitive dissonance reduction? The role of explicit memory and attention in attitude change. Psychological Science, 12, 135-140. PDF

Lieberman, M. D., & Rosenthal, R. (2001). Why introverts can't always tell who likes them: Multi-tasking and nonverbal decoding. Journal of Personality and Social Psychology, 80, 294-310. PDF

Lieberman, M. D. (2000). Introversion and working memory: Central executive differences. Personality and Individual Differences, 28, 479-486. PDF

Lieberman, M. D. (2000). Intuition: A social cognitive neuroscience approach. Psychological Bulletin, 126, 109-137. PDF