As stated in earlier chapters, our species and other primates share different memory systems. However, James McGaugh argues in Chapter 9 that, although forgetting is the common fate of most of our experiences, mechanisms exist that somehow permit us to create lasting memories of our more important experiences. The author explores such mechanisms. Several neurobiological systems link this selective capacity to emotional arousal, giving clues about how humans and other animals reach memory-enhancement episodes by means of an activation of brain regions such as the amygdala. The fact that some subjects are able to keep highly superior autobiographical memory raises the question of how this capacity might be associated with genetic and brain particularities.
Self-awareness and the capacity to evaluate others’ acts and their consequences are among the main components of altruistic behavior. Three chapters in these proceedings deal with different aspects of altruism and its more extreme related behaviors. In Chapter 10, Barbara Oakley examines the mechanistic bases of biased altruism, in which attempts to promote the welfare of others result in unanticipated harm. She defends the need for quantitative models of altruistic behavior along a spectrum ranging from strong benefit to extreme harm. These models might help to scientifically distinguish between beneficial and harmful egoistic behavior, as well as clarify the relationships between egoism, altruism, and pathological altruism.
Next, in Chapter 11, Sarah Brosnan begins her contribution with a question: What leads us to care about justice? She proposes a comparative
approach to clarify why justice, which is a highly important component of our values, is so difficult to achieve. By means of experiments on primates’ answers to perceived inequities in social interactions, Brosnan concludes that humans are not alone in responding negatively to differential treatment. Although nonhuman primates do not show a sense of justice in the same sense that humans do, understanding their responses may help to anticipate, prevent, and perhaps solve problems arising from the human perception of inequity.
Beyond direct perception of equality/inequality in social relationships, altruism and, more generally, human cooperation can be related to indirect reciprocity based on reputation. Since social reputation is directly observed, but widely spread by communication, indirect reciprocity can reach highly sophisticated patterns. In Chapter 12, Erez Yoeli et al. offer experimental results on large-scale (a total of 2,413 participants) cooperation between small groups under laboratory conditions. Since subjects were California residents of 15 homeowners’ associations that voluntarily participated in an energy-saving program, the experiment matched real-world conditions of cooperation. Yoeli and coworkers’ results provide evidence that observable participation in favor of public goods promotes cooperative behavior. The authors hold that reputational concerns were the driving force to reach such a high level of indirect cooperation, suggesting easy and practical ways to improve future public policy initiatives.
Next, Robert Zatorre and Valorie Salimpoor review empirical evidence for the neural substrates of several aspects of musical perception. First, the authors identify the auditory cortical circuits that are responsible for encoding and storage of tonal patterns. Then, they study the functional role of brain areas, such as the nucleus accumbens, codifying the reward value of music. The authors suggest that the cortical system, highly evolved, decodes tonal or rhythmic relationships present in music, thereby generating expectations about upcoming events based on the subjects’ former events. In turn, the striatal dopaminergic system would add the emotional arousal associated with these predictions.
Experimental approaches to visual issues constitute the next contribution to this colloquium. In Chapter 14, Leanne Chukoskie and coworkers study how subjects search a novel scene for a target whose location was stochastically drawn on each trial from a fixed prior distribution. Participants rapidly learn where to search, looking near previously rewarded locations and avoiding previously unrewarded sites. A reinforcement-learning model, similar to that used previously to examine both foraging animal behavior and neuronal firing of dopaminergic cells, can describe the resulting search performance. In addition, this search performance approaches the theoretical optimum on this task. Thus, the authors offer
a framework for considering how prior experience guides saccade choice during natural vision.
A complementary phenomenon provides the focus for Oshin Vartanian and coworkers, who in Chapter 15 provide clues on how variation in contour impacts aesthetic judgments and approach decisions about the places in which we live and work, thereby influencing how we feel and act. Subjects are more likely to judge spaces as beautiful if they are curvilinear than rectilinear. Curvilinear spaces activate the medial orbitofrontal cortex, a region strongly implicated in reward and that is particularly activated among architects compared to nonarchitects when assessing the aesthetic value of buildings. In contrast, contour has no impact on approach decisions. Contemplating curvilinear spaces activates the precentral gyrus—a region engaged in motor imagery and the planning of voluntary motor movement. Although curvilinear spaces did not result in a greater likelihood of deciding to enter such areas, they might facilitate the production of visual and motor imagery consistent with movement planning in that context. The authors conclude that their research sheds light on a fundamental question—why is it that we have come to prefer the places that we do?
Finally, by analyzing the dynamics of brain functional connectivity, Camilo Cela-Conde and coworkers in Chapter 16 offer the first identification of brain networks engaged within distinct time frames during the appreciation of beauty. A fast aesthetic perception of the beautiful/ not-beautiful condition of each visual stimulus appears within 250–750 ms, whereas further aesthetic appreciation processes are subsequently performed in the 1,000- to 1,500-ms range. The delayed processes activate a brain network matching the default mode network, present during subjects’ resting state.