This chapter starts with key evidence, which suggests that all of the biological accounts of hunger in Chapter 2 – irrespective of their other shortcomings – are incomplete. Henry Molaison (HM) had a bilateral resection of his medial temporal lobes and was densely amnesic. He also did not experience hunger – unless food was placed in front of him. Other similar cases are examined, pointing to the importance of declarative learning and memory in hunger. Models of specific hunger are then reviewed. Since Cannon, all these models share a key similarity. They rely on learning and episodic memory processes. A model of general hunger is then examined that utilises interoceptive (e.g., stomach rumble) and temporal cues (e.g., it’s lunchtime). The basis of this model in learning is described, alongside the experimental and neuropsychological evidence for this account, and the importance of developmental processes. Interactions between specific and general hunger are explored, as is the important topic of how hunger is turned off by physiological satiation and satiety processes. Finally, the linkages of this psychological model to the biological accounts of Chapter 2 are revisited.

There are a wide range of sexual desires and intensities. What kind of motivational system could generate this? Appetitive and consummatory behaviour are distinct. There are on-line and off-line contributions. Hormones sensitize sexual motivation. There are organizational and activational phases of hormone action. People offer 237 reasons why they have sex. Wanting and liking are distinct. Sexual desire and sexual arousal are distinct but interactive. Excitation transfer is discussed. There are three levels of inhibition. The chapter discusses different brain regions and neurochemicals. The chapter describes ‘sexual priors’, the Coolidge Effect and the relevance of ‘life-history theory’. Sexual fantasy is rooted in part in incentive motivation. The complexities of sexual orientation are discussed, in terms of the incentive motivation model. Sexual desire often does not exist in isolation. Rather, it can interact with attachment, anger/aggression, and certain drugs (i.e. stimulants). The chapter then considers a number of paraphilias.

This chapter revisits Tinbergen’s four types of explanation. Features of motivation include arousal and activation, flexibility, layers of control, the opponent-process theory, excitation transfer, and the sensitization of particular stimulus–response connections. Similarities between motivations are discussed; for example, the dopaminergic pathway from the VTA to the NAcc underlies each motivation and wanting versus liking. The chapter describes interactions and competition between different motivations. Inadequacies of drive are noted. Evolutionary mismatch also applies to contemporary fears. The topic of need is revisited in the context of examples of where it arises in various chapters (e.g. the need for heat). The opponent process theory of motivation is described in terms of imprinting and withdrawal from drugs. The distinction between regulation and control, introduced in the context of temperature regulation, is revisited. Liking/pleasure often correlates with positive reinforcement but not always. The motor act involved in behaviour has a reinforcement value.

Chapter 5 begins with a review and critique of the classic, natural kinds, account of emotional experience and communication.It summarizes LeDoux’s research on survival circuits, then Barrett’s theory of cultural construction of emotions.It discusses research on alternative theories, including self-attribution, excitation transfer, and facial feedback, and emotion as part of communication strategy.It discusses Damasio’s evidence that emotion plays a vital role in reasoning.It closes with the role of signals and metaphors in communicating emotion.