This chapter focuses on individual differences in motivation and personality and how motivation affects the link between thinking and doing. A tribute to the work of Donald Broadbent, the chapter supports and furthers observations about individual differences in performance, learning, and motivation. The focus is primarily on various states of arousal, defined as the "inverse probability of falling asleep." The main claims of the chapter include:

• Individual differences in personality and motivation must be taken into account for proper understanding of human information processing.

• The availability and allocation of cognitive resources are affected by individual differences combined with situational manipulations.

• Motivation is the vital link between thought and action, knowing and doing.

• Motivation affects all stages of information processing.

The chapter addresses the relationship between cognitive processes and caffeine, impulsivity, Attention Deficit Disorder (ADD), hyperactivity, anxiety, time of day, and monetary incentives. The authors claim a great deal has changed since Broadbent's 1958 discussion of individual differences, in terms of a theoretical understanding of these dimensions. They advocate deriving a model to further this understanding from the neurobiological model of Jeffrey Gray, the multiple dimensional models of affect of Watson and Tellegen, and those of Thayer. Finally, the authors assert that differences in affective reactions to feedback, rates of learning, performance, dimensions of impulsivity-extraversion-surgency, anxiety-emotionality, and behavioral differences must all be integrated into an adequate model of how individual differences can affect motivation and performance.

This chapter, though based more on psychology than education, can yield valuable information to educators. Several cognitive maps, charts, and tables provide insight into how individual differences can affect learning. Situational outcomes regarding rewards and punishments are addressed, which may facilitate classroom management knowledge. Some generally important assertions for educators include:

• High arousal at learning inhibits immediate retrieval of the information presented but facilitates later recall of that information.
• When information needs to be integrated and complex decisions need to be made, an optimal level of arousal seems to be present.
• Caffeine can either facilitate or hinder arousal, depending on whether the individual is high impulsive or low impulsive.
• Increases in effort and arousal facilitate the ability to sustain rapid rates of information transfer but also inhibit some aspect of working memory.

Though some of the information may seem to be filled with jargon used primarily by psychological practitioners, interesting and useful information for cognition and instruction can also be found in this chapter.