Research on executive control has rapidly grown over the last 15 years. There has been an increasing conjunction of psychology and neuroscience, not only in brain imaging, but also in single-neuron studies in monkeys (Stoet & Snyder Reference Stoet and Snyder2004; Reference Stoet and Snyder2009).
There is general agreement that the functions involved in executive control are used to coordinate and resolve conflicts between more basic processes. There are a number of different mechanisms that are part of the executive control family: (1) flexibility – the capacity to switch attention between different tasks; (2) goal setting – the capacity to set a goal; (3) planning, including initiation and sequencing – the capacity to determine a series of steps necessary to reach a goal; (4) inhibitory control – the capacity to suppress distracting or irrelevant information and thoughts; (5) monitoring – the capacity to monitor whether actions result in their intended outcome; (6) adjustment – the capacity to adjust a course of action even after it has been initiated; and (7) maintenance – short-term maintenance of information related to the above functions; for example, goal setting implies that the brain can maintain the goal representation for a certain time.
Vaesen lists only some of these executive functions, namely, inhibitory control, planning, and monitoring. Further, he lists autocueing; that is, the capacity to think about things other than those triggered by external stimuli. This use of autocueing was introduced by Donald (Reference Donald1993; cited by Vaesen), who states that animals “are creatures of conditioning, and cannot ‘think’ except in terms of reacting to the present or immediately past environment” (p. 146). Donald continues: “Humans alone have self-initiated access to memory, or what may be called ‘autocueing’” (p. 146). The difficulty with the concept is that autocueing has not received much attention from other researchers; further, research in the past decade has unequivocally shown that animals actually use internal representations to guide the processing of external stimuli (often referred to as endogenous control). Such internal representations can, for example, encode which potential responses are relevant in a certain task context; and such internal representations enable animals to respond in ways that are quite different from the nature of the external stimuli. A number of laboratories have successfully recorded single neurons encoding endogenously activated action and task representations (for a review, see Stoet & Snyder Reference Stoet and Snyder2009).
What is most important for this commentary, though, is that there is a difference in the abilities of humans and monkeys to switch between endogenously controlled task representations. Extensive research has demonstrated that monkeys are more flexible in rapidly switching between tasks than are humans, who even with long training can still not switch as rapidly as monkeys can (Caselli & Chelazzi Reference Caselli and Chelazzi2011; Stoet & Snyder Reference Stoet and Snyder2003; Reference Stoet and Snyder2007).
Therefore, by some measures, monkeys outperform humans in mental flexibility. We hypothesize that although humans are at a disadvantage in laboratory task-switching experiments, this limited flexibility might come as an advantage for cognitive development associated with the construction and use of complex tools. (With “complex tools” we mean constructed tools.) Limited mental flexibility supports concentration. We know that humans are good at concentration. The human skill to concentrate develops mostly before the age of 10, although it seems to continue improving during adolescence. Concentration is a necessary component of long-lasting and complex tasks, some of which may have played an important survival role in prehistory, including keeping a fire burning, cooking, hunting a herd of animals for days, and designing and using complex tools. Our ability to concentrate is likely to have co-evolved with and may even have preceded our ability to use tools. Hence, a human's limited mental flexibility in comparison with a monkey's may actually be a key element in the causal chain that led to tool use.
Research on executive control has rapidly grown over the last 15 years. There has been an increasing conjunction of psychology and neuroscience, not only in brain imaging, but also in single-neuron studies in monkeys (Stoet & Snyder Reference Stoet and Snyder2004; Reference Stoet and Snyder2009).
There is general agreement that the functions involved in executive control are used to coordinate and resolve conflicts between more basic processes. There are a number of different mechanisms that are part of the executive control family: (1) flexibility – the capacity to switch attention between different tasks; (2) goal setting – the capacity to set a goal; (3) planning, including initiation and sequencing – the capacity to determine a series of steps necessary to reach a goal; (4) inhibitory control – the capacity to suppress distracting or irrelevant information and thoughts; (5) monitoring – the capacity to monitor whether actions result in their intended outcome; (6) adjustment – the capacity to adjust a course of action even after it has been initiated; and (7) maintenance – short-term maintenance of information related to the above functions; for example, goal setting implies that the brain can maintain the goal representation for a certain time.
Vaesen lists only some of these executive functions, namely, inhibitory control, planning, and monitoring. Further, he lists autocueing; that is, the capacity to think about things other than those triggered by external stimuli. This use of autocueing was introduced by Donald (Reference Donald1993; cited by Vaesen), who states that animals “are creatures of conditioning, and cannot ‘think’ except in terms of reacting to the present or immediately past environment” (p. 146). Donald continues: “Humans alone have self-initiated access to memory, or what may be called ‘autocueing’” (p. 146). The difficulty with the concept is that autocueing has not received much attention from other researchers; further, research in the past decade has unequivocally shown that animals actually use internal representations to guide the processing of external stimuli (often referred to as endogenous control). Such internal representations can, for example, encode which potential responses are relevant in a certain task context; and such internal representations enable animals to respond in ways that are quite different from the nature of the external stimuli. A number of laboratories have successfully recorded single neurons encoding endogenously activated action and task representations (for a review, see Stoet & Snyder Reference Stoet and Snyder2009).
What is most important for this commentary, though, is that there is a difference in the abilities of humans and monkeys to switch between endogenously controlled task representations. Extensive research has demonstrated that monkeys are more flexible in rapidly switching between tasks than are humans, who even with long training can still not switch as rapidly as monkeys can (Caselli & Chelazzi Reference Caselli and Chelazzi2011; Stoet & Snyder Reference Stoet and Snyder2003; Reference Stoet and Snyder2007).
Therefore, by some measures, monkeys outperform humans in mental flexibility. We hypothesize that although humans are at a disadvantage in laboratory task-switching experiments, this limited flexibility might come as an advantage for cognitive development associated with the construction and use of complex tools. (With “complex tools” we mean constructed tools.) Limited mental flexibility supports concentration. We know that humans are good at concentration. The human skill to concentrate develops mostly before the age of 10, although it seems to continue improving during adolescence. Concentration is a necessary component of long-lasting and complex tasks, some of which may have played an important survival role in prehistory, including keeping a fire burning, cooking, hunting a herd of animals for days, and designing and using complex tools. Our ability to concentrate is likely to have co-evolved with and may even have preceded our ability to use tools. Hence, a human's limited mental flexibility in comparison with a monkey's may actually be a key element in the causal chain that led to tool use.