What is the study of human cognition emotion and behavior in relation to others?

1.2 Cerebral Lateralization as a Foundation for Higher Cognitive Function

Placing human cognition within an evolutionary framework is important when considering the emergence of cognitive abilities because our modern sophisticated human abilities will likely be founded upon evolutionarily early vertebrate brain organization and function. Through natural selection, evolutionary innovations build on existing neural architecture. New functional components do not spontaneously emerge. Rather, the existing architecture is extended and/or modified (Finlay, 2007). As a result, sometimes we find that a system that we are using for one cognitive function hardly resembles the foundation components for which it was originally designed (e.g., Finlay, 2007). For example, a left hemisphere dominance for producing routine, goal-oriented sequences of motor actions may have been extended to support the syntactic structure underpinning language function (e.g., Greenfield, 1991). Conversely, a right hemisphere dominance originally designed for avoiding environmental threats may have been extended to support the sophisticated emotion processing present in modern human social cognition (e.g., Forrester et al., in press) (for a review, see Vallortigara et al., 2011).

The presence of lateralized motor function in humans and other animals provides a unique strategy to investigate the evolution and development of cognition within and between species under a common framework of a shared evolutionary history. Although ontogeny (the development of the individual) does not recapitulate phylogeny (the evolution of the species) in the literal sense (Ehrlich et al., 1974), during human development, higher cognitive abilities scaffold, build upon, and bootstrap early perceptual and motor capabilities, which are governed by cerebral lateralization of function (e.g., D’Souza and Karmiloff-Smith, 2011). In humans, we consider primary sensory and motor functions to represent the core building blocks of mental processing (Hommel et al., 2001) (Fig. 1).

This chapter focuses on the evolutionary and developmental links between social motor biases and higher cognitive process in humans and other species (e.g., Bradshaw and Rogers, 1993).

Working memory

The notion that human cognition is very dependent on a WM system for the maintenance and manipulation of information has a long history in general models of cognition (e.g. Anderson, 1983; Baddeley, 1986; Norman and Shallice, 1986). Although there is no single generally accepted model of WM, there is agreement that all models of WM must be able to address some key issues. Perhaps the most central is the general bottleneck in capacity for maintaining information in the focus of attention, while at the same time there are also modality specific (e.g. verbal and visual-spatial) processing limitations (Miyake and Shah, 1999). The concept of WM is also closely tied to the executive control functions of cognition because the information that is actively maintained in WM largely determines the next set of cognitive operations to be executed (e.g. the role of WM in the ACT-R model; Anderson, 2004).

Because the concept of WM plays a central role in explaining human performance, a number of studies have investigated SD effects on WM using a variety of tasks including memory-scanning tasks, short-term recall tasks and the N-back task (e.g. Mu et al., 2005; Smith et al., 2002). Global performance on all WM tasks can be influenced by the process of getting information into WM and decision and response processes in addition to maintenance and manipulation of information in WM. Interpreting performance decrements on these tasks as reflecting problems with WM requires careful consideration of the task components and the use of indices of performance that isolate the processes of interest.

The task impurity problem in WM tasks can easily be demonstrated with a memory-scanning task based on the classic studies by Sternberg (1966, 1969). Variants of this task have been used in several studies of SD effects on WM (e.g. Mu et al., 2005; Nilsson et al., 2005; Tucker et al., 2010). On each trial of the Sternberg task the subject is given a memory set with digits or letters as stimuli, with varying memory set sizes, typically from two to six items. The memory set is removed from view and a probe stimulus is presented. The task is to decide as quickly as possible whether the probe item came from the memory set. RTs on the task are a linear increasing function of the size of the memory set. The slope of the RT function over set size is a relatively pure measure of the efficiency of scanning WM. In contrast, overall mean RT on Sternberg trials also contain the time to encode the probe, make a decision and execute the response. Nevertheless, some studies cited as showing that SD impairs WM have either failed to manipulate set size or used a control condition in which both stimulus encoding and the memory load varied between conditions (e.g. Mu et al., 2005).

Recent data from Tucker et al. (2010) confirm the risk in using overall performance on the memory-scanning task as an index of WM functions. Mean RTs of SD subjects were much longer than baseline, and since the Sternberg task is considered a classic WM task, it would be tempting to conclude that WM is substantially impaired by SD. However, Tucker et al. decomposed the function relating RT to set size into memory scanning (slope) and non-WM (intercept) components. The results were striking. There was no effect of SD on the memory-scanning rate. The effect on mean RT in the Sternberg task was entirely in the non-WM aspects of the task (see Fig. 1).

Because WM tasks involve cognitive processes other than WM, SD effects on WM tasks can be due to non-WM sources. So, while a battery of WM tests may all show SD effects, which may produce an estimate of a substantial effect of SD on WM in a meta-analysis, the effect is not necessarily a WM effect. Only by using task analysis and extraction of the appropriate index to isolate WM processes can we draw conclusions about SD effects on WM.

What is the study of human behavior and emotions?

What is the relation between emotion and cognition?

What is cognition and emotion in psychology?

Is the study of human behaviors and cognitive processes?