During the early part of the 20th century, psychology was dominated by the school of thought known as behaviorism, which emphasized that psychological processes could only be examined at the level of observable behaviors. This approach assumed that all behaviors could be understood in terms of simple stimulus–response (S–R) relationships and that references to mental processes were neither useful nor valid. To this extent, the behaviorists viewed all mental processes as a black box whose internal workings are not directly observable, and are inconsequential to understanding how behaviors are governed by environmental stimuli.
Driven in part by the inability to explain more complex behaviors, the field of psychology underwent a major paradigm shift in the 1950s, which later became known as the cognitive revolution. The internal processes of the black box once ignored by the behaviorists now became the primary interest in the emerging field of cognitive psychology. Consequently, understanding what occurs inside the “box” (the human mind) was viewed as essential for explaining complex human behaviors. Coinciding with this new direction, researchers began to observe similarities between human cognition and the early computers of the time. Both humans and computers could be viewed as general symbol manipulators, which can “take in” information, perform mental operations on the data, and finally output the information via behaviors and actions (e.g., images on a monitor). As a result, references to computers became a central metaphor for exploring human cognition, as it could provide direction and useful analogies for how humans process information mentally.
Humans as Information Processors
Based on this perspective, humans are fundamentally considered to be processors of information, with cognition understood as a sequence of computational processes. That is, information in the environment, such as words on a page, are taken in; stored in various memory systems; and processed via mental operations that encode, transform, and give meaning to the information through comparison with previously stored information (i.e., memory). Central to this approach is the suggestion that all information is encoded as internal symbolic representations of the external reality. These mental representations are constructed for all knowledge, information, ideas, and memories and are the subject of mental operations.
Systematic attempts have been made to study the capabilities and limitations of human information processing. Just as computers have certain limitations regarding speed of processing and how much information can be processed at any one time, similar limitations have been investigated with regards to human information processing. Given that mental operations occur within a black box, and thus are not directly observable, researchers have adapted and created a number of experimental methods from which overt behaviors are used to infer knowledge about the underlying cognitive processes. Chief among these approaches has been the use of chronometric methods, which emphasize the use of reaction times (RTs) to infer the temporal properties of mental operations. The Dutch physiologist F. C. Donders was the first to use such RT tests to determine the time needed for certain mental operations. Specifically, Donders argued that the duration of mental operations could be determined by subtracting the RTs of various types of tests(e.g., simple RT, choice RT, go or no go RT) that have different cognitive processing requirements.
Three Stages of Information Processing
Every conscious action by humans, including those of athletes during action execution, is believed to be a consequence of response selection from long-term memory (LTM). LTM consists of a hierarchical structure neural network, which stores information after interacting with the environment. By definition, response selection indicates adaptive behavior based upon the capacity to solve problems. This “behavioral effectiveness” is directed by cognitive processes and mental operation. The effectiveness of these processes consists of the richness and variety of perceptions processed at a given time—that is, the system capacity to encode (store and represent) and access (retrieve) information relevant to the task being performed. From an information-processing perspective, motor behaviors consist of encoding relevant environmental cues through the utilization of attentional strategies, processing the information through an ongoing interaction between working memory and LTM, making an action-related decision, and executing the action while leaving room for refinements and modifications. Under pressure, changes in each of these components are seen. These changes are sequential in nature (i.e., they begin with the perceptual components, continue with the cognitive components, and end with the motor system).
Based on Donder’s subtractive method, a number of different processing stages are conceived to exist between the presentation of a stimulus and the initiation of a response (see Schmidt & Lee,2011). Specifically, at least three information-processing activities must occur during RT. First, the presentation of a stimulus must be detected and identified—the stimulus-identification stage. Next, the proper response to the stimulus must be chosen—the response-selection stage. Finally, the selected response must be prepared by the motor system and initiated—the response-programming stage. In the past 50 years, a number of studies have been conducted to determine the processing limitations of each of these stages as well as the factors that influence processing performance.
The stimulus-identification stage consists of the mental operations concerning the sensing and encoding of environmental information. As a stimulus contacts the body’s sensory systems, it is taken in and encoded such that the neurological impulses activate the appropriate mental representation and knowledge associated with the information. A number of stimuli-related characteristics have been found to impact the speed at which the system is able to detect and encode relevant environmental stimuli. The clarity of the stimulus (i.e., how distinct and clear the stimulus appears) has been found to significantly impact the speed at which processing occurs during this stage. Specifically, RTs have been found to be slower when the stimulus is less defined compared to when the stimulus is presented with increased clarity (e.g., blurry vs. sharp picture). Similarly, the intensity at which the stimulus is presented impacts the speed of identification, with more intense stimuli resulting in faster RTs. Likewise, the modality of stimulus presentation has been found to influence the speed at which a stimulus is detected, as tactile and auditory stimuli have been found to result in faster RTs compared to visually presented stimuli. Once the stimulus is detected, it must also be correctly identified. In real life, the stimuli are often complex, and decisions must be made regarding a complex set of features. The ability to recognize patterns or features within the information set is important. Research indicates that task familiarity significantly influences the ability to quickly identify relevant features and patterns within the environment.
Following the detection and identification of the stimulus, a decision must be made regarding how to respond (i.e., what action to take). This stage is referred to as the response-selection stage. As with the previous stage, research has identified a number of different factors that influence the speed and selection of responses during this stage of processing. Not surprisingly, the time it takes for a person to decide upon a response has been shown to be influenced by the number of possible response choices they have. As the number of S–R alternatives increases, associated increases in choice RTs are observed. The mathematical relationship between RT and the number of response alternatives is given by Hick’s law, which states that choice RT is linearly related to the Log2ofthe number (N) of S–R alternatives. Additionally,the compatibility, or the degree of fit, between the stimulus and response has been shown to influence RTs. For example, when the presentation of a stimulus and the required motor response are spatially congruent (e.g., left stimulus and left response), RTs are quicker compared to when the stimulus and response are spatially incongruent (e.g., left stimulus and right response).
The final processing stage concerns the programming and initiation of the selected response, known as the response-programming stage. During this stage, the selected response must be compiled and transformed into overt muscular activity. F. M. Henry and D. E. Rogers demonstrated that the complexity of the movement required during the response is a critical factor in the latency of RTs during this stage. Specifically, responses that require more complex movements show larger latencies before the initiation of the response. This increased latency in responding is suggested to result from the additional time needed to prepare and program the upcoming motor action. A number of key factors relating to movement complexity have been identified which significantly influence this stage of processing. First, as the number of movement parts increases, corresponding increases in RT latencies are observed. For instance, responding to a stimulus with a simple finger movement is initiated faster compared to a response in which the whole arm must be utilized. Additionally, the accuracy requirements of the movement affect RT. As the precision demands of the movement response increase, increases in RT and movement time (MT) latency are likewise observed. Finally, responses with longer movement durations display increased RT and MT to initiate the motor response.
Conclusion
With the emergence of cognitive psychology, the view that humans are processors of information became the dominant framework from which to consider mental operations. In this regard, mental operations are viewed to consist of a series of information processing steps that begin with the taking in of information from the environment, processing that information, and then outputting the information via movement responses. Based on this framework, significant advancements have been made in the areas of intelligence, attention, decision making (DM), linguistics, and memory. Although more recent theoretical perspectives, such as ecological psychology and dynamical systems, provide alternative accounts of cognitive functions, the theoretical roots of information processing remain a strong influence in modern psychology.
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