Introduction

In many situations, humans interact with systems. During these interactions, the operator must perceive information and transform information into different forms. Sometimes these transformations lead to errors. Understanding these transformations and thus understanding information processing, is important for predicting and modeling human-system interactions.

Three approaches to information processing

There are three distinct approaches to information processing: the classic stage-based approach; the ecological approach and cognitive engineering or ergonomics.

The classic stage-based approach

In this approach, the digital computer is used as a metaphor to human behavior. Information is seen as passing through a number of discrete stages. So, there is a distinction between a perceptual stage and a stage of execution and action, which is based on the morphological distinctions between perceptual and motor cortex. Proof for this approach comes from the fact that different tasks and environmental factors have a different influence on different stages. Within this approach, processing does not always start at stage 1: sometimes processing starts when someone gives a response.

The ecological approach

This approach places more emphasis on the integrated flow of information through the human rather than making a distinction between stages. It also emphasizes the interaction between humans and the environment. This approach is most relevant to describing human behavior in interaction with the natural environment, so it is used most when designing controls and displays that mimic characteristics of the natural environment. 

The cognitive engineering approach

This approach is a hybrid of the stage-based and ecological approach. On the one hand, it is based on a very careful understanding of the environment and tasks constraints within which an operator works. On the other hand, this approach places great emphasis on modeling and understanding the knowledge structures that expert operators have of the domain.

Selecting information

Broadbent's book lead to that human information processing is now seen as part of a filtering process. This filtering happens through mechanisms of human attention. Attention has three different modes: selective attention, focused attention and divided attention.

Selective attention

Selective attention refers to how attention is focused on a particular object in the environment for a certain period of time. It is influenced by four factors: salience, effort, expectancy and value. So, selective attention dictates where attention is given to.

Focused attention

Focused attention is used to maintain processing of the desired sources and avoid the distracting influence of potentially competing stimuli.

Divided attention

This is the ability to process more than on attribute or element of the environment at a given time.

Visual search

When people are looking for something in a cluttered environment (for instance when they are looking for a sign by the roadway), they use selective and focused attention as well as discrimination. Visual search models are used to predict the time that is required to find a target. These predictions can be very important for safety and productivity.

The most simple model of visual search is the 'serial self-terminating model'. In this model, it states that search space is filled with items of which most are nontargets (so, distractors). The mean time to find a target is modeled to be RT = NT/2. N is the number of items in the space and T is the time that is needed to examine each item and determine that it is not a target before moving on to the next. This model is influenced by three factors: bottom-up parallel processing, top-down processing and target familiarity. Bottom-up processing is about that for example all targets are 'highlighted',  so that searching for these targets is easier. Top-down processing is about how the operator's knowledge or expectations influence the information processing. For example, location expectancy will create search strategies that scan the most likely locations first. Another influence is the expectancy of whether a target will be present or not. This is called the 'target prevalence rate'. A third factor that influences visual search is target familiarity: this means that repeated exposures to the same consistent target can speed the search for that target and reduce the likelihood that the target may be missed.

Perception and data interpretation

The Signal Detection Theory 

When designing displays, it is very important that critical targets must be detectable in the environment. However, assuring this detectability can be difficult. It is often the case that changes in a scene are missed. However, sometimes it is also the case that people respond as if they saw something, while there was no target. This is called a false alarm. The SDT provides a framework for describing the processes that can lead to both types of errors. 

Expectancy, context and identification

Prior knowledge can also influence the ability to identify enormous numbers of objects. For example, it seems that objects and attributes are recognized more quickly when they are embedded in consistent contexts, rather than when they are presented alone or in different, inconsistent contexts. For example, words are more easily identified when they are embedded in sentences, compared to when words are presented alone.

Judgments of Two-Dimensional Position and Extent

Spatial judgements that are required to read even everyday graphs, are prone to systematic distortions. A few examples of these distortions are that people overestimate the values that are represented in bar graphs; perceptual flattening of line graphs with respect to the y-axis, which results in larger underestimations of the represented data as the reader follows the line from its origin; cyclic patterns of bias in estimations of part- whole relationships that are dependent on the number of available reference points on the graphs; distance distortions between cursor locations and target/icon locations induced by the shape of the cursor.

Judgments of Distance and Size in Three-Dimensional Space

There are five kinds of cues that help during perception:

When making judgements in spaces, human perception depends on different cues that provide information about the relative or absolute distance from the viewer. Many of these cues are called pictorial cues, because they cues can be used to generate the impression of depth in 2D pictures.

Next to pictorial cues, there are five cues that have to do with characteristics of the viewer: Motion parallax: this refers to that objects moving at a constant speed across the frame will appear to move an greater amount if they are closer to an observer than they would if they were at a greater distance. Binocular disparity: this refers to the difference in viewpoint of the two eyes. Stereopsis: this is the use of binocular disparity to perceive depth (think about 3D displays). Accommodation and binocular convergence: these cues result from the natural adjustment of the eyes that is needed to focus on specific objects at different distances. 

Comprehension and cognition

Working Memory limitations

There is a limited number of ideas, sounds and images that we can maintain and use in our mind. For example, the items in the working memory are lost when they are not repeated. This is called the memory span. Baddeley developed a four-part model of the working memory, which includes two temporary storage systems: the phonological loop and visuospatial sketchpad. These subsystems are used by a central executive, which manipulates the information in these stores and creates multimodal representations of coherent objects. These representations are then held in an episodic buffer. 

Knowledge about the working memory has some implications for design:

Whenever possible, try to avoid codes that are too long for the memory capacity; when it is necessary to use codes that exceed this limits, use methods such as parsing material into lower units (chunking); because information from working memory is lost after a few seconds, systems should be designed in such a way that they can use the information (think about voice menu systems: in these cases, the users should be able to make a choice immediately); the need to scan should be minimized if a person must hold spatial information in the sketchpad; avoid the need to transfer information from one subsystem into the other before further transformations or integrations can be made; if working memory subsystems are updated too rapidly, old information may interfere with new; interference in working memory is most likely when-to-be remember information is similar in either meaning or sound; the capacity of working memory varies between people.

Planning and problem solving

In contrast with cognitive activities that are heavily driven by information the environment, the information-processing tasks of planning and problem solving are more dependent on the interplay between information that is available in the long-term memory and information-processing transformations carried out in working memory. 

Planning

Planning can depend on two types of cognitive operations: planners may depends on scripts that they have stored in their long-term memory which are based on past experience; planning may involve guess work and some level of mental stimulation of future activities.

Problem solving, diagnosis and troubleshooting

These three activities are related to each other: they all have in common that there is a goal to be obtained by the human operator, that information to achieve that goal is currently missing and that some physical action or mental operation must be taken to seek these entities. 

Metacognition 

The term metacognition refers to a person's knowledge about his or her own cognitive processes and the use of this information to regulate performance. Education is the most active area of research on metacognition: researchers have looked at how students' beliefs about their own information-processing capabilities influence learning strategies and ultimate academic success.

Most researchers make a distinction between metacognitive knowledge and metacognitive control processes. 

Action selection

In the stage of action selection and execution, it is important to look at the speed with which information is processed from perception to action. This speed is described in 'bandwidth': the amount of information processed per unit time. Units of information is described in bits.

Findings related to action selection

Response times for either rule-or skill based behavior is longer when there are more possible choices. 

When people do not expect certain stimuli, they may respond more slowly. 

Practice leads to that frequent events will be responded to more rapidly, but also expertise (and thus practice) in something may lead to less speedy processing for rare events, compared to novice events.

Spatial compatibility

The spatial compatibility of a display influences speed and accuracy of the control respones. One relates to the location of the control relative to the display and the other relates to how the display reflects control movement.

Modality

Machine systems are progressively more becoming executed by voice. There are three characteristics of voice control in the context of information processing: voic options allow more possible responses to be given in a shorter period of time compared to hand-control; voice options represent more compatible ways of transmitting symbolic or verbal information; voice options are valuable in environments when the eyes or hands are otherwise engaged.

Multiple-task performance

In multiple-task environments, there is a distinction between three different modes of multiple-task behavior: perfect parallel processing, degraded concurrent processing and strict serial processing. Perfect parallel processing means that two (or more) tasks are performed concurrently as well as either is performed alone, degraded concurrent processing means that both tasks are performed concurrently but one or both suffers, and strict parallel processing means that only one task is performed at a time.

When two tasks are similar, this may lead to confusion. Easier tasks are more likely to be performed perfectly compared to more difficult tasks. Also, when the two tasks are different, then this may lead to better performance.

By interviewing many different individuals information can be gathered for intelligence purposes. Not all these individuals want to cooperate though, think of suspects and prisoners. But information can also be gathered from other individuals. While getting information, investigators need to be aware of memory distortion and interrogation influences. Also they need to be able to detect deception.

Interviews and interrogations

At the end of the nineties a distinction was made between interviews and interrogations. Interviews are usually nonaccusatory. The investigator needs to evaluate the accuracy and completeness of the stories. Interrogations are more coercive and can use strategies such as confrontation and minimization. Here, the investigator needs to be aware not to lead to false confessions or erroneous inferences about lying and truth telling.

Three important areas of research that can help maximize the accurate information and minimize inaccurate information are memory distortion, false confessions, and detecting deception.

Memory distortion

Many times after people have already experienced an event they are exposed to new information afterwards. This information can supplement or alter their memory, leading to errors in accurately trying to report what happened. Typical experiments have shown that misinformation can cause very large deficits in memory, such as seeing non-existing items and recalling incorrect details.

Some important questions, such as when people are especially prone to being influenced by misinformation, and if we are all susceptible to misinformation, can be answered much better based upon recent research.

Factors that influence the power of misinformation

• People are more vulnerable to the influence of misinformation as time passes. The more time there is between the event and the misinformation, the higher the chance that the misinformation will be incorporated into the memory.

• Also important is the method by which the misinformation is delivered. People are more likely to pick up the information if they get it from another person.

• Young children and elderly are more susceptible to misinformation.

• People with dissociative experiences are more susceptible to misinformation, because they distrust their own memories.

The cognitive interview

The cognitive interview was developed in the mid-eighties. It incorporates different techniques derived from basic principles of cognitive and social psychology, and it is supposed to help getting better information about past experiences. This type of interview can bring out a lot more information than more conventional strategies.

To keep in mind during an interview or interrogation

People are constantly exposed to new information after the event has passed. The researcher should look for instances in which this exposure may have influenced the individual’s memory. Especially when the individual doesn’t have a good memory of the event, it is important to remember that that person is more susceptible to misinformation.

If a person makes a claim it is important to explore possible sources of suggestion. Think of the media, films, interrogations, and even self-generated misinformation.

Another important point to keep in mind is that confidence is irrelevant. Even if a person is very detailed and absolutely sure of his story, this does not make it true.

Finally, it is important to be aware of a useful manual for training police on how to gather information.

False confessions

One paradigm to investigate false confessions is the cheating paradigm. Here, the participants are accused of giving help to another person who is solving a problem, after a clear instruction that the two must not work together. Many participants eventually confess falsely. Another paradigm to study false confessions used tampered video evidence to make people admit to an act they didn’t commit.

There are many different reasons as to why someone would confess to something they didn’t do. Some people confess for attention, or to protect someone. Also, bluffing can increase the likelihood of a false confession. In a coerced-compliant false confession, a person confesses even though they know that they didn’t do it, but they think it will lead to less negative outcomes than not confessing. In a coerced-internalized false confession a person confesses after false evidence is supplied (like saying someone failed the polygraph).

Vulnerable groups

Especially children, juveniles, and the mentally challenged are vulnerable to making false confessions.

Taping

One important paper suggested that all interrogations should be videotaped. This way, potential suggestion or coercion can be documented.

Misconceptions

There are several misconceptions when it comes to false confessions. Such as that false confessions do not happen that often, that only vulnerable people falsely confess, that the study of police interrogation is still at its beginning, and that suspects are sufficiently protected by their rights.

How to verify a confession

Confessions should always be verified. There are several things that can be done to contribute to this verification. First of all, the conditions under which the report was made have to be reported (e.g. was there coercion?). Secondly, the details in the confession need to be compared to what is known about the event. The confession is more valuable if the person has details that only he could have known and that have not been reported in another place. Finally, it needs to be investigated if there were conditions that could have made the person falsely confess (e.g. fatigue, isolation, false evidence).

Detecting deception

Results from experimental studies have shown that many people can tell an untrue story without showing any obvious clues that they are lying, such as gaze aversion or fidgeting. This popular belief can have very negative consequences for cultural and ethnic groups that engage more in gaze aversion in their everyday lives.

Clues

Several strategies can be used to detect deception:

• By using a particular interviewing approach, such as the information-gathering style of interviewing, witnesses are asked open-ended questions. The focus is on gathering information, and not on accusing the witness. This is a very good approach, because it gives the investigator a lot of information which can be compared to the other data.

• Another good approach is to ask unexpected questions, such as “Who finished their dinner first?”. Liars will more often come up with an answer, because they fear that if they do not know the answer, they look guilty.

• Withholding event facts from a suspect can be used to trap the suspect in inconsistencies (e.g. not telling the suspect you found his fingerprints, until after he admitted to never have been at the crime scene).

• Increasing the intensity of the interview can make lying more difficult, because lying takes a lot of cognitive effort.

Torture

It has become public that often coercive interrogation techniques are used on individuals that are being suspected of terrorism. These are sometimes called enhanced interrogation techniques, and include the repeated induction of shock, stress, anxiety, and torture. However, there is a lack of evidence that these methods actually work and reveal information that otherwise would not have been revealed. Also, they may just do the opposite of what they are intended to do.