Brief introduction to cognitive psychology applied to investigation and forensics.
by Paola Giannetakis
Behavior is the result of complexes mental processes that take place within our brain and it is clear that for the most we are not aware of such processes taking place, this implies a series of important considerations. The effects of these processes may produce a concrete impact on decisional processes that can influence dramatically the proceedings especially in high demand tasks and in specific professions.
For example, we tend to believe to have control over the way we perceive the reality, we tend to overestimate the capability of memorizations of information.
I will try to explain briefly a series of processes to highlight the limitation of human brain.
We store information in our memory, what is working memory? Working memory is a cognitive system that maintains and elaborates information; it processes simultaneously both the incoming information and the retrieval of information.
According to Baddeley, the working memory manipulates the information through three components: the phonological loop, the central executive and the visuospatial sketchpad.
The visuospatial sketchpad (VS) holds visual and spatial information, this means that for example, the VS retains the information of how a word is written and where is spatially located but also is the place in which are retained and manipulated visual images. According to Shepard and Mezler, their experiment of comparing objects demonstrates how the VS is involved in the process of visual imagery; they presented four objects and asked to subjects to indicate whether these objects were the same or different objects, the subjects recognized the objects as being the same but rotated, this answer occurred in few second and they used the mental rotation function that is a function located within the visuospatial sketchpad’s function.
The central executive (CE) is the place in which the most part of the work of the working memory takes place. It is a kind of controlling mechanism of different tasks that are performed simultaneously, for example cooking and speaking by phone at the same time, its functions are also evident where there is the need to filter relevant stimulus between others. The CE pulls the information from the long-term memory and coordinates both the PL and VSP; synthetically we can say that it coordinates this information and combines them.
The phonological loop (PL) holds verbal and auditory information; the phonological store and the articulatory rehearsal process compose the phonological loop. The phonological store maintains the linguistic information and the articulatory rehearsal control the process of articulatory recurrence based on inner speech, the articulatory rehearsal is also able to refresh the memory traces and send them back to the phonological store. To demonstrate the presence of PL’s components, Baddeley, in a series of experiments, has identified a number of phenomena present in various tests of memory, which may include the effect of word length, articulatory suppression effect, the effect of phonological similarity. These three effects support the concept of the Phonological Loop as a system specialized for languages:
Phonological Similarity effect; is the confusion that take places when there are similar sounding words, Conrad’s experiments proved that people confuse similar sounding letters as F and S when words are processed in the phonological store part of the PL.
Word length effect; occurs because is easier to remember lists with short words rather then lists with long words, a similar effect is detectable in the action of recalling numbers, Baddeley, in his experiment, demonstrated that short words are easier to be remembered respect to long words.
Articulatory suppression; occurs when there is the repletion of an irrelevant sound, because speaking interferes and therefore has a negative effect on recalling. Baddeley did an experiment by asking subjects to pronounce “the “ before the words to be remembered, and he found out that there was a negative performance on memory.
Memory performance improvement
There are five ways by which is possible to increase the effectiveness of studying:
Elaborate: a process by which is possible to translate the information to the long term memory, elaboration refers to rethinking and reflecting about what was read, such as thinking about by practical examples or using graphic tools to match information.
Generate and test, according to the generation effect, and the testing effect, producing situations in which is necessary to take active roles has a positive effect in encoding and in the long-term retrieval. For example the “talking out loud” technique helps retrieval, simulating a classroom teaching situation may help to retain and recall information. Retest the effective learning that was done, such as reading and thinking about what was read. Answering to questions regarding the reading is a powerful tool to retain information.
Organize: organize the reading, using notes and doing outlines in an organized manner. Doing schemas and synthesize information can help to reduce the load of the memory and increase the recall of details. (i.e. chunking)
Match learning and testing conditions: we know that memory should be better when learning and testing conditions are matching. In this sense, students should study in the same place where they will do the examinations. And to avoid the association of learning in just one place is recommended to study in more different places. One study of Smith demonstrated that students recall better when they studied in more locations rather then in one.
Make breaks: taking breaks and sleeping increase the memory performance, the memory performs better when the entire material is divided into more parts, short sessions of study increase memory and recall of information is more then after a long session of study. It is demonstrated that is easier to remember those things studied little before going to sleep. This suggested that is more efficient to make pauses while studying and avoid long sessions.
Lastly avoid the Illusion of Learning: Illusion of learning occurs when students think they are learning while they are not learning enough, this occurs when they reread the material, or when they highlight while reading. Studies have demonstrated that students highlighting and not highlighting did the same at examinations.
The persons are subject to suggestion, in the specific; we know that a person’s memory can be influenced by the facts that happen soon after the event occurred. The Misinformation effect, occurs when, misleading information given to the person after the event may alter the description the person will do of that event. Loftus made an experiment, utilizing the misleading postevent information (MPI), by giving false information on a specific event, and demonstrated that those subjects that received the MPI effectively did recall false memories. Loftus did an experiment in which subjects saw slides of a car and a series of signs and the car hitting the pedestrian. Some subjects were offered misleading information and these subjects effectively recalled details not present in the original slides but present in the MPI.
MPI can replace the original memory: according to the process of reconsolidation, is possible that reactivating the memory can lead to a replacement or to interference.
MPI can produce interference; the original memory is replaced by a new memory as consequence of the retroactive interference. An example is when words of two different languages in a short interval of time, there is the chance that on information substitutes the other.
MPI produces source monitoring effect: Lindsay did an experiment in which participants were viewing a series of slides of a subject stealing money, the story was narrated while the slides were presented. When the participants went back to recall their stories, some of them listened to a similar story filled with misleading information, a number of these participants recalled the misleading information as it was real. The experiment made by Hyman, focused on the study of false memories, false events details were created and told to the participants from their parents, a large percentage of them recalled these false events as being real. Knowing about some events although they were unreal, conditioned their memories.
Memory is fallible; eyewitness testimony is a field in which we should accurately consider all aspects of memory especially its fallibility. There are a number of errors related to eyewitness testimony, we know that generally is difficult to perceive one’ person’s face as the result of inaccurate memory A large number of experiments have demonstrated that is not only difficult to identify someone but there are also some specific additional difficulties that may impair the correct identification and the review of criminal conviction of innocents show that a large number of false identification have been made in the past and are still occurring.
These are common errors that occur:
Errors associated with attention: the emotional state of a person can influence his/her attention during the crime. One of the most known is the weapon effect, that occurs when the attention is pointed toward the weapon rather then toward the offender, in one study made by Stanny and Johnson, it was evident that witnesses were able to recall guns rather then perpetrator’s details when a gun was firing during the crime.
Errors due to familiarity: some times bystanders of a crime can be identified as perpetrators, a familiarity for a face can produce a misleading identification, this is also defined as the source monitoring effect. Ross did an experiment in which two groups of participant saw or a female or a male teacher reading to students, then all the subjects saw a video where the female teacher was robbed and they were asked to pick a suspect from a line up, although the perpetrator was not in the line up, those participants who saw the video with the male teacher picked up the male teacher as the suspect. This also happen when the perpetrator was present in the line up, even in a smaller percentage the male teacher was identified as the perpetrator.
Errors due to suggestions: suggestibility is a delicate factor in the testimony accuracy; it is in facts known that questioning a testimony may influence his retrieval of information. Suggesting information can cause suggestions, give a feedback to identification can suggest the witness, and the post identification feedback effect is common and refers to giving positive feedbacks to witness after they made identification.
Post event questioning effects: the post event questioning can increase the confidence of the eyewitness. In facts, according to Chan, the questioning after a crime, although necessary, may produce suggestion, misinformation and have effects on the accuracy of the memory. This should depend on the reactivation of the memory that could cancel or modify the previous memory, this memory can receive positive reinforcements but also negative effects.
In order to correct the problem of the inaccurate eyewitness testimonies, cognitive psychologists have made a number of suggestions for law-enforcement.
As result of a number of studies that demonstrated that witnesses picked up suspects even when not present in, researchers suggested that the belief that the perpetrator is in the line up increases the chance that an innocent may be picked up casually, therefore, at the moment of inviting the witness to pick a suspect from the lineup, the witness must be informed that is possible that the suspect may not be present in that line up, this decreases the chance of casual pick up of an individual. A study of Lindsay and Well demonstrated that in simultaneous line up was much more likely that innocent perpetrators were picked up, compared to the sequential line up. Therefore is suggested to prepare a sequential line up. To increase valid identification is necessary to fill the line up with similar individuals to the perpetrators, this is suggested as researches demonstrated that there is not a decrease in accuracy of picking up the right person, while there is a decrease in picking up the wrong person. The official that is responsible for organizing the line should not be aware of the identity of the perpetrator in order avoid any influence or post effect on the witnesses. Apply the cognitive interview, based on principles of memory retrieval, in this specific technique the witness is allowed to retrieve freely and is also questioned and helped to retrieve. For example going back to the scene and relive similar emotional states, has proved to be effective in recalling more detailed information with an higher level of accuracy. This technique is suggested as it has proved to help recover a larger quantity of information compared to the classic style of interview.