Types of Evidence

¶ … Evidence The Three Types of Evidence Within the Federal Rules of Evidence, there are two specific types -- direct evidence and circumstantial evidence (Unit 2, n.d.). In both of these two groups, there are three types of evidence which will be discussed here. These are demonstrative, testimonial, and physical. It is important to explain what each one of these is, how they are different from one another, and also to give an example of each kind of evidence for clarity of understanding.

All evidence, however, no matter what category it falls into, must be both material and relevant in order to comply with rules of admissibility. Demonstrative evidence is generally used as a visual aid (Unit 2, n.d.). In other words, it can include maps, graphs, charts, and many other types of aids that may be used in the court room in an attempt to prove either innocence or guilt. Because of this, demonstrative evidence can be very important.

An example of demonstrative evidence would be the x-ray showing the instruments left inside the patient in a malpractice suit against a doctor. This type of evidence is often very strong and can sometimes also be shocking to a judge and a jury when it involves visual aids that are obscene, graphic, or painful to see.

It often sways a jury to some extent because it can be used to show the suffering of an individual, although it must be relevant to the specific case at hand before a judge will allow it. It must not be shown simply for shock value, but to make a relevant and significant point about the case. Testimonial evidence relies on the senses of the witness -- what did that witness see, hear, etc. (Unit 2, n.d.).

For example, a witness that saw a robbery take place and heard the gunman threaten the victim and demand money could come into the courtroom and give testimonial evidence. This is why witnesses are often called upon to give testimony or to testify. Regardless of the term used, however, what those witnesses are doing is providing testimonial evidence that may or may not be helpful in the conviction of someone who has committed a crime.

How well the witness remembers the event, whether the witness is credible, and the testimony of other potential witnesses can all affect testimonial evidence. If there are many other witnesses that did not see the same thing, if the recollection of the witness is unclear or if the witness' story keeps changing, or if there is a question of witness credibility (i.e.

The witness was drunk at the time, for example), then the testimonial evidence that is given by the witness may be seen as not being very important to the case, or may be largely discounted by the judge or the jury due to the circumstances surrounding it. Physical evidence is the most significant of the three types of evidence, and is considered to be indisputable (Unit 2, n.d.). This type of evidence is also largely considered to have neutrality.

It is not designed to sway the judge or jury one way or the other -- it is simply a fact. Physical evidence, for example, would be the gun that the individual used to rob the victim. If that gun is found, and especially if the defendant's fingerprints are on it or if the gun is registered to that individual, then the gun can be shown to the judge and the jury as physical evidence of the weapon used to commit the crime.

Physical evidence is often said to provide a high level of certainty, and where there is certainty, there is generally seen to be proof (Unit 2, n.d.). This alleged showing of proof is the main reason that physical evidence is so important and why it is so highly sought after by the prosecution. Some types of evidence are often controversial, such as DNA testing or "ballistic fingerprints." Another significant area of controversial evidence is "brain mapping" where an electroencephalogram takes a picture of the brain.

These are being used more frequently today in cases of head injury where cat scans, MRIs, and EEG studies are normal, but where the individual still has problems stemming from the injury (Alverson & Smagac, 1998). In this controversial test, the electrical activity in the brain is measured and then a computer is used to compare the findings with a group of 'normal' brains, in order to determine whether there is actually an abnormality (Alverson & Smagac, 1998).

Once this has been done, the computer produces a colored 'map' of the brain that allows the trained individual to see whether there is a normal reading, or whether the test indicates that there is a problem that is not being detected on other tests (American Academy of Neurology, 1989).

This type of evidence would be considered to be demonstrative evidence, since it is a 'demonstration' of what the computer was able to do, and would be presented in the form of a color map or picture of the brain that was studied. In many states, there have been cases regarding brain mapping, and so far all of those states have ruled that this type of evidence is inadmissible (Alverson & Smagac, 1998). I feel that the courts are right in not admitting this type of evidence, since it is.