PART ONE
Deception is a conscious and intentional act, usually meant to foster a certain conviction or belief in another person, this belief is however, considered false by the person deceiving. Depending on which type of liar one is, there are certain cues that fall under verbal and none-verbal which can be of help in identifying a lie.
One can be an occasional liar, frequent liar, habitual liar, or professional liar. Depending on the type of liar, one will elicit different behavioral cues which might be difficult to catch but not impossible. The prudent thing to do is establish a baseline with the individual for how they react, wile telling the truth, there is no limit to how long it takes to establish this, as long as it yields results by enabling the interrogator to see a discrepancy when a lie is told.
Though there are several cues that could indicate a lie, the following three are significant responses. Pupil dilation, slow/fast speech and silence. Certain cues are because of emotional responses in the limbic systems, however, others are attributed to cognitive responses, and researchers have repeatedly established that it takes more mental effort to tell a lie than the truth (DePaulo et al., 2003).
The cue that would hold the greatest validity is the pupil dilation, since it is measured using a tool that uses eye detector technology to show the changes in a person’s pupil while they are lying. The tool is based on the person’s cognition, and once a baseline has been established with true yes or no questions, and the machine picks up the movements in the pupil, it becomes easy to use this “eye detector” to catch a lie. Slow/fast speech and silence don’t hold as much water in this case, since they can be influenced by other factors, without necessarily meaning one is lying.
PART 2
With respect to juveniles, as the special population, the indicators that have been aforementioned are all valid, starting with the pupil dilation, this is a neurological response that one has no control over; this is because it is because this area is controlled by the autonomic part of the nervous system. Once a base line is established and the pupil response resonate with a false answer or a truthful answer, it naturally becomes easier for the interrogator asking the juvenile questions to conclude he/she is lying or telling the truth . The aspect of speech however is a little bit different. Everyone has their speed of speech, however, this can be affected by various factors including mental stress, fatigue and even anxiety or fear. If a juvenile being interrogated initially starts out speaking fast and the base line establishes a point of truth, if at some point they change the pace of speech due to a lengthy interrogation, fatigue, having talked too much or even fear it would not be wise to conclude that they were now lying. Similarly, the converse applies. The same thing applies to silence, though this cue probably holds a higher validity than slow or rapid speech. In several instances when people don’t want to say something that will implicate them during an interrogation they remain silent, and it also happens once one has been caught in a lie. Deception is clearly evident in how people behave during the lie, however it is essential to be able to cross out and eliminate all other behavioral aspects that might lead one to a wrong conclusion or judgment (Semple & McComb, 1996).
References
DePaulo, B. M., Lindsay, J. J., Malone, B. E., Muhlenbruck, L., Charlton, K., & Cooper, H. (2003). Cues to deception. Psychological Bulletin, 129(1), 74–118. http://doi.org/10.1037//0033-2909.129.1.74
Semple, S., & McComb, K. (1996). Behavioural deception. Trends in Ecology & Evolution (Personal Edition), 11(10), 434–437. http://doi.org/10.1016/0169-5347(96)20068-0
