In movies it is shown that through polygraph test it can be found whether a person is lying or not. But we all know that it is not correct. What I am asking can the polygraph test be modified, more data collected so that it becomes more accurate ? Also is there any alternative to polygraph machine to find whether a person is lying ?
Polygraphs are fundamentally flawed because they measure physiological stress responses (heart rate, sweating, breathing) rather than deception itself, but newer fMRI studies looking at actual brain activity patterns during deception are way more promising since they can detect specific neural signatures when someone constructs a false narrative vs recalls a true memory.