This document discusses how psychologists detect lies through microexpressions. It defines microexpressions as involuntary contractions and relaxations of facial muscles that last 1/25 to 1/15 seconds. Psychologists use the Facial Action Coding System (FACS) to study microexpressions, which codes facial movements based on the underlying facial muscles. Certain facial action units have been linked to specific emotions like happiness, sadness, and fear. Studying microexpressions through high-speed video cameras allows psychologists to distinguish brief emotions that may indicate deception.

1. LIES and Micro
expression

2. • According to a research done by psychologists a
person speaks an average of 2 lies in a day.
• Humans are not biologically made to lie.
• Are lies harmful?
Did you know?

3. • Lets consider what happens when people lie.
NOW…..

4. • Motivational impairment effect

5. Look at this video

6. • Eyes and the hands are not coordinated in the same
direction
• They blink their eyes 2 seconds
• BUT why?
Common facts in the two
cases?

7. •
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Increased pupil size
More nervous
Less eye contact
Press their lips together
Less relaxed posture
More blinking of eyes
Quick and easy method to
detect a lie

8. • Micro expressions
How do psychologists detect
lies?

9. • What is Micro expression?
• Involuntary contraction and relaxation of the
facial muscles.
Examples: 1. Smirks
2. Frowning
3. Smiles
4. Movement of eyelids and eyebrows
Micro expressions

10. • Micro expressions are better understood
using the FACS

11. • What is FACS?
• It stands for Facial Action Coding System

12. A Part of the List of Action Units and Action
Descriptors (with underlying facial muscles)
AU Number
FACS Name
Muscular Basis
0
Face
1
Inner Brow Raiser
Frontalis(pars medialis)
2
Outer Brow Raiser
Frontalis(pars lateralis)
4
Brow Lowerer
depressor glabellae, depressor supercilli,
5
Upper Lid Raiser
palpebrae superioris ,superior tarsal muscle
6
Cheek Raiser
orbicularis oculi(pars orbitalis)
7
Lid Tightener
orbicularis oculi(pars palpebralis)
8
Lips Toward Each Other orbicularis oris
9
Nose Wrinkler
levator labii suprioris alaeque nasi
10
Upper Lip Raiser
levator labii superioris, caput infraorbitalis
11
Nasolabial Deepener
zygomaticus minor.
12
Lip Corner Puller
zygomaticus major
Etc…

13. • Consider only emotion-related facial actions. Examples of these are:
Emotion
Action units
Happiness
6+12
Sadness
1+4+15
Surprise
1+2+5B+26
Fear
1+2+4+5+20+26
Anger
4+5+7+23
Disgust
9+15+16
Contempt
R12A+R14A

14. Study of Micro expressions
• Micro expressions can be difficult to recognize as they
last only 1/25 to 1/15 of a second
• A camera is used to distinguish distinct emotions

16. • Study Micro expression by Using of photographs

18. • Thank you all for you attention..
Any question will be
welcomed.