PSYC 191 Day 18 Essay examples

Submitted By Kathleen-Chung
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PSYC191 Week 8 Day 2
Watching your emotions

Using fMRI to detect lies is more effective?

Magnetic resonance imagining (MRI) scanners have been used medically since the 1970s o Developed by Paul Lauterbur (university of Illinois) and Peter Mansfield
(university of Nottingham)


Developments that led to functional MRI (fMRI) are credited to Seiji Ogawa and
Ken Kwong (1990s)


Advantages: non-invasive, repeatable, excellent spatial resolution

Ross, P. (2003)

Traditionally, polygraph has been used for lie detection o Measures physiological responses associated with anxiety


Does anxiety = lying?

Are different parts of your brain active when you’re lying compared to when you’re telling the truth?

Method: o o


Group 1:

Participants were asked to select one of three envelopes, each of which contained a card (5 of clubs) and $20

They were asked to memorize the card and put the envelope with the card and money back in their pocket

Told that if they could keep the card a secret, they could keep the $20


Participants were given a different card (2 of hearts)

They were asked to tell the truth

All participants were tested with fMRI – task asked “do you have this card?” and participants responded ‘yes’ or ‘no’

Conclusions o MRI has potential as a lie detecting tool

Usefulness in court?


Revealed the brain regions involved in lying

Dorsolateral prefrontal cortex

Can MRI be used for lie detection? o Similar findings in a study using line ups of human faces


Found to be as reliable as the polygraph

Which is still not admissible in court

Thoughts out of tune

Cognitive dissonance

Festinger, L. & Carlsmith, J. M.

Precious studies showed that when your behaviour is contrary to your attitude, your attitude will change to align with your behaviour

Explained by 1) mentally rehearsing the speech and 2) thinking of arguments in favor to the forced position

However, studies that offered monetary reward for giving a speech with a forced viewpoint showed that larger rewards produced less attitude change than smaller awards – difficult to explain!

Festinger suggested cognitive dissonance occurs when two simultaneously held cognitions are psychologically inconsistent

Cognition: o ‧

Dissonance: o ‧

A tension or clash resulting from the combination of two disharmonious or unsuitable elements

Cognitive dissonance: o ‧

Mental processes of thinking, acquiring knowledge, and understanding through though experience

The discomfort caused by holding conflicting cognitions (e.g. ideas, beliefs, values, emotional reactions) simultaneously

Festinger theorized that the way to reduce cognitive dissonance is to alter your opinion to agree with behaviour

Changes in opinion would be greatest when cognitive dissonance is large

Method: o Designed a study called “measures of performance”


Participants were 71 male intro psychology students


Empty and refill a try of 12 spools