Hypnotism and Subliminal Perception


Subliminal Perception

Lecture 7 (last 1 for Test 1) 2/11/04

…You Decide

Could 1/30 th of a second really influence impressions of Al Gore?

SUB-liminal Perception?

• Minimum stimulation necessary to detect a particular stimulus – Normal senses can • smell one drop of perfume in a 3-room apartment • See a candle 30 miles away • Hear a watch ticking 30 feet away • What about stimuli below the absolute threshold?

– Can they influence us?

Sensation without perception?

Subliminal = stimuli that sensory system

responds to

, but due to

short duration subtle form

, don’t reach


or of cognition – Can’t report the info was


– “Awareness” of info about environment depends on variety of cortical areas – Many studies demonstrate perception without awareness… Many call them hoaxes…

Quick Survey

1. Do you think you are influenced by subliminal messages in advertising?

2. Do you think you are influenced by everyday advertisements that you perceive consciously (e.g. laundry detergent, beverages)?

3. Suppose you had a choice to listen to one of two speeches that argued against a position you believe in, such as whether marijuana should be legalized. In speech A, the person presents arguments against your position; in speech B, all arguments are presented subliminally.

Which speech would you rather listen to?

1. 80% college students preferred not to receive a subliminal message b/c they thought it might influence them in an undesirable way.

2. 28% preferred not to receive a regular ad b/c it might influence them undesirably.

3. 69% chose speech A; 31% chose B (subliminal) • Why are people afraid? Should you be?


Subliminal Persuasion

• New Jersey, 1957: – Over 6 weeks, 45,699 ppl – “Eat Popcorn” – 57.5% – “Drink Coke” – 18.1% • “Minds have been broken and entered”

More recently…

• 2 teenage boys committed suicide after listening to Judas Priest… – Lyrics promoted Satanism and suicide • Rock music w/ satanic messages when played backwards – Beatles, The White Album: “John is dead now, miss him, miss him, miss him.” – Led Zeppelin, Stairway to Heaven • “Human brains are capable of receiving, scanning, deciphering, storing and later reacting to subliminal or subconscious messages”

Led Zeppelin, Stairway to Heaven

• "I sing because I live with Satan. The Lord turns me off. There's no escaping it. Here's to my sweet Satan. Whose power is Satan. He will give you 666. I live for Satan." • Examples: Madonna , Backstreet , Metallica

Not the last of it…

• Sexual imagery in ads – Wilson Bryan Key: “sex” in ice cubes, nude figures in images from butter to icing in cake mix ads.

– Even if images aren’t consciously perceived, they put us in good mood and pay more attention to ad

Vokey & Read, 1985

• Recorded sentences • Backmasked • What did you perceive?

– Gender (m – f) – Type (? - statement) – Meaning similarity, meaning vs. nonsense… • Behavioral influence?

– Homonym task (“Climbing a mountain…”)

Perceptual set

• Perhaps listeners can “hear” a “message” that actually isn’t there • Jabberwocky and Psalm 23 – “I saw a girl with a weasel in her mouth” – When instructed to listen • 90% hear • Yes, messages are there, but are not effective


Can subliminal messages influence you in a desirable way?

• Subliminal self-help tapes - $50 million – Relax, you are good, you are capable, calm • Utah’s South Pt. Prison • Texas Rangers’ Pitching Staff • Department Store Music

Contents vs. Expectation

• Greenwald, et al. 1991 – Fill out self esteem scales; memory tests – Self-help tapes: Improve memory or boost self-esteem – Every day for 5 wks.

• Hear classical musical… • The Catch

Where would you predict an increase?

MEMORY TAPE SELF ESTEEM TAPE ACTUAL M label SE label M label SE label Expectation ACTUAL ?








The Results


ACTUAL M label SE label M label SE label Expectation ACTUAL ~ ~ ~ ~ PERCEIVED * memory improved * SE improved * memory improved * SE improved

Evidence For… In lab

• Flashed – Kitten & romantic couples VS.

– Werewolf & dead body • Pictures of people – Perceived a flash of light, BUT – Rated people associated with kittens & couples more positively

More FOR

• How much do you like these Chinese ideographs?

1 Not at all 2 3 4 5 6 7 A lot

• Word search puzzle – Hidden primes: Neutral vs. achievement words • Buzzer stops P’s at 3 minutes • Hidden cameras detect who keeps working – 57% achievement condition

Conclusions so far

• Subliminal cues in a controlled lab setting – Simple judgments & actions – Short term effects • Conscious perception – influences long term purchases – Health • Although we can perceive subliminal cues, won’t persuade us to take action unless already motivated or expecting…

What about perception with NO physical stimulus?



Extrasensory Perception

An ability to perceive in absence of ordinary sensory info – 57% Americans believe in ESP • 3 types: – Telepathy – Clairvoyance – Precognition-

The Case For

• Rhine, 1934 • Special ESP deck • Guess symbol on each card – Telepathy- sender looked, P read mind – Clairvoyance- cards placed face down – Precognition- predicted before deck shuffled • 100,000 responses – Using 25 cards, P’s averaged 7.1 correct!

High followed by low

• Methodological problems • Hoaxes • Live stage psychics have associates circulating through crowd, spying on conversations… • Uri Geller- bend metal without touching it • James Randi- same stunts through trickery – “Mind sees what it expects to see.” • PERCEPTUAL SETS

James Randi Educational Foundation offers $1 million “to anyone who can show, under proper observing conditions, evidence of any paranormal, supernatural, or occult power or event.”

Ganzfeld Procedure

• Bem & Honorton, 1994 • All sensory information reduced • “receiver” in reclining chair in sound proof chamber with ping-pong balls, red light, earphones, white noise »In Separate room, “sender” concentrates on visual stimuli »32% hit rate > chance!


• Illusions of Connection – PPl mistakenly attribute coincidences to Psi as false alarms – Perceptual system creates patterns and connections that do NOT exist • Illusions of Control – PPl mistakenly feel in control of what are really chance events • Illusions of memory – Selective memory makes coincidences appear to occur more frequently than they actually do

TEST: Monday

• Lectures 1-7 & Chapters 1-5 • Focus on ideas, not facts – Understand, don’t memorize • Apply studies discussed to overall themes – What’s the point?

• Focus on important diagrams & terms, not minor details • Study together