Subliminal Priming Task

Background

In general, priming procedures are simple response-timed binary categorization tasks of items from two target categories (e.g. positive vs. negative adjectives). Priming Procedures assume that people respond faster if the target category was already 'mentally activated' by briefly presenting items (called 'primes') that are closely connected in one's mind. For example, a person should be faster to quickly categorize the target word 'good' as 'positive' after the brief presentation of the prime word 'ice-cream' than after the brief presentation of the prime word 'famine'. Priming procedures can thus be used to study implicit attitudes. Faster reaction times to targets after primes from a specific category are interpreted as indicative of an existing relationship/association between the categories in the person's mind.

If the primes are presented with a temporal duration that can be consciously processed, the primes are called 'supraliminal'. If the duration of the primes is so short that they are presented outside one's conscious awareness, the primes are called 'subliminal'.

It has long been debated whether it is possible to influence people's thoughts, judgments, or behaviors by information presented outside of one's awareness. For example, in 1957 James Vicary, a market researcher, claimed that flashing "Drink Coca-Cola" in a movie theater massively increased sales of the drink. The data could not be replicated, however, and he finally admitted in 1962 that he completely fabricated the data. Nevertheless, several reproducible studies support the subtle influence of subliminally presented information. In 1982, for example, John A. Bargh and Paula Pietromonaco showed the hostility-related subliminal primes influenced participants to rate an ambiguously described character named 'Donald' as significantly more hostile compared to a control group. Anthony Greenwald and colleagues demonstrated in 1996 semantic priming effects of carefully controlled visually masked subliminal primes, though the effect was short-lived and rapidly decayed. In 1998, Anthony Greenwald and Sean Draine investigated a response window procedure that forced participants to respond faster to targets than they normally would. By using this response procedure, they reliably demonstrated that participants made more errors in classifying prime-incongruent targets (e.g. the prime was a typical female name and the target a typical male one) than congruent ones, supporting the subtle influence of the subliminally presented primes.

Michael A. Olson and Russell H. Fazio demonstrated in 2001 that new attitudes can be formed through unconscious, implicit evaluative conditioning, bypassing conscious awareness. Using subliminal priming as the dependent variable in 2002, they could show that positively and negatively conditioned Stimuli (CS) - used as the subliminal primes- produced significant affective priming effects and thus provided further support that attitude formation through classical conditioning does not require any conscious processing of the CS at time of attitude measurement.

Task Procedure

The Millisecond Subliminal Priming Paradigm, based on the Olson and Fazio procedure from 2002, assumes that the primes used (here: two names of Pokemon characters) are already classically conditioned to be positively (CS+) and negatively (CS-) valenced. Without first classically conditioning the two prime stimuli, no affective priming effect is expected.

The procedure starts out with a practice block of 16 trials in which participants have to sort the targets as negative or positive words via keyboard presses. The practice phase uses pseudo-primes to achieve the same 'look' as the test trials. The test consists of 2 blocks that run 32 trials each. Across all 64 test trials, each of the two primes is paired once with one of the 32 adjectives (16 positive; 16 negative). All 32 adjectives are sampled ONCE during each block.

Each trial presents a forward mask of alphanumeric characters for 56ms. The prime itself is presented for 28ms and immediately followed by a backward mask (same alphanumeric characters as the forward mask), that stays on screen for 42 ms to wipe out any lingering iconic memory of the prime words. After a further delay of 98ms, the target adjective appears, and participants must respond by pressing the 'A' or 'L' key for positive or negative items as fast as possible (the response key assignment is counterbalanced across participant groups).

Note: actual presentation timing depends on the vertical refresh rate of the display. Fazio and Olson (2002) ran their study on a 72Hz monitor that can refresh the screen (and thus present new information) every 14ms.

What it Measures

Subliminal priming is a priming paradigm to measure the strength of stimuli relationships triggered without conscious awareness

Psychological domains

• Implicit Cognition: Cognitive processes not under conscious control

Main Performance Metrics

• Difference in categorization speed: mean response times for categorizing positive and negative targets paired with CS+ and CS- primes

Psychiatric Conditions

The following patient groups have been studied with subliminal priming to help pinpoint the information processing stage at which deviations from normal can be observed:

• Anxiety/Panic Disorders
• Major Depressive Disorder (MDD)
• Schizophrenia
• Parkinson's

Test Variations

References

Search Google Scholar for peer-reviewed, published research using the Inquisit Subliminal Priming Task.

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Fazio, Russell H., et al. “Variability in Automatic Activation as an Unobtrusive Measure of Racial Attitudes: A Bona Fide Pipeline?” Journal of Personality and Social Psychology, vol. 69, no. 6, 1995, pp. 1013–1027.

Greenwald, A. G., Draine, S. C., & Abrams, R. L. (January 01, 1996). Three Cognitive Markers of Unconscious Semantic Activation. Science, 273, 5282, 1699.

Draine, S. C., & Greenwald, A. G. (January 01, 1998). Replicable unconscious semantic priming. Journal of Experimental Psychology. General, 127, 3, 286-303.

Michael A. Olson, M.A. & Fazio, R.H. (2002). Implicit acquisition and manifestation of classically conditioned attitudes.