Self-specific priming effect

Pannese and Hirsch, 2010

The “self” “other” distinction• Very advantageous cognition in animals (people).

• Humans acquire the self-other distinction between 18 and 24 months (Amsterdam, 1972; Lewis et al., 1989).

The “self” “other” distinction• Chimps and orangutans can also make the self-

other discrimination (Gallup, 1970; Suarez and Gallup, 1981).

• So can elephants and dolphins (Plotnik et al., 2006; Reiss and

Marino, 2001). – Remember this if you ever see “but see” or

“although see” in a citation.

Self recognition and consciousness• Some have argued that self recognition implies

consciousness (Gallup, 1977) and Theory of mind (Gallup,

1982).

• Mirror recognition correlates with the use of “I” and self-emotions such as pride, shame, and guilt (Howe and Courage, 1993; Lewis et al., 1989).

Self recognition and consciousness• Mirror recognition may simply involve matching

motor cues with mirror feedback (Mitchell, 1993).

• Platek et al. (2004) challenge this by showing that self-recognition can be facilitated by:– Exposure to ones own body odor.– Seeing or hearing ones own name.– Thus, cross-modal facilitation.

Self recognition and consciousness• Platek et al. (2004) interpret this as being cross-

modal facilitation exclusively for a self-face.

• But other work has shown cross-modal priming for non-self faces (Calder and Young, 1996).

Self recognition and consciousness• Bredart (2004) suggests that cross-modal priming

is a graded phenomena.

• It occurs for both ones self and others, but it is stronger for the self.

Self-face processing advantage• There are 2 advantages for self-faces:– They are faces (Lavie et al., 2003).– They are self-referential (Gray et al., 2004).

• Thus, self-faces benefit from prioritized processing based on their unique saliency.

Self-face processing advantage• They tested the self-face advantage hypothesis

by using masked priming.

• Prior research has shown that targets that start being processed earlier relative to the prime are more strongly affected by the prime (Eimer and

Schlaghecken, 2003).

• Prediction: if self-faces are processed earlier than non-self faces, they will being more affected by primes.

Methods• 12 “healthy” participants (7 M, mean age 30).

• Each person brought one close friend or domestic partner, one friend of medium familiarity, and one acquaintance.

• All were photographed.

Methods• Celebrity photos were used in the “famous”

condition and a public database was used to find photos in the “unknown” condition.

• Self photos were mirror reversed.

• 208 photos were shown in each condition.– Different poses were used in the self and familiar

conditions.– Famous and unknown conditions used 208 different

people (unrecognized celebrities were considered unknown).

MethodsPeriliminal primes: 33 msSubliminal primes: 17 msPhotos were counterbalanced for gender and identity.

Methods• Afterwards, participants completed a forced-

choice test to assess visibility of primes.

• Non-self target faces were presented with self- and non-self primes (self-face primes 50%).

• d’ was used to asses the standardized difference between signal present and absent.– d’ = z(H) – z(FA)

Results• Discrimination (d’) was at chance for subliminal,

but not periliminal primes.• Subliminal primes only enhance self-face.

Results• No RT differences for unprimed self and any

other faces.

• RTs for congruent and incongruent trials did not differ for primed non-self faces compared to unprimed non-self faces.

• RTs for incongruent self-face primes were slower than unprimed self-faces when the target was a self-face.

Discussion• Priming is believed to initiate an early response

selection (Schlaghecken, Bowman, and Eimer, 2006).

• Responses should be faster if a prime activates a response selection that is congruent with the actual behavioral response selection (Enns and Oriet, 2007).

• This only occurred for self-face subliminal prime trials, but it also occurred for familiar faces in the periliminal prime trials.

Discussion: 3 potential mechanisms• The self-face may induce a burst of awareness

which “spills” over to enhance processing of neighboring stimuli (primes).

• GNW predicts conscious stimuli reorganize the GNW which in turn can affect the processing of unconscious information (Dehaene and Naccache, 2001).

• Thus, primes become more visible in the presence of a self-face by benefiting from extra processing resources.

Discussion: 3 potential mechanisms• If we assume the neural populations

preferentially activated by self- and non-self faces are distinct, primes may benefit from prolonged processing immediately after a self-face prime.

• Face selective neurons display prolonged activity after a prime (Rolls and Tovee, 1994).

• A second stimulus can interrupt and replace this activity, but only if the neural populations respond to both stimuli.

Discussion: 3 potential mechanisms• The perceptual load model predicts increased

perceptual load results in decreased detection of irrelevant stimuli (Lavie et al., 1995).

• However, semantically related task-irrelevant information can enter visual awareness despite high perceptual load (Koivisto and Revonsuo, 2007, 2009).

• Thus, it may be semantic processing of the self-face prime that leads to the self-specific priming effect.

Evolution advantage of self-recognition• There may be a cognitive gap dividing great apes

from other mammals (Gallup, 1970).

• However, language is not needed for self-recognition suggesting a gradient of consciousness (Singer, 2001).

– More evolved animals are more conscious.

– Adults with their larger cortex are more conscious than young children.

Frontal lobe damage and self-recognition• Species capable of self-recognition have large

frontal lobes (Semendeferi, Damasio, and Frank, 1997).

• Acquiring self-recognition coincides with large increases in the size of frontal lobe in kids (Amsterdam, 1972).

• Damage to the frontal lobe impairs self-recognition (Weinberger, 1993).

Conclusions• Consistent with early self-face processing, self-

specific subliminal priming was found.

• This is the first psychophysical evidence supporting that the self-face benefits from privileged processing.