Expressing fear enhances sensory acquisition
This presentation is the property of its rightful owner.
Sponsored Links
1 / 28

Expressing fear enhances sensory acquisition PowerPoint PPT Presentation


  • 96 Views
  • Uploaded on
  • Presentation posted in: General

Expressing fear enhances sensory acquisition. Susskind et al., Nature Neuroscience, 11 , 843-850 (2008). Presented by: Kara Hawkins. Overview of Susskind’s Story. Everybody talks about the behavioural & neural bases of emotional expression recognition Ekman, Izard, Adolphs, Gallese

Download Presentation

Expressing fear enhances sensory acquisition

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Expressing fear enhances sensory acquisition

Expressing fear enhances sensory acquisition

Susskind et al., Nature Neuroscience, 11, 843-850 (2008)

Presented by: Kara Hawkins


Overview of susskind s story

Overview of Susskind’s Story

  • Everybody talks about the behavioural & neural bases of emotional expression recognition

    • Ekman, Izard, Adolphs, Gallese

  • But what about the production of emotional expression?

    • Why do our facial expressions look the way they do?

    • Darwin (origin of facial expressions)

  • Principle of form

  • Principle of function

  • Provide evidence for Darwin’s view that facial expressions look the way that they do because their form serves a function that is beneficial to the survival of the organism


Paul ekman

Paul Ekman

  • Social communication

  • Cultural invariance in the recognition of facial expressions

Ekman, P. & Friesen, W. J. Pers. Soc. Psychol., 17 124-129 (1971)


Carroll e izard

Carroll E. Izard

  • Innate & universal facial expressions

  • Developmental & cross-cultural research

Izard, C.E. Psychol. Bull., 115, 288-299 (1994)


Ralph adolphs

Ralph Adolphs

  • Demonstrated the existence of dedicated neural substrates for the recognition of emotion from facial expressions

Adolphs, R. Behav. Cogn. Neurosci. Rev. 1, 21-62 (2002)


Expressing fear enhances sensory acquisition

Adolphs,R. Behav. Cogn. Neurosci. Rev. 1, 21-62 (2002)


Ralph adolphs1

Ralph Adolphs

  • Demonstrated the existence of dedicated neural substrates for the recognition of emotion from facial expressions

  • Suggested a common circuitry for perceiving & generating facial expressions

Adolphs, R. Behav. Cogn. Neurosci. Rev. 1, 21-62 (2002)


Vittorio gallese

Gallese & Adolphs have begun to consider some of the mechanisms involved in the production of facial expressions, however they have not addressed the questionof why particular facial muscle actions are associated with specific emotional states

Vittorio Gallese

  • Suggested that emotion recognition is “accomplished through mirroring motor actions to infer the mental states of others”

  • Shared emotional experiences result from simulated action and thus emotional resonance (empathy) in the observer

Gallese, V. Philos. Trans. R. Soc. B. Biol. Sci., 362, 659-669 (2007)


Why do we look the way we do in certain situations

Why do we look the way we do in certain situations?

Whalen P.J. & Kleck R.E. Nat. Neurosci., 11, 739-740 (2008)


Charles darwin

Charles Darwin

  • This sort of question was first seriously asked by Darwin (The Expression of the Emotions in Man and Animals, 1872/1998)

  • Facial expressions originated for the purpose of modifying preparedness for perception & action (i.e. augmenting or diminishing exposure to environmental stimuli)


Joshua susskind et al

Joshua Susskind (et al.)

  • Sought evidence for two of Darwin’s principles

  • 1) Principle of form: Emotions with opposite functions are opposites in facial action

  • 2) Principle of function: Facial expressions originate in action patterns serving adaptive information processing


1 principle of form

1) Principle of form

  • Used a computer-graphics based model of facial appearance to examine the action tendencies underlying and opposing fear expressions

  • Specifically interested in the physical appearance of the facial expression of fear


Face stimuli

Face Stimuli

  • 8 face exemplars for each of the 6 basic emotions were used to train the appearance model


Computer model

Computer model

  • Represents each face as a vector in a multidimensional space, coding variations is shape & surface reflectance

  • Expression prototypes for fear & disgust were created by averaging the vector representations of all exemplars from these two categories

  • Faces were then synthesized at successive intervals along “expression trajectories” (from the prototypical expression to the antiprototypical expression, i.e. an expression containing opposing shape & surface reflectance features)


Expressing fear enhances sensory acquisition

Prototypical fear

Antiprototypical fear

  • Fear antiprototypes were most similar in structure to disgust (r = 0.69)

  • Disgust antiprototypes were most similar to fear (r = 0.69) and surprise (r = 0.70)

Prototypical disgust

Antiprototypical disgust


Subjective ratings

Subjective ratings

  • Fear antiprototype was rated maximally as disgust

  • Disgust antiprototype was rated maximally as fear


Vector flow fields

In sum, according to this computer animation model, the physical appearance (form) of fear, an emotion associated with sensory vigilance, opposes the physical appearance of disgust, an emotion associated with sensory rejection.

Antifear to fear

Antidisgust to disgust

Vector flow fields

  • Derived from the surface deformations that occur as the face moves from:

Spreading longitudinal action

Contracting longitudinal action


2 principle of function

2) Principle of function

  • Does this opposition in the physical appearance of facial expressions of fear & disgust reflect evolutionarily adaptive action tendencies?

  • If so, these expressions should retain some residue of this function

  • Several studies were conducted to measure differences in sensory regulation when the face is posed to simulate the expression of fear and when it is posed to simulate the expression of disgust


Visual field estimation experiment

135°

45°

Fear

Neutral

baseline

  • Also demonstrated that participants could detect

  • objects at farther eccentricities in the upper visual

  • field during the fear condition

  • Together, these results demonstrate that fear

  • expressions enhance and disgust expression reduce

  • the overall size of the visual field & stimulus

  • detection in the upper visual field.

315°

225°

Vertical eye-size relative

to neutral

Disgust

Size of upper-visual field

relative to neutral

Visual-field estimation experiment


Eye movement experiment

Both average & peak velocities

increased from disgust to fear

Reliably faster than

neutral expressions

According to these results, expressions of fear enhance and expressions of disgust decrease the velocity of horizontal saccadic eye movements during target localization.

Pronounced slowing

relative to neutral expressions

Eye movement experiment


Nasal inspiration experiment

Increased mean air-flow

velocity over time

Increased inspiration volume

Since changes in air intake can be explained by a variety of factors & may not necessarily reflect structural changes in sensory capacity, the authors decided to expand upon these findings by taking a look at changes in the internal anatomy of the nasal passages.

Decreased mean air-flow

velocity over time

Decreased inspiration volume

Nasal inspiration experiment


Mri of nasal passage case study

Fearful axial slice

Disgusted axial slice

Disgust

Neutral

Fear

Closed

Dilated

MRI of nasal passage: case study


Expressing fear enhances sensory acquisition

These results indicate that fearful facial expressions facilitate nasal passage dilation, while disgusted facial expressions result in sealing off these nasal passages, which normally remain open. These changes in nasal anatomy may be responsible for the changes in nasal inspiration revealed in the previous experiment

MRI of nasal passage: case study

Volume of air cavity in ventral

portion of nasal passages

Average overall air cavity

volume


Summary of support for darwin s principles

Summary of support for Darwin’s principles

  • Fear & disgust were shown to be near opposites in form, supported by opposing action patterns

  • A parallel opposition in function between fear & disgust was reveled by evidence for enhanced visual-field size, saccadic velocity, & nasal inspiration capacity in fear & the direct inverse in disgust


What do these results mean

What do these results mean?

  • The authors suggest that human facial expressions likely originated in an innate functional capacity to alter sensory processing & sensory exposure (i.e. egocentric function)

  • But they are maintained & have been further shaped based on social pressures (i.e. empathetic function)

  • In other words, the functional & signal (communication) value of facial expressions have probably co-evolved such that the functional importance for the sender is coupled with communicative importance for the receiver


Non human primates

Non-human primates

  • Idea supported by observing facial expressions in non-human primates

  • These expressions serve as innate protective reflexes, but like human expressions they have become important for social communication

Andrew, R.J. Science, 142, 1034-1041 (1963); Whalen P.J. & Kleck R.E. Nat. Neurosci., 11, 739-740 (2008)


Take home message

Take home message

  • Facial expressions may have originally evolved based on their adaptive role in preparing the organism for perception & action

  • It is likely, however, that the form & function of facial expressions in the present day reflect selection pressures from both biological & social sources


Thank you

Thank You!


  • Login