The Body in Embodiment: Specifying the Role of Peripheral Input in Grounded Cognition

There is increasing scientific attention to the role that the body plays in
human mental functioning. The view is bolstered by an exponential growth in
supportive evidence revealing that mental contents are often grounded in bodily
experiences and that models that rely on symbolic, abstract, and amodal
representations are not sufficient to account for such observations. In this
emerging work on embodiment, *simulation*, namely the reenactment of
perceptual, motor, and introspective states as a central mechanism for human
functioning, has become a central explanatory point of reference. The
accumulating empirical evidence has revealed important roles of extero- and
interoceptive simulations for many psychological phenomena. The current program
is designed to answer a question that is left open in current embodiment
research: where are the causal sources of embodiment effects located in the
stream between retrieval of motor programs, virtual simulation, signalling
motor commands downstream and finally proprioceptive and interoceptive feedback
from executing the motor response in the body*s periphery?

The goal of the planned studies is to determine the significance of afferent
and efferent motor processes in facial expressions that may impact evaluative
judgments or responses induced by linguistic and pictorial representations of
facial expressions. To specify the nature of the simulation processes, we shall
make use of a unique sample of patients who have a left- or a right-sided
facial paralysis.

General:
Affective stimuli (verbal, or pictures of facial expressions) will be shown on
a computer screen. Due to the special nature of the patients (one sided facial
paralysis), this type of presentation should have distinct effects for the
patient sample. Measures of the facial muscles (electromyography, EMG) will be
done with use of electrodes placed on the skin. This is a non-invasive type of
measurement, of which the patient will not feel anything. Besides EMG, we will
also measure reactions and reaction times.

Planned experiments:
1. Questionnaire consisting of: Satisfaction With Life Scale, SF-12, Fear of
Negative Evaluation Scale, Social Avoidance and Distress Scale, Beck Depression
Inventory-II, Dizziness Handicap Inventory, and a few additional questions.
Additionally, the participant will grade himself on the House Brackmann scale.
2: Emotion recognition task, with manipulation of noise. Participants will see
emotional (happy, angry) and neutral facial expressions, with different
gradations of noise (10-80%). Participants shall decide as quickly and
accurately as possible whether the face they see on the screen is an emotional
or neutral one. Dependent variables: (i) reaction times, (ii) accuracy, (1
study), and (iii) EMG (corrugator and zygomatic, two sided) (other study).
3. Visual presentation of verbal stimuli (emotional and neutral sentences).
Dependent variables: (i) reading time of the different types of sentences, (ii)
mistakes in answering questions about the sentences, (1 study), and (iii) EMG
(corrugator and zygomatic, two sided) (other study).
4. Chimeric faces test: Participants will see faces, showing the expression
(happy or angry) in the left or right half of the face. Participants judge each
face on emotionality. Dependent variables: (i) emotionality judgments, (ii)
bias to the left or the right visual field, (1 study) and (iii) EMG (corrugator
and zygomatic, two sided) (other study).

Patients will fill out a questionnaire at home once (approximately 0.5- 1 hour)

Patients will partake in 3 experiments at their home, these will be done on a
laptop, all three in one morning or afternoon (total duration about 1.5 hours,
including breaks: 2 hours). The experimenter will be there to do the
experiments with the patients and to answer any questions.

Patients will be asked to come to Utrecht University once to participate in
studies on the computer. Here their facial muscle activity will also be
measured, which patients may experience as a bit uneasy. These studies together
will take approximately 3 hours in total.

There are no risks tied to these studies, except for the fact that the skin may
become somewhat irritated or red on the spots where the electrodes will be
placed for the studies taking place at Utrecht University.