Do we mimic other people’s facial emotional expressions in a congruent way (i.e. are facial emotional expressions contagious)?MK1
i. How does attachment orientation predict the extent to which subjects engage in facial mimicry at the automatic level (i.e. rapid facial mimicry) and at the cognitively-controlled level of processing (i.e. delayed facial mimicry)?
ii. How do self-report measures of impulsivity predict the extent to which subjects engage in facial mimicry over the whole 2000 ms time-window?
1.0 AIMS, HYPOTHESES
The activation of the zygomaticus major muscle will increase and the activation of the corrugator supercilii muscle will decrease while observing others’ happy facial expressions. Observing others’ sad facial expressions will elicit the opposite pattern of activation. There will be no specific EMG activation in response to the neutral facial expressions.
i Individuals with a secure attachment style will demonstrate typical levels of facial mimicry (as mentioned in the section above); i.e. they will represent a baseline to which insecure individuals will be compared.
ii Dismissing individuals will show a similar level of mimicry to secure individuals at the automatic level, whereas at the cognitively controlled level of processing they will mimic happy facial expressions more and sad facial expressions less than secure individuals.
iii Preoccupied individuals have a negative image of the self and positive of the other people. They will mimic similarly to secure individuals but more exaggerated at both levels of processing.
iv Fearful attachment orientation represents individuals that doubt about self and others, and avoid personal contacts with other people. They will mimic the least compared to the other attachment orientations.
ii. High impulsive individuals will mimic more than low impulsive individuals.
Subjects will be healthy young adults aged between 18 and 35. They will be screened prior to the start of the experiment and excluded in case of a) suffering from a neurological or psychiatric disease, b) taking psychoactive medication/substances such as antidepressants, antiepileptics, antipsychotics or hard drugs, c) suffering from claustrophobia, or d) pregnancy. We will test a total of 55 subjects that will participate for either payment (voucher of 10 Euros) or course credits (1-course credit). The procedure described in 5.1 and 5.3 has been issued and approved by the Ethical Commission of the Faculty of Social Sciences at Radboud University Nijmegen (Nr. ECSW2016-0905-396).
2.2 Measurement instruments (tools, apparatus, etc.)
My master’s thesis is the continuation of the pilot study where 38 stimuli, 19 female models per condition (happy and sad facial expressions), were selected from the set of validated pictures from the Radboud Faces Database (RaFD) (Langner et al., 2010). In the present study, we included neutral facial expressions of the same models such that we were able to assess the EMG response under control conditions. Therefore, 57 stimuli, 19 female models per condition (happy, sad, and neutral), will be included in my master’s thesis project. Stimuli will be presented with Presentation (Neurobehavioral Systems).
EMG will be measured using 6 surface Ag-AgCl electrodes (1-cm-diameter) placed over the zygomaticus major muscle and corrugator supercilii muscle, with the ground electrode placed on the forehead at the border of the hairline and the mastoid reference electrode, with the sampling frequency of 2500 Hz.
The Attachment Styles Questionnaire (ASQ) (Van Oudenhoven et al., 2003), mentioned in section 2.0, is applied to assess attachment style. It is designed as a bipolar proportional scaling method of adult attachment, ranging from -1 to +1 (Hofstee & Ten Berge, 2004), and is composed of 24 items. Each questionnaire item is rated on a 5-point scale; strongly disagree (-1), disagree (-0.5), neutral (0), agree (+0.5), strongly agree (+1). Subjects have to indicate how strongly the statements reflect their personal experience about close relationships. The inventory administers individual measures on each of the four attachment orientations; secure, preoccupied, fearful, and dismissing, as in, every individual receives scores on all four attachment scales (Van Oudenhoven et al., 2003).
The Barratt Impulsiveness Scale (BIS-11) (Patton et al., 1995), already mentioned in 2.0, is the most widely cited measurement of impulsivity and is used for assessing personality/behavioral construct of impulsivity. It contains 30 items that are describing common impulsive or non-impulsive behaviors and preferences. They reflect behavioral and cognitive styles associated with impatience, hyperactivity, planning, reflection, and forethought. Each item is scored on a 4-point scale; rarely/never (1), occasionally (2), often (3), or almost always/always (4), with a higher score indicating greater impulsivity. The following three subscales are identified: motor impulsivity, non-planning impulsivity, and attentional impulsivity, that we can delimit to six first-order factors: motor and perseverance, self-control and cognitive complexity, and attention and cognitive instability, respectively. Motor impulsivity reflects action without forethought, non-planning impulsivity an emphasis on the present, and attentional impulsivity a reduced ability to maintain attention toward a stimulus (Patton et al., 1995). We will form two groups of high and low impulsive individuals by a median split on the BIS-11 score.
Subjects will be instructed to attend to the pictures presented on the screen with the cover task of remembering the characteristics of the presented people. The purpose of the cover task will be to distract subjects from the real purpose of the study. They will be seated in an adjustable chair at a distance of approximately 60 cm away from the monitor. EMG data will be recorded for approximately 20 minutes. The task will consist of three blocks, with two one-minute-long breaks in between. Each block will consist of 76 pseudorandomized trials, and every chosen facial expression will be repeated four times. Those trials will be prepared using the program Mix (van Casteren & Davis, 2006) for a generation of (pseudo)randomized orders. Subjects will be exposed to 19 different pictures depicting female faces with three different facial expressions (happiness, sadness, and neutral) from the RaFD (Langner et al., 2010), to make up a total of 57 different stimuli. Before each stimulus, there will be a ‘beep’ to make sure that the subject is attentive through the whole experiment. Following this, subjects will be asked to answer some questions about the people they saw on the screen and the characteristics they can remember just for the purposes of the cover task. This will be followed by a series of questionnaires; ASQ and BIS-1