Cognitive functioning under different social psychological conditions

It is known that people perform more poorly than expected, given one's skill,
in situations where the pressure to perform is high (i.e., where the desire to
excel is maximal ; see Baumeister,1984; Beilock, Kulp, Holt, & Carr, 2004). As
noted by Beilock and Carr (2005), the consequences of suboptimal performance,
especially on examinations, include poor evaluations by mentors, teachers, and
peers, lost scholarships, and relinquished educational and employment
opportunities. By investigating the relationship between performance pressure
and individual differences in working-memory capacity (WMC), these authors
observed that the individuals most likely to fail under performance pressure
are those who, in the absence of pressure, have the highest potential for
success (i.e., high-WMC individuals). Performance pressure, they reasoned,
hinders the most qualified people by consuming the WMC they use in low-pressure
circumstances to devise complex (resource demanding) strategies and produce
superior performance. In their study, however, Beilock and Carr (2005) focused
only on arithmetic problems (involving both subtraction and division). More
recently, Gimmig, Huguet,Caverni and Cury (2006) examined the generality of
Beilock and Carr's (2005) conclusion using a task (Raven*s Standard Progressive
Matrices or SPMs) known to measure fluid intelligence (Gf), and they revealed
that pressure to perform high in high-powered people is not confined to tasks
involving acquired skills and knowledge but encompasses fluid reasoning
abilities or intelligence. These findings help us to understand how individuals
who score high versus low on working memory tests, perceive high performance
pressure situations. Taken together, these new findings have strong
implications for the assessment of people's intellectual capacity.

The key objectives of the performance tests in the present study are:

- To test for the effect of performance pressure during intellectual assessment
on MZ and DZ twins.

- To study how genetic and environmental estimates derived from path models of
the classical twin study differ according to the performance pressure condition
(pressure vs non-pressure).

Previous studies have tried to link IQ performance to resting state
EEG characteristics, e.g., power, coherence, and long-range temporal
correlations in amplitude fluctuations (Smit et al., 2005;
Linkenkaer-Hansen et al., in prep). Only low correlations between these
measures of brain organisation and cognitive ability have been reported. In
part, these low correlations may reflect the poor standardization of
resting-state EEG recordings as well as the failure to account for individual
differences in sensitivity to performance pressure during IQ testing.

Test research, questionnaires, statistical analyses

Participants have to visit the VU when they are 17 or 18 years old for a 5 hour
test session. They have to perform three computerised cognitive tasks. During
this performance their heart rate and cardiac sympathetic and parasympathetic
control are measured by non-invasive recording of the ECG and the thorax
impedance cardiogram (7 spot electrodes). Blood pressure will be measured
before the testing session and afterwards. In addition length and weight will
be measured.
There are two testing conditions: in one condition participants will experience
pressure to perform well, in the other condition participants will experience
no pressure. The instructions by the experimenter before the testing session
determines the condition (see appendix 1). After the cognitive tasks subjects
are asked to fill in 4 computerised questionnaires. The cognitive assessment is
followed by a debriefing (see appendix 2). After a break (lunch) they will
undergo two eyes-closed rest EEG experiments of 5-¬10 minutes followed by a
multiple-choice questionnaire about their experiences during the experiment.
The EEG session will take up to one and a half hour, including the preparation
of the 128-channel EEG cap.
Parents of the participants and the participants themselves are asked to
collect at home (one week before the assessment) DNA by buccal (cheek) swabs.