Swiss Graduate School for Cognition, Learning, and Memory


Eva Aeschlimann

The impact of mental ability on sensory discrimination and working memory functioning in children and young adults: A cognitive-neuroscience approach to neural efficiency (A functional near-infrared spectroscopy study)

PhD student: Eva Aeschlimann

Supervisors: Thomas Rammsayer & Claudia M. Roebers (Psychology)

Why people differ in intelligent behavior is an issue that has been occupying researches for more than a century. The neural efficiency hypothesis (NEH) is one discussed explanation. The hypothesis suggests that individuals with higher mental ability (MA) show less brain activity compared to individuals with lower MA. To the best of our knowledge, no study investigated the NEH with a working memory task and functional near-infrared spectroscopy (fNIRS). The aim of the present study was to examine neuronal efficiency in 9- and 12-year-old children solving a classical working memory task while measuring brain activity with fNIRS.

MA was assessed with the Cattel’s Culture Fair Test (CFT 20-R). Only children with an intelligence quotient below the 40th percentile or over the 85th percentile participated in the fNIRS measurement. During the fNIRS measurement, children solved a letter-number sequencing task and a matrix span task. Brain activity was measured by a FOIRE-3000/8 fNIRS system (Shimadzu, Japan).

Photo Eva

During the first year of my PhD (2013- 2014) I have developed the paradigm, have familiarized myself with the technique of near infra-red spectroscopy that is so far only very seldom used outside of acute medical treatment for infants. In the second year of my PhD, I have screened more 600 9- to 12-year-old children in terms of their fluid intelligence to get my sample of high versus low IQ children together. By now, together with my PhD colleague who runs the same study with adults we have tested over 120 participants under NIRS – recording, with each of these measurements bringing about 6 to 8 working hours for us. Nevertheless, we now have preliminary data indicating that the two MA groups showed different oxyhemoglobin responses in pre-frontal brain regions while solving our working memory tasks which is consistent with the neural efficiency hypothesis. In addition, results provide evidence for fNIRS as a feasible method to investigate the NEH in children.

I am planning to finish my PhD in 2017. We are currently writing up papers on children’s and adult data.