W4: tDCS on the Inversion Effect

Question 1

What did Civile et al 2016 aim to study by examining the effects of tDCS?

Answer 1

Aimed to expand the work on perceptual learning/expertise and inversion effect by examining the effects of tDCS on the checkerboard inversion effect found in Civile et al 2014 to investigate if a brief brain stimulation technique can modulate the checkerboard inversion effect.

Question 2

How did Civile et al 2016 conduct their procedure?

Answer 2

Half of ppts assigned to active stimulation condition- half to sham. tDCS montage selected was that previously used by Ambrus et al 2011- to modulate categorisation learning for pattern stimuli. Ppts had to categorise a set of checkerboards from two diff categories- A and C. They then had to identify if they had seen the checkerboard or not.

Question 3

What did Civile et al 2016 find and what do their results suggest?

Answer 3

Results found that in the sham group, there was an effect on the novel group with variability. The inversion effect was seen for familiar checkerboard.

The anodal tDCS can reduce checkerboard inversion effect by affecting performance for upright familiar checkerboard, therefore disrupting perceptual learning. Suggests that if the same tDCS procedure can affect similarly also the inversion effect for faces then we would have some evidence for this phenomenon to be based on expertise rather than specificity.
Results bring support to perceptual learning account based on the MKM model.

Cathodal stimulation did not have any effects on the inversion effect nor performance.

Question 4

What are some critiques of the work conducted by Civile et al 2016?

Answer 4

1. Unclear reasoning on the tDCS targeted area

It is the first work in the literature that looked at the effects of tDCS in inversion effect- results could be seen as far reaching. Debate as to whether the tDCS can enhance face recognition.

2. Low overall recognition performance

There was also a low overall recognition performance for the anodal tDCS. Could suggest that the anodal tDCS disrupted performance in general rather than influencing perceptual learning specifically.

3. Lack of tDCS control groups

Exp 1 should have included an active control group and experiment 2 should’ve included a sham group

4. Theoretical validation

Is the MKM model the only one to explain the results obtained?