How can self-awareness be controlled and varied in a laboratory setting? I was reading on deindividuation and its relation to self awareness. In many places, in the text that I am reading, it is mentioned that experiments were conducted to measure the effect of self-awareness on deindividuation. 

I have been trying to think about this but have so far not been able understand as to how self-awareness can be controlled as a variable in such experiments. So, in laboratory settings, and without using alcohol or other substances, how can self-awareness of an individual be varied, controlled and measured as an independent variable?

I tried searching for this as well, but I couldn't find anything helpful.
I'm not sure about a direct connection to research on deindividuation, but in general self awareness, sense of ownership and sense of agency can be altered by experimental methodologies that manipulate the perceived relationship between actions and the effects of those actions. These types of experiments are sometimes called behavioural illusions.
A common example of this is the rubber hand illusion, where participants are shown a fake hand that is stroked by a brush and end up experiencing sensations of being brushed in their own hand. https://www.youtube.com/watch?v=sxwn1w7MJvk
The original paper on this is:

Botvinick, M., &amp; Cohen, J. (1998). Rubber hands ‘feel’ touch that eyes see. Nature, 391(6669), 756. doi:10.1038/35784

But there are many other types of behavioural illusions...
Subliminal or perceivable primes can influence participants' experiences of self generated actions:

Aarts, H., Custers, R., &amp; Wegner, D. M. (2005). On the inference of personal authorship: Enhancing experienced agency by priming effect information. Consciousness and Cognition, 14(3), 439–458. doi:10.1016/j.concog.2004.11.001
Dijksterhuis, A., Preston, J., Wegner, D. M., &amp; Aarts, H. (2008). Effects of subliminal priming of self and God on self-attribution of authorship for events. Journal of Experimental Social Psychology, 44(1), 2–9. doi:10.1016/j.jesp.2007.01.003


Providing false or virtual representations of participants limbs can lead to changed feelings of ownership and agency for those limbs:

Wegner, D. M., Sparrow, B., &amp; Winerman, L. (2004). Vicarious agency: Experiencing control over the movements of others. Journal of Personality and Social Psychology, 86(6), 838–48. doi:10.1037/0022-3514.86.6.838
Slater, M., Perez-Marcos, D., Ehrsson, H. H., &amp; Sanchez-Vives, M. V. (2009). Inducing illusory ownership of a virtual body. Frontiers in Neuroscience, 3(2), 214–220. doi:10.3389/neuro.01.029.2009


and hypnosis can also be used to alter self awareness:

Connors, M. H., Barnier, A. J., Coltheart, M., Cox, R. E., &amp; Langdon, R. (2012). Mirrored-self misidentification in the hypnosis laboratory: Recreating the delusion from its component factors. Cognitive Neuropsychiatry, 17(2), 151–176. doi:10.1080/13546805.2011.582287
McConkey, K. M., Szeps, A., &amp; Barnier, A. J. (2001). Indexing the experience of sex change in hypnosis and imagination. The International Journal of Clinical and Experimental Hypnosis, 49(2), 123–138.
Rahmanovic, A., Barnier, A. J., Cox, R. E., Langdon, R. A., &amp; Coltheart, M. (2012). That’s not my arm: A hypnotic analogue of somatoparaphrenia. Cognitive Neuropsychiatry, 17(1), 36–63.


Unfortunately, there aren't really any standardised measures for specifically measuring self awareness. In most of these studies participants are simply asked to describe experience or rate, for example, how in control they felt. A scale was recently developed to measure sense of agency in hypnosis and this should also be adaptable to other contexts:

Polito, V., Barnier, A. J., &amp; Woody, E. Z. (2013). Developing the Sense of Agency Rating Scale (SOARS): An empirical measure of agency disruption in hypnosis. Consciousness and Cognition, 22(3), 684–696. doi:10.1016/j.concog.2013.04.003