Is a decision caused by a prior brain state?

Question

I apologise if this should be asked on another stack, such as PhysicsSE. If so, please let me know, and I'll delete the question. I tried a very similar question on Biology SE, and was referred here.

The reason I ask is because a user on PhilosophySE claims decisions are the first causes in causal chains. He states that this is a "trivial obviosity" and requires no supporting evidence. Am I justified in being skeptical of this position?

As far as I can tell from research on the web, outside of certain quantum events, no first causes exist in the natural world. Everything has an antecedent cause. Because of this, I've always assumed decisions were the result of prior brain states. Is this assumption correct?

I've done a fair bit of searching on the web, and I can't find much other than some discussion about decisions being predictable by up to 11 seconds. This would seem to suggest there is at least something about the state of a brain which is identifiable before we consciously make a decision... but this may not mean that such a brain state is responsible for the decision.

Answer 1

"Cause" is a tricky word with multiple operational meanings. Most often in experimental science the word "cause" means something more similar to the word "influence" in a colloquial sense.

In that sense, past brain state certainly causes future decisions, and we know that because it's possible to manipulate decisions by changing brain state, like by electrical stimulation. One particular experiment would be this one:

Hanks, T. D., Ditterich, J., & Shadlen, M. N. (2006). Microstimulation of macaque area LIP affects decision-making in a motion discrimination task. Nature neuroscience, 9(5), 682-689.

Here the decision is a perceptual one, as well as an associated motor response: monkeys are determining which direction some dots are moving, and they make a decision about which way to look to indicate their choice. They're rewarded if they get it right. Stimulating in a particular brain area biases their decisions.

Arnon Weinberg's answer to a different question at https://psychology.stackexchange.com/a/10983/14382 is an example of a study like the type you link to, showing that we can predict future decisions from past brain activity. I think this is useful information, too, and should not be discounted just because you cannot state that it is responsible. The mere temporal precedence is enough to refute the idea that a decision is a "first cause". If A happens before B, and A and B are associated, then there must either be a causal chain between A and B, or there must be something else prior to A that somehow causes both A and B (again, "causes" here is in the "influence" sense), or else it must be possible for future events to cause past ones (something that I am not aware of any evidence for). That's the only way to create an association.

Answer 2

It should be obvious just by the existence of the question "Why did you do that?" that decisions are not First Causes. If they have an answer for "Why" they did something, their brain didn't just miraculously or randomly pick that choice. Their reasons had some influence on why they made that choice.

Further, I would ask them to really examine their own decision making process. Mine, personally goes something like this.

1. Sensory input goes in.
2. I combine sensory input with past memories/preferences.
3. I act on the result.

Like for example, if I wanted to buy a car, I would base my pick on the cars I see available and on my past knowledge of my budget and what specs I'm looking for, and then I make my decision. If decisions really were First Causes, I could cut out 1 and 2 and it would still work fine. Although really, I guess even knowledge that I need a new car in the first place is a prior brain state.