PHPSpec: Configuration of Output Format

I am using PHPSpec, but whenever a test fails I get the following:

It does say, where my tests fail, but it does not output what exactly was returned, thus being rather unhelpful.

I tried to format the output by creating a phpspec.yml file and putting it in my project folder, but right now it only looks like this:

formatter.name: dot

Is there any other way to configure phpspec, so that I get an output, that is actually helpful? (By showing what was returned and what expected?)

Thanks in advance.