are these the Controlled Variables, or did I go overboard?

Question

We trained planaria the always turn left in a maze.

Are these the Controlled variables, or is it unnecessary information?:
-all planaria were given the same task to learn
-leads were stimulating each planaria for the same length of time, and were held at the same distance ((we shocked them with leads and a battery))
-all planaria used the same T-Maze
-planaria started the maze at the same spot
-were shocked at first sign of a right turn

Did I miss anything, or added something useless?

Answer 1

I agree with chickdoc101. Some really great points. I'd just like to add three more:

-Temperature - sometimes variations in temperature can have unexpected effects on organisms, and on such a simple one, could possible alter the effectiveness of the conditioning.

-Light levels - make sure that no one is casting a shadow or otherwise altering light levels (make sure that lighting is uniform throughout the maze). Planaria have simple eyespots and variations in light levels could alter their course.

-Chemoattractants - most simple organisms are very sensitive to chemical changes in their environments. I'd stir the water up between trials, to ensure that the previous planaria didn't leave a chemical trail behind that the next one might follow.

You've got most of the big variables listed, though. When it comes to this sort of thing, it's hard to be too thorough. When you present data, the first thing people do is look at your experimental design and controls. If you can account for everything, it makes your data that much more compelling (plus, it's always fun to say 'I already thought of that, and controlled for it' to a really nitpicky professor).

Happy science!

Answer 2

Ya some controls and their mention may seem silly to outsiders.
But as the researcher,
it's your time, effort, reputation etc. on the line.
You don't want to repeat an exp. over again and change/add something 6 months later because you or someone else made a "but what if" comment.

Your design sounds reasonable to me.

My only "curiousity" comment off the top of my head:
Have a duplicate experiment where you train them to always turn *right* in a maze.
Just to see if you get similar results here vs the *left* exp.
Someone can argue certain species as a whole
or members within a species
might have a tendancy to turn one direction more than the other.

Also, regardless of what direction it was heading to,
when shocked, an animal might suffer a momentary brain trauma and have a tendancy to go in one direction more so than the other.

Do some runs where you don't do any shocking.
Just let them run throught the maze on their own.
Do a statistical analysis of individuals vs. number left or right turns within the maze.
See if there is a tendancy or maybe just random.

Also do a pre-shock prior to being place in the maze and running.

Case in point,
following irreversible chemical lesioning of brain regions of rats,
they might only turn in left/counter clockwise circles.

Another wierd one is, often when human are observing other humans or highly evolved animals in an exp.
Could the human be influencing the animal to do something.
e.g. via eye movement, hidden verbal or gesture cues?
In which case the observer should be blindfolded, bound, gagged, purhaps not even in the same room.

But my real Qs for you are:
Do two wrongs make a right?
Do three lefts make a right?
Americans drive on the right side of the road while Brits drive on the wrong/left side.
Are "lefty" planaria in their "right" mind"?
I've heard of the "No Child Left Behind Act", but never the "No Planaria Makes a Left Act"

Best Wishes