Resources

Table and chairs / one kilogramme of clay*/ clay tools / partition or platform / brushes sticks / pen and paper / ruler / Audio recorder.

The Rubber Hand Illusion is a well know experiment in which …recent studies have sbuilt on this model using a replica stone hand, empty spaces. It is widely regarded that the model hand must be significantly hand like in order for the illusion to work for example attempting the illusion with an entirely ‘unfeasible object’, such as a plank of wood, and balloons have proved less successful.

The unfeasible object workshop uses two variations on the rubber hand illusion, the clay hand illusion and the unfeasible object illusion. In this workshop several new artistic methods are introduced; The use of a blind drawing before and after the experiment, and the use of clay, with which to model the object, offering the participant opportunities to make decisions and suggestions about what form they would make and how the experiment could be conducted. Performing this within the context of a group workshop opens the possibility that participants can conduct experiments on each other and even invent their own new experiments.

The workshop requires a minimum of two people, but can be adapted for very large groups depending on the resources available. For larger groups it is recommended to simplify the workshop [use only steps, 1,4,5 and 6]. When working with a single participant the workshop can last up one hour. As an extension of this workshop it is also interesting to try the invisible hand experiment [insert link] the same process using empty space.[ See also the dis-orientations workshop] [INSERT DIAGRAM OF PLATFORM] This shows a typical arrangement for the clay hand and unfeasible objects experiments. The tabletop is populated with clay modelling tools the clay as well as a small drumstick, and a number of different brushes. Participants sat opposite the experimenter. The index finger is placed under the platform where the experimenter can stroke and tap the participant’s real hand under the platform [40x25cm and 15cm high] which is also used to place the clay object upon for the experiment.

Procedure outline

Perform 1st Spontaneous sensation experiment
Perform 1st measurement of proprioceptive drift
Make blind drawing
Make object
Stimuli until ownership reported / Or 10 mins passes
Make distortions to clay while ownership is reported.
Remove object Measure P-drift
Make blind drawing of hand.
Ask Q1-8 / make note of object realness
Make unfeasible object 1 [repeat 4 -9
Make unfeasible object 2 repeat 4-9
Finish – 2nd Spontaneous sensations experiment

Methods:

Spontaneous sensations experiment

Participants often find it difficult to articulate the sensations they are having during this experiment. the spontaneous sensations experiment can be thought of as a preparation. It is particularly useful since it relates to the hand. Used and in conjunction with the final drawing to see if there are any differences in levels of sensations perceived.

[Link to SS page]

Measuring Proprioceptive Drift

before the experiment start participants placed their hand under a platform a piece of paper is placed onto the platform and they’re asked to indicate the position of the index finger underneath the platform using a pen . the accuracy of this mark in relation to the actual position of the index finger is known as proprioceptive miss localization. We would expect an increasing degree of miss localization indicating at the participants are increasingly unsure about the position of their real hand underneath the platform as the experiment goes on. In my own research and others generally, they find an increase in proprioceptive drift suggesting a movement away from the real hand and towards the object used in the experiment.

Blind drawing

4 blind drawings of the hand one before experiment and one after each experiment. In my own research I find that these drawings became more distorted as the experiments went on suggesting A disruption of body image as the experiment progress

Making of Clay Hands and unfeasible objects

Make one that looks as hand like as possible. the second and third experiments will repeat this process sunbg unfeasible objects that you have created.

HR 1- Hand Like 1: looks real and is reasonably well sculpted.

HR 2- Hand Like 2: has 5 fingers and resembles a hand. It is hand like.

HR 3- Hand Like 3: has significant transformations [scale and form]

HR 4- Unfeasible: does not look like a hand – Abstract form

HR 5- Unfeasible: does not look like a hand – It resembles something else.

HR 6- Other: ………….. describe

Stimuli

Place the hand in front of you where your real hand would be. You may want to use a coat over the end of the clay hand [where your arm would be] to make it look like its joined to you. Hide your real hand on the other side of a screen

Start audio recorder. Instruct the participant “Please stare at the clay hand. Keep focussed on the hand. Concentrate hard. I want you to try to imagine that this is your hand.”

Do experiment up to 5-10 mins [make record of time until ownership]

Start audio recorder / takes two pencils or brushes to tap or stroke both hands at the same time, in synchronisation. It will take some practice.

After a while they might* begin to feel like the clay hand is their own hand. Keep asking how it feels. Do experiment up to 5-10 mins [make record of time until ownership]

Distortions to clay

When the participant believes the clay object is their own, try slowly squishing the clay or reshaping it. Try tapping out of synchronisation or tapping the clay object while not tapping the real object– this might make them feel like their hand has gone numb.

Introspective [semi-structured] Interviews

It is important to talk to the participants throughout the process [See notes[1]]. Some ideas for probing Questions to be asked during the experiment: How does it feel? How do you feel? Can you explain the sensations you are experiencing? Where you are feeling this? What word would you use to explain the way you/it feel[s] Do you have any unusual sensations, and can you describe them? How do you feel about the clay hand at the moment? How do you feel about your real hand at the moment? How intense is this sensation? How comfortable do you find this sensation? Have these feelings changed over time?

Post experiment questionnaire

10 questions based on the original questions used in the early RHI experiments (Botvinick and Cohen, 1998). These Questions are rated on a ‘Likert scale’ ranging from strongly agree (+3) to Strongly Disagree (-3)

It seemed as though the touch I felt was caused by the touch to the clay hand / object.
I felt as if the clay hand/object was my hand.
It felt as if my hand were drifting towards the clay hand/object.
It seemed as if I had more than one right hand
It seemed as if the touch I was feeling came from somewhere between my own hand and the clay hand/object.
It felt as if my hand was turning into the same material as the clay hand.
It appeared as if the clay hand/object was drifting towards my hand.
I felt I had some agency over the clay hand/object.

Notes:

Each participant will be very different in what they make and therefore in how the experiment is performed. Similarly Conveying the feelings and sensations experienced during the illusion can be difficult. [Participants have often stated that they don’t have words to explain what they are feeling, they know something strange is happening but often won’t have the words to describe it. The workshop leader must work In collaboration with the participant to map these sensations, always asking for feedback using various probing questions to elicit a response

Rating types of participant:

E1. Strong believer: Instant wow reaction, Laughing, an immediate reaction what going on/how are you doing that? The illusion works, They feel full ownership over the object.

E2. Believer: They some feel ownership over the object.

E3. The amused: Instantly laughs/face lights up. They know something strange is going on and the sensation amuses them. But They do not entirely believe its their hand.

E4. Ambiguous: Somethings happening, talkative, able to explore feelings openly. Maybe feels like their hand a bit.

E5. The “desperate to believe”. Really disappointed that it doesn’t work, keen to keep experimenting.

E6. it’s not working: Nothing happens. Maybe sceptical. Have little to say about it.

E7: Other:

[1] This is a deceptively simple Workshop . The artistry comes in the ability of the experimenter to draw the participant into the illusion. especially when using unfeasible objects for the illusion . Through my research I find that not all participants able to experience this illusion.

After explaining what will happen in the workshop there are certain types of reaction initiated It’s worth taking notes of these. Classically this will go along the lines of “I won’t be any good at this I’m not creative.” which is partly to do with the Fact that they have been asked to make something From clay and this to them seems like a creative activity. So it is important to emphasise that these objects are not judged in terms of artistic quality, It is an experiment . The active blind drawing helps participants Also serves to disrupt ideas about a drawing that is good or bad; rather the act of drawing is an experiment Participants need to feel at ease with the making and not to feel that it’s going to be measured on how good it is .