Neurology Commons^™

Learning From Mistakes: Improving Initial Fingertip Force Scaling By Observing Lifting Errors, Gavin Buckingham, Minnie Tang, Paul Gribble, Melvyn Goodale

Gavin Buckingham

• When lifting objects that are lighter or heaver than we expect them to be, individuals typically misapply forces in a way that reflects their prior expectations of heaviness.

• Because we lift in this predictive way, large and small cubes elicit these characteristic errors even when they are adjusted to have equal mass. Lifters will apply too much force to a large cube and substantially less force to a small cube – errors that are rapidly corrected with repeated lifts (Flanagan & Beltzner, 2000).

• When watching others lift objects, an observer’s motor system automatically reacts in a way …

A Dissociation Between Perception And Action In The Material‐Weight Illusion, Gavin Buckingham, Jonathan Cant, Kai-Ling Kao, Melvyn Goodale

Gavin Buckingham

We examined what forces are applied to objects that elicit this illusion when they are lifted.We predicted that:

(1) Forces on early trials will scale to each participant’s expectations of how much a particular block will weigh ‐ excessive force will be applied to the metal block and insufficient force applied to the polystyrene block.

(2) Forces on later trials will scale to the real weight of each block ‐ identical levels of force applied to all the blocks.

(3) MWI will persist throughout ‐ polystyrene block will feel the heaviest, metal block will feel the lightest.

Grasping And Lifting Different Materials, Gavin Buckingham, Jonathan Cant, Melvyn Goodale

Gavin Buckingham

The material from which an object is made can determine how heavy it feels (Seashore, 1899). Interestingly, a metal block that has been adjusted to have the same size and mass as a polystyrene block will feel lighter than the polystyrene block. We recently showed that participants experiencing this material-weight illusion’ (MWI) do not apply forces that match their perceptual experience of heaviness ‐ just like in the size‐weight illusion ( Flanagan & Beltzner, 2000).

Our previous study showed that forces on early trials were scaled to each participant’s expectations of how much a particular block should weigh ‐ excessive …