MLDS (version 0.1-5)

Get6pts: Find All 6-point Conditions in data.frame

Description

Get6pts enumerates all 6-point conditions from a difference scaling experiment and is used as one of the input arguments for calculating an observer's likelihood for his performance on 6-point conditions.

Usage

Get6pts(x, ...)

Arguments

x

an object of class mlds.

...

Possibility of sending additional arguments but currently unused.

Value

• A list of three same size data.frames with an attribute, indices that is a three column data.frame with the same number of rows as each of the three data.frames. Each data.frame is of the format from a difference scaling experiment. Same named rows indicate three trials that form a 6-point condition, i.e., given the 6-tuple of stimuli, a, b, c, a', b', c',
• A
  data.frame indicating the trials (a, b) vs (a', b')
• B
  data.frame indicating the trials (b, c) vs (b', c')
• E
  data.frame indicating the trials (a, c) vs (a', c')
• The attribute gives the row numbers from which the trials were obtained from the original data.frame.

Details

The 6-point condition is defined on 6-tuples of points, a, b, c, a', b', c', ordered on a physical scale. The condition requires that if the pair $(a, b) > (a', b')$ and the pair $(b, c) > (b', c')$, then $(a, c) > (a', c')$.

References

Maloney, L. T. and Yang, J. N. (2003) Maximum likelihood difference scaling. Journal of Vision, 3(8):5, 573--585, http://journalofvision.org/3/8/5/, doi:10.1167/3.8.5.

See Also

SwapOrder, lik6pt, simu.6pt

Examples

data(kk1)
kk.6pt <- Get6pts(mlds(SwapOrder(kk1)))