Cook (1995) criticizes the work of Jacobs and Kosslyn (1994) on spatia
l relations, shape representations, and receptive fields in neural net
work models on the grounds that first-order correlations between input
and output unit activities can explain the results. We reply briefly
to Cook's arguments here (and in Kosslyn, Chabris, Marsolek, Jacobs, &
Koenig, 1995) and discuss how new simulations can confirm the importa
nce of receptive field size as a crucial variable in the encoding of c
ategorical and coordinate spatial relations and the corresponding shap
e representations; such simulations would testify to the computational
distinction between the different types of representations.