Higher order Boltzmann machines (Sejnowski, ~1986)
	• The usual energy function is quadratic in the states:
	• But we could use higher order interactions:
		• Unit k acts as a switch. When unit k is on, it switches in the pairwise interaction between unit i and unit j. – Units i and j can also be viewed as switches that control the pairwise interactions between j and k or between i and k.