diff --git a/source/Rbm.cpp b/source/Rbm.cpp
index 7e5fe87..a8f566e 100644
--- a/source/Rbm.cpp
+++ b/source/Rbm.cpp
@@ -361,12 +361,21 @@ void Rbm::train(arma::mat const &batch, IListener* pListener)
 			// Adjust weight and biases
 			inc_bv = m_params.momentum*inc_bv + m_params.learningRate/numcases*dbv;
 			inc_bh = m_params.momentum*inc_bh + m_params.learningRate/numcases*dbh;
-			inc_whv = m_params.momentum*inc_whv + m_params.learningRate*(dwhv/numcases - m_params.weightDecay*m_whv);
+			inc_whv = m_params.momentum*inc_whv + m_params.learningRate*dwhv/numcases;
 
 			m_bv += inc_bv;
 			m_bh += inc_bh;
 			m_whv += inc_whv;
 
+			// Weight decay applied directly to the weights, outside the
+			// momentum recursion above -- folding it into inc_whv would let
+			// momentum geometrically amplify its effective strength to
+			// roughly weightDecay/(1-momentum), well past the configured value.
+			if (m_params.weightDecay != 0.0)
+			{
+				m_whv -= m_params.learningRate*m_params.weightDecay*m_whv;
+			}
+
 			progress += dProgress*miniBatchSizeActual;
 			status.progress = (int)(progress + 0.5);