Memory devices including a controller configured to cause the memory device to apply a positive first voltage level to a first data line selectively connected to a first string of series-connected memory cells while applying a second voltage level, higher than the first voltage level, to a second data line selectively connected to a second string of series-connected memory cells; while applying the first voltage level to the first data line and applying the second voltage level to the second data line, applying a third voltage level to a particular access line coupled to a memory cell of a first string of series-connected memory cells selected for programming, wherein a differential between the third voltage level and the first voltage level is configured to increase a threshold voltage of the memory cell selected for programming, as well as other apparatus containing similar memory devices.