The meaning of "disriminated against" is a subset of the meanings which may be conveyed by "discriminated".
Adding "against" could be held, as @Irene suggests, to complete the meaning of the verb, but arguably it modifies the meaning or selects a subset of the possible meanings.
"To discriminate" has a clear meaning in its own right and "discriminate against" has a different meaning with clear connotations of opprobrium or unfavorable action which are not expressly conveyed by "discriminate" alone. .
By itself "discriminate " does not have any sense of assigning relative values - it just carries the sense of having distinguished a difference, and perhaps of having acted differently due to a distinguished difference, but still not in a positive or negative sense. Properly it implies "discriminated between".
Also, "discriminated against" indicates that there is a corresponding and inseparable "discriminated in favour of" taking place simultaneously. The two may be seen as "different faces of the same coin, but not necessarily so.
eg if a selection process 'discriminated against students with low stature' it necessarily discriminates in favour of those with greater stature. So "discriminated against is a subset of the total process taking place. But in another example the positive act and negative act could be separate. eg put money in the accounts of xxx. Took money from the accounts of yyy.
While "discriminated" or "discriminated between" may suggest that the process has negative and positive connotations this is not necessarily the case.
"Each day he discriminated whether the day's date was divisible by 7" [or not]
< "or not" added to clear brain filters. >
The two comments so far:
Stated that 'discriminated' was used incorrectly in the last sentence above. It's nice to be so certain of one's usage, I imagine.
Queried whether 'discriminated whether' was valid
Needless to say, I consider the usage valid.
Below are a few 'more of the same' samples from the web.
At 40,000 odd Gargoyle hits it's not overly common usage.
However, decide for yourself:
Note that
Samples from the net:
Some of these are far more euphonic than others
Some are questionable.
Some 'feel' very right.
Nature, letters.
Attention modulates synchronized
neuronal ®ring in
primate somatosensory corte
- Monkey M3 discriminated whether bars (6.0 mm long) presented successively to a distal ®ngerpad had
the same or different (by 908) orientations
Springer images
- Tilt discrimination display in which subjects discriminated whether both lines were tilted to the right or left (shown) of vertical
Patent
[Video signal convering apparatus and method]( It is discriminated whether the input video signal is an interlaced video signal or not, and it is discriminated whether the input video signal is a video signal from a film source based on a film.) - Awkward
- It is discriminated whether the input video signal is an interlaced video signal or not, and it is discriminated whether the input video signal is a video signal from a film source based on a film.
The Journal of Neuroscience
Neural Activity in Cortical Area V4 Underlies Fine Disparity Discrimination
Author names Asian? English used generally seems extremely competent.
- Monkeys discriminated whether the center disk of a dynamic random-dot stereogram was in front of or behind its surrounding annulus
Patent. 4 uses.
Awkward feel.
Probe method
- According to the method, it can be discriminated whether or not the wafer is circular. Also, it can be discriminated whether or not a detecting member having a tactile sense detecting the contact between the probe needles and the chip is used when measuring. Moreover, it can be discriminated whether or not the range of the chips to be measured on the wafer is designated. Also, it can be discriminated whether or not the tips of the needles are polished.
Pubmed
Sexual victimization and adolescent weight regulation practices: a test across three community based samples.
- Sexual victimization was associated more strongly with extreme forms of weight regulation and significantly discriminated whether girls would choose multiple weight regulation forms.