Ujian untuk kemunculan mens rea mungkin:

(a) subjektif, di mana mahkamah harus puas bahawa yang dituduh sebenarnya mempunyai elemen mental yang diperlukan hadir dalam mindanya pada waktu yang berpatutan (untuk secara bertujuan, mengetahui, tidak berhati-hati dsb) (lihat persetujuan);(b) objektif, di mana elemen yang perlu mens rea menuduh pada yang telah dituduh, pada dasar bahawa seorang bertimbang rasa akan mempunyai elemen mental dalam keadaan sama (untuk kelalaian); atau(c) gabungan, di mana ujian adalah subjektif dan objektif.

Mahkamah akan mempunyai sedikit kesukaran dalam menubuhkan mens rea jika ada sebenarnya bukti – misalnya, jika yang dituduh membuat suatu admissible admission. Ini akan memuaskan suatu ujian subjektif. Tetapi sebahagian agak besar yang dituduh melakukan jenayah tidak membuat admission seperti yang dikatakan tersebut. Oleh itu, sesetengah peringkat keobjektifan harus ditanggung sebagai asas yang mana untuk menuduh komponen yang perlu. Ia sentiasa adalah bertimbang rasa untuk menganggap bahawa orang dari kecerdikan biasa menyedari keliling fizikal mereka dan dari hukum biasa sebab dan kesan (lihat penyebaban). Oleh itu, apabila seorang merancang apa yang dilakukan dan apa yang tidak dilakukan, dia akan memahami lingkungan likely outcomes dari kelakuan yang diberikan pada skala gelincir dari "inevitable" ke "probable" ke "possible" ke "improbable". The more an outcome shades towards the "inevitable" end of the scale, the more likely it is that the accused both foresaw and desired it, and, therefore, the safer it is to impute intention. If there is clear subjective evidence that the accused did not have foresight, but a reasonable person would have, the hybrid test may find criminal negligence. In terms of the burden of proof, the requirement is that a jury must have a high degree of certainty before convicting. It is this reasoning that justifies the defences of infancy, and of lack of mental capacity under the M'Naghten Rules, and the various statutes defining mental illness as an excuse. Self-evidently, if there is an irrebuttable presumption of doli incapax - that is, that the accused did not have sufficient understanding of the nature and quality of his actions – then the requisite mens rea is absent no matter what degree of probability might otherwise have been present. For these purposes, therefore, where the relevant statutes are silent and it is for the common law to form the basis of potential liability, the reasonable person must be endowed with the same intellectual and physical qualities as the accused, and the test must be whether an accused with these specific attributes would have had the requisite foresight and desire.

In English law, s8 Criminal Justice Act 1967 provides a statutory framework within which mens rea is assessed. It states:

A court or jury, in determining whether a person has committed an offence,(a) shall not be bound in law to infer that he intended or foresaw a result of his actions by reasons only of its being a natural and probable consequence of those actions; but(b) shall decide whether he did intend or foresee that result by reference to all the evidence, drawing such inferences from the evidence as appear proper in the circumstances.

Under s8(b) therefore, the jury is allowed a wide latitude in applying a hybrid test to impute intention or foresight (for the purposes of recklessness) on the basis of all the evidence.