These four songs along with the five of volume three, which Mahler composed between 1887 and 1890, are often performed together and represent a distinctive stage in Mahler's development. Brentano and Armin's collection of German folk poetry Das Knaben Wunderhorn (The Youth's Magic Horn) is the source of the texts, and represents the primary source of Mahler's inspiration for the next fourteen years. It is in these earliest songs from this collection (he composed many more) that several of Mahler's most characteristic traits were first developed. In particular, he introduced here the artistic and ironic use of popular elements as expressive devices. Although Mahler was attempting to imitate the folk song style of the texts, he used many devices from the art song, which lend a subtle sophistication and complexity to these sometimes simple-sounding settings. The combination of structural and artistic subtlety with a popular and folk-inspired stylistic naïveté was to become a hallmark of Mahler's music for the next several years.
Um schlimme Kinder artig zu mächen (To Teach Naughty Children to Good), with its bourrée-inspired rhythm and almost silly cuckoo calls introduces a humor best described as keck, meaning "cheeky" or "pert." This style is quite important to Mahler's earlier Symphonies. The song is in simple strophic form.
An even more folk-like setting is Ich ging mit Lust durch einen grünen Wald (Full of Joy I walked through a green wood). The widely spaced intervals of the vocal line and the stylized birdcalls are distinctively Mahlerian. The musical form is a simple da capo.
In Aus! Aus! (Over! Over!), Mahler altered the order of the text stanzas to match his musical form. It is a rondo-like form where each verse is preceded and followed by a recurring passage or ritornello. To depict the departure of the girl's soldier lover, Mahler used the military effects of a quick march rhythm, horn fifths and drumbeats. This is the first time we hear these effects which eventually become such important parts of Mahler's symphonic style. The alternation of the military march with the mock-plaintive whining of the soldier's lover is a humorously ironic touch.
Very similar in style and form to Um schlimme Kinder artig zu mächen, Starke Einbildungskraft is the shortest and simplest song of the collection. The pert humor of the text is reflected perfectly in Mahler's newly formed keck style.