While I can't say anything about the tribal cultures you might be thinking of, I can tell you that it happened quite a bit during the violence that marred the late Roman republic.

The first ones who used the practice during those years were I believe Gaius Marius and Lucius Cornelius Cinna, who after their successful march on Rome would enact a bloody purge among their political enemies, and afterwards displayed their severed heads on the Rostra, the speaker's platform used for addressing the public.

Then when Lucius Cornelius Sulla took Rome back from the Marians after his own second march on Rome, he copied this practice from his nemesis Marius to use them for the victims of his own, much more formalized purges, the proscriptions.

And finally, when Mark Antony, Marcus Aemilius Lepidus and Gaius Octavian (the man who would go on to become Caesar Augustus, first emperor of Rome) revived Sulla's proscriptions after the formation of the second triumvirate, they also brought back the classic old Rostra decorations. Probably their most famous victim was Marcus Tullius Cicero, the famous advocate and orator, who had not only his head but also his hand displayed in this way, ostensibly because it had written the Philippics, a series of scathing polemics against Mark Antony.

In Britain, heads were displayed prominently on London Bridge into the 18th century. This was meant to act as a deterrence, as well as a display of authority. Edit: it would typically be prominent 'criminals' who would be reserved pride of place.

It was done in a number of cultures in Native North America. Chacon and Dye note that among Northwest Coast groups, human heads and their adornment were an important vehicle for status displays. They were manipulated while alive by cranial deformation, tattoos, and adornment with labrets, ear spools and other jewelry. It is not surprising then that skulls taken in battle were often displayed as war trophies. The authors note that the Kwakwaka'wakw (formerly Kwakiutl) were frequent practitioners of skull display.

Edit: Now that I have time and after further reading; the taking and display of human heads was a widespread practice among the Nu-cha-nulth (Nootka), Haida, and Tsimshian. Menzies, a botanist with Vancover's exploration of the Northwest describes the display of two skulls taken in battle:

[We] saw two human heads impaled upon the points of two poles erected a few yards asunder & and about 12 feet high, part of the Skin and Chin was hanging down but the rest of the face teeth & long black hair was entire in each... The poles had a degree of uniformity that required a good deal of effort (Newcombe 1928 in Chacon and Dye).

Skull display was a prestige maintenance activity that extended back to the prehistoric period (around 1850 BCE). Many Northwest groups believed that the skull was the residence of the soul. Decapitating an enemy and displaying the skull demonstrated ownership and thus prestige. This notion that the skull was the location of the soul was reflected in other cultural practices. Skulls of former chiefs were curated in special buildings and boxes and it is reported that some individuals slept on a bed of these skulls in an attempt to garner power from them.

Chacon and Dye, 2007

The Taking and Displaying of Human Body Parts as Trophies by Amerindians, Springer Science and Business Media

It was used as a deterrent to crime even in the 17th century. After the Bohemian nobility's revolt against the Habsburg Monarchy where they deposed the Catholic Ferdinand Habsburg with the elector Palatine Frederick, (since he was the leader of the protestant), Austria invaded to restore order, sparking the 30 Years War.

After the decisive Battle at White Mountain, where the Bohemian Estates lost to the Habsburgs and their allies, The Habsrburgs executed 27 leaders of the revolt (3 nobles, 7 knights and 17 burghers) in what is known as the Old Town Square execution. 12 heads were then put on display hanging in metal cages (fixed into place by iron spikes) from the Old Town Bridge Tower of the Charles bridge (6 on each side). Though 1 head was removed from the following year in May 1622 (Jáchym Ondřej Šlil) on the request of his widow, the other 11 continued to hang there until 1631 when the Saxon Armies entered the city and interred them in the Church of Our Lady before Týn.

The effects of the executions and display are readily visible in history. Placed on the only bridge that spanned an Imperial city and important center of trade in Central Europe, and especially due tot he aristocratic birth of the executed, everyone could clearly see the severe consequences to upsetting the Habsburgs. After this revolt, Bohemia would not rebel against their Habsburg overlords for another 300 years.

Sources: Toulky Českou Minulostí Volume. 4, Petr Hora-Hořejš, Baronet 1995

Královská Cesta, Jiří Všetečka, Panorama 1998

The New England colonists did this to Metacom (King Philip) after King Philip's War in the latter half of the 1670s. After being killed in battle, Metacom's body was dismembered. The man who shot him got to keep Metacom's hands. As for his head, it was placed on a pike over the gates of Fort Plymouth and remained there for two decades.