The so-called herding instinct is a social tendency in humans to identify with and model many behaviors and beliefs after a larger group of individuals with whom they identify. This is sometimes referred to as "following the herd".

Since the herding instinct includes both behavior and belief, the term 'herd behavior' describes only a part of this complex phenomenon in humans.

Although the results that come from the herding instinct can sometimes come from active choice to follow a particular group or style, it most often comes from subconscious choice, choices one makes without even being aware of it.

The herding instinct in humans manifests in a number of ways. Three of the largest/most evident manifestations are in

• Buying and selling goods and services,
• buying and selling financial assets, and in
• religio-cultural group affiliation and practice.

Buying and selling goods and services -- whether it be clothes or cars, the places one eats out or the kinds of foods one chooses to prepare at home, or the choice to purchase therapeutic massage, acupuncture or manicures, the human tendency to herd is a significant factor in all of our choices. While much behavior in the modern developed world tends toward conspicuous consumption or consumerism, the herding instinct in humans is often quite contrary among different groups. For example, others are influenced by the herding instinct in their choice to be anti-consumerist or anti-globalist. While some buy to be status-enhancing , others buy/wear to lower their apparent status, while others avoid drinking coffee at Starbucks or eating at Planet Hollywood for reasons that are not wholly rational; i.e., are in some part to identify with their herd.

Buying and selling financial services -- herding belief, and behavior, is seen in the majority typically seen in the financial markets who tend to 'move with the market,' or 'follow the general market trend.' Similarly, there is a much-smaller contrarian or 'counter-trend' herd that may be observed in most financial markets.

Cultural-religio group affiliation and practice is also greatly influenced by the human instinct to herd. While humans are complex, and thus can and do make rational (and irrational) choices counter to their current group identification, especially in adolescence, this is not the norm for most. The more typical result seen in human society is to stick with the 'herd' (cultural identification, ethnic identification, religious identification, tribal/clan identification, etc.) that one was born into and raised with. Furthermore, even when, say, the adolescent choice is to leave the cultural-religio herd they were raised in, they virtually always settle into a new herd rather than living life as a loner or hermit.

The herding instinct in humans can have both positive and negative effects.

See also collective consciousness, social psychology