I count myself as one of the many Russel fans, but I have to admit that if
this article were my first encounter with his thoughts then my opinion on him
would probably be very different.

In this speech Russel loosely identifies 3 competing views regarding what
constitutes the central motives behind human actions:

- His own view, that he states upfront: All human activity is prompted by
desire and men differ from each others and from animals mainly because they
desire different things.

- All human activity is governed by a sense of virtues (Russel focus on "sense
of duty" but I think it's fairer to enlarge this class of arguments a bit).
This is a major leitmotiv in conservative worldviews although Russel does not
name it as such.

- All human activity is governed by the material circumstances in which they
live, mentioned rather "en passant", and the landmark of the other end of
the spectrum as far as worldview is concerned, the one that cannot be named.

Russel goes on by enumerating (some of?) those desires/motives:
acquisitiveness, rivalry, vanity and love of power.

He gives some illustrations, many of which are funny but none convincing.

His posits that the most important determinant of human behavior is how much
one is sensible to each of those desires, yet he has to concede that human
desires do not merely differs in intensity but also in quality, noting that,
for instance, acquisitiveness can come in various shapes: accumulation of
money for some, of potatoes for others. But then, one might ask, what causes
some to seek gold rather than potatoes ? Russel's answer: it depends on
the material circumstances that one was subjected to in childhood. Oh, but
wait...

All in all, I find this speech not only unconvincing but actually reactionary
in the sense that it seems to ignore what we actually know about behaviors,
desires and feelings (especially today, but maybe even in 1950). And we know
actually a thing or two about behaviors of social apes, but that's not usually
written in sociology books nor in psychology books nor in history books. One
have to resort to evolutionary sciences or even better: primatology.

Russel mentions observing apes in the zoo and recognizes that they
can exhibit curiosity ("escape from boredom"). Youtube addicts might remember
that viral video of a chimp entertaining himself by teasing a tiger. But that
goes well beyond that: primatologists have indeed observed a range of motives
in chimps that are familiar to us humans. But when its about chimps we don't
tell ourselves stories about idealized motives: at the end of the day, it's
all about mating partners, although the chimps themselves may believe in
more sophisticated explanation.

Desires and feelings, it turns out, might not be that unique. It is no longer
believed that they originates from the human-only evolved cortex, but
more likely from the brain stem, of ancient descent and thus commonplace in
the animal kingdom. We don't know what it feels like to be a bat, except that in
some way we do know: the bat experiences fear, hunger, sexual attraction,
social competition, tiredness, curiosity... We have no idea what the world
"feels like" for a bat, having different senses and different brainpower, but
the desires and emotions we can recognize easily, because we share many of
them.

So if one is after what makes human actions distinct, one should probably look
at something else than desires.