Q: How many attention heads does the base model use?
According to the context, the base model uses **h = 8 parallel attention heads**.
3 source chunks
but
its
application
should
be
just
-
this
is
what
we
are
missing
,
in
my
opinion
.
<EOS>
<pad>
Figure 4: Two attention heads, also in layer 5 of 6, apparently involved in anaphora resolution. Top:
Full attentions for head 5. Bottom: Isolated attentions from just the word ‘its’ for attention heads 5
and 6. Note that the attentions are very sharp for this word.
14
but
its
application
should
be
just
-
this
is
what
we
are
missing
,
in
my
opinion
.
<EOS>
<pad>
Figure 5: Many of the attention heads exhibit behaviour that seems related to the structure of the
sentence. We give two such examples above, from two different heads from the encoder self-attention
at layer 5 of 6. The heads clearly learned to perform different tasks.
15
i ∈ Rdmodel×dk, W K
i ∈ Rdmodel×dk, W V
i ∈ Rdmodel×dv
and W O ∈ Rhdv×dmodel.
In this work we employ h = 8 parallel attention layers, or heads. For each of these we use
dk = dv = dmodel/h = 64. Due to the reduced dimension of each head, the total computational cost
is similar to that of single-head attention with full dimensionality.
3.2.3 Applications of Attention in our Model
The Transformer uses multi-head attention in three different ways:
July 12, 2026, 10:33 a.m.