Shepard-Luce Choice Rule

The Shepard-Luce choice rule is a choice rule for a human to identify if an object $x$ is in a category $i$.

$$ P(\text{x is i}) = \frac{\nu(x, i)}{\sum_{j\in R} \nu(x, j)} $$

• $\nu(x,i)$: strength of evidence that $x$ is $i$
• $R$ all the responses categories of categories for $x$. $j$ is one category out of $R$. $i$ has to be a category of $R$.

The Shepard-Luce choice can be used in both choice modes and race models.