addEventListener("click",...) firing immediately
<p>I'm trying to create some appropriately-placed instructional tooltips that users click through to understand how the site interface works. Each tooltip has a "next" link that toggles the visibility of the previous and next tooltips by modifying the classes (and hence, css).</p>

<p>Here's some simplified code that is supposed to do this:</p>

<pre><code>function displayTooltip(t){
  //...some code to determine the tooltip IDs "next" and "previous"
  document.getElementById(previous).className = "tooltip invisibleTooltip";
  document.getElementById(next).className = "tooltip";
}

document.getElementById("tooltip-link1").addEventListener("click", displayTooltip(2));
</code></pre>

<p><code>displayTooltip</code> is called immediately (and correctly toggles the class) when I paste this code into the console (or on page load). If I replace <code>displayTooltip</code> with an <code>alert()</code>, it fires when I click, as anticipated. What am I doing wrong?</p>