diff --git a/src/useReactions.test.tsx b/src/useReactions.test.tsx
new file mode 100644
index 00000000..6b11a71a
--- /dev/null
+++ b/src/useReactions.test.tsx
@@ -0,0 +1,164 @@
+/*
+Copyright 2024 New Vector Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only
+Please see LICENSE in the repository root for full details.
+*/
+
+import { render } from "@testing-library/react";
+import { FC, ReactNode } from "react";
+import { describe, expect, test } from "vitest";
+import { MatrixRTCSession } from "matrix-js-sdk/src/matrixrtc/MatrixRTCSession";
+import {
+  EventTimeline,
+  EventTimelineSet,
+  EventType,
+  MatrixClient,
+  MatrixEvent,
+  Room,
+  RoomEvent,
+} from "matrix-js-sdk/src/matrix";
+import EventEmitter from "events";
+import { randomUUID } from "crypto";
+
+import { ReactionsProvider, useReactions } from "./useReactions";
+
+const membership = [
+  "@alice:example.org",
+  "@bob:example.org",
+  "@charlie:example.org",
+];
+
+const TestComponent: FC = () => {
+  const { raisedHands } = useReactions();
+  return (
+    <div>
+      <ul>
+        {Object.entries(raisedHands).map(([userId, date]) => (
+          <li key={userId}>
+            <span>{userId}</span>
+            <time>{date.getTime()}</time>
+          </li>
+        ))}
+      </ul>
+    </div>
+  );
+};
+
+const TestComponentWrapper = ({ room }: { room: MockRoom }): ReactNode => {
+  const fakeRtcSession = {
+    on: () => {},
+    off: () => {},
+    room,
+    memberships: membership.map((sender) => ({
+      sender,
+      eventId: "!fake:event",
+      createdTs: (): Date => new Date(),
+    })),
+  } as unknown as MatrixRTCSession;
+
+  return (
+    <ReactionsProvider rtcSession={fakeRtcSession}>
+      <TestComponent />
+    </ReactionsProvider>
+  );
+};
+
+function createReaction(sender: string): MatrixEvent {
+  return new MatrixEvent({
+    sender,
+    type: EventType.Reaction,
+    origin_server_ts: new Date().getTime(),
+    content: {
+      "m.relates_to": {
+        key: "🖐️",
+      },
+    },
+    event_id: randomUUID(),
+  });
+}
+
+function createRedaction(sender: string): MatrixEvent {
+  return new MatrixEvent({
+    sender,
+    type: EventType.RoomRedaction,
+    origin_server_ts: new Date().getTime(),
+    content: {},
+    event_id: randomUUID(),
+  });
+}
+
+export class MockRoom extends EventEmitter {
+  public constructor(private readonly existingRelations: MatrixEvent[] = []) {
+    super();
+  }
+
+  public get client(): MatrixClient {
+    return {
+      getUserId: (): string => "@alice:example.org",
+    } as unknown as MatrixClient;
+  }
+
+  public get relations(): Room["relations"] {
+    return {
+      getChildEventsForEvent: () => ({
+        getRelations: () => this.existingRelations,
+      }),
+    } as unknown as Room["relations"];
+  }
+
+  public testSendReaction(sender: string): void {
+    this.emit(
+      RoomEvent.Timeline,
+      createReaction(sender),
+      this,
+      undefined,
+      false,
+      {
+        timeline: new EventTimeline(new EventTimelineSet(undefined)),
+      },
+    );
+  }
+}
+
+describe("useReactions", () => {
+  test("starts with an empty list", () => {
+    const room = new MockRoom();
+    const { queryByRole } = render(<TestComponentWrapper room={room} />);
+    expect(queryByRole("list")?.children).to.have.lengthOf(0);
+  });
+  test("handles incoming raised hand", () => {
+    const room = new MockRoom();
+    const { queryByRole, rerender } = render(
+      <TestComponentWrapper room={room} />,
+    );
+    room.testSendReaction("@foo:bar");
+    rerender(<TestComponentWrapper room={room} />);
+    expect(queryByRole("list")?.children).to.have.lengthOf(1);
+    room.testSendReaction("@baz:bar");
+    rerender(<TestComponentWrapper room={room} />);
+    expect(queryByRole("list")?.children).to.have.lengthOf(2);
+  });
+  test("handles incoming unraised hand", () => {
+    const room = new MockRoom();
+    const { queryByRole, rerender } = render(
+      <TestComponentWrapper room={room} />,
+    );
+    room.testSendReaction("@foo:bar");
+    rerender(<TestComponentWrapper room={room} />);
+    expect(queryByRole("list")?.children).to.have.lengthOf(1);
+    room.emit(
+      RoomEvent.Redaction,
+      createRedaction("@foo:bar"),
+      room,
+      undefined,
+    );
+    rerender(<TestComponentWrapper room={room} />);
+    expect(queryByRole("list")?.children).to.have.lengthOf(0);
+  });
+  test("handles loading events from cold", () => {
+    const room = new MockRoom([createReaction(membership[0])]);
+    const { queryByRole } = render(<TestComponentWrapper room={room} />);
+    expect(queryByRole("list")?.children).to.have.lengthOf(1);
+  });
+});
diff --git a/src/useReactions.tsx b/src/useReactions.tsx
index b665c43f..1d09e112 100644
--- a/src/useReactions.tsx
+++ b/src/useReactions.tsx
@@ -131,8 +131,7 @@ export const ReactionsProvider = ({
         if (content?.["m.relates_to"].key === "🖐️") {
           addRaisedHand(sender, new Date(event.localTimestamp));
         }
-      }
-      if (event.getType() === EventType.RoomRedaction && event.getSender()) {
+      } else if (event.getType() === EventType.RoomRedaction) {
         // TODO: check target of redaction event
         removeRaisedHand(sender);
       }
@@ -145,7 +144,7 @@ export const ReactionsProvider = ({
       room.off(MatrixRoomEvent.Timeline, handleReactionEvent);
       room.off(MatrixRoomEvent.Redaction, handleReactionEvent);
     };
-  }, [room, raisedHands, addRaisedHand, removeRaisedHand]);
+  }, [room, addRaisedHand, removeRaisedHand]);
 
   return (
     <ReactionsContext.Provider