Erro ao executar a migration.

Olá.

Criei o arquivo de migration AdicionaCampoAssistido com o comando

php artisan make:migration adiciona_campo_assistido --table=episodios

e alterei o aquivo para adicionar o campo 'assistido' na tabela 'episodios'

<?php

use Illuminate\Support\Facades\Schema;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Database\Migrations\Migration;

class AdicionaCampoAssistido extends Migration
{

    public function up()
    {
        Schema::table('episodios', function (Blueprint $table) {
            $table
                ->boolean('assistido')
                ->deafault(false);
        });
    }
    public function down()
    {
        Schema::table('episodios', function (Blueprint $table) {
            $table->dropColumn('assistido');
        });
    }
}

Mas quando vou executar a migration com o comando php artisan migrate acontece o seguinte erro:

C:\Users\Usuario\Desktop\Alura\controle-series>php artisan migrate
Migrating: 2019_11_29_154138_adiciona_campo_assistido

   Illuminate\Database\QueryException  : SQLSTATE[HY000]: General error: 1 Cannot add a NOT NULL column with default value NULL (SQL: alter table "episodios" add column "assistido" tinyint(1) not null)

  at C:\Users\Usuario\Desktop\Alura\controle-series\vendor\laravel\framework\src\Illuminate\Database\Connection.php:664
    660|         // If an exception occurs when attempting to run a query, we'll format the error
    661|         // message to include the bindings with SQL, which will make this exception a
    662|         // lot more helpful to the developer instead of just the database's errors.
    663|         catch (Exception $e) {
  > 664|             throw new QueryException(
    665|                 $query, $this->prepareBindings($bindings), $e
    666|             );
    667|         }
    668|

  Exception trace:

  1   PDOException::("SQLSTATE[HY000]: General error: 1 Cannot add a NOT NULL column with default value NULL")
      C:\Users\Usuario\Desktop\Alura\controle-series\vendor\laravel\framework\src\Illuminate\Database\Connection.php:452

  2   PDO::prepare("alter table "episodios" add column "assistido" tinyint(1) not null")
      C:\Users\Usuario\Desktop\Alura\controle-series\vendor\laravel\framework\src\Illuminate\Database\Connection.php:452

  Please use the argument -v to see more details.