unshift(@($this->{Memory}),$this->{Senses});

##</code><code>##

my $this = {
    Memory => ["foo"],
    Senses => "bar",
};

unshift @{$this->{Memory}}, $this->{Senses};

use Data::Dumper; print Dumper $this;

__END__
$VAR1 = {
          'Senses' => 'bar',
          'Memory' => [
                        'bar',
                        'foo'
                      ]
        };