The Articulate Mammal (42 page)

A fourth general difficulty concerns compression of information. Humans need thinking space to let information ‘sink in’, and they comprehend best if they are presented only with a small amount of new information at one time. This is why Longfellow’s poem
The Song of Hiawatha
is so easy to follow. Each line repeats some information from the previous one, so there is only a small amount of new material in each one:

By the shores of Gitche Gumee,

By the shining Big-Sea-Water,

Stood the wigwam of Nokomis,

Daughter of the Moon, Nokomis.

Dark behind it rose the forest,

Rose the black and gloomy pine-trees,

Rose the firs with cones upon them;

Bright before it beat the water,

Beat the clear and sunny water,

Beat the shining Big-Sea-Water.

This slow dropping of information contrasts strikingly with the overcompressed:

THIS IS THE BUS THAT THE CAR THAT THE PROFESSOR THAT THE GIRL KISSED DROVE HIT.

A further difficulty involves the repetition of items and structures. It is difficult to process a sentence which contains the same word twice, or more
than one instance of the same type of structure, especially if the similar constructions are one inside the other. Take the sentence:

THIS IS THE BUS [THAT THE VAN [THAT THE CAR HIT] HIT].

This sentence with the repeated word HIT is more difficult than:

THIS IS THE BUS [THAT THE VAN [THAT THE CAR HIT] COLLIDED WITH].

And the sentence above, which has a so-called relative clause inside another relative clause, is more difficult than a relative clause inside a different type of clause:

I EXPECT [THAT THE BUS [WHICH HIT THE VAN] IS DAMAGED].

In fact, it is so difficult to process one type of clause inside another similar one, that at least one linguist has suggested excluding such sentences from a grammar altogether. But this is not a workable suggestion, because it would also exclude perfectly good sentences such as:

THE OCTOPUS [WHICH THE FISHERMAN [YOU WERE TALKING TO] HAD CAUGHT] LOOKED QUITE REVOLTING.

This is a relative clause inside another relative clause.

Another difficulty, which seems to be partly a general psychological one, and partly a linguistic one, is the difficulty of backward processing (Grosu 1974). In English we normally move forwards when we process sentences. For example, it is easy to comprehend:

MARY, PETER AND PRISCILLA PLAY THE FLUTE, THE PIANO AND THE GUITAR RESPECTIVELY.

In this, the order of the people and the instruments they play moves from left to right:

It is considerably more difficult to understand:

MARY, PETER AND PRISCILLA PLAY THE GUITAR, THE PIANO AND THE FLUTE REVERSELY.

Here, the instruments are given backwards, and you have to reverse the order in which they occur before you can sort out who is playing what:

The same kind of reversal occurs in the sentence:

THE CAR THAT THE PROFESSOR THAT THE GIRL KISSED DROVE CRASHED.

Backward processing (and compression) may also be why it is difficult to understand:

MY AUNT’S EMPLOYER’S SON’S UMBRELLA’S COLOUR IS YELLOW.

compared with the left-to-right uncompressed sentence:

THE COLOUR OF THE UMBRELLA OF THE SON OF THE EMPLOYER OF MY AUNT IS YELLOW.

though alternative explanations are possible (Yngve 1961/1972; Miller and Chomsky 1963; Frazier and Rayner 1988).

Another partly linguistic, partly psychological factor which increases comprehension difficulty is the omission of surface ‘markers’. These are items which help to identify the various constructions. The fewer clues available for recognizing a structure, the more difficult it will be to identify. This is true whether we are dealing with a sentence in a language, or a partly hidden object in front of our eyes. Just as a picture of a face which lacks a nose may take longer to recognize than one with eyes, nose and mouth all complete, so a sentence with a word seemingly missing will take longer to comprehend (Fodor
et al.
1968; Hakes 1971; Fodor
et al.
1974). For example:

THE CROW THE FOX FLATTERED LOST ITS CHEESE.

is more difficult than:

THE CROW WHICH THE FOX FLATTERED LOST ITS CHEESE.

In the second sentence WHICH is retained, enabling speakers to note more quickly that they are dealing with a relative clause. Similarly:

SEBASTIAN NOTICED THE BURGLAR HAD LEFT FOOTPRINTS.

takes longer to comprehend than:

SEBASTIAN NOTICED THAT THE BURGLAR HAD LEFT FOOTPRINTS.

Here, the word THAT gives an immediate indication to the hearer that he is dealing with a so-called ‘complement structure’.

Yet another factor which straddles the gap between psychological and linguistic difficulties is the presence of a negative. In general, negative sentences take longer to comprehend than affirmative ones. However, within negative sentences there are some strange discrepancies which relate to the hearer’s expectations about his world. For example, it is easier and quicker to negate an expected fact than an unexpected one: it takes less time to comprehend the sentence:

THE TRAIN WAS NOT LATE THIS MORNING

if you had
expected
the train to be late. If the train was normally on time, the same sentence would take longer to process. Similarly:

A WHALE IS NOT A FISH and A SPIDER IS NOT AN INSECT.

are simpler, and take less time to understand, than:

A WHALE IS NOT A BIRD and A SPIDER IS NOT A MAMMAL.

because hearers had
expected
the whale to be a fish and the spider an insect (Wason 1965).

Let us now summarize this section. We have listed a number of general factors which can make a sentence more difficult to understand. We noted that short-term memory space is limited, that there seems to be a constraint on the number of sentoids that can be processed simultaneously, that unmarked interruptions are difficult to deal with, and so is a sentence which contains too much compressed information. We saw that repetition of items and structures causes problems, and so does backward processing. The deletion of surface clues slows down syntax recognition, and negatives delay sentence processing.

THE STORY SO FAR

A great deal of work still needs to be done before we fully understand what is happening when we comprehend speech. But, as we have seen, there are a number of ways in which we can usefully approach the problem. First, we can explore the lexicon, looking in particular at how words are identified, at the treatment of ambiguous words, and at the role of verbs. Second, we can build up a list of basic assumptions that hearers make about their language, and note the strategies which they utilize when they understand sentences. Third, we can explore both the step-by-step stages and the multiple actions which are taking place as a human tries to interpret what they hear. Fourth, we can assess the general psychological difficulties which affect speech processing. A final step, still in the future, is to integrate all these various strands into a coherent model of speech comprehension.

A further issue is how general background information is combined with the linguistic facets of a sentence. The tricky and voluminous question of how humans represent the world they live in has not been examined in this book.

Resolving these problems might seem impossible, considering the conflicting views of psycholinguists. But certain facts are becoming clear. Above all, the human mind is an amazingly powerful machine, capable of multiple parallel processing. The major question for the future is how it manages to amalgamate everything together into a manageable whole, instead of getting lost in the umpteen possibilities which are inherent in the data.

Let us now turn to the topic of speech production. As we shall see, this presents us with even more problems than comprehension.

11

____________________________

THE CHESHIRE CAT’S GRIN

How do we plan and produce speech?

‘I wish you wouldn’t keep appearing and vanishing so suddenly,’ said Alice. ‘You make one quite giddy.’

‘All right,’ said the Cat; and this time it vanished quite slowly, beginning with the end of the tail, and ending with the grin, which remained some time after the rest of it had gone.

‘Well! I’ve often seen a cat without a grin,’ thought Alice; ‘but a grin without a cat! It’s the most curious thing I ever saw in all my life!’

Lewis Carroll,
Alice in Wonderland

It is tantalizingly difficult to observe how anyone actually plans and produces speech. When somebody utters a sentence, we have very little idea how long it actually took to plan it, and what processes were involved. It is equally hard to devise experiments to test what is going on. There are relatively few reported in psycholinguistic journals, compared with the thousands available on speech comprehension. Consequently, we shall be very tentative over any conclusions we draw. As Fodor
et al.
commented over a quarter-century ago: ‘Practically anything that one can say about speech production must be considered speculative, even by the standards current in psycholinguistics’ (1974: 434). Almost the same is true in the twenty-first century: ‘There has been less research on language production than on language comprehension … The investigation of production is perceived to be more difficult than the investigation of comprehension’ (Harley 2001: 349).

Clues to what is happening are infuriatingly elusive. In fact, there seems to be only one situation in which we can actually catch a speaker as he mentally
prepares an utterance, and that is when someone is trying to recall a forgotten name. The name is often on ‘the tip of their tongue’, but they cannot quite remember it. Their mind is not completely blank as far as the word is concerned. A teasing and seemingly uncatchable wraith of it remains. He is left with a ‘kind of disembodied presence, a grin without the Cheshire Cat’ (Brown 1970: 234). This ‘tip of the tongue’ phenomenon will be discussed on pp. 225–6.