Perception Verbs plus Infinitive or Gerund

When you catch someone doing something - you see her leave, you hear the door close, you feel the floor shake - Spanish gives you a tidy two-way choice. The verbs of perception (ver, oír, escuchar, sentir, mirar, notar) take either an infinitive or a gerund after their object, and the choice quietly changes what you are reporting: the whole action, or the action in progress.

• La vi salir. (I saw her leave / go out.) - the complete going-out, start to finish.
• La vi saliendo. (I saw her leaving.) - a snapshot, caught mid-departure.

Same event, two camera angles. This page sorts out which to pick, how the pronouns work, and why ver is not quite mirar.

The infinitive: perceiving the whole action

Perception verb plus infinitive reports the action as a single, complete whole. You witnessed the event from beginning to end, or at least you view it as one finished unit.

• La vi salir. (I saw her leave.)
• Oí cerrar la puerta. (I heard the door close / be closed.)
• Los oí cantar. (I heard them sing.)
• Sentí temblar la casa. (I felt the house shake.)
• Vimos aterrizar el avión. (We watched the plane land.)

This is the default structure and the one to reach for when in doubt. The infinitive gives no sense of the action stretching on; it is the event, boxed up and reported.

The gerund: perceiving the action in progress

Swap the infinitive for a gerund (-ando / -iendo) and you freeze the action mid-flow. You caught it happening, ongoing, without claiming to have seen the whole thing.

• La vi saliendo. (I saw her leaving - on her way out, mid-action.)
• Lo oí cantando. (I heard him singing away - the singing was in full swing.)
• La noté temblando. (I noticed her trembling - it was ongoing.)
• Los vi jugando en el parque. (I saw them playing in the park.)

The gerund adds live, unfolding colour: the action was underway when your senses landed on it. Compare the pair directly:

• Oí a Juan tocar el piano. (I heard Juan play the piano.) - a whole performance, or the fact that he played.
• Oí a Juan tocando el piano. (I heard Juan playing the piano.) - I caught him mid-tune, the playing in progress.

If you could say "in the middle of doing it" or "away" in English (singing away, working away), the gerund fits. If you mean the complete act, use the infinitive.

The pronoun: the doer is a direct object

The person or thing you perceive is the direct object of the perception verb, so it takes a direct-object pronoun placed before the conjugated verb:

• La vi salir. (I saw her leave.)
• Los oí cantar. (I heard them sing.)
• Lo sentí temblar. (I felt it shake.)

Use lo / la / los / las for the perceived doer, never the indirect le / les - it is a direct object, not an indirect one.

Naming the doer: perception verb + object + verb

If you spell out who you perceived rather than using a pronoun, the doer sits between the perception verb and the infinitive or gerund. When that doer is a person, you need the personal a:

• Vi a Pedro arreglar el coche. (I saw Pedro fix the car.) - whole action.
• Vi a Pedro arreglando el coche. (I saw Pedro fixing the car.) - caught mid-repair.
• Oí a los niños jugar. (I heard the children play.)
• Escuché a mi vecina cantar. (I listened to my neighbour sing.)

The a marks the human object being perceived. Drop it and the sentence sounds wrong: not vi Pedro arreglar, but vi a Pedro arreglar. With a non-person, no a is needed: oí cerrar la puerta.

ver vs mirar, oír vs escuchar

All six verbs share the identical structure, but they split into passive perception and deliberate attention:

• ver = to see (it reaches your eyes). mirar = to watch, to look at (you point your gaze).
• oír = to hear (it reaches your ears). escuchar = to listen to (you point your attention).
• Vi a Juan cruzar la calle. (I saw Juan cross the road.) - it simply happened before me.
• Miré a Juan cruzar la calle. (I watched Juan cross the road.) - a chosen act of watching.
• Oí a los niños cantar. (I heard the children sing.) - the sound arrived.
• Escuché a los niños cantar. (I listened to the children sing.) - on purpose, attending.

Pick ver or oír for what merely reached your senses, mirar or escuchar for what you actively watched or listened to. The infinitive-or-gerund choice works the same across all four.

sentir and notar: feeling and noticing

Sentir (to feel, to sense) and notar (to notice) join the club, most often with the infinitive for a whole event, and the gerund when the sensation was ongoing:

• Sentí temblar la casa. (I felt the house shake.)
• Sentí la casa temblando. (I felt the house shaking - ongoing.)
• Noté a alguien acercarse. (I noticed someone approach.)
• La noté llorando. (I noticed her crying.)

Keep sentir here on the perception side. It reports what you sensed, not anything you caused.

The verbs at a glance

Not the same as the causative

This pattern looks like the causative hacer / mandar + infinitive, but the meanings are opposite. A perception verb reports what you witnessed someone doing on their own; the causative means you caused the action:

• La vi salir. (I saw her leave.) - she left, I watched.
• La hice salir. (I made her leave.) - my doing, not just my watching.

If the subject only sensed the event, it is a perception verb. If the subject brought it about, it is a causative. They share the infinitive structure, so keep them apart by meaning.

Common mistakes English speakers make

Reaching for the gerund by default. English says "I saw her leaving" as readily as "I saw her leave", but Spanish treats the infinitive as the neutral choice for a whole action: la vi salir. Save saliendo for when you genuinely mean mid-action.

Using the indirect pronoun. The doer is a direct object: la vi, los oí, not le vi, les oí. Use lo / la / los / las.

Dropping the personal a. With a named person you must keep it: vi a Pedro arreglar el coche, never vi Pedro arreglar.

Confusing ver with mirar, oír with escuchar. For what merely reached you, use ver / oír; for deliberate attention, mirar / escuchar. Escuché la conversación is nosier than oí la conversación on purpose.

Treating it as a causative. La vi salir is not I made her leave. Perception reports; hacer + infinitive causes.

See also

• The Spanish gerund: adverbial uses and traps - where the -ndo form works on its own and where English wrongly imports "-ing".
• The present progressive: estar + gerundio - the gerund's other main job, ongoing action right now.
• The uses of the infinitive - the form that does the whole-action job here and the noun jobs elsewhere.
• Causative verbs: hacer and mandar + infinitive - the lookalike that means make someone do something, not merely see them do it.
• Object pronouns - the la / los / lo that mark the perceived doer.
• The Spanish grammar cheatsheet has the perception-verb table on one card.