diff --git a/R/motifs.R b/R/motifs.R
index 5414a06712..4968d79d3b 100644
--- a/R/motifs.R
+++ b/R/motifs.R
@@ -24,7 +24,7 @@ triad.census <- function(graph) { # nocov start
 #' @inheritParams count_motifs
 #' @keywords internal
 #' @export
-graph.motifs.no <- function(graph, size = 3, cut.prob = rep(0, size)) { # nocov start
+graph.motifs.no <- function(graph, size = 3, cut.prob = NULL) { # nocov start
   lifecycle::deprecate_soft("2.0.0", "graph.motifs.no()", "count_motifs()")
   count_motifs(graph = graph, size = size, cut.prob = cut.prob)
 } # nocov end
@@ -39,7 +39,7 @@ graph.motifs.no <- function(graph, size = 3, cut.prob = rep(0, size)) { # nocov
 #' @inheritParams sample_motifs
 #' @keywords internal
 #' @export
-graph.motifs.est <- function(graph, size = 3, cut.prob = rep(0, size), sample.size = vcount(graph) / 10, sample = NULL) { # nocov start
+graph.motifs.est <- function(graph, size = 3, cut.prob = NULL, sample.size = vcount(graph) / 10, sample = NULL) { # nocov start
   lifecycle::deprecate_soft("2.0.0", "graph.motifs.est()", "sample_motifs()")
   sample_motifs(graph = graph, size = size, cut.prob = cut.prob, sample.size = sample.size, sample = sample)
 } # nocov end
@@ -54,7 +54,7 @@ graph.motifs.est <- function(graph, size = 3, cut.prob = rep(0, size), sample.si
 #' @inheritParams motifs
 #' @keywords internal
 #' @export
-graph.motifs <- function(graph, size = 3, cut.prob = rep(0, size)) { # nocov start
+graph.motifs <- function(graph, size = 3, cut.prob = NULL) { # nocov start
   lifecycle::deprecate_soft("2.0.0", "graph.motifs()", "motifs()")
   motifs(graph = graph, size = size, cut.prob = cut.prob)
 } # nocov end
@@ -110,7 +110,8 @@ dyad.census <- function(graph) { # nocov start
 #'   directed graphs and sizes 3-6 in undirected graphs.
 #' @param cut.prob Numeric vector giving the probabilities that the search
 #'   graph is cut at a certain level. Its length should be the same as the size
-#'   of the motif (the `size` argument). By default no cuts are made.
+#'   of the motif (the `size` argument).
+#'   If `NULL`, the default, no cuts are made.
 #' @return `motifs()` returns a numeric vector, the number of occurrences of
 #'   each motif in the graph. The motifs are ordered by their isomorphism
 #'   classes. Note that for unconnected subgraphs, which are not considered to be
@@ -125,10 +126,12 @@ dyad.census <- function(graph) { # nocov start
 #' motifs(g, 3)
 #' count_motifs(g, 3)
 #' sample_motifs(g, 3)
-motifs <- function(graph, size = 3, cut.prob = rep(0, size)) {
+motifs <- function(graph, size = 3, cut.prob = NULL) {
   ensure_igraph(graph)
-  cut.prob <- as.numeric(cut.prob)
-  if (length(cut.prob) != size) {
+
+  if (!is.null(cut.prob)) cut.prob <- as.numeric(cut.prob)
+
+  if (!is.null(cut.prob) && length(cut.prob) != size) {
     cut.prob <- c(
       cut.prob[-length(cut.prob)],
       rep(cut.prob[-length(cut.prob)], length(cut.prob) - 1)
@@ -138,7 +141,7 @@ motifs <- function(graph, size = 3, cut.prob = rep(0, size)) {
   on.exit(.Call(R_igraph_finalizer))
   res <- .Call(
     R_igraph_motifs_randesu, graph, as.numeric(size),
-    as.numeric(cut.prob)
+    cut.prob
   )
   res[is.nan(res)] <- NA
   res
@@ -156,7 +159,8 @@ motifs <- function(graph, size = 3, cut.prob = rep(0, size)) {
 #' @param size The size of the motif.
 #' @param cut.prob Numeric vector giving the probabilities that the search
 #'   graph is cut at a certain level. Its length should be the same as the size
-#'   of the motif (the `size` argument). By default no cuts are made.
+#'   of the motif (the `size` argument).
+#'   If `NULL`, the default, no cuts are made.
 #' @return `count_motifs()` returns  a numeric scalar.
 #' @seealso [isomorphism_class()]
 #'
@@ -168,10 +172,12 @@ motifs <- function(graph, size = 3, cut.prob = rep(0, size)) {
 #' motifs(g, 3)
 #' count_motifs(g, 3)
 #' sample_motifs(g, 3)
-count_motifs <- function(graph, size = 3, cut.prob = rep(0, size)) {
+count_motifs <- function(graph, size = 3, cut.prob = NULL) {
   ensure_igraph(graph)
-  cut.prob <- as.numeric(cut.prob)
-  if (length(cut.prob) != size) {
+
+  if (!is.null(cut.prob)) cut.prob <- as.numeric(cut.prob)
+
+  if (!is.null(cut.prob) && length(cut.prob) != size) {
     cut.prob <- c(
       cut.prob[-length(cut.prob)],
       rep(cut.prob[-length(cut.prob)], length(cut.prob) - 1)
@@ -181,7 +187,7 @@ count_motifs <- function(graph, size = 3, cut.prob = rep(0, size)) {
   on.exit(.Call(R_igraph_finalizer))
   .Call(
     R_igraph_motifs_randesu_no, graph, as.numeric(size),
-    as.numeric(cut.prob)
+    cut.prob
   )
 }
 
@@ -198,7 +204,8 @@ count_motifs <- function(graph, size = 3, cut.prob = rep(0, size)) {
 #'   in directed graphs and sizes 3-6 in undirected graphs.
 #' @param cut.prob Numeric vector giving the probabilities that the search
 #'   graph is cut at a certain level. Its length should be the same as the size
-#'   of the motif (the `size` argument). By default no cuts are made.
+#'   of the motif (the `size` argument).
+#'   If `NULL`, the default, no cuts are made.
 #' @param sample.size The number of vertices to use as a starting point for
 #'   finding motifs. Only used if the `sample` argument is `NULL`.
 #'   The default is `ceiling(vcount(graph) / 10)` .
@@ -224,8 +231,10 @@ sample_motifs <- function(
   sample = NULL
 ) {
   ensure_igraph(graph)
-  cut.prob <- as.numeric(cut.prob)
-  if (length(cut.prob) != size) {
+
+  if (!is.null(cut.prob)) cut.prob <- as.numeric(cut.prob)
+
+  if (!is.null(cut.prob) && length(cut.prob) != size) {
     cut.prob <- c(
       cut.prob[-length(cut.prob)],
       rep(cut.prob[-length(cut.prob)], length(cut.prob) - 1)
@@ -244,7 +253,7 @@ sample_motifs <- function(
   on.exit(.Call(R_igraph_finalizer))
   .Call(
     R_igraph_motifs_randesu_estimate, graph, as.numeric(size),
-    as.numeric(cut.prob), as.numeric(sample.size), sample
+    cut.prob, as.numeric(sample.size), sample
   )
 }
 
diff --git a/man/count_motifs.Rd b/man/count_motifs.Rd
index 3952cb1ccb..8d25e6d3c4 100644
--- a/man/count_motifs.Rd
+++ b/man/count_motifs.Rd
@@ -4,7 +4,7 @@
 \alias{count_motifs}
 \title{Graph motifs}
 \usage{
-count_motifs(graph, size = 3, cut.prob = rep(0, size))
+count_motifs(graph, size = 3, cut.prob = NULL)
 }
 \arguments{
 \item{graph}{Graph object, the input graph.}
@@ -13,7 +13,8 @@ count_motifs(graph, size = 3, cut.prob = rep(0, size))
 
 \item{cut.prob}{Numeric vector giving the probabilities that the search
 graph is cut at a certain level. Its length should be the same as the size
-of the motif (the \code{size} argument). By default no cuts are made.}
+of the motif (the \code{size} argument).
+If \code{NULL}, the default, no cuts are made.}
 }
 \value{
 \code{count_motifs()} returns  a numeric scalar.
diff --git a/man/graph.motifs.Rd b/man/graph.motifs.Rd
index 00ff37371b..e1481b26a0 100644
--- a/man/graph.motifs.Rd
+++ b/man/graph.motifs.Rd
@@ -4,7 +4,7 @@
 \alias{graph.motifs}
 \title{Graph motifs}
 \usage{
-graph.motifs(graph, size = 3, cut.prob = rep(0, size))
+graph.motifs(graph, size = 3, cut.prob = NULL)
 }
 \arguments{
 \item{graph}{Graph object, the input graph.}
@@ -14,7 +14,8 @@ directed graphs and sizes 3-6 in undirected graphs.}
 
 \item{cut.prob}{Numeric vector giving the probabilities that the search
 graph is cut at a certain level. Its length should be the same as the size
-of the motif (the \code{size} argument). By default no cuts are made.}
+of the motif (the \code{size} argument).
+If \code{NULL}, the default, no cuts are made.}
 }
 \description{
 \ifelse{html}{\href{https://lifecycle.r-lib.org/articles/stages.html#deprecated}{\figure{lifecycle-deprecated.svg}{options: alt='[Deprecated]'}}}{\strong{[Deprecated]}}
diff --git a/man/graph.motifs.est.Rd b/man/graph.motifs.est.Rd
index 0fdc61c397..cbd1fdbcad 100644
--- a/man/graph.motifs.est.Rd
+++ b/man/graph.motifs.est.Rd
@@ -7,7 +7,7 @@
 graph.motifs.est(
   graph,
   size = 3,
-  cut.prob = rep(0, size),
+  cut.prob = NULL,
   sample.size = vcount(graph)/10,
   sample = NULL
 )
@@ -20,7 +20,8 @@ in directed graphs and sizes 3-6 in undirected graphs.}
 
 \item{cut.prob}{Numeric vector giving the probabilities that the search
 graph is cut at a certain level. Its length should be the same as the size
-of the motif (the \code{size} argument). By default no cuts are made.}
+of the motif (the \code{size} argument).
+If \code{NULL}, the default, no cuts are made.}
 
 \item{sample.size}{The number of vertices to use as a starting point for
 finding motifs. Only used if the \code{sample} argument is \code{NULL}.
diff --git a/man/graph.motifs.no.Rd b/man/graph.motifs.no.Rd
index 238fedc1b4..bf016df237 100644
--- a/man/graph.motifs.no.Rd
+++ b/man/graph.motifs.no.Rd
@@ -4,7 +4,7 @@
 \alias{graph.motifs.no}
 \title{Graph motifs}
 \usage{
-graph.motifs.no(graph, size = 3, cut.prob = rep(0, size))
+graph.motifs.no(graph, size = 3, cut.prob = NULL)
 }
 \arguments{
 \item{graph}{Graph object, the input graph.}
@@ -13,7 +13,8 @@ graph.motifs.no(graph, size = 3, cut.prob = rep(0, size))
 
 \item{cut.prob}{Numeric vector giving the probabilities that the search
 graph is cut at a certain level. Its length should be the same as the size
-of the motif (the \code{size} argument). By default no cuts are made.}
+of the motif (the \code{size} argument).
+If \code{NULL}, the default, no cuts are made.}
 }
 \description{
 \ifelse{html}{\href{https://lifecycle.r-lib.org/articles/stages.html#deprecated}{\figure{lifecycle-deprecated.svg}{options: alt='[Deprecated]'}}}{\strong{[Deprecated]}}
diff --git a/man/sample_motifs.Rd b/man/sample_motifs.Rd
index a7b50afbd0..26207a803c 100644
--- a/man/sample_motifs.Rd
+++ b/man/sample_motifs.Rd
@@ -20,7 +20,8 @@ in directed graphs and sizes 3-6 in undirected graphs.}
 
 \item{cut.prob}{Numeric vector giving the probabilities that the search
 graph is cut at a certain level. Its length should be the same as the size
-of the motif (the \code{size} argument). By default no cuts are made.}
+of the motif (the \code{size} argument).
+If \code{NULL}, the default, no cuts are made.}
 
 \item{sample.size}{The number of vertices to use as a starting point for
 finding motifs. Only used if the \code{sample} argument is \code{NULL}.
diff --git a/tests/testthat/test-motifs.R b/tests/testthat/test-motifs.R
index 3d85c2c95b..5b5430389e 100644
--- a/tests/testthat/test-motifs.R
+++ b/tests/testthat/test-motifs.R
@@ -10,7 +10,7 @@ test_that("motif finding works", {
   mno2 <- count_motifs(b, cut.prob = c(0, 1 / 3, 0))
   expect_equal(
     c(mno0 / mno, mno1 / mno, mno2 / mno),
-    c(0.654821903845065, 0.666289144345659, 0.668393831285275)
+    c(0.674541153079009, 0.666138135417257, 0.665968250372803)
   )
 
   mno3 <- count_motifs(b, cut.prob = c(0, 1 / 3, 1 / 3))
@@ -18,7 +18,7 @@ test_that("motif finding works", {
   mno5 <- count_motifs(b, cut.prob = c(1 / 3, 1 / 3, 0))
   expect_equal(
     c(mno3 / mno, mno4 / mno, mno5 / mno),
-    c(0.443959957465819, 0.441952797125797, 0.446004870037941)
+    c(0.441707407617142, 0.445633639755617, 0.440527650363994)
   )
 
   ######################
@@ -31,18 +31,18 @@ test_that("motif finding works", {
   m0 <- motifs(b, cut.prob = c(1 / 3, 0, 0))
   m1 <- motifs(b, cut.prob = c(0, 1 / 3, 0))
   m2 <- motifs(b, cut.prob = c(0, 0, 1 / 3))
-  expect_equal(m0 / m, c(NA, NA, 0.653972107372707, NA, 0.653993015279859, 0.612244897959184, 0.657514670174019, 0.63013698630137, NaN, 0.538461538461538, NaN, 0.565217391304348, NaN, NaN, NaN, NaN))
-  expect_equal(m1 / m, c(NA, NA, 0.669562138856225, NA, 0.66808158454082, 0.73469387755102, 0.670819000404694, 0.657534246575342, NaN, 0.769230769230769, NaN, 0.739130434782609, NaN, NaN, NaN, NaN))
-  expect_equal(m2 / m, c(NA, NA, 0.666451718949538, NA, 0.665291458452201, 0.591836734693878, 0.666683528935654, 0.671232876712329, NaN, 0.753846153846154, NaN, 0.565217391304348, NaN, NaN, NaN, NaN))
+  expect_equal(m0 / m, c(NA, NA, 0.672381747145621, NA, 0.674984795380304, 0.63265306122449, 0.675738567381627, 0.698630136986301, NaN, 0.784615384615385, NaN, 0.608695652173913, NaN, NaN, NaN, NaN))
+  expect_equal(m1 / m, c(NA, NA, 0.66650229488298, NA, 0.666263300123518, 0.63265306122449, 0.66845406717928, 0.671232876712329, NaN, 0.6, NaN, 0.695652173913043, NaN, NaN, NaN, NaN))
+  expect_equal(m2 / m, c(NA, NA, 0.663265435142687, NA, 0.667442050021631, 0.653061224489796, 0.666278834479968, 0.657534246575342, NaN, 0.661538461538462, NaN, 0.652173913043478, NaN, NaN, NaN, NaN))
 
   m3 <- motifs(b, cut.prob = c(0, 1 / 3, 1 / 3))
   m4 <- motifs(b, cut.prob = c(1 / 3, 1 / 3, 0))
   m5 <- motifs(b, cut.prob = c(1 / 3, 1 / 3, 0))
-  expect_equal(m3 / m, c(NA, NA, 0.445611905574732, NA, 0.442789875290769, 0.448979591836735, 0.444695973290166, 0.424657534246575, NaN, 0.369230769230769, NaN, 0.608695652173913, NaN, NaN, NaN, NaN))
+  expect_equal(m3 / m, c(NA, NA, 0.439062322193984, NA, 0.441742794264253, 0.408163265306122, 0.44431657223796, 0.438356164383562, NaN, 0.415384615384615, NaN, 0.478260869565217, NaN, NaN, NaN, NaN))
 
-  expect_equal(m4 / m, c(NA, NA, 0.439251981944392, NA, 0.439284975327761, 0.73469387755102, 0.445088021044112, 0.465753424657534, NaN, 0.630769230769231, NaN, 0.565217391304348, NaN, NaN, NaN, NaN))
+  expect_equal(m4 / m, c(NA, NA, 0.439770385262173, NA, 0.441040560282398, 0.224489795918367, 0.438752023472278, 0.534246575342466, NaN, 0.430769230769231, NaN, 0.391304347826087, NaN, NaN, NaN, NaN))
 
-  expect_equal(m5 / m, c(NA, NA, 0.439985332979302, NA, 0.440288166730411, 0.346938775510204, 0.44159753136382, 0.452054794520548, NaN, 0.323076923076923, NaN, 0.347826086956522, NaN, NaN, NaN, NaN))
+  expect_equal(m5 / m, c(NA, NA, 0.444436015122204, NA, 0.445736750036052, 0.489795918367347, 0.445353601780656, 0.575342465753425, NaN, 0.415384615384615, NaN, 0.347826086956522, NaN, NaN, NaN, NaN))
 })
 
 test_that("sample_motifs works", {